Electrical BMS and Battery Upgrade .... Quandry

[Boots in Action]

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 %

Agreed @jazzeddie1234 regarding lithium charging. Totally different to AGM charging. I believe that the difference in charging efficiency between lithium and AGM is something like 10% or more. That is 100 amps out needs more than 110 amps in to regain FULL charge, not to mention the extra time needed, Although some good AGMs (Odyssey?) can be recharged from dead flat to 80% charge in a very short time IF CHARGER IS CAPABLE OF SUCH OUTPUT (100A), this usually means more heat than lithium (not good for longevity!!) and of course, the final 20% is very slow for battery to reach the 100% mark..

 

[jazzeddie1234]

Yes AGMs do suffer longevity problems with fast charging. I think 10% (.1C) of quoted capacity is the standard and 30% (.3C) is considered very high. Whereas lithium is .3C (ish) for cheap BMS ones and 1C is common for good lithiums. I use my 30A power supply, the setec and full solar to recharge the caravan and it still takes hours
.

 

[Hitting the road]

Just an update...I mentioned above that since I had fitted the BMPRPO 300 Amp shunt to my battery pack, along with the Commlink Bluetooth receiver, that the JHub doesn't work as it is supposed to according to the sales blurb from BMPRO. The JHub showed the batteries in constant discharge, while the battery level indicator merely flashed full / empty / full / empty...

When I contacted BMPRO while traveling, eventually getting a response after chasing them up, then sending them photos of the set up, they had no answer and suggested I send the Shunt & Commlink back to them for testing.

When I got back from the trip I sent the Shunt & Commlink back to them at my expense of course. Three weeks later, Sunday, I received the Shunt & Commlink back in the mail...nothing in the box just the items...no explanation nothing?
So I emailed them back and asked them...

"Good morning,
I haven’t had any communication at all from BMPRO with regard to my query as to whether the item was faulty, or why I was unable to link the Shunt with the Commlink via Bluetooth as per instructions.
Would you be so kind as to let me know what was found…and why the Shunt and Commlink did not work as intended."
Many thanks...kind regards...

The below is what I received back;

"Thank you for your email.
The BC300 tested well and had no faults found. The Commlink was replaced under warranty due to a fault found with it that can cause intermittent Bluetooth drop outs
Kind Regards,"

That was it... no apologies for the zero communication, nothing...but at least they paid for the return!

Gotta, say, not overly impressed with BMPRO so far. I'll refit the Shunt and Commlink and see if it works as intended. If it does Happy Days...if it doesn't I'll be jettisoning all the BMPRO equipment in the van and putting my own setup in as above...

 

[Drover]

I have noticed while Ive been researching some of these set ups that some add ons will only work with certain versions of the models, might be the case with this lot...

 

[Hitting the road]

True...in some cases older set ups may not accept the newer add ons...so before I spent the $300 odd dollars on the Shunt I checked the specifications and fitment...according to BMPRO the JHub with their BMS should operate as intended. I had also sent them photos of my battery set up, wiring, and the shunt fitment along with the wiring of the Commlink, at no point did a BMPRO say there was any problem. They did suggest trying a couple of things early in the piece which did nothing...so they were across what my set up was. They just suggested there may be a fault with the Shunt / Commlink.
I won't get to re fit the Shunt and try it out until we take the van away again in January...I hope it works as intended with the Shunt and Commlink actually communicating...

 

[Boots in Action]

True...in some cases older set ups may not accept the newer add ons...so before I spent the $300 odd dollars on the Shunt I checked the specifications and fitment...according to BMPRO the JHub with their BMS should operate as intended. I had also sent them photos of my battery set up, wiring, and the shunt fitment along with the wiring of the Commlink, at no point did a BMPRO say there was any problem. They did suggest trying a couple of things early in the piece which did nothing...so they were across what my set up was. They just suggested their may be a fault with the Shunt / Commlink.
I won't get to re fit the Shunt and try it out until we take the van away again in January...I hope it works as intended with the Shunt and Commlink actually communicating...

Unfortunately @Hitting the road, that is "progress" and waits for no one. It is a case of "keep up", or " get up to date with the latest" or" get out of the way" and be left behind!!!

 

[Drover]

Unfortunately @Hitting the road, that is "progress" and waits for no one. It is a case of "keep up", or " get up to date with the latest" or" get out of the way" and be left behind!!!

.Progress in which way ??? Progress into how to extract $$ from your pocket yearly as you chase the must have updated gizmo or progress to make your holiday more enjoyable by having trouble free tech, the former I think ..........

Been tidying up and sorting out the lads EH parts, oh the days of simplicity but also the horror memories as I packed and wrapped some old Dizzies and coils, it wasn't all great times, soon as the electronic ignition kits came out I had one in my old Nissan Patrol, GR8 days for sure...... then they ruined it all with all the other techo rubbish which like many things turned a simple repair into a megga job..

 

[Boots in Action]

.Progress in which way ??? Progress into how to extract $$ from your pocket yearly as you chase the must have updated gizmo or progress to make your holiday more enjoyable by having trouble free tech, the former I think ..........

