When to fill batteries???

[1javelin]

  Okay, fished for around 5 hours yesterday on a pretty fast river with high winds, and ran into some rocks at the end of the day because my tmotor didn't have enough juice in it.    I've got 81 lb. Minn Kota, so it should've done the job.  Figured something is wrong, so I checked my batteries when I got home and they seem a little low to me.    How high do I fill them??  I know to use distilled water, it says that as did the guy who sold me the boat, but how close to the top am I supposed to come allowing room for expansion?  Any and all help appreciated so this doesn't happen again. 

[Langer]

I too ran into the same issue first time out with my batteries.  I have no idea if this is right or not, but I just added water until it just started to come out the top, I did this for each cell, then re-capped. I put some baking soda onto the overflow to nuetralize the acid then just cleaned them up. I havent had an issue since, but dont know if what I did was correct or not....

[Revtro]

I've always filled mine all the way up to the top and let the cap push the excess out.  Never had a problem.

[Cy]

I'm sorry to be the barer of bad news but you guys are all over filling your batteries!  I first want to qualify my expertise on this subject a little so you all don't just think I pull this stuff out of my...you know.    I went to college to be an automotive mechanic and I spent several years before that working on battery operated floor care equipment.  I have had classes and a lot experience with batteries and battery powered equipment.

You should only fill a battery just enough to cover the plates.  What are plates you ask?  The plates are the comb looking things you see each cell of the battery.  The reason you don't want to add to much water is because when you charge the battery you will just boil that much more water out of the battery and make a nasty mess.  You can also damage the battery if the vents are not working properly and the water can't escape. 

You guys should really go and draw some to the water off the cells as soon as you can.

The last little fun fact about batteries I want to tell you is, you can safely store your batteries on the concrete floor of you garage.  Concrete does not drain the charge out of today's batteries.  That was true back in the day when batteries came in wood and rubber cases.

Cy

[1javelin]

I'll take more advice if someone knows anything else through either experience or expertise, but thanks for the advice so far guys.  Looks like if nothing different is posted by this time tomorrow I will be filling them up.
  After just reading Cfruel's post while trying to post mine, I think I will lighten up my load.  How do I see the cells though, with a flashlight maybe?

[motocross269]

I was told at some point in my life that it is best to refill them when they are at a low discharge point.  Is that true???

[Revtro]

Cfruel, thanks for the tips.  I've never had a problem filling mine all the way up, but why take chances?  I guess I'll go pull a little out with a turkey baster. 

It's easy to see the plates with a flashlight. BTW

[Cy]

Rev's right you should be able to see them with a flashlight no problem.  Do not use a lighter!!!  Battery and/or gas fumes can very explosive, but I am sure everyone knows that.

I have not heard filling batteries on a low charge makes a difference but I have always heard just keep them filled.

[cwinsiii]

Your supposed to fill the battery's after charged all the way.

The water expands as the battery charges.

[Revtro]

Ahh, maybe that's why I've never had a problem filling them all the way.  I always keep them on the onboard charger, so they're always charged up.  I've never filled them cold.  Great tips guys.  Thanks!

[djkimmel]

You know how some guys can just pretty much get away with anything while other guys deviate one time... BOOM!!!

If you want a quick fill without a flashlight, or maybe your batteries are hard to see into because of location, I've been told to fill them up until the fluid just touches the inside bottom of the hole/vent. As soon as it looks like water will come up into the hole, stop. If you can see the water level just below the bottom inside of the vents, even better.

You have to leave room for gas/expansion. Never seen it, but batteries can explode. Read about it now and then in the news. Youch!

I also found out along the way that maintenance free doesn't always mean maintenance free when it comes to wet cell batteries (gel or AGM are different). Lot's of good summary data on Deka Batteries Site about choosing batteries, types of batteries and things to know about batteries.