Battery replacement

[hitthebricks]

So far I've replaced my TM batterys 5 times since 2001. What killing these batterys? I charge them after each use, bring them in during winter and keep them charged, only the TM is hooked up to them. All the batterys that did make it 2 years seemed weak during the second year and the baterys that died after one year would have a bad cell. Only one battery would be dead but I always replaced both. Anyone have any suggestions to stop this problem!

Thanks,

HTB

[Jim Almquist]

Have you been using the same charger ? You might very well be over charging the batteries if it is not made for deep cycle batteries.

[Eric Wettschreck]

Are they deep cycle batteries? It has to be asked.

Deep cycle batteries like to be drained to within an ounce of their life, then slow trickle charged back to life. If they are only half dead and recharged you're slowly taking their life away.

As Jim said, check your charger also. It's possible the charger is not functioning properly.

[BobT]

The question about battery type is a good one. Make sure you are buying deep cycle batteries for your trolling motor. A starting battery will not like it much in that application.

On a related note, try deep-cycling your battery and recharging once in a while before ruling them DOA. Simular to NiCad batteries, some deep cycle batteries need to cycle very low and back again to avoid developing a capacity memory. Deep-cycling them can restore some of this lost capacity. It does seem that some mfr. claim this isn't needed but it doesn't hurt to try.

Also, have you paid attention to the battery fluid levels? If the fluid gets low, the battery can become contaminated and this will shorten its life.

What about how they are handled. If the batteries are subjected to a lot of banging around they can revolt. Strap them down in your boat if they're not tied down so they don't bounce around. Move them toward the rear of the boat so they aren't subjected to the beating at the bow in rough water.

[MuskieJunkie]

Ouch. We know it's not the batteries, to go through that many is only 8 years something must be really wrong. So it has to be the trolling motor or the charger you're using (the only 2 things that are every hooked to them).

I would think you're only option is to replace 1 or both of those. Maybe send your TM in to get tested??