House battery for existing infrastructure

[Safariescapepod]

Early in my camper van conversion and wanting to run some wiring before new wall paneling. I want to have a house battery to run lights, radio, charge phone/laptop, and run a fan. My hope was to use as much of the existing infrastructure as possible (like the wiring for the interior lights to to connect LEDs and the factory radio). My thought was to rewire the power supply to the interior fuse box so that it came from the house battery. That would allow me to use all interior power w/ the ignition off and prevent the risk of killing my starter battery. My rough calculations lead me to believe this would use about 454 watts with all appliances running at the same time. Image attached was my idea as an amateur wiring diagram.

1) Most important - Does anyone see why this won't work? I read a lot of posts but haven't seen anyone that has tried this.

2) Any suggestions for a good battery for this kind of power consumption (no refrigerator)? One 12v versus two 6v in series (taking space into consideration)?

Thanks for your time.
Andy

[N6KB]

I've done it like that before. I recommend you actuate the relay only when the engine is running and alternator can be charging both batteries. If you use accessory power, without engine on, to actuate the relay, it sort of defeats the purpose. The "house" battery could discharge the "starting battery" if you have accessory power on without engine running. Might want to have a toggle switch to control the relay. Like a ON/OFF/ON three position toggle switch. One position could be "Auto" which actuates the relay automatically when the engine is running, and the other on position could be manual override which you would use cautiously.

[copperhead]

JCurrently going through a conversion myself. JMO, but if your adding a house battery, I'd skip tying it into the existing wiring.

https://www.astrosafari.com/viewtopic.php?f=9&t=143918

Keeping thing separate seemed simpler to me and IMO I'd rather keep OEM wiring separate from my house system..unless your van has a factory or after market upgrade. Basically power on battery side of van with controller/output or separate fuse panel then larger gauge routed to opposite side with similar fuse panel. That give you shorter runs for accessories and more options for later upgrades. Again..JMO.

FYI..I bought a Mightymax 100ah battery off amazon for about 180, but I'm also running a fridge.. Also would recommend battery isolator for easy battery protection.

[Sailing_Faith]

This is exactly what I did... no ACR relay required, and complete control over charging. To read more about it check out this thread; https://www.astrosafari.com/viewtopic.php?f=76&t=104562

I've done it like that before. I recommend you actuate the relay only when the engine is running and alternator can be charging both batteries. If you use accessory power, without engine on, to actuate the relay, it sort of defeats the purpose. The "house" battery could discharge the "starting battery" if you have accessory power on without engine running. Might want to have a toggle switch to control the relay. Like a ON/OFF/ON three position toggle switch. One position could be "Auto" which actuates the relay automatically when the engine is running, and the other on position could be manual override which you would use cautiously.

[AstroWill]

Your setup would work fine. That is how they used to do them on the Tigers, using a continuous duty relay tied to the ignition switch. Then they switched to ACRs.

A charger would make the batteries last longer, but adds cost. For the price of an ACR these days, it's kinda silly to go any other way IMO. Don't even have to mess with tying into your ignition wiring. It's all automatic and you can't forget to turn it off, or in the case of being linked to the ignition switch if someone leaves it in the acc position.

Personally I wouldn't mess with the factory wiring to the extent possible, adding additional dim-able lighting would probably be a better experience.

As far as battery recommendations, commercial/industrial deep cycle batteries are the best. That is why you see the 6v golf cart batteries used :)