6V Batteries - Won't start generator

Camorhino wrote:

Crazy Cooter wrote:
Is the jumper wire connecting the two batteries large enough?

I think Cooter is on the right track here. You need a larger cable between the 2 6volts to carry the amperage needed to start the gen set.

Yep most folks don't realize in a series set up the weakest link be it battery or cables will limit what you get out of the pack.
2, 1000 amp batteries will only get you 150 amps if hooked up with 6 gauge wire.

I would go for a stupid large cable between the batteries, and from the frame ground to the neg terminal of the bottom battery. By stupid I am saying 0 or larger. Most everything goes from the pos terminal to ground, so just doing the middle and ground side will help a lot. Fwiw, I am running 4/0 on everything - 4 cables between my 3 12 volt batteries, and 1 to ground. I also run 4/0 both ways to the inverter/charger, but that is another subject.

Crazy Cooter wrote:
Is the jumper wire connecting the two batteries large enough?

I think Cooter is on the right track here. You need a larger cable between the 2 6volts to carry the amperage needed to start the gen set.

rayjc33 wrote:
Just to verify that I should not need to change the way that the starter on the generator is wired when I put the two 6v batteries in correct. It's really simple the way you wire them to make them 12v, so I am just trying to think of all the reasons it might now of worked?

You have a POOR/CORRODED/HIGH resistance connection, most likely the one between the 2 6 volt batteries. Can supply low levels of current flow, but "ask" for motor starting current, the high resistance connection opens.

Burnish clean ALL battery posts/connectors.

It sometimes happens that the poor connection is inside the battery, carries "lite" loads only. To much torque tightening the battery connections?

So I put the batteries back on today, this time using a bigger jump wire from the two batteries and they started the generator twice. A little sluggish turning over the 2nd time. They probably need charged up also. Thanks again for all the advice.

Sounds to me like the batterys just need charging, plug the rig in.

Is the jumper wire connecting the two batteries large enough?

Two six volts wired in series is a twelve volt battery so no, nothing to change on the gen. Also, true deep cycle batteries are not all rated in cranking amps, but have plenty to start a generator or anything else. For example, the smallest 6v Lifeline offers puts out 925 amps at 32 degrees. More than most car batteries. So, either they are dead or wired wrong/backward. Recheck wiring and give them a good charge. I'm betting it's the latter.

Just to verify that I should not need to change the way that the starter on the generator is wired when I put the two 6v batteries in correct. It's really simple the way you wire them to make them 12v, so I am just trying to think of all the reasons it might now of worked?

It clicked and then I lost everything. None of the 12v stuff would work in the trailer. The generator I have is an Onan 4000