Solar The Solar Panel Thread

[mikerezny]

Panels mounted and wired up, connected via elevated conduit so theres no damming, or interference to the roof water run off. The conduit proved to be the most difficult part

Hi,

Nice neat job. Do you think there is any chance that wind flowing across the long piece of conduit running across the van will cause an oscillation? If so, it might be worth putting a small stand off along the conduit. Not in the centre, but somewhere about 2/5 of the way along to avoid harmonics.

cheers
Mike

 

[Boots in Action]

Panels mounted and wired up, connected via elevated conduit so theres no damming, or interference to the roof water run off. The conduit proved to be the most difficult part

View attachment 63821

View attachment 63822

Looking very very good @Crusty181 !! 156w from panels and 151.7w into battery. Very efficient conversion.. Congrats! However, if I am thinking correctly, the panel voltage should be somewhere around 60 volts if you have the panels connected in SERIES. With only 19 odd volts (which is good for each panel), I do believe that you have connected the panels in PARALLEL.

 

[mikerezny]

Looking very very good @Crusty181 !! 156w from panels and 151.7w into battery. Very efficient conversion.. Congrats! However, if I am thinking correctly, the panel voltage should be somewhere around 60 volts if you have the panels connected in SERIES. With only 19 odd volts (which is good for each panel), I do believe that you have connected the panels in PARALLEL.

Or the panels may not have been wired in series with the correct polarity:
controller +ve --> (+ve panel 1 -ve) --> (+ve panel 2 -ve) --> (+ve panel 3 -ve) --> controller -ve

cheers
Mike

 

[Boots in Action]

Or the panels may not have been wired in series with the correct polarity:
controller +ve --> (+ve panel 1 -ve) --> (+ve panel 2 -ve) --> (+ve panel 3 -ve) --> controller -ve

cheers
Mike

Hey Mike @mikerezny , are those SC4 connectors able to be connected pos of one panel to neg SC4 connector on the next panel for all three panels etc. Then at each end of the string, one would be left with a pos SC4 connection from the first panel connected, and a Neg SC4 connector from the last panel in the string. And those final Pos and Neg leads would still have the SC4 connectors on, which would have to be cut off and terminated into junction box?? Do you think @Crusty181 has done all that??

 

[mikerezny]

Do you think @Crusty181 has done all that??

I have absolutely no idea how he has wired it. I don't know about the SC4 connectors, but it seems logical that the +ve sc4 connector of one panel would mate with the -ve of the next panel.
cheers
Mike

 

[Crusty181]

Hi,

Nice neat job. Do you think there is any chance that wind flowing across the long piece of conduit running across the van will cause an oscillation? If so, it might be worth putting a small stand off along the conduit. Not in the centre, but somewhere about 2/5 of the way along to avoid harmonics.

cheers
Mike

The original plan included a plastic clip-in wall bracket for that conduit, but the Bunnings store I got the conduit from didnt have any stock. I'm in various Bunnings stores regularly so I find one in due course. I was more concerned with sag in the longer conduit over time particularly in hot sun, I presumed that the varying wind speed and turbulence from the other roof goodies wouldn't allow harmonic vibration to develope ... but my only training in that area is limited to one Youtube vid of the Tacoma Narrows.

Looking very very good @Crusty181 !! 156w from panels and 151.7w into battery. Very efficient conversion.. Congrats! However, if I am thinking correctly, the panel voltage should be somewhere around 60 volts if you have the panels connected in SERIES. With only 19 odd volts (which is good for each panel), I do believe that you have connected the panels in PARALLEL.

Or the panels may not have been wired in series with the correct polarity:
controller +ve --> (+ve panel 1 -ve) --> (+ve panel 2 -ve) --> (+ve panel 3 -ve) --> controller -ve
cheers
Mike

That screen dump is of a test of a single panel I did to make sure I didn't have a repeat of my last disastrous solar panel purchase

Hey Mike @mikerezny , are those SC4 connectors able to be connected pos of one panel to neg SC4 connector on the next panel for all three panels etc. Then at each end of the string, one would be left with a pos SC4 connection from the first panel connected, and a Neg SC4 connector from the last panel in the string. And those final Pos and Neg leads would still have the SC4 connectors on, which would have to be cut off and terminated into junction box?? Do you think @Crusty181 has done all that??

