Two smaller (less $) batteries vs one big one?

[woytovich]

So, this is an academic exercise mostly... bear with me.

In a street rig that gets used in cold weather 1/2 of the year that doesn't have a bunch of electronic accessories or a winch...

Question: 2 cheaper batteries wired together all the time (no expensive dual battery system) or one larger battery?

With 2 batteries if one were to fail the other would still start/run the truck.

With 2 batteries you would get higher CCA than with a single battery, and presumably more battery cranking longevity.

For example:

Sears Diehard Gold Group 27 $125 x2 = $25 825CCA x2 = 1650CCA (weighing 50lbs each)

Sears DieHard Platinum Group 65 $250 930CCA (weighing 60lbs)

Other batteries could be substituted of course.... these are just for example.

mark

 

[enfield]

I'm no expert, but I believe that the platinum offers more than just CCA. For instance, they are supposed to hold a charge for much longer than a standard battery. If you just need the extra amperage for winter starts, I would think two cheaper batteries would be fine.

 

[60Works]

Without isolation, one bad battery will kill the good one. It won't function as a back up. That said, I ran a setup like that for 8-9 years without issues. If either battery got week, I replaced both. They have to be the exact same battery too. It doubles everything; cost, weight, capacity.

Bottom line, either go with one premium battery or use an isolation set up.

 

[murf]

Without isolation, one bad battery will kill the good one. It won't function as a back up. That said, I ran a setup like that for 8-9 years without issues. If either battery got week, I replaced both. They have to be the exact same battery too. It doubles everything; cost, weight, capacity.

Bottom line, either go with one premium battery or use an isolation set up.

Agreed. I subscribe to the idea of one platinum diehard and a small antigravity microstart jumper http://antigravitybatteries.com/microstart/ for backup. The one large sears super single takes a lot of use/draw without a whimper.

 

[murf]

Here is a trip report I did about heavy usage and the results if it helps...

https://forum.ih8mud.com/threads/se...-setup-and-run-time-test.810637/#post-9347843

 

[Cruzerman]

If you really want to do the two battery setup, you could go with two 6-volts units hooked in series. You wouldn't have a "spare" battery, but you would have one very big battery and wouldn't have to deal with the "one killing the other" or isolation. However, it also seems like you'd have two points of failure rather than one.