So I think my group 34 AMG is toast. Its voltage is a little low, even after a desulfate and charge, but worse than that I feel like I the capacity just isn’t there anymore. even after a full charge I don’t get more than a few hours running a fridge at less than 2 amps/hr.

From reading into it it sounds like AGM batteries might be a bad choice for my application on account of them needing a high top off voltage and my truck not being able to supply it.

Problems:

  • They say a starting battery shouldn’t be discharged bellow 10%, which only leaves me about 4 hours fridge time where I need about 12.
  • The trouble is that deep cycle batteries really don’t like being called on for cranking duty either...which is what will happen most often.
  • AGM batteries (which can dual cycle) don’t seem to be getting an adequate charge on my system.

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So, if you needed a reliable wet cell battery, but it also needed to handle about 24 Ahr of drain on a semi-regular basis...what would you buy?

Go cheaper wet cell starter and hurt the battery only occasionally (on trips)?

Go slightly more expensive marine and hurt the battery less more often?

Go expensive AGM and plug in every night?

Ideally I will be going dual battery in the future, one for house one for starting so don’t recommend that...I have tonight to install it all before I leave.