# Charging My Battery



## aleximom (Mar 31, 2009)

Newbie here with a question about my battery. I've winterized the TT and brought home the battery. Storing it in my garage as recommended by so many on here. I also know I need to recharge it periodically. I checked a couple of links I found, but I'm still not sure about a couple of things. I have an Outback factory installed Interstate Deep Cycle Marine Battery. When I did my walk through with the dealership I asked about the need to add distilled water to my battery and the guy told me I didn't need to do that (I was familar with this type of maintenance as I have to add water periodically to the battery on my sump pump in my home). I'm now questioning if he was right. I've looked at the battery and there are definitely 2 covers that seem like they would pop up, however they are covered with all the dire warnings about acid. There is absolutely no mention anywhere on the battery to add distilled water periodically.

So, that's question number one -- do you think the dealership was right, and how would I know for sure?

My next question has to do with charging the battery while here at home. I have a Sears DieHard Battery Charger. It's rated for a 12/2 amp charge (12 amp charge for 6 or 12 volt battery). It has a deep cycle setting, so I'm thinking it will work on my TT battery. Will it?? Is this an acceptable means of charging my battery? I've read about a trickle charge . . . have no idea what that means.

Any advice from some of you more experienced RVers would be greatly appreciated. Suzanne


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## Lmbevard (Mar 18, 2006)

As far as adding distilled water, It would be best to go ahead and check it before you charge it for the last time before storage and during heavy use. I finally follow my own advice and had a couple cells a little low. Does no harm in checking.

If you are storing the battery, you shouldn't have to charge the battery. If you start with a fully charged battery, then it should be ok for the winter. As far as the charger you have, it should work ok. The charger built in to the OB will do the best job of charging an maintaining the battery during the time it's in service. So far I've gotten 3 years out of the cheap battery that came with the unit. If you are going to do a lot of boondocking, you may want to upgrade the batteries to something more heavy duty.


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## thefulminator (Aug 8, 2007)

I once worked in the warehouse of a battery sales company. Here is my two cents.

From experience I can tell you that when you charge the battery with your home charger, take the plastic caps off. When the battery charges, some of the water breaks down into hydrogen and oxygen which is a very volatile mixture. You will see bubbling occur with a typical household charger which is the breaking down process. I one watched a guy get thrown across a room when he bumped a battery that was charging, causing a spark which ignited the oxygen in the top of the battery. It completely blew out the side of the battery. Acid was all over the place including all over him.

Where I live, the water has very few minerals in it so I can fill my battery with tap water. Use distilled water when your water supply has minerals in it because they can combine with the acid in the battery and neutralize the reaction. The openings into the cells of most batteries have a split shaft going down to the acid with a ring at the bottom. Only fill to the ring. The air space allows for thermal expansion of the acid and the split allows for the gasses to vent out of the case.

There is an old wives tale about batteries not taking a charge on a garage floor. This is partially true. A battery needs to warm up inside to allow the reaction for charging to take place. This is one of the reasons people have problems with failing batteries during the winter. If it gets really cold outside and you have a short commute, the battery never gets warm enough to take a charge and eventually won't start the car. A concrete garage floor make a very good heat sink and can do the same thing. If you set a battery directly on the concrete and try to charge it, the floor can pull the heat out of the battery faster than your charger can put it in. It never charges no matter how long you try. Set your battery on something to isolate it from the floor like wood blocks and the battery has a chance to retain enough heat to charge.

One last thing that a lot of people don't believe. I have seen this so I know that it works. If the top of the battery is dirty with road grime, dirt, etc, the battery can discharge right through that stuff. I used to deal with a lot of farmers who would bring in the batteries out of their equipment wondering why they would discharge for no reason. I would take a voltage meter, touch a probe to one battery post and drag the other probe through the gunk on top of the battery. I would show them how the voltage would change while moving the probe across the top of the case. The gunk, especially when it was moist, would conduct the electricity between the posts, essentially shorting them and draining the battery. Be sure to clean your batteries (with the caps on) with a brush and water. Soap also helps if the gunk is greasy. Dry the top off before charging.


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