Been tidying up and sorting out the lads EH parts, oh the days of simplicity but also the horror memories as I packed and wrapped some old Dizzies and coils, it wasn't all great times, soon as the electronic ignition kits came out I had one in my old Nissan Patrol, GR8 days for sure...... then they ruined it all with all the other techo rubbish which like many things turned a simple repair into a megga job..

You got that right Ian!! They also call it commercialization. It keeps the economy going!!!! Don't fix anything anymore - just replace it!! The "throwaway society" .

 

[Hitting the road]

When I bought my very first caravan, a 22' tandem axle Franklin back in the mid 70's...I didn't even look at any "off grid" set up...it didn't even have a 12v battery in it. All it had was 3 or 4 x 240v lights....and a basic electric stove...no gas even. I think I paid around $3600.00 for it brand new off the lot...lol. Nothing complicated at all. I lived in it for a few months while fruit picking back in the day as a "permanent" in a caravan park.
I also used to tow it with my EH Holden, as I had done some work done to the car it towed it sort of ok. Sure didn't have GVM's and GCM's to worry about, and as the van had hydraulic over ride brakes nothing too complex. Like what were the Manufacturers GVM and GCM of an EH Holden anyway...did they even have one? As you write drover..."the days of simplicity"...lol

 

[Drover]

Would borrow my Dads pop top Franklin, little single axle job, on the back of the G60 in the 70's, which didn't even know it was there, had a gas fridge, which thinking back could have done with one of my fridge upgrade mods, lights could be 12v from the Nissan, had a gas stove but that was for our flash camps, usually we were up in the bush on a gnarly FWD track, camping in our tent with Esky and Tilly lamp, great days well before it became the thing to do, if you had a FWD back then it was used as such ............ When we got the Engel it was a truck battery which gave 3 days of use enough for a weekend up bush, bush being only 20 min drive before you needed to lock in the front diff into some pretty good wild country .....................Glad we did it all before they shut everything down and fixed roads up for the yuppie class, now to many creaks and groans to handle jump ups and corrugations thats why I have a yuppie vehicle now...... We are amazed at how we managed to get away so often as I wasn't always around but when home we would be off every 2nd weekend ......................

I don't miss the rough stuff or warm beers one bit though I do like some of the modern stuff.......... just take care not to get sucked in by the PR Blurb, like CDs/DVDs will last forever, yeah right I said...................

 

[Drover]

Yarn the other day with a fella I know at club, he's a very cluey solar- battery fella, wish I had thought of him when I was doing my set up, would have saved a lot of swotting up, he said I had chosen well for my $$ as not all batteries can be hooked up to others and that mine won't be over taxed at present ..... he's had some with batteries in parrellel that wont' work properly or at all as the BMS can't play with other BMS units, its all in the fine print as some can only have a certain number connected and heavy drains like invertors can mean charging up may be problematic as the batteries won't even out charge or settle ... He even said multiple batteries used with high loads need to be individually bench charged to get all with an even charge... So by shear luck I did it right ..... He did mention that I should replace all my panels for same, same and use the old ones on my shed or mod to portable , too hot to try and get him to check mine out, besides no money for new panels, tyres have eaten the piggy bank...

 

[Drover]

Well I found a Utube vid on my Kings 120ah Lithium and it seems I have chosen well, which is a good thing, mine has been running very well to date and has had a fair bit of work, even shuts down and will recharge okay .............. In the vid the fella shows that the low temp shut off on his wasn't doing its job but since mine charges from the Epever which has a temp probe its not an issue.....

 

[Boots in Action]

Well I found a Utube vid on my Kings 120ah Lithium and it seems I have chosen well, which is a good thing, mine has been running very well to date and has had a fair bit of work, even shuts down and will recharge okay .............. In the vid the fella shows that the low temp shut off on his wasn't doing its job but since mine charges from the Epever which has a temp probe its not an issue.....

Well, I have never been a fan of any Kings' products, but I must say I am mighty impressed!!! As for the extreme cold test, unlikely to be a problem in most of Queensland, except in the outback or in the Granite Belt Stanthorpe or close by. However, "most"?? batteries would be enclosed inside a "warmer"?? vehicle or van so maybe not too much of a worry??

And Ian @Drover, although your MPPT solar controller may have a thermal probe (usually for heat control in hot weather while charging), I do not believe it works in reverse, that is reduces/stops charging when the solar controller internal temp is as low as in the BMS in the Lithium battery requirements. Also, the solar controller may be some distance from battery and in a cooler or warmer position, AND your temperature sensor may be just for the controller. The separate temperature probe on my MPPT controller is taped to the top of my AGM battery close by, and provides a separate temperature protection for the battery . The solar controller also has its own temperature sensor for internal protection. A good talking point!!!

