Electrical BMS and Battery Upgrade .... Quandry

[Drover]

Here's the thing:
2x AGMs fitted one or both are getting sad, namely just shed power quickly under load so was asked about upgrade to Lithium, fitting or choosing a lithium isn't a problem, the van has a "BMPro BatteryPlus35 SR" (BM BP)fitted so not Lithium compatable ...........
Replacing with a BM Pro unit which is lithium does up the cost of the upgrade and is very easy being just plug and play, the limited panel watt isn't really a problem as who has ever seen 300 plus watts on their display let alone 200w .........................

The other option is add a decent MPPT solar reg with a display and turn the BM BP unit into a big distribution panel with feed to aux from load on solar reg none direct from battery and add a mains lithium charger for if ever needed but I think the unit may have a hissy and give problems to a flick the switch only type operator ...

Any other ideas ?????

I'm leaning to the completely upgraded BMS unit using a Lithium BMPro BatteryPlus 35 HA , ease of fitting and no changes to cabling and the feed to the display unit is the same so just a change pf panels as access to cable runs in walls is not possible ....................... Going to be a slightly expensive mod to replace batteries, the saving in kgs is welcomed ..... at least the new regs for lithium storage doesn't apply but will upgrade the battery compartment to be sealed anyway ................ If they decide to spend the money .......... Of course there is an upgrade option but its not a cheaper option really and I think its a modded unit anyway.

 

[jazzeddie1234]

You know my views on 'compatibility'. The only things I look out for are desulfation cycles, terminal charging voltages, charging current, and disconnect voltages.

Your SR as far as I can tell has no desulfation cycle, 14.4v terminal charge voltage (vs 14.6v for 'lithium option'), 30ish A charging current (same), lower disconnect voltages (10.5 vs 12.0) and lower reconnect voltages (12.8 vs 13.8)

I rarely set my mppt above 14.4 as we are talking about a few % top up charge which reduces lithium life anyway

The only other thing that may be slightly out is the state of charge indication in that lithiums will be fully recharged earlier than other types. But mine works well enough

Personally I would put a good voltmeter across the batteries to confirm 14.4 is the max out and spend the money on beer

 

[Drover]

You know my views on 'compatibility'. The only things I look out for are desulfation cycles, terminal charging voltages, charging current, and disconnect voltages.

Your SR as far as I can tell has no desulfation cycle, 14.4v terminal charge voltage (vs 14.6v for 'lithium option'), 30ish A charging current (same), lower disconnect voltages (10.5 vs 12.0) and lower reconnect voltages (12.8 vs 13.8)

I rarely set my mppt above 14.4 as we are talking about a few % top up charge which reduces lithium life anyway

The only other thing that may be slightly out is the state of charge indication in that lithiums will be fully recharged earlier than other types. But mine works well enough

Personally I would put a good voltmeter across the batteries to confirm 14.4 is the max out and spend the money on beer

That was my first thought, if just me I would have went for it but I just couldn't confirm or not if it had a desulphate cycle in it or not and not able to change configuation I didn't want to chance it, my own set up I can write my own story so have set the charge voltage at the 14.4 and cut out at 12.5 or somewhere, lower than max anyway for the same reason and when at rest its at the same 100% as if I gave it full charge anyway ................ The batteries BMS will shut down before the SR so wouldn't be an issue really just hope it can restart it ...

As it is the price of a conversion is more than wanted to pay for 5 weeks use a year and in 3 -4yrs they will be going for a new rig as they shed some grommets ..................... So unless I can get a firm outlook on the SR being okay he will stay AGM, understandable really ............ I will research some more but my virus scanner and Telstra are blocking the BMPro web site but I have downloaded all the specs earlier .........

I'm going to bench his AGM's and just see if its one playing up or they are both getting sad and also check if its just a case of using too much juice, these modern vans have about 20 lights in them which may be led but it adds up to a lot and kids tend to leave things on (mine wouldn't, well only once).
Early days in the project ....................

 

[Hitting the road]

Tell you what I have done Drover...bit long winded sorry. In my situation I was chasing weight reduction more than capacity prior to heading off on our Lap. A while back I had replaced the single 100a AGM the van came with, with 2 x 140a AGM's weighing 33kg each which was ridiculous imo. So, I opted to replace the 2 x 140a 66kg AGM's with 2 x 135a 26kg Lithiums, and though losing 10 amps was gaining more anyway...and a handy 40kg saving!

