3rd battery with a 12v converted truck

[jdeoliveira74]

ok I am looking to run a third battery in the rear of the truck to power a say 3000 watt inverter. This is my daily driver used for work and play. Will the altonator be able to handle the charging and how long will it last using a 3000 watt inverter with out truck running. Was also thinking maybe solar panel on top to help with charging.

 

[idM1028]

Did you do the Roscommon 12V conversion? Theres a way to add a third isolated battery to the truck with the Roscommon method. You may also want to think about going to a heavier duty alternator if you're worried about the electrical load. I.E. something like this: LEECE-NEVILLE NEW ALTERNATOR 2800JB - Listing # 22061 Ahwooga - Buy Sell Parts for New and Used Cars Trucks Motorcycles Keep in mind the 27-series alternators were designed more for big, heavy duty, applications.

 

[choll]

I did the Roscommon conversion. Can i add the third battery inside the truck just by adding the battery cables to the terminals on the passenger side rear seat wall.

 

[kapnklug]

Choll, yes you could add a third battery wired to the radio terminals in the back, but it would be the equivalent of just adding another battery in parallel with the main batteries, meaning the driver side alternator still would not work. Better would be to run a third battery with a shared ground and separate positive terminal to run dedicated loads. You can still use the radio terminals, but disconnect the positive one at the main 12V bus and connect it to a new terminal bus that you install on the firewall. Connect the driver side alternator, and all 3rd battery loads, to this bus also. If you want you can connect a Ford-type starter solenoid wired between the two busses, to combine the systems from a dashboard switch.

 

[Jerchambers]

Did you do the Roscommon 12V conversion? Theres a way to add a third isolated battery to the truck with the Roscommon method. You may also want to think about going to a heavier duty alternator if you're worried about the electrical load. I.E. something like this: LEECE-NEVILLE NEW ALTERNATOR 2800JB - Listing # 22061 Ahwooga - Buy Sell Parts for New and Used Cars Trucks Motorcycles Keep in mind the 27-series alternators were designed more for big, heavy duty, applications.

Could you replace the 27si with this alternator in the 24V system? Just for increase in power. If so, how would you wire the exciter plug to it so the idiot light still works?

 

[idM1028]

Looks like its got a couple of bolts on the back for the voltage regulator. That's all your idiot light is wired into. Thats the nice part about the Roscommon Conversion. You can use a conventional style 12V alternator. The trucks came from the factory with two isolated ground alts, but you can drop a conventional style alternator into the driver side position no problem. I put an autozone alt for a '75 Caddy into my GEN 1 position. The only problem I've had with it was the bearing went out on the first which caused the fan to hit the case. I took it back to autozone and had it replaced free of charge (lifetime warranty )

 

[jdeoliveira74]

When i got my truck it was already converted to 12v and it looks like a hack job to me the driver side alt wiring is there and taped up and zip tied to the alt bracket. Havent had any charging problems alt alt on passenger side seems to be putting out 14 volts constistantly 13.25 under heavy load. I Guess I can find a larger more powerful alt and add the third battery.