I have absolutely no idea how he has wired it. I don't know about the SC4 connectors, but it seems logical that the +ve sc4 connector of one panel would mate with the -ve of the next panel.
cheers
Mike

Ive listened well, the panels are connected in series as per the "controller +ve --> (+ve panel 1 -ve) --> (+ve panel 2 -ve) --> (+ve panel 3 -ve) --> controller -ve" The MC4 connectors on each simply daisy-chain neg to pos from panel to panel. I had to add short "extension leads" between the panels, but those leads also had to be made up through the conduit with the MC4 already attached on each end. The conduit also had directional "polarity" because it was to be thread attached to the rear panel only, and sleeved through the frame of the side panels so it could only go one way, as could the MC4s. All that took an unexpected amount of thought, and checking ... and then checking x 12. It would be impossible to mount the panels, then run the cable through the mounted conduit and then fit off the MC4s, so the 3 x conduits were pre-ordained with the cable and MC4s already fitted off. I had to frig about feeding the conduit and their MC4s through the very snug holes in the panel frames whilst balancing 3 x large panels on blocks of wood on 3 separate sides of the van whilst perched 10ft off the ground on 2 not quite high enough ladders. The conduit thread end had a nut that had to threaded over the MC4, into the panel frame recess and then attached in an area the size of a 4 year olds hand ..... under a 2 inch gap with my 6 inch hand. All this was happening about 6 inches further way than the actual length of my arm, under the panel, all by feel .... did I mention the dodgy ladders

Because Jayco roofs aren't reinforced I had to plank the roof to get to the terminal box to remove the 6mm auto wire Jayco had used and replaced it with solar cable. I took photos of everything (something Ive always done) and it was the following day I started to question the final MC4 connection fit-off on the wires into the terminal box. Checked the pics and found id wired the terminal box wires as per the panel polarity. The panel connections were simple to daisy chain, but that meant the final MC4 connectors had to be reversed .... which meant Id continued the daisy chain neg to pos and pos to neg running to the controller. With way too much work to get at the terminal box wires and refit MC4 connectors for proper polarity, I sighed, shook my head .... and then just swapped the neg and pos on the MPPT controller .... couple of labels attached and disaster averted.

Thanks guys for all your advice and encouragement, I sure I would have otherwise either glued pieces of useless glass to my roof or set the van on fire

 

[Boots in Action]

The original plan included a plastic clip-in wall bracket for that conduit, but the Bunnings store I got the conduit from didnt have any stock. I'm in various Bunnings stores regularly so I find one in due course. I was more concerned with sag in the longer conduit over time particularly in hot sun, I presumed that the varying wind speed and turbulence from the other roof goodies wouldn't allow harmonic vibration to develope ... but my only training in that area is limited to one Youtube vid of the Tacoma Narrows.



That screen dump is of a test of a single panel I did to make sure I didn't have a repeat of my last disastrous solar panel purchase



Ive listened well, the panels are connected in series as per the "controller +ve --> (+ve panel 1 -ve) --> (+ve panel 2 -ve) --> (+ve panel 3 -ve) --> controller -ve" The MC4 connectors on each simply daisy-chain neg to pos from panel to panel. I had to add short "extension leads" between the panels, but those leads also had to be made up through the conduit with the MC4 already attached on each end. The conduit also had directional "polarity" because it was to be thread attached to the rear panel only, and sleeved through the frame of the side panels so it could only go one way, as could the MC4s. All that took an unexpected amount of thought, and checking ... and then checking x 12. It would be impossible to mount the panels, then run the cable through the mounted conduit and then fit off the MC4s, so the 3 x conduits were pre-ordained with the cable and MC4s already fitted off. I had to frig about feeding the conduit and their MC4s through the very snug holes in the panel frames whilst balancing 3 x large panels on blocks of wood on 3 separate sides of the van whilst perched 10ft off the ground on 2 not quite high enough ladders. The conduit thread end had a nut that had to threaded over the MC4, into the panel frame recess and then attached in an area the size of a 4 year olds hand ..... under a 2 inch gap with my 6 inch hand. All this was happening about 6 inches further way than the actual length of my arm, under the panel, all by feel .... did I mention the dodgy ladders