My 2018 built van has a BMPRO J35B distribution unit in it which is not Lithium compatible feeding to a JHUB display. I pondered what to do about charging the Lithiums, should I upgrade to a new BMPRO J35D distribution unit which does have a Lithium charging profile as it is "plug and play" and would directly replace the J35B? The van also has a single (160w I believe) panel on the roof routed through the existing BMPRO.)

The downside for me was the quite low amps acceptance of the J35D for a solar array...of only maybe 27 amps (350w) but mainly the limited 15v - 25v input according to the spec. I had previously fitted an MPPT charger wired and fused direct to the batteries that accepts up to 80v or 450w input and I had fitted an external plug up the front of the van....which works well. (I had a look at the BMPro BatteryPlus 35 HA you mentioned, but as you noted it has a fairly low solar input limit...being I prefer panels in series it wouldn't suit me either.)
Being there is so little room in the Jayco I had to mount the MPPT in the drawer under dinette so as to be able to open it to read it. The MPPT gives me charging rate, amps input, and battery voltage etc) When I put out the current external panels I have them wired in series so they send average 40v to the MPPT. Going forward I want to mount at least one additional panel to the roof and upgrade the existing one....being a Pop Top I need to be mindful of weight.

Anyway, I opted to buy a Victron 30amp Lithium compatible charger with Bluetooth, and just unplug the J35B from the mains, but leave it as a fuse / distribution centre. I wasn't considering upgrading the whole system at that point, rather I guess just using a band aid approach.

Being the MPPT was wired direct to the battery, when plugged in to mains charging, or with the solar panels connected charging direct, any voltage in or out of the batteries would not appear anywhere. So...I also bought a BMPRO 300 amp shunt to fit to the battery pack with a "Commlink" Bluetooth connector to go in the wiring between the J35B and the JHUB...according to BMPRO's sales blurb the Shunt would communicate with the Commlink and feed information to it so I could see what was going in and out of the battery via the JHUB.
(NB: I had correctly connected the Shunt to the negative battery terminal with all connections then to the Shunt. The existing roof mounted solar panel I have taken off the J35B and can plug it directly in to the MPPT when I wish to so as not to interfere with the external panels when connected)

Ok...the negatives...solar panels work fine and never have an issue, the Victron too charges the batteries fine when on shore power....but...the JHUB tells me nothing, It shows the battery discharging all the time whether on mains or solar. The battery level indicator either oscillates between full and empty or indicates 3/4's full. No percentage shows. The solar indicator for input shows zero at all times, and usually the grey water tank level indicator and the battery level indicator oscillate between each other full / empty
I contacted BMPRO and they were not helpful at all imo. Just send the Shunt back to us and we will test it they said. If it is faulty we will replace it...if it is not then basically bad luck.

The lack of readout on the JHUB hasn't bothered me all that much as I have the MPPT readouts to go on, plus the Victron Bluetooth tells me what it is doing when charging...the batteries have worked well off grid running the usual TV, radio, lights, water pump, phone recharges etc etc. Though the most we were off grid in one run was six days...water became more the issue there.

If I get no assistance from BMPRO then I will have to upgrade the monitoring system. I do like to have info at my fingertips, and I do not like things not working as they should. So it will probably mean replacing the J35B with something superior along with the JHUB...BMPRO Customer service was pretty hopeless in that I had to chase them for a response to my emails so who knows how long it will take them to respond to my query...I posted their Shunt back to them for evaluation 2 weeks ago.

 

[Drover]

Yep @Hitting the road , I remember you telling me about it, I looked at similar and thought just too much stuffing around and the Trek display unit will be problematic plus having to use blutooth stuff is really long term pain in bum with most things................... The solar watts amount is really bench top BS as you will never see that much from the panels anyway, at least I have never seen it with my various set ups, I have 560w on hand and have at most seen 220w and I can see no sense of going series, cable length isn't an issue and I can add panels easily in parrellel ....... so can't see any advantage.......

