four 6v batteries, 2 CCs, 12v and 24v loads simultaneously

Aeronb

We are looking into setting up a charging station at our R/C airplane club's flying field.  Some members have 12v chargers and others have 24v chargers.  Will it work?  If we had two CCs with each set to charge a pair of batteries, then have the batteries all series together for 24v.  I would put two sets of leads out from each pair of batteries so that we would have access to 12v from each.  I hope this would help even the discharge from each half of the battery bank.  I would never parallel these leads.

Will each of the CCs work independently on their respective battery bank and bring it to a full charge?  At some point, due to uneven usage, one half of the bank might be at say; 75% SOC, and the other half could end up at say; 90%.  Maybe then someone comes along and puts on a 24v load and brings them down another 5% each.  All along the CCs are doing their job to get the batteries back up to full charge.  At some point when loading is light one pair comes up to full and some time later the other one does too.

I can't find a reason why this shouldn't work.  But I have a feeling that I'm missing something.  Any comments and insights are greatly appreciated.

Regards,
Aeron

mike95490

If you have a string of batteries totaling 24V, and  you pull power of some in the middle, you are unevenly discharging some of the batteries.  A 24V controller will NOT be able to sense this, and some of the batteries will fail prematurely.

Solution,

Best
 2 battery banks, 1 at 12V and other at 24V, with 2 chargers

Next best
 Split the charging, using 2 ISOLATED chargers, each charging 12V of the bank.   You will find out quickly what chargers are NOT isolated, because there will be sparks and smoke

Next best
split the bank apart and charge one 12v section one day, move the charger to the other 12v section next day, and then reconnect to a 24V bank,   Lots of connecting and moving around

Aeronb

mike95490 said:

If you have a string of batteries totaling 24V, and  you pull power of some in the middle, you are unevenly discharging some of the batteries.  A 24V controller will NOT be able to sense this, and some of the batteries will fail prematurely.

Solution,

Best
 2 battery banks, 1 at 12V and other at 24V, with 2 chargers

Next best
 Split the charging, using 2 ISOLATED chargers, each charging 12V of the bank.   You will find out quickly what chargers are NOT isolated, because there will be sparks and smoke

Next best
split the bank apart and charge one 12v section one day, move the charger to the other 12v section next day, and then reconnect to a 24V bank,   Lots of connecting and moving around

Option number one hadn't even crossed my mind.  I guess that's why these forums are in such high demand.  The only down side to that one is the additional investment in a couple more batteries.  Option number two is the one I think I was trying to describe so it seems that the plan is at least viable.
Thanks for your help.

littleharbor2

There are charge controllers which charge 12 or 24 volt which have a 12 volt power port which you can tap 12volt out of. I'm not sure how well they work or what kind of loads they can supply.

mcgivor

Aeronb said:

mike95490 said:

If you have a string of batteries totaling 24V, and  you pull power of some in the middle, you are unevenly discharging some of the batteries.  A 24V controller will NOT be able to sense this, and some of the batteries will fail prematurely.

Solution,

Best
 2 battery banks, 1 at 12V and other at 24V, with 2 chargers

Next best
 Split the charging, using 2 ISOLATED chargers, each charging 12V of the bank.   You will find out quickly what chargers are NOT isolated, because there will be sparks and smoke

Next best
split the bank apart and charge one 12v section one day, move the charger to the other 12v section next day, and then reconnect to a 24V bank,   Lots of connecting and moving around

Option number one hadn't even crossed my mind.  I guess that's why these forums are in such high demand.  The only down side to that one is the additional investment in a couple more batteries.  Option number two is the one I think I was trying to describe so it seems that the plan is at least viable.
Thanks for your help.

Option number one, is the one which will be the least problematic, trying to tap 12V from a 24V bank will result in disappointment. What you spend up front will save you in the long run.