Hello everyone
I have a campervan here with a starter battery of 24 vaults and the domestic battery is 12 V DC, I wanted to use a trickle down charger to charge the domestic batteries whilst the motor is running. But it seems to me there’s nothing out there that does this specifically. I found some DC to DC charge Converters that give out 12 vaults which in theory could work but I’m not sure. The starter battery Consists of 12V 90 batteries,And the domestic batteries are to 6 V 205 A each.

 

You can use a Buck down regulator like the LM2596 chip or similar,.
A lead acid battery is charged at a Constant Voltage of 13.8Volts.

 

Welcome to AAC.

I believe this is going to take something a little more substantial than a buck converter. Charging a battery can draw a lot more amperage. You have TWO 12V 90A batteries for your starter and (assuming) TWO 6V 205A batteries. Are the 6V batteries deep cycle batteries? If so then chances are you're going to need something quite substantial to charge them because there's a chance you could drain those batteries significantly, meaning recharging is going to take a lot of current. I'm no expert on charging batteries so I can't give you numbers. But as @Dodgydave said, float charge for a 12V lead acid battery is 13.6V (or 6.8V per 6V battery).

 

Two batteries, why not charge in series.?
Max.

 

Yes you are right they are deep cell batteries.

 

do you think something like this might work?

https://www.amazon.de/dp/B01KQWWVTY...rds=24v+auf+12v+wandler&qid=1573292038&sr=8-3

 

do you think something like this might work?

https://www.amazon.de/dp/B01KQWWVTY...rds=24v+auf+12v+wandler&qid=1573292038&sr=8-3

Note that the colour is 30A, but the current rating is 5A

 

You do not need a 12V supply, but a 13.8V one as mentioned above a couple of times.
13.8V versions of that supply are available.

 

You do not need a 12V supply, but a 13.8V one as mentioned above a couple of times.
13.8V versions of that supply are available.
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yeh this all seams to be going over my head. Thanks though will look in to this..

 

If you are interested, there is a pretty good web site that talks about care and feeding of batteries. Here is the Lead/Acid link...
https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

 

You need a series/parallel switch for starting and charging. You can find them at Texas Industrial Electric Company. Your alternator can handle all of the charging needs if this was the way it was equipped with starting and house batteries.

 

Okay thanks guys for your help I actually live in the UK. But I think I found something: http://www.battery-management-voltage-converter.com/m.e1199_60a_24v-12v_battery_charger.html this looks good right??

 

It looks like it fits your requirements. I am a little skeptical though as I have never seen one in action. I prefer a series parallel switch and using the vehicle alternator as it is a proven method. Check out any reviews you can find but it sounds like it fits the bill. Good luck.

 

It looks like it fits your requirements. I am a little skeptical though as I have never seen one in action. I prefer a series parallel switch and using the vehicle alternator as it is a proven method. Check out any reviews you can find but it sounds like it fits the bill. Good luck.

Thank for your feedback