With previous experience trying to get info from manufacturers being a waste of time more often than not especially if you trying to integrate other products...

 

[Boots in Action]

Tell you what I have done Drover...bit long winded sorry. In my situation I was chasing weight reduction more than capacity prior to heading off on our Lap. A while back I had replaced the single 100a AGM the van came with, with 2 x 140a AGM's weighing 33kg each which was ridiculous imo. So, I opted to replace the 2 x 140a 66kg AGM's with 2 x 135a 26kg Lithiums, and though losing 10 amps was gaining more anyway...and a handy 40kg saving!

My 2018 built van has a BMPRO J35B distribution unit in it which is not Lithium compatible feeding to a JHUB display. I pondered what to do about charging the Lithiums, should I upgrade to a new BMPRO J35D distribution unit which does have a Lithium charging profile as it is "plug and play" and would directly replace the J35B? The van also has a single (160w I believe) panel on the roof routed through the existing BMPRO.)

The downside for me was the quite low amps acceptance of the J35D for a solar array...of only maybe 27 amps (350w) but mainly the limited 15v - 25v input according to the spec. I had previously fitted an MPPT charger wired and fused direct to the batteries that accepts up to 80v or 450w input and I had fitted an external plug up the front of the van....which works well. (I had a look at the BMPro BatteryPlus 35 HA you mentioned, but as you noted it has a fairly low solar input limit...being I prefer panels in series it wouldn't suit me either.)
Being there is so little room in the Jayco I had to mount the MPPT in the drawer under dinette so as to be able to open it to read it. The MPPT gives me charging rate, amps input, and battery voltage etc) When I put out the current external panels I have them wired in series so they send average 40v to the MPPT. Going forward I want to mount at least one additional panel to the roof and upgrade the existing one....being a Pop Top I need to be mindful of weight.

Anyway, I opted to buy a Victron 30amp Lithium compatible charger with Bluetooth, and just unplug the J35B from the mains, but leave it as a fuse / distribution centre. I wasn't considering upgrading the whole system at that point, rather I guess just using a band aid approach.

Being the MPPT was wired direct to the battery, when plugged in to mains charging, or with the solar panels connected charging direct, any voltage in or out of the batteries would not appear anywhere. So...I also bought a BMPRO 300 amp shunt to fit to the battery pack with a "Commlink" Bluetooth connector to go in the wiring between the J35B and the JHUB...according to BMPRO's sales blurb the Shunt would communicate with the Commlink and feed information to it so I could see what was going in and out of the battery via the JHUB.
(NB: I had correctly connected the Shunt to the negative battery terminal with all connections then to the Shunt. The existing roof mounted solar panel I have taken off the J35B and can plug it directly in to the MPPT when I wish to so as not to interfere with the external panels when connected)

Ok...the negatives...solar panels work fine and never have an issue, the Victron too charges the batteries fine when on shore power....but...the JHUB tells me nothing, It shows the battery discharging all the time whether on mains or solar. The battery level indicator either oscillates between full and empty or indicates 3/4's full. No percentage shows. The solar indicator for input shows zero at all times, and usually the grey water tank level indicator and the battery level indicator oscillate between each other full / empty
I contacted BMPRO and they were not helpful at all imo. Just send the Shunt back to us and we will test it they said. If it is faulty we will replace it...if it is not then basically bad luck.

The lack of readout on the JHUB hasn't bothered me all that much as I have the MPPT readouts to go on, plus the Victron Bluetooth tells me what it is doing when charging...the batteries have worked well off grid running the usual TV, radio, lights, water pump, phone recharges etc etc. Though the most we were off grid in one run was six days...water became more the issue there.

If I get no assistance from BMPRO then I will have to upgrade the monitoring system. I do like to have info at my fingertips, and I do not like things not working as they should. So it will probably mean replacing the J35B with something superior along with the JHUB...BMPRO Customer service was pretty hopeless in that I had to chase them for a response to my emails so who knows how long it will take them to respond to my query...I posted their Shunt back to them for evaluation 2 weeks ago.

