Ford e450 shortie dual battery question

[JDoftheSea]

Hi all! I'm a skoolie newbie, just purchased a 2005 *mostly* converted Ford e450 Super Duty Shuttle (gas) but am working out the kinks. My main holdup right now is the dual battery system to the start bank and interior. Both are lead acid, one under hood and one on driver's side behind chassis in a little locker.

Its my understanding that both are wired for the start bank and the interior, however I have gotten rid of the wheelchair lift and so not sure that I need the two batteries wired together anymore? Has any one had any luck separating these dual battery systems? Am I being unreasonable here? Ideally I would like to keep the start bank/engine battery totally separate from the battery for the interior as I am going to have more energy needs in the future (fridge, sink, different lighting system, infrared oven-maybe. lol) so would really prefer to have an AGM I could charge off the solar perhaps?

Anyways, I don't know why I am so averse to the dual battery system for everything. I just can't wrap my head around it for some reason and would feel safer I guess knowing that if I drain my system for my electrical needs in the middle of nowhere I will still be able to drive the bus

I'm a physician and thought I was somewhat intelligent....until I started trying to figure out engines, electricity and solar...Guess I should have paid more attention in physics lol! Any help/advice would be super appreciated!

[john61ct]

Starter should be isolated from any drains from the House loads - stuff you run when stationary off grid.

House bank should take advantage of the high-current charging available from alternator while driving.

If that is your **only** source of power between shore power hookups, then an IGN-wired solenoid (relay) will do the job, say $70.

If you will have a genset and/or solar system to recharge House, and want Starter to also benefit, then a VSR/ACR is called for, a bit more expensive but really no more complicated.

[JDoftheSea]

Originally Posted by john61ct

Starter should be isolated from any drains from the House loads - stuff you run when stationary off grid.

House bank should take advantage of the high-current charging available from alternator while driving.

If that is your **only** source of power between shore power hookups, then an IGN-wired solenoid (relay) will do the job, say $70.

If you will have a genset and/or solar system to recharge House, and want Starter to also benefit, then a VSR/ACR is called for, a bit more expensive but really no more complicated.

Thank you! What about a Redarc DC to DC Battery Charger? Or would this be overkill in a 2005? It sounds like this works well for newer "smart" alternators but maybe not needed in an older model?

[john61ct]

DCDC charger are only needed for lead banks, when the voltage at the posts is significantly outside the charging range spec'd by the mfg of the House bank.

Personally I would rather buy batteries whose profile matches the alternator output.

LFP banks need a DCDC for current limiting, to protect the alternator, but I would only buy ones like Sterling and Kisae, custom adjustable voltage setpoints, ideally also CV stage / Absorb time.

Redarcs are not adjustable.