TQA
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This should be OK PROVIDING both batteries are of the same construction type. But mixing say a flooded wet cell with an AGM will not work.
Salar panels to two batteries
- Thread starter KAM
- Start date
This should be OK PROVIDING both batteries are of the same construction type. But mixing say a flooded wet cell with an AGM will not work.
William_H
Well-Known Member
I have to disagree here in terms of a low current solar charging system. We are not concerned with cut off voltages or charge regimes just trying to trickle a bit into the batteries so i reckon they will live happily jumpered together. olewill
TQA
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Yes it would be OK if we had a CONTINUOUS trickle charge. We do not there will be long periods when there is no charge and the batteries are still connected. As the 'resting ' voltages are different you get one discharging the other.
xeitosaphil
Well-Known Member
Would that happen in a battery bank of different size Amp Hours also, say 2 x 110Ah + 1 x 90Ah ?
VicS
Well-Known Member
No, not if they are the same type
rogerthebodger
Well-Known Member
And a similar age
ghostlymoron
Well-Known Member
i don't think the age is important.
whiteoaks7
Well-Known Member
Forgive me for not reading the three pages worth of answers but this might help:
The simplest solution, which we have used for some years, is to ignore the alternator charge circuit whatever its type and simply make a split charge diode arrangement dedicated to the solar panels using Schottky diodes. Schottky diodes are readily available (Maplin etc) and have a very low forward current so shouldn't fool the controller. So panels - controller - diodes - batteries. Just ensure the diodes have enough capability to carry the maximum current you will ever get from the controller.
Sorry, mouth before brain: I don't know if your particular controller will be able to draw its power from the panels, something for you to check. Diodes are only a few pence each tho so you could experiment and report back. One other point about all split charge systems is that a duff battery will always get preferantial treatment, hogging all the supplied power. Been there...
The simplest solution, which we have used for some years, is to ignore the alternator charge circuit whatever its type and simply make a split charge diode arrangement dedicated to the solar panels using Schottky diodes. Schottky diodes are readily available (Maplin etc) and have a very low forward current so shouldn't fool the controller. So panels - controller - diodes - batteries. Just ensure the diodes have enough capability to carry the maximum current you will ever get from the controller.
Sorry, mouth before brain: I don't know if your particular controller will be able to draw its power from the panels, something for you to check. Diodes are only a few pence each tho so you could experiment and report back. One other point about all split charge systems is that a duff battery will always get preferantial treatment, hogging all the supplied power. Been there...
Last edited:
GrahamM376
Well-Known Member
I have 2 domestic banks with a regulator to each and a split charge diode between the panel and the regs. Reason for the split charge is because I was getting back feed through one of the regs at night, balancing the banks. Other alternative is to buy a twin output regulator.
KAM
Well-Known Member
Yes the diodes seem the best option but the controller display goes blank if there is not much power to it from the panels. Its probably working OK when its sunny but I can't always see whats happening. I'll run a trial with the diodes as well.
CatCouple
Active Member
variation on the same theme: I have 2 x 100w panels connected to an MPPT controller, single output, connected to one bank of batteries. I hadnt made it clear to the supplier that I had a Catamaran with two banks of batteries. trying to make the best of a bad job the initial thinking was that I would connect the MPPT unit to the starboard bank as that circuit includes the fridge and inverter for the Freezer the biggest amp guzzlers. But I am not really happy with this set up and want to charge both banks of batteries from the solar panels. As a work around how about I connect the output from the controller to the output leads from the 220v 50a battery charger? That circuit feeds both batteries. Would this work? The controller has a 'Load ' output as well, could that be used to supply the other bank with charge? The other alternative is to buy another controller I suppose
RichardS
N/A
variation on the same theme: I have 2 x 100w panels connected to an MPPT controller, single output, connected to one bank of batteries. I hadnt made it clear to the supplier that I had a Catamaran with two banks of batteries. trying to make the best of a bad job the initial thinking was that I would connect the MPPT unit to the starboard bank as that circuit includes the fridge and inverter for the Freezer the biggest amp guzzlers. But I am not really happy with this set up and want to charge both banks of batteries from the solar panels. As a work around how about I connect the output from the controller to the output leads from the 220v 50a battery charger? That circuit feeds both batteries. Would this work? The controller has a 'Load ' output as well, could that be used to supply the other bank with charge? The other alternative is to buy another controller I suppose
If the 12V output from the charger connects to both battery banks you can certainly connect the solar panel regulator to the charger outputs. I have done the same with my two channel regulator since my charger has three outputs, one to the house bank and one to each engine battery. I bridge the house bank outputs and connect the bridged output to one solar channel with the second solar channel connected to the house bank output.
Richard