@Hitting the road, are you running the electrical load through the MPPT controller? I would forget about the Jhub all together and just use the readouts from your MPPT controller. You can get all the info from there. I do not have a blue tooth Vitron, but my MPPT controller provides real time readouts for amps in/out, battery voltage, solar panel voltage, battery temperature (for auto charge voltage adjustment), and visual icons to boot, Cumulative figures are also available by selection of keys. So all the info is available at my finger tips on the MPPT controller. Note that I have all my electrical loads through the MPPT controller "load' terminals, so no need for a shunt and still able to charge battery/ies via Setec ST20 Series III. Unfortunately, I am too far committed to AGM style system to be able to change to Lithium, as the changeover cost would be significant and at this stage, I do not have a requirement for high power items..

 

[Boots in Action]

Yep @Hitting the road , I remember you telling me about it, I looked at similar and thought just too much stuffing around and the Trek display unit will be problematic plus having to use blutooth stuff is really long term pain in bum with most things................... The solar watts amount is really bench top BS as you will never see that much from the panels anyway, at least I have never seen it with my various set ups, I have 560w on hand and have at most seen 220w and I can see no sense of going series, cable length isn't an issue and I can add panels easily in parrellel ....... so can't see any advantage.......

With previous experience trying to get info from manufacturers being a waste of time more often than not especially if you trying to integrate other products...

Hey Ian, we have spoken about this before. As you know, I have 580 watts of folding solar panels (2 X 200w and 1 X 180w, all at 18.7 volts or more) connected in series giving me around 58 volts under light load - remember Schotty diodes in place of the silicon types? I agree that the total of the "rated" panel output is most unlikely to be reached under field conditions. In any case, my MPPT controller is rated at 100v max and 30 amps input with the unit capable of limiting input to the max levels if limits exceeded.

As you and I have discussed, if you connected your panels in SERIES, current output would be LIMITED to the output of the smallest (weakest?) panel , but your voltage would be a lot higher, and in your case, that may not be beneficial as you have different size panels on your roof.

I have seen up to 27amps input at 16.8v on my controller under very good cool sunny conditions and low battery/ies. That would be over 450 watts!! Don't be misled about the advantages of series connections verses parallel. MPPT controllers really take advantage of EXCESS voltage that is above correct charging voltage for battery and convert this extra voltage into extra amps, especially in cloudy or dim conditions. @Hitting the road has also taken advantage of this fact with his panels in SERIES.

Noticed on one of your recent pictures, that you had your portable folding panel deployed to catch the sun in the most favourable position, something that is difficult to achieve when panels are fixed on roof of van.

Always difficult to get info from manufactures as you said, as staff often are not technically minded, are unable to visualize what you are trying to do and don't want to take a chance that YOU do not know what YOU are doing. Can't blame them when I see what some people are doing either!!

 

[Hitting the road]

@Hitting the road, are you running the electrical load through the MPPT controller? I would forget about the Jhub all together and just use the readouts from your MPPT controller. You can get all the info from there. I do not have a blue tooth Vitron, but my MPPT controller provides real time readouts for amps in/out, battery voltage, solar panel voltage, battery temperature (for auto charge voltage adjustment), and visual icons to boot, Cumulative figures are also available by selection of keys. So all the info is available at my finger tips on the MPPT controller. Note that I have all my electrical loads through the MPPT controller "load' terminals, so no need for a shunt and still able to charge battery/ies via Setec ST20 Series III. Unfortunately, I am too far committed to AGM style system to be able to change to Lithium, as the changeover cost would be significant and at this stage, I do not have a requirement for high power items..

Hi Boots...I am only running the solar input through the MPPT at this point. Though interesting you ask that question as it piqued my interest. I pulled up the manual on the MPPT I have, and it also has positive and negative terminals for running any load through it. The MPPT basically gives me readouts on solar input and battery level now, but it can show load as well as other info it appears. The JHUB also has water tank level readouts which is about the only thing that works reasonably well anyway.

I guess all loads could be run through the MPPT, as it does have the positive and negative load connectors. The only way I see to do it would by way of creating a dedicated insulated busbar with individually fused connection points for the various load connections...which is probably not much different to how the current load distribution set up is in the J35B.

