Jump to content
Sign in to follow this  

Discharge TM batteries?

Recommended Posts

I was told recently by an auto supply house that you occasionally need to totally discharge your TM batteries to prevent them from acquiring a memory.  I've always heard the opposite, that you should never totally discharge a deep cycle battery.  Anyone have an answer?

Share this post

Link to post
Share on other sites

The idea that batteries have  "memories" seemed to originate with Ni-Cad batterys. It was common for the nicad folks to discharge their batterys to "equalize them" that is to bring all of the batterys in a string to the same state of discharge. Then when the striing was re-charged, all would be at maxumum capacity and there fore the string would provide maximim power. Of course you do not use ni-cads with your trolling motor.

Folks using flooded lead-acid batterys used a different approach. In order to "equalize " their batterys, or rather all of the cells in their battery, they overcharged them at a safe rate. This brings all of the cells up to the same voltage, and provides the user with the maximum capacity the battery is capable of delivering.

Completely discharging a deep cycle lead- acid battery is sternly discouraged by the lead-acid battery manufacturers. Deep discharge batterys should not be discharged below a 20% state of charge, and the cranking batterys should not be discharged below 80% state of charge. Doing so will dramatically shorten their life.

New battery technology now on the horizon promises batterys that can be discharged to very low levels for a thousand or more cycles. Both Lithium and nano-carbon lead batterys show consideral promise. However our wallets will take a significant beating for the priviledge of owning one. The last quote I got from a chinese firm was for $2200 dollards for a single 100 AH 12 v lithium battery. Of course you can get them at a discount if you need 1000s of them.

So for now we are still stuck with 90 year old technology, and I think it would be a good idea to pay attention to the manufacturers warnings about depth of discharge.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

  • fishing

    fishing forum

    fishing rods

    fishing reels


    bass fish

    fish for bass