Because Jayco roofs aren't reinforced I had to plank the roof to get to the terminal box to remove the 6mm auto wire Jayco had used and replaced it with solar cable. I took photos of everything (something Ive always done) and it was the following day I started to question the final MC4 connection fit-off on the wires into the terminal box. Checked the pics and found id wired the terminal box wires as per the panel polarity. The panel connections were simple to daisy chain, but that meant the final MC4 connectors had to be reversed .... which meant Id continued the daisy chain neg to pos and pos to neg running to the controller. With way too much work to get at the terminal box wires and refit MC4 connectors for proper polarity, I sighed, shook my head .... and then just swapped the neg and pos on the MPPT controller .... couple of labels attached and disaster averted.

Thanks guys for all your advice and encouragement, I sure I would have otherwise either glued pieces of useless glass to my roof or set the van on fire

Well @Crusty181 , you simply amaze me! Notwithstanding all the problems both electrical and structural, you have overcome them all. And you plead ignorance of most of these things!! Great work and something you can really be proud off. Whilst @mikerezny and I could foresee some of the issues from afar, nothing stopped you. The photo dump of results of just one panel augurs well that your whole setup should be excellent. Please provide feed back when fully tested so others can see how it is done. Good luck.

 

[mikerezny]

Hey @Crusty181,
if your diodes arrive in time, you don't want them, and @Boots in Action does, I will be going up to Qld and I would be happy to hand deliver them.

cheers
Mike

 

[Drover]

Well @Crusty181 , you simply amaze me! Notwithstanding all the problems both electrical and structural, you have overcome them all. And you plead ignorance of most of these things!! Great work and something you can really be proud off. Whilst @mikerezny and I could foresee some of the issues from afar, nothing stopped you. The photo dump of results of just one panel augurs well that your whole setup should be excellent. Please provide feed back when fully tested so others can see how it is done. Good luck.

We are all amazed that a wood butcher managed something that couldn't be hit with a hammer.........lol,lol,lol.......now just have to find some sun.....

 

[mfexpanda]

We are all amazed that a wood butcher managed something that couldn't be hit with a hammer.........lol,lol,lol.......now just have to find some sun.....

 

[Joves]

Hi Brains-Trust,

Hope all are well.

I'm sure this has been answered throughout this thread and apologies for not having read through all 64 pages to see if it has, so I will try keep these couple of question brief.

I have just purchased one of these ultra-thin portable 300W folding solar panels:
https://www.catch.com.au/product/ki...Sk55x0-b-79LU8Re8N_onjO3pkROBTMxoCeFQQAvD_BwE

Our Expanda currently has 2x160W roof-mounted panels feeding into 2x105ah AGM batteries. We also have a third 105ah AGM battery in a portable Projecta Power Hub box. The intention was initially to have the Projecta Power Hub power our 65 litre Waeco fridge whilst freecamping and the 300W portable solar panel feed power back into that battery. However, as it is a sizeable panel, I think it would make a perfect supplement to the current solar setup in/on the van, particularly if parked in a shady position.

Now, for my couple of questions:

1. Would it be as simple as having an anderson plug connected to the a-frame and wired into the current van solar controller to then have potentially 620W of solar going back into the vans batteries (under perfect conditions for all panels, which I know we really don't get, but you catch my drift), with the 300W portable panel connected?

2. Is there a way of configuring the wiring (by way of say, a double anderson adaptor), which could feed power from the 300W portable panel into both the Projecta Power Hub and the van's batteries at the same time?