Jaycar currently has a simple 150 amp busbar with 10 x 10 amp terminals on it for about $28.00...each of those connectors could easily be fused with button type fuses.
If I were to build my own basic load distribution / fuse point I could do away with the J35B totally in fact...leaving the Victron to deal with the 240v stuff.
The downside is if I want to add an Inverter at some point, it would still have to be connected directly to the batteries as the MPPT is limited to 30 amps via the load terminals, so any draw would not register, but battery condition / voltage still would via the MPPT. Viable you reckon?
But I will have to do some serious head scratching on that one and figure out whether doing so is viable for me and worth it...given on selling of the van at some point and not having a too complex system. (I bought the 300 amp shunt originally with adding an inverter in mind.)

The other small down side is the location of the MPPT to read, there is just no where to mount it at eye level in a cupboard or similar. At least as it is in the drawer, I can readily slide the drawer out to read it or alter it, just like opening a cupboard. I guess not having to lift and remove seats and covers off the battery compartment to access is a good thing.

As you noted, like you I am a convert of connecting solar panels in series rather than parallel for the benefits of low light voltage conversion to amps. I had experimented with panels in both parallel and series and found that being in series gives me longer input through the day...especially in low light conditions...
I plan to update the roof top panels on the van, replace the 160w with a 200w, and also add another 200w as I do have room and by centrally mounting the additional panel it the weight addition would be no more than 10kgs and not at an end.
Those two panels would also be in series connected to the MPPT, and then either by way of switching or plugs be able to add the current 400w of external panels as well giving me theoretically 800w...or 80v and still be further expandable...(mainly want to be able to park in shade and have panels in the sun, so if the van mounted panels are shaded then I can isolate and use the external.)

 

[Drover]

Yep boots, its horses for courses this parallel versus series caper, since my cable run is shortish and I plug and play panels my idea is more amps is the way to go, series would mean a lot of stuffing around to add a ground panel .... It has crossed my mind to set up in series and see if any advantage, maybe one day I will do a test but the ability to set up a portable panel quickly when camped in shade is still a winner...... As it is it all works very well so will leave it alone, it will pull a small charge on a rainy day so why fiddle with it .... I have thought about schlockies for ages but lifting panels up, nah...............




@Hitting the road that is why I dropped that sort of set up idea once I had a good look at things in this van, like most of them its all in a small cupboard, wring in the wall and the display on other side of van and batteries under the seat, no room in the current cupboard to mount anything extra, so a decent MPPT reg would have to go elsewhere and would need to have the load go to the BMPro so just a lot of ginning around to set it all up and not possible to hide the wiring, something I didn't want to do for someone who just wants set and forget. I think he's just going to go another set of AGM's ...... though I did say I could do a whole new set up with new power board, MPPT reg and mains charger, would all fit in the little cupboard and have a display on the door....... of course the cost end sup the same as a new BMPro unit............. Any invertor I would just direct connect to battery, big cable, big lugs and nothing in between, no loss or hot spots... you can still see the battery state.

 

[Hitting the road]

Didn't mean to hijack your thread either...but I do hear you when it comes mucking around with the van electrics. I guess it is all in the name of making it work just a bit better?

 

[Drover]

Didn't mean to hijack your thread either...but I do hear you when it comes mucking around with the van electrics. I guess it is all in the name of making it work just a bit better?

Hey not hi jacking, original question been covered and its just natural progression ................ It always sounds more complicated than it is, usually and the way some vans are wired up doesn't make things easy either................ My mates van just had a simple 1230 solar reg fitted, it had always intrigued me why it only had the POS on the load connection fitted no NEG wire, when I redid his wiring for a new mains charger and battery set up I found the solar reg was feeding the system from the load POS and they saved some wire by using the battery NEG wire ........... or something like that anyway it was a cheapy mod... solar reg in cupboard inside with RCD and pump HWS switches while main fuse block and stuff was in the front boot all fitted before they put the skin on the van so removal of battery charger and fuse panel was indeed tricky and difficult................. his battery had a birds nest of wires sprouting from it which I managed to remove to another fuse block so battery only had wires for load, charging and a nice HD set for an external anderson for compressor, van mover etc or portable with own reg...... All the time the word is KiSS..............