 

[Drover]

@Boots in Action , since I had to do the Lithium set up manually for mine, its all programmed to shut off at 0c, with other settings just off the max for the BMS, in theory the Epever will cut off before the BMS, something a sparky advised to give better life to a Lithium and it has a temp probe fitted to the battery to monitor it ..................... I double checked to make sure the programme did as been awhile since I wrote it in, the Epever is pretty much an all singing and dancing device Ive found ................ even though the battery is in its own insulated compartment it doesn't seem to keep out the cold or heat and on hot days I will open the door to catch any breeze and the boot will be open to do same for the rest of the power station gear.

I have the latest software update for it but am worried about flashing it in case it bricks and I have read the remote monitor may not work after its flashed so while its all working well will leave well enough alone, could open a can of worms.

 

[Boots in Action]

@Boots in Action , since I had to do the Lithium set up manually for mine, its all programmed to shut off at 0c, with other settings just off the max for the BMS, in theory the Epever will cut off before the BMS, something a sparky advised to give better life to a Lithium and it has a temp probe fitted to the battery to monitor it ..................... I double checked to make sure the programme did as been awhile since I wrote it in, the Epever is pretty much an all singing and dancing device Ive found ................ even though the battery its in its own insulated compartment it doesn't seem to keep out the cold or heat and on hot days I will open the door to catch any breeze and the boot will be open to do same for the rest of the power station gear.

I have the latest software update for it but am worried about flashing it in case it bricks and I have read the remote monitor may not work after its flashed so while its all working well will leave well enough alone, could open a can of worms.

Ian, I believe you are all over it!! Great stuff!

 

[Drover]

Its amazing really, years of stuff ups the lessons have sunk in ................................. better write them down before they sink out of reach.

 

[Hitting the road]

Just got back from 8 nights off grid...very happy with the 2 new 200w panels I put on the roof. Where the old 160w panel did very little, previously I had to muck around and put out my 2 x 200w folding panels whenever I was doing an overnight...the batteries (2x135amp Lithium) are now recharged by mid day-ish just with the roof panels.
I haven't changed the MPPT or BMS...though I am seriously thinking I need to update the MPPT as it really doesn't give me as much info as I would like. It would be very good to have a remote readout or even Bluetooth.
Gotta say the BMPRO BMS is really next to useless with what it can provide...it is only there now to tell me how much water is in the tanks, but I am seriously considering updating the water level indicators as well...

 

[Drover]

Gotta say the BMPRO BMS is really next to useless with what it can provide...it is only there now to tell me how much water is in the tanks, but I am seriously considering updating the water level indicators as well ...

Never a great fan of BMPro units, if you went series with your panels that might be your problem as its chopping the voltage (most seem to have a 25v max) or just a conflict between the BMPro system and the batteries BMS.... Problem with them that I can see is that all/most once they have a LV shutdown you have to recover the battery with another charger as they won't recharge it .................................... what BMPro unit is fitted ?? ....................

To replace economically is to shut down the BMPro charging system and just run it as a load distributor disconnected from battery, solar going to MPPT unit along with MPPT charging battery and MPPT load connected to BMPro 12v input, that should work ... then MPPT unit operation can be viewed from a remote monitor, a good MPPT cntorller can handle higher voltage input so series isn't an issue, just have to marry up MPPT contorller lithium specs to match the battery BMS specs so all work in harmony.................. of course all depends on which BMPro is fitted some may not be happy with getting down graded.

 

[Hitting the road]

Yeah, the BMPRO BMS in my setup is purely a distribution / fuse point as it is only good for 300w or 20 amps solar input anyway...the specs do not give a max voltage input from solar but it wouldn't be very high.
I have a separate Victron battery charger, with capacity to carry out a "cold" battery start up if ever the batteries ran flat. The BMPRO is unplugged, and the solar panels are not connected through the BMPRO at all, but are connected through a separate 80v input capacity MPPT solar regulator.
The current MPPT gives me input voltage / amps and battery charge level...and of course lets me know when the battery bank is full.

My two new roof solar panels are wired in series as I am a fan of higher voltage going to the MPPT rather than amperage, being voltage loss is much less than what the amps loss would be over distance. The 2 x 200w portable panels are wired in series as well and plug directly in to the input of the MPPT should I be using them...I have 30m of good heavy cabling to connect them if need be, hence the series setup so as not to lose input.

I want to fit an MPPT that gives me a Bluetooth connection capability, the current MPPT has a WiFi connection but I have been unable to ever get it to work.

 

[Hitting the road]

Just adding, I was seeing 43v - 44v at the MPPT with the two roof panels in series which I was reasonably happy with, even though the new panels will allegedly each generate 24.1v at open circuit...the MPPT doing it's job?

What was weird though, and I didn't really have the opportunity to spend time on it, was when I connected the portable panels as well out of curiosity. Though the day had moving cloud cover...with the two sets of panels both wired in series and connected at the MPPT, input, I thought I would see up to 80v at the MPPT being each pair would be sending around 42v - 44v each to the MPPT....but I only saw around around 43v input, with both sets or just one set.
Not sure whether the MPPT was "clipping" the input voltage as it wasn't required?
I really need to have a decent day without clouds moving over to muck about with the set up and try to understand what is going on.