Ok, a third question:

3. Am I looking at this completely wrong and missing a very obvious solution/setup due to my absolute cluelessness?

Any advice, both by way of answering my questions to suggestions on how to best apply the items I currently have, will be most humbly appreciated!

Cheers all,
Joves

 

[Crusty181]

We are all amazed that a wood butcher managed something that couldn't be hit with a hammer.........lol,lol,lol.......now just have to find some sun.....

I personaly favour Wood Artist. Chippies are the wood butchers.

 

[Crusty181]

Hey @Crusty181,
if your diodes arrive in time, you don't want them, and @Boots in Action does, I will be going up to Qld and I would be happy to hand deliver them.

cheers
Mike

Sure, just shout out before your leaving

 

[Clewsy]

Awesome job on persevering through that, sounds like it was a mission! Good end result by the looks.

Agree a conduit clip or 2 will help. Didn't think of drilling through the side of the panel for them.

They made it look so easy in the Jayco factory tour when the roof is at ground level.

 

[Boots in Action]

Hi Brains-Trust,

Hope all are well.

I'm sure this has been answered throughout this thread and apologies for not having read through all 64 pages to see if it has, so I will try keep these couple of question brief.

I have just purchased one of these ultra-thin portable 300W folding solar panels:
https://www.catch.com.au/product/ki...Sk55x0-b-79LU8Re8N_onjO3pkROBTMxoCeFQQAvD_BwE

Our Expanda currently has 2x160W roof-mounted panels feeding into 2x105ah AGM batteries. We also have a third 105ah AGM battery in a portable Projecta Power Hub box. The intention was initially to have the Projecta Power Hub power our 65 litre Waeco fridge whilst freecamping and the 300W portable solar panel feed power back into that battery. However, as it is a sizeable panel, I think it would make a perfect supplement to the current solar setup in/on the van, particularly if parked in a shady position.

Now, for my couple of questions:

1. Would it be as simple as having an anderson plug connected to the a-frame and wired into the current van solar controller to then have potentially 620W of solar going back into the vans batteries (under perfect conditions for all panels, which I know we really don't get, but you catch my drift), with the 300W portable panel connected?

2. Is there a way of configuring the wiring (by way of say, a double anderson adaptor), which could feed power from the 300W portable panel into both the Projecta Power Hub and the van's batteries at the same time?

Ok, a third question:

3. Am I looking at this completely wrong and missing a very obvious solution/setup due to my absolute cluelessness?

Any advice, both by way of answering my questions to suggestions on how to best apply the items I currently have, will be most humbly appreciated!

Cheers all,
Joves

Hi @Joves , whilst I have never been in favour of thin flexi solar panels, they do have the great advantage of being light and very portable compared to the glass type panels. To answer your questions:
1. Yes about connecting an Anderson plug to A frame and wiring the line into the Current solar controller AS LONG AS THE VAN CONTROLLER HAS THE CAPACITY TO HANDLE THE HIGHER CURRENT!! As you would be connecting this extra panel in PARALLEL , the voltage will be the same but total POTENTIAL amps will be much higher. Also, the controller on flexi panel (if provided) should be bypassed - not removed as you can still use the panel independently if necessary if controller still there. The OCV should be fairly close to the 160w panels on roof for best results. With 2 X 105ah AGM batteries connected in parallel, the higher current into these batteries should not be a problem as they can handle nearly 30A each in charge, so with 2 batteries, this current will be split into both batteries. See attached on what I have done for all my solar input on my Penguin as no panels on roof.
2. Yes, remembering that connecting a lower charged battery to a higher charged one leads to the high one trying to charge the low one. It would be as simple as connecting a wire across the POS and NEG terminals of van batteries and wired to another separate Anderson plug on A frame similar to mine in attached. This should not be a problem when charging. Just make sure they are clearly marked otherwise a wrong connection to the wrong Anderson plug will cause big problems. Do NOT use a double adaptor Anderson plug!! The external solar MUST go through the van controller firstly to charge the van batteries. By connecting your van batteries to your Power Hub, all you are doing is connecting an extra battery in parallel with the van batteries. No problems, but remember., all the batteries are being charged and may not be even unless done for a while to equalize voltage.
3. Not applicable to you at all. Just ask any further questions you may have and do as suggested and all should be well.
Reminder: Note the attached for your suggested arrangement.