 

[Boots in Action]

Hi Boots...I am only running the solar input through the MPPT at this point. Though interesting you ask that question as it piqued my interest. I pulled up the manual on the MPPT I have, and it also has positive and negative terminals for running any load through it. The MPPT basically gives me readouts on solar input and battery level now, but it can show load as well as other info it appears. The JHUB also has water tank level readouts which is about the only thing that works reasonably well anyway.

I guess all loads could be run through the MPPT, as it does have the positive and negative load connectors. The only way I see to do it would by way of creating a dedicated insulated busbar with individually fused connection points for the various load connections...which is probably not much different to how the current load distribution set up is in the J35B.

Jaycar currently has a simple 150 amp busbar with 10 x 10 amp terminals on it for about $28.00...each of those connectors could easily be fused with button type fuses.
If I were to build my own basic load distribution / fuse point I could do away with the J35B totally in fact...leaving the Victron to deal with the 240v stuff.
The downside is if I want to add an Inverter at some point, it would still have to be connected directly to the batteries as the MPPT is limited to 30 amps via the load terminals, so any draw would not register, but battery condition / voltage still would via the MPPT. Viable you reckon?
But I will have to do some serious head scratching on that one and figure out whether doing so is viable for me and worth it...given on selling of the van at some point and not having a too complex system. (I bought the 300 amp shunt originally with adding an inverter in mind.)

The other small down side is the location of the MPPT to read, there is just no where to mount it at eye level in a cupboard or similar. At least as it is in the drawer, I can readily slide the drawer out to read it or alter it, just like opening a cupboard. I guess not having to lift and remove seats and covers off the battery compartment to access is a good thing.

As you noted, like you I am a convert of connecting solar panels in series rather than parallel for the benefits of low light voltage conversion to amps. I had experimented with panels in both parallel and series and found that being in series gives me longer input through the day...especially in low light conditions...
I plan to update the roof top panels on the van, replace the 160w with a 200w, and also add another 200w as I do have room and by centrally mounting the additional panel it the weight addition would be no more than 10kgs and not at an end.
Those two panels would also be in series connected to the MPPT, and then either by way of switching or plugs be able to add the current 400w of external panels as well giving me theoretically 800w...or 80v and still be further expandable...(mainly want to be able to park in shade and have panels in the sun, so if the van mounted panels are shaded then I can isolate and use the external.)

Yes @Hitting the road, your MPPT controller can provide you with lots of info IF loads are connected through the controller. And yes, NOT heavy loads such as compressors or inverters which require high current. My simple arrangement has similar problems in positioning the MPPT controller where it can be easily seen. being a Penguin, I do not have any hard surfaces on the walls - only canvas. So I placed it at floor level at the side of bed. Can still see it if standing up and close, otherwise lay on floor for full read!!

Just a word or two on connecting loads to MPPT controller. I have the full story on a post way back, but the short story is as follows:
!. You must disconnect and insulate the electrical feed between the Setec/Jpro and the input to the main distribution point for all the loads. I found it easier to just disconnect the power from Setec to accessories junction. Insulated these with terminal blocks as they still have potential. For me easier that trying to disconnect at terminals on battery.
2. Then manufacture a suitable wire to handle the total load current from OUT terminals on MPPT controller to the input for all the accessories. (the same place as the wires you removed that went to battery). My max load for all accessories is fused at 20A and each individual accessory load has its own 10A fuse, so it acts as a busbar really.
3. The MPPT controller now has all the info going into the battery or through the load terminals. Solar input into the MPPT controller is as per normal, Power to/from battery is still available via the battery terminals connected to MPPT controller for charging battery/ies via 240v system and/or solar charging. When no charging from solar, power is drawn from battery via battery through the MPPT controller and out through the load terminals, which are then sensed and provide the readout.
4. Another thing that happens is that the MPPT controller has its own setting for low voltage disconnect. This allows you to have a setting that will activate a lot earlier than the Jhub setting which is usually set too low (my thinking anyway!) at 10.5v or thereabouts. You can also set the low voltage reconnect to what you want and not rely on the Jhub which is usually around 12.8v - check your manual for exact figures. Your MPPT settings will work for all accessories connected THROUGH the MPPT controller BUT NOT FOR ANYTHING CONNECTED DIRECTLY TO BATTERY TERMINALS - COMPRESSOR/INVERTER. However, battery voltage is still available at all times.

