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12V Leisure Battery/Alternator Charging 24V Battery Bank

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Sep 9, 2020
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I have a 600W solar panels wired up in 2 arrays at 36V charging a 24V battery bank (4-100aH Battleborn Batteries).

Is there a product I can use to charge the 24v battery bank with my van's alternator? Since I'm not charging 12v starter to 12v leisure I am not sure if a DC to DC battery charger (such as the Renogy 20A DC to DC charger) would work. Any help would be much appreciated!
 
Welcome to the forums!

I'll move this thread over to the vehicle section to see anyone there can tell you what they do.
 
Maybe one of these chargers would work for your application (not sure which brand is best in detail, but a quick search brought them up). They are 12v to 24v DC-DC chargers:




I guess make sure whichever one you choose supports a good lithium battery charge profile.
 
Not sure if this is a solution for your issue. But this is what I am thinking...

I am looking at getting 8 * 280Ah batteries in series for 24V, charging those batteries from solar would require more solar panels than what I can potentially fit on the van. So I am looking to use shore power and charging from the alternator as options. Now my background is electrician and I wonder if I could use an12V 1000W inverter connected to the alternator with some form of a switch, run the 120VAC (240VAC in Europe) to the input of the shore power to charge the leisure battery with a much thinner cable. (Will have to have a manual/automatic switch to make sure that only one source of 120/240VAC is connected at the time.)

To me it seems like a cost effective solution, is this something any one has tried, or is there any reason why it shouldn't work with the (optional 220A) alternator in a pro master?
 
Not sure if this is a solution for your issue. But this is what I am thinking...

I am looking at getting 8 * 280Ah batteries in series for 24V, charging those batteries from solar would require more solar panels than what I can potentially fit on the van. So I am looking to use shore power and charging from the alternator as options. Now my background is electrician and I wonder if I could use an12V 1000W inverter connected to the alternator with some form of a switch, run the 120VAC (240VAC in Europe) to the input of the shore power to charge the leisure battery with a much thinner cable. (Will have to have a manual/automatic switch to make sure that only one source of 120/240VAC is connected at the time.)

To me it seems like a cost effective solution, is this something any one has tried, or is there any reason why it shouldn't work with the (optional 220A) alternator in a pro master?

If I understand this right; you are thinking of...

12VDC alternator > 1000W 12VDC inverter to 120VAC > 120VAC through inverter/charger combo to 24VDC?

Unless there is something I am missing, I like that idea; you are going to want an inverter/charger anyways (at least I would) and I don't think loses would be too much of a worry for that 12VDC > 120VAC > 24VDC conversion since you're running off the engine and just getting what you can from the alternator.
 
For my own purposes, I just couldn't fit two alternators under the hood (DT466E, International 3800). Space taken up by onboard air and just a lack of space in general. I suppose that leaves me with one of the following?
  1. Replace 12V alternator with 24V alternator. Has output to 24V leisure battery, also has output to 24V to 12V buck converter to charge starter battery.
  2. 12VDC alternator > 1000W 12VDC inverter to 120VAC > 120VAC through inverter/charger combo to 24VDC.
  3. Keep the battery bank 12V 4s2p and get a 12V 200A BMS (any good ones out there?).
  4. Keep the battery bank 12V, divide into two 4s banks, each with a JDB 12V 120A BMS, paralleled after the BMS. That way I get the solid, reliable JDB BMS, plus some redundnacy in case one bank goes down. I assume I would need a Cyrix battery combiner after the BMS and before the loads, to make this work safely?
 
For my own purposes, I just couldn't fit two alternators under the hood (DT466E, International 3800). Space taken up by onboard air and just a lack of space in general. I suppose that leaves me with one of the following?
  1. Replace 12V alternator with 24V alternator. Has output to 24V leisure battery, also has output to 24V to 12V buck converter to charge starter battery.
  2. 12VDC alternator > 1000W 12VDC inverter to 120VAC > 120VAC through inverter/charger combo to 24VDC.
  3. Keep the battery bank 12V 4s2p and get a 12V 200A BMS (any good ones out there?).
  4. Keep the battery bank 12V, divide into two 4s banks, each with a JDB 12V 120A BMS, paralleled after the BMS. That way I get the solid, reliable JDB BMS, plus some redundnacy in case one bank goes down. I assume I would need a Cyrix battery combiner after the BMS and before the loads, to make this work safely?

For my situation, I went with option 4. I did not use a combiner.
 
For my situation, I went with option 4. I did not use a combiner.
I'd be running up to 2500 watts (12V x 104A x 2 batteries). I'm thinking of using 2 JBD or Daly BMS and then after the BMS, simply connecting in parallel at a distribution block. I'd be pulling up to 2500 watts for maybe 30 minutes with an induction cooker. Is this simply too much for 12v? Should I go to 24v? I just don't know how to charge from the 12v alternator to the 24v bank and get more than 50 amps without absolutely breaking the wallet.
 
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