If connecting your power pack to van batteries, do not use the solar connection on power pack if provided. Use one of the other INPUT connections. Some power Packs have a connection for solar and have their OWN solar controller.

 

[Joves]

Hi @Joves , whilst I have never been in favour of thin flexi solar panels, they do have the great advantage of being light and very portable compared to the glass type panels. To answer your questions:
1. Yes about connecting an Anderson plug to A frame and wiring the line into the Current solar controller AS LONG AS THE VAN CONTROLLER HAS THE CAPACITY TO HANDLE THE HIGHER CURRENT!! As you would be connecting this extra panel in PARALLEL , the voltage will be the same but total POTENTIAL amps will be much higher. Also, the controller on flexi panel (if provided) should be bypassed - not removed as you can still use the panel independently if necessary if controller still there. The OCV should be fairly close to the 160w panels on roof for best results. With 2 X 105ah AGM batteries connected in parallel, the higher current into these batteries should not be a problem as they can handle nearly 30A each in charge, so with 2 batteries, this current will be split into both batteries. See attached on what I have done for all my solar input on my Penguin as no panels on roof.
2. Yes, remembering that connecting a lower charged battery to a higher charged one leads to the high one trying to charge the low one. It would be as simple as connecting a wire across the POS and NEG terminals of van batteries and wired to another separate Anderson plug on A frame similar to mine in attached. This should not be a problem when charging. Just make sure they are clearly marked otherwise a wrong connection to the wrong Anderson plug will cause big problems. Do NOT use a double adaptor Anderson plug!! The external solar MUST go through the van controller firstly to charge the van batteries. By connecting your van batteries to your Power Hub, all you are doing is connecting an extra battery in parallel with the van batteries. No problems, but remember., all the batteries are being charged and may not be even unless done for a while to equalize voltage.
3. Not applicable to you at all. Just ask any further questions you may have and do as suggested and all should be well.
Reminder: Note the attached for your suggested arrangement.

If connecting your power pack to van batteries, do not use the solar connection on power pack if provided. Use one of the other INPUT connections. Some power Packs have a connection for solar and have their OWN solar controller.View attachment 63828

@Boots in Action, you are an absolute superstar. Thank you so much for your reply. Your solution seems absolutely perfect and covers a couple of other questions I thought I was going to have to ask, the most particular being whether there is a way that I can connect both the portable solar panel to the solar input of the entire van and the Power Hub in parallel with the existing van batteries at the same time, in effect increasing the solar input to effectively 620W and van battery storage to 315ah. Your solution of installing two separate Anderson plugs seems to solve this absolutely brilliantly and is something I would not have even considered.

Just so I am understanding correctly, can I please ask if this is how it would work:

1. Install one Anderson plug, connected directly to the vans current controller/regulator (this would best be exiting to the A-frame near the 12-pin connector). I would use this as a direct input for the portable solar panel, manually bypassing the panels built-in regulator when connected to the van (which the panel is capable of doing).

2. Install a second Anderson plug, connected directly to the positive/negative terminals of the vans existing batteries (this would probably be best exiting the van in a different location, such as the awning side of the van where the battery could sit and have small appliances/beer fridge, etc. plugged into it, thus minimising the risk of confusing the connections). I would plug the Power Hub into this, which would effectively put the Power Hub battery in parallel with the other van batteries.

Main considerations/concerns:

3. Ensure the current van controller has the capacity for the extra amps produced by the portable solar panel. If not, upgrade the solar controller to one with an appropriate amp rating.

4. Am I right in reading that the fact that the portable solar panel has a 300w output and the existing panels are 160w each may pose a problem?