Hope this helps. Could save you a lot of time and money too. The main issue as @Drover found was running the wire from MPPT controller to accessories distribution point. Mine was easy, just a matter of only one metre, but Daughter's; van meant running wire up wall beside fridge to solar controller.
Good luck!!

 

[Hitting the road]

Thanks Boots...fortunately all the electrical is accessible in one place in my van, under the dinette...batteries, MPPT, charger and BMS. Pretty straight forward to carry out any mods as above being set up the way it is. I had noted that the MPPT also has adjustable settings for low voltage disconnect / reconnect too as you wrote.
I have decided on a plan...I will remove the J35B totally, then run all loads through a busbar arrangement connecting through the MPPT as you suggest. I can easily add a remote battery condition readout above the fridge where the existing JHub is located. There is a hole in the paneling already anyway which will need to be covered...I can easily fit an aftermarket water tank level gauge set to replace the JHub that currently does that job.
The Victron will just do it's thing with the 240v input, I can add a remote Bluetooth indicator among the new gauges I fit as they do have that sort of thing available.
Cost wise won't be too much at all, a whole lot cheaper than buying a complete new BMS, and much simpler too.

Going forward any other mods will be very easy to make. I will have a BMPRO 300 amp shunt with Commlink to sell as will have no use for it. Along with the J35B and JHub too I guess which will be fine for anybody upgrading an older AGM system to solar input capability.

If I do decide to fit an inverter later on it will just have to wire straight to the batteries...

 

[Drover]

Thanks Boots...fortunately all the electrical is accessible in one place in my van, under the dinette...batteries, MPPT, charger and BMS. Pretty straight forward to carry out any mods as above being set up the way it is. I had noted that the MPPT also has adjustable settings for low voltage disconnect / reconnect too as you wrote.
I have decided on a plan...I will remove the J35B totally, then run all loads through a busbar arrangement connecting through the MPPT as you suggest. I can easily add a remote battery condition readout above the fridge where the existing JHub is located. There is a hole in the paneling already anyway which will need to be covered...I can easily fit an aftermarket water tank level gauge set to replace the JHub that currently does that job.
The Victron will just do it's thing with the 240v input, I can add a remote Bluetooth indicator among the new gauges I fit as they do have that sort of thing available.
Cost wise won't be too much at all, a whole lot cheaper than buying a complete new BMS, and much simpler too.

Going forward any other mods will be very easy to make. I will have a BMPRO 300 amp shunt with Commlink to sell as will have no use for it. Along with the J35B and JHub too I guess which will be fine for anybody upgrading an older AGM system to solar input capability.

If I do decide to fit an inverter later on it will just have to wire straight to the batteries...

Probably the simplest way to do it really, my Epever solar reg while having a screen also has a remote display which is perfect in that it shows me everything and is in an easy position to modify settings, no need to rely on poxy phone apps, the only thing I can't monitor is when the invertor is running as its direct from battery but then I know what it is doing as I can see the battery state though my invertor has a remote display so not only can I see whats happening I can turn it on/off from inside van .................. Hooking up an invertoer to anything other than a direct battery connection is not a good idea at anytime, power loss and the possibility of having a hot spot meltdown is there..........

 

[Boots in Action]

Thanks Boots...fortunately all the electrical is accessible in one place in my van, under the dinette...batteries, MPPT, charger and BMS. Pretty straight forward to carry out any mods as above being set up the way it is. I had noted that the MPPT also has adjustable settings for low voltage disconnect / reconnect too as you wrote.
I have decided on a plan...I will remove the J35B totally, then run all loads through a busbar arrangement connecting through the MPPT as you suggest. I can easily add a remote battery condition readout above the fridge where the existing JHub is located. There is a hole in the paneling already anyway which will need to be covered...I can easily fit an aftermarket water tank level gauge set to replace the JHub that currently does that job.
The Victron will just do it's thing with the 240v input, I can add a remote Bluetooth indicator among the new gauges I fit as they do have that sort of thing available.
Cost wise won't be too much at all, a whole lot cheaper than buying a complete new BMS, and much simpler too.

