Adding a second battery for 706 D282

[Dirt Don]

Does someone have a schematic on how to hook up the second battery?

 

[matthies]

Is there a chance that one off the batteries was dead and charged up backwards ?? If you have a fluke meter, check and see if they both read the same. Ran into this once before.

 

[Janicholson]

I have been operating my 706 with one battery and would like to add a second for a better winter starting. I hooked a new second battery up in parallel (Positive to starter and negative to ground, same as other side battery). When I do this, both batteries sound like they are boiling. Any help would be appreciated.

Welcome to YT forums and PartsASAP. If you check the polarity of the batteries with any meter you should be able to assess the correctness of the battery polarity of each. If one of them was marked incorrectly, or charged up from beginning backwards, that would cause the severe discharge you are likely seeing upon hookup. (there should be very little sparking if the polarities match, and massive sparking if they do not. Jim

 

[Dirt Don]

Is there a chance that one off the batteries was dead and charged up backwards ?? If you have a fluke meter, check and see if they both read the same. Ran into this once before.

I believe the issue was having two different size batteries. seems fine now that we matched them up.

 

[Janicholson]

I believe the issue was having two different size batteries. seems fine now that we matched them up.

State of charge will make a difference, but size should not. Have the battery that was used first tested. Jim

 

[BarnyardEngineering]

I believe the issue was having two different size batteries. seems fine now that we matched them up.

I agree, it probably had nothing to do with "size."

What batteries were in the tractor when you were having the problem? What batteries are in there now?

Your 706 is "supposed" to have two long skinny 6V batteries installed on either side of the steering column, wired in series. After 60 years, anything's possible. On all of ours, the two skinny 6V batteries have been replaced with a single large Group 31 truck battery, for example. Some people have switched to two 12V skinny batteries. We're not even going to get in to the "janky" solutions.

Either you by chance picked the weak battery to replace, or you have two 12V batteries in parallel and the new good battery is enough to overcome the old weak battery.