5. If I ensure that all batteries are 100% charged prior to setting it all up and running the Power Hub in parallel, would the overall charge and draw be distributed evenly across all three batteries?

This is absolutely brilliant, if I am in fact understanding it correctly. It would give me an infinitely portable solar panel and Power Hub, utilising the regulator on the solar panel, when used together in isolation from the van. But then it would significantly increase my vans solar and battery storage capacity when freecamping, without having to commit to a permanent space and payload stealing installation in the van when camped at powered sites.

Thank you so much again @Boots in Action, this has gotten me pretty excited. Sorry for all of these questions/clarifications, I just want to know that I am understanding it all correctly before getting things underway. I reckon, if I get this right, the only other thing our van may need is a Truma gas ducted heating system installed for us to be set for some pretty comfortable, relatively worry-free freecamping ventures!

 

[Drover]

@Boots in Action has covered it well as usual, he lays in wait for these questions ..................... I once looked at similar where I could add my ute aux battery to the vans batteries and solar, in the end I didn't as it would be just a lot of stuffing around to connect and match for optimum charge which would never happen due to mismatching, instead I modified my portable panel so it could connect directly to van batteries or ute aux thru its controller or to the vans batteries via it's controller, this gave plenty of flexibility did not require any major changes to be made just plug an play......also remember with that much solar providing charge you would only be getting max use if your batteries were right down which would actually mean you don't have enough storage which by what you have described you haven't...

I would keep your portable panel to be just that along with your power pack with the panel set up to supplement the van if required or just keep the power pack charged best of both, I don;t think you would gain much in the real world by coupling the lot together.

 

[Boots in Action]

@Boots in Action, you are an absolute superstar. Thank you so much for your reply. Your solution seems absolutely perfect and covers a couple of other questions I thought I was going to have to ask, the most particular being whether there is a way that I can connect both the portable solar panel to the solar input of the entire van and the Power Hub in parallel with the existing van batteries at the same time, in effect increasing the solar input to effectively 620W and van battery storage to 315ah. Your solution of installing two separate Anderson plugs seems to solve this absolutely brilliantly and is something I would not have even considered.

Just so I am understanding correctly, can I please ask if this is how it would work:

1. Install one Anderson plug, connected directly to the vans current controller/regulator (this would best be exiting to the A-frame near the 12-pin connector). I would use this as a direct input for the portable solar panel, manually bypassing the panels built-in regulator when connected to the van (which the panel is capable of doing).

2. Install a second Anderson plug, connected directly to the positive/negative terminals of the vans existing batteries (this would probably be best exiting the van in a different location, such as the awning side of the van where the battery could sit and have small appliances/beer fridge, etc. plugged into it, thus minimising the risk of confusing the connections). I would plug the Power Hub into this, which would effectively put the Power Hub battery in parallel with the other van batteries.

Main considerations/concerns:

3. Ensure the current van controller has the capacity for the extra amps produced by the portable solar panel. If not, upgrade the solar controller to one with an appropriate amp rating.

4. Am I right in reading that the fact that the portable solar panel has a 300w output and the existing panels are 160w each may pose a problem?

5. If I ensure that all batteries are 100% charged prior to setting it all up and running the Power Hub in parallel, would the overall charge and draw be distributed evenly across all three batteries?

This is absolutely brilliant, if I am in fact understanding it correctly. It would give me an infinitely portable solar panel and Power Hub, utilising the regulator on the solar panel, when used together in isolation from the van. But then it would significantly increase my vans solar and battery storage capacity when freecamping, without having to commit to a permanent space and payload stealing installation in the van when camped at powered sites.

Thank you so much again @Boots in Action, this has gotten me pretty excited. Sorry for all of these questions/clarifications, I just want to know that I am understanding it all correctly before getting things underway. I reckon, if I get this right, the only other thing our van may need is a Truma gas ducted heating system installed for us to be set for some pretty comfortable, relatively worry-free freecamping ventures!

