Is this wise?

[nate6472]

I have a primary and secondary battery, connected by a manual transfer switch. They are connected except when the rover is off. The secondary powers lighting and keeps the primary from loosing power for starting. Can using two batteries when starting and running damage anything? Thanks in advance

[4flattires]

Can using two batteries when starting and running damage anything?

This is a common practice in high amp draw starting situations...typically diesels. I'm guessing you (or someone) set this up to handle a situation, you might share that.

Damage? No, not in a parallel setup. It's no different than in a jump start situation.

But if there is no increased electrical reserve required by your truck, I would much rather carry 60lbs of tools, fuel, or a frosty beverage-based payload than one of a lead/acid composition. Just my 2c.

[nate6472]

I set this set up to run extra electrical devices while overnighting without taxing the primary battery. I guess I could only carry secondary when overnighting, saving weight.

[4flattires]

I set this set up to run extra electrical devices while overnighting without taxing the primary battery.

Ahhh, different story. So this second battery is a deep cycle then? Low draw amp, long draw time span. Much different than a typical starting battery, high draw amp, low draw time span. If this is the case, your manual switch is fine, you know when to disconnect it. Otherwise there are automatic battery isolator products out there that protect the starting battery from draining once the accessory battery has (or is) beginning to expire.

Search battery isolators. You'll typically find this in RV situations.

[SafeAirOne]

I've looked for it but can't find the online page of do's and don'ts of dual battery setups. It was on one of the isolator/battery management system manufacturer's sites, IIRC. I thought it was Hellroaring.com but I can't find it there. I think I read that mixing 'normal' and deep cycle batteries in a dual battery setup was a no-no, but I can't find the reference on that. I'll keep looking...

[nate6472]

Both of these batteries are off the self "starting" batteries

[Donnie]

Perko makes the switch that you are looking for.. U can choose 1 / 2 or both batteries & also comes with a lock & key position, Donnie