Going forward any other mods will be very easy to make. I will have a BMPRO 300 amp shunt with Commlink to sell as will have no use for it. Along with the J35B and JHub too I guess which will be fine for anybody upgrading an older AGM system to solar input capability.

If I do decide to fit an inverter later on it will just have to wire straight to the batteries...

Decided to go back and provide more info just in case you may need more. You probably don't, but here it is anyway. On my previous post #2 direction, I forgot to remind you that you need a neg return from neg on MPPT load terminal to the same place (different polarity of course) as you have for the Pos lead, but of course you probably knew that. The attached rough diagrams will provide more details for you.
The last picture refers to the original wires coming from battery to fuse distribution point for all accessories. These are the wires I disconnected from distribution point and insulated as these wires as still connected to battery and hence have 12 volt potential. Hope this clarifies any issues.

PS. I think you new thinking will solve all if not most issues. Good luck!

 

[jazzeddie1234]

I prefer using a battery monitor as very little wiring change is required. It counts the watts in and out so SOC is much more accurate. My drifter panel was fine but limited to 100amps so no use with my big inverter. I now use a Juntek VAT 1300 on my van batteries and same on the ute tray ones. It's not perfect but has lots of battery protection functions for the money of around $50. There is a junctek kg something version which is a later model and talks to your phone at around $150

 

[Boots in Action]

I prefer using a battery monitor as very little wiring change is required. It counts the watts in and out so SOC is much more accurate. My drifter panel was fine but limited to 100amps so no use with my big inverter. I now use a Juntek VAT 1300 on my van batteries and same on the ute tray ones. It's not perfect but has lots of battery protection functions for the money of around $50. There is a junctek kg something version which is a later model and talks to your phone at around $150

@jazzeddie1234 , the MPPT controller I have also shows amps in and out in real time, as well as a cumulative total for any period you decide upon. Every morning, I check total amps in and amps out and then reset to zero again, but it could be any time period from hours to days. State of charge is also available as battery voltage is always shown and the following chart shows SOC for my AGM. There are also more sophisticated (and dearer) MPPT controllers that provide even more details. So I do not see the necessity to have a Juntek unless using high currents which would not be wired through the load terminals of the controller in any case. Unfortunately my MPPT controller is not a good guide of SOC if using Lithium.

 

[Hitting the road]

Certainly looks like there are many options when it comes to power set ups and battery monitoring, besides the packaged systems such as BMPRO, Victron, Profecta, Redarc and so on supply, which are good in that they have all functions within the single BMS...easy and simple to install.
But, can come at a fairly hefty price too. Interesting that Juntek you mention jazzeddie1234, I hadn't yet looked at any system monitors to include in my mods so I do seriously need to do some research as I put this together...

 

[Drover]

Not a fan of the one unit does all as if one part fails the whole thing usually shuts down and when you read the fine print they really aren't all that great, of course most folk go overboard and buy everything that the saleman says and end up with heaps of techo bling that isn't really needed but looks good......My tank gauges are seperate and I even have a stand alone voltmeter and as I said before my Invertor does it own thing as well .... and I have never had anything other than fridge supply from the tug .......................

Now that I have moved to Lithium my rig is truly Off Grid, while it has been Solar only for 8 years the back up was always there to charge from genny, used maybe twice in all that time but now the charger isn't really lithium capable but it would still work if I watch it, may replace it with a small lithium charger just for peace of mind anyway, the whole show is run from a $250 solar reg (Epever XTRA ) with its $50 remote monitor .................. which has far better specs than some of these big multi units ................ if the reg dies I have 2 days to find another though my old back up solar reg would probably do the job good enough .... I think many go overboard on what is really needed...... Having a 3 way fridge does put different slant on things, a compressor fridge would mean I would have back up for the back up and at least 4 batteries to keep the show on the road if one craps out ......; and the old Engel (45 yrs young) would be in the Jeep for sure.

 

[jazzeddie1234]

I check total amps in and amps out and then reset to zero again

That's a pretty reliable method for lithium! Each chemistry has an efficiency loss between discharge and recharge with lithium being the most efficient - from memory it's in the range of 1% so, for example, 100 amps out needs 101 amps in to recharge. You can easily confirm 100% SOC by watching the terminal voltage which rises from 13.x volts to 14.4V in the last few %