Ideas on Battery Maintenance

[flyboy]

I think I have seen threads on this topic but I can't get a search to turn up anything now.

I want to get some opinions on battery maintenance from viewers.  I am running a 24V system with Exide Nautilus Gold NG 27 batteries, a Minn Kota MK 345 charger and a Minn Kota Fortrex trolling motor.

My batteries are about 14 months old and I have no complaints.  I typically charge my batteries after each trip and if the time before the next trip is lengthy (two weeks or more) I will charge them the night before the trip.  I pop the battery covers during charging and to date have only added distilled water when necessary.  Recently it takes a bit longer to charge and I have noticed that my specific gravity on the acid is in the fair range, not the good range.

My questions are:  Any of you out there add battery acid during charging to raise the specific gravity and are there things that you do differently to maintain your batteries?

[Wayne P.]

Read this, especially the Battery Don'ts section:

http://www.batteryequaliser.com/products/product_battery_maintenance.htm

[Way2slow]

You started off with good batteries and a good charger.  Why did you shoot yourself in the foot by not leaving the charger pluged in, and on 24/7 to keep the batteries maintained  while not in use? 

By charging when you return and then again the night before you went out again, you have probably let the batteries sulphate, which will not happen if you let the charger do what's it's designed to do, stay on all the time and keep a maintenance charge on the batteries.   It doesn't take but one extended period between charges for a battery to self discharge.  Once it self discharges below 80% it starts to sulphate.  Once a plate sulphates, it will not fully charge.  A Battery Minder maintainer will desulphate them if it's not too heavy, but that's about the only hope.  No amount of charging with a standard charger will do it.

Also, do not remove the caps when charging, that only cause the battery to loose additional water.  Never add acid to a battery once it has been added the first time (when new).

[flyboy]

Way2Slow

Thanks for your input.  I had to leave my boat in my sister's barn for a few months during construction on a new house, hence I could not leave the charger connected.  The batteries seem fine now, the only deficiency is the minor drop in specific gravity.  I have a question about leaving the caps on during the charging process.  For around forty years I have been told that the possibility of a minor explosion could spew battery acid all over the place.  Has that philosophy changed?  Also, when I was a kid I worked for a guy that rebuilt batteries and sold them as reconditioned/used batteries. We would charge the battery after changing a dead cell and add acid after charging to raise the specific gravity.  That was back in the early 60s'.  It seemed to work well but it was on auto batteries.  Is that technique a bad thing for a deep cycle?

Thanks for your input

[Way2slow]

I think all manufactors recommend leaving the caps on to prevent water loss.  I agree, back in the 60's and my service station days, you was always told to charge with caps off, but when done, everything around was wet.  Just like you always charged on a wood CocaCola krate, that you couldn't sit a battery on concrete.  Again, wrong.

When you charge, you only loose water, not sulfuric acid.  You only loose acid by sulphation, which can only be recovered by desulphation.  Adding additional acid only eats the plates more.  I know I've reclaimed batteries also by flushing them with 100% lye, the distiled water and then adding new acid, they do it frequently with industrial fork lift batteries, but these have thick solid lead plates and can handle it a little better.  On your small TM batteries, it's usually short lived after doing that.  I've tried it on brand new batteries that sat on the shelf and sulphated.  Just didn't get enough use to make it worth while.  Adding small amounts of concentrated sulfuric to get the specific gravity can be done, but then if the sulphation desolves any, it's way too hot and in either case, it eat the crap out of your old plates that have been etched one tim.

Before trying drastic measures, I would just by a Battery Minder for about $45, hook the batteries in parallel (it will do several batteries at one time) when you store the boat and leave it connected for about a month or two and see what they do then.  I've used batteries I've desulphated like that and gotten a long service life from them.

As for the explosion, that can happen with caps on or off, probably more apt with caps off.   Disconnecting a charger that's still on or anything that causes a spark right after a charge or heavy discharge when the cells are full of gas, it can go BOOOM. 

There are also two more common strengths of electrolite.  One used for many cranking batteries that gives a 1.260  specific gravity and one commonly used in deep cycle batteries that has more sulfuric acid that gives a 1.285 specific gravity.

[flyboy]

Way2slow

Thanks for all your valuable input.