A Basic Battery Question

10-16-2006, 07:25 PM

How much water do you put in the battery? I don't see any fill line or other such indicator. I added some water (distilled, I at least knew that much) but I wasn't sure how much was necesary. Can you damage the battery with too much water?
Cheri

10-16-2006, 08:00 PM

I looked down the 3 wells and I saw water at the bottom. Did not see a plate. Maybe that means the water was covering it. I added enough water to raise the level about half way up the well. But I had no idea if that was right or wrong.
Cheri

10-16-2006, 08:02 PM

Wait, I just reread your post. (Curses that the edit function doesn't work

) There was a slot that ran vertically up the side of each well. So I was supposed to fill to the top of that?
Cheri

**B_and_D** · 10-16-2006, 09:04 PM

I went out to the TM and got my "RV Electrical Systems" book by Bill and Jan Moeller. Under the topic "battery safety & maintenance" they talk about how to fill a battery. They discuss not having your face right above the battery to check to the level because the sulfuric acid might get into your eyes and cause blindness and suggest using a mirror.

They say to never let the electrolyte (water) to get below the top of the plates. If you can't see the plates, then the water is probably covering them. The plates run vertically through the battery, so if the level was low and the plates were visible, you would see the tops of several plates right next to each other. In the batteries that I've seen (which would be a few of our car batteries) with a low-electrolyte level, the plates appear somewhat "corrugated", like cardboard. They say that "the cell should be filled just to the level of the ridge, or bull's eye, around the bottom of the fill-pipe tube. Too much water does not allow space for gassing to occur, and ...the electrolyte may boil out of the cell."

So, to me, it doesn't sound like overfilling will damage your batteries, but it's best to leave some room at the top. I'm not sure what they mean by the above sentence and reference to "bull's eye". I'd just add a bit at a time and make sure that there was some room at the top. The book recommends using a small paper cup and crushing it sideways so that it makes a spout for pouring.

I've always wondered about this myself; sometimes I get a little generous with the distilled water and worry that I've done something wrong

.

**Denny_A** · 10-16-2006, 11:22 PM

The majority of trailer battery problems can be solved by using an Absorbed Glass Mat (AGM) battery. They are sealed for life, have no liquid to freeze, don't outgas when charging, and hold a charge longer. Here's a link:

http://www.windsun.com/Batteries/Bat...at%20Batteries

An AGM is worth the extra expense!

Denny_A

10-17-2006, 11:23 AM

Thanks for all the input. Looks like I actually need to add more water rather than having added too much as I feared.
Thanks Folks!
Cheri

10-17-2006, 09:00 PM

When I have a battery question, I ask our battery guys. B and D is correct, you do not fill to the the top of the slots in the fill tube. Batteries vent when charging and the slot is there to let the gas escape. On the advice of the battery guys at work, I never add water as long as the plates are covered and the battery is not loosing water. If the battery is loosing water, they said to fill it to the bottom of the tube with the slot is in or a little above the bottom of the tube, but NEVER to the top of the slot. We have lots of batteries and all our battery men do is work on batteries and battery chargers. Why do we have so many batteries? I work for an electric company. When there is a blackout or other power issues we need the monitoring equipment to keep working. Every electrical substation of any size you see has a 135 VDC string in it or at least that is what we use. They also handle the battery plants at our microwave sites.

**commodor47** · 10-18-2006, 09:10 AM

The water level in your battery depends on the battery size and type. Make sure the battery is fully charged before adding additional water to the cell(s).

"After a full charge, the water level should be even in all cells and usually 1/4" to 1/2" below the bottom of the fill well in the cell (depends on battery size and type)."

The above is quoted from: //http://www.windsun.com/Batteries/Battery_FAQ.htm

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