Reason for 2 batteries on 12v conversion

[trooper632]

After converting a M1008 to the 12 volt conversion, I was reading that only one of the batteries spins the starter if this is the case, is there a need for both batteries. What are the benifits of having two batteries, also the thread stated that there was no need for the starter relay, that you could cross the red wire with the purple wire to bypass it, I'm a little confused. I did the Roscoe 12 volt conversion because the M1008 did not have a starter or either alternator, figured it was cheaper to do the 12 volt conversion. Only difference I noticed was the starter turns over slower, it may be because the starter is made in china (crap) but didnt know it when I bought it (ebay).

 

[Warthog]

The dual batteries are usually required on Deisels because of the large amerage required to crank the high compression engines.

The batteries should be connected in parallel. Positive to positive and negative to negative.

The rosscommon conversion does not require that the starter relay be removed.

 

[trooper632]

no it doesnt, it was written by another SS on a 12v conversion thread

 

[Bighurt]

My F350 needs both batteries when its below 0°F, CCA is effected by temperature, colder the battery lower the amperage. Colder the motor longer the starter needs to spin before she starts, thus 2 batteries in anticipation of cold climate.

Not sure if this applies to Texas trucks, but here in the north, I need all the battery power the truck can muster.

 

[det rebel]

yes you need the two battery it gets cold enough here that we need them even need block heaters

 

[M1031CMT]

You need the two batteries. Pretty much all diesels (including civilian trucks) have two. The only diesels I have seen with just one battery are small ones in cars which don't require as much amperage to get started.

 

[Warthog]

no it doesnt, it was written by another SS on a 12v conversion thread

Huh?

 

[ryan77]

You need 2 batteries because its a diesel and that motor is tighter then a bull's ass in a windstorm!!!