Well now that your excitement has settled down @Joves and you have some idea of the concepts, here are some more options for you to think about.
1. Item #1. Correct with the following suggestions. Connection and installation of Anderson plug for flexi panel should be as close to batteries as possible to reduce voltage loss due to length of connecting cable. Correct that these wires from panel should bypass the panel controller and be connected to the solar input terminals on van controller with the other solar input wires from roof panels. For safety sake, I would place an in-line 20A fuse on the pos wire preferably somewhere you can get easy access if necessary .
2. Correct and a good plan too. Once again, for safety sake, I would have a 40A fuse on pos line to/from battery. Remember, that this connection is ALWAYS live and can take power in and out. In/out for your power hub (depending on hub battery condition) and also IN for other purposes such as charging your van batteries with a "smart charger" instead of your limited van system, and also OUT for high power devices such as air compressors etc (thank @Drover for that idea). Hence the need for heavier fuse depending on what current draw any device you connect may demand.
3. Suggest a 40A controller to well and truly cover any high power from ALL panels just in case you get "ideal" conditions and all batteries are low. If having to upgrade to a higher controller, consider getting an MPPT controller, although dearer are much more efficient particularly in low light conditions and periods of sun and shade caused by clouds.
4. Not the optimum for max output, but still quite workable. The main issue is that the flexi panel should have the same (or close to) the same Voc and Vmp as the panels on the roof. The closer the better, but unless you are pedantic about all the issues, (angle to the sun, heat of panel and efficiency of cells) it is still acceptable. Have a look at the specs of the panels and try it out. You can always use your multi meter, clamp meter for measuring voltage and current if you are worried. You may not achieve the theoretically high point but you will get more current than not connecting the flexi panel in parallel with van controller and batteries.
5. You do not have to worry about all the batteries being 100% charged at the same time, as that will probably not happen often. Connecting all the batteries up in parallel, regardless of charge (except dead flat below 10.0 volts) will not cause any hassles. The high batteries will drop in voltage as they try to charge up the lower voltage battery/ies and the lower battery/ies will steal the volts from the higher voltage batteries and slowly get charged. However, when charging is happening, current is distributed according to need and eventually evens out the voltage and SOC of all the batteries. That may not be Exactly what happens as a lot of other factors are involved, but is a simple explanation. A lot depends on wiring and connections.

I hope all this information helps you achieve what you want out of panels and battery/ies.

 

[Boots in Action]

@Boots in Action has covered it well as usual, he lays in wait for these questions ..................... I once looked at similar where I could add my ute aux battery to the vans batteries and solar, in the end I didn't as it would be just a lot of stuffing around to connect and match for optimum charge which would never happen due to mismatching, instead I modified my portable panel so it could connect directly to van batteries or ute aux thru its controller or to the vans batteries via it's controller, this gave plenty of flexibility did not require any major changes to be made just plug an play......also remember with that much solar providing charge you would only be getting max use if your batteries were right down which would actually mean you don't have enough storage which by what you have described you haven't...

I would keep your portable panel to be just that along with your power pack with the panel set up to supplement the van if required or just keep the power pack charged best of both, I don;t think you would gain much in the real world by coupling the lot together.

Thanks for the compliment @Drover , but "Laying in wait" sounds a bit primeval. I like to think that I am fairly knowledgeable on this subject, but @mikerezny ("Mickey Mouse from down south) has pulled me up a few times. However, whilst I do not necessarily agree with some of your comments sometimes, there are plenty of other areas where I am happy to accept your experienced comments. Cheers

 

[mikerezny]

When connecting up batteries in parallel there is a chance of some quite high currents flowing between the batteries until they equalise. It would not be all that hard to exceed the maximum charge rate of the battery and thus possible shorten its life.

If it was me I would have a set of leads with alligator clips art each end with a couple of meters of smallish gauge wire such as 1-2mm sq and connect the batteries in paralle for 15 - 30 minutes or so. The resistance of this lead would limit the initial current flow.

cheers
Mike