Battery Charging and Electrical Problem

05-26-2005, 10:25 PM

Hello,

I recently bought a 2720 and have several questions on charging.

How long does it take to fully charge my TM batteries from my home and can I overcharge the batteries if I leave it plugged in for too many days?

Also, my two front night lights are not working despite having a good fuse and new bulbs. All other lights and fans work. Any suggestions?

Your insights and advice will be much appreciated.

Thanks in advance for your responses.

Brian

**2manypets** · 05-27-2005, 06:32 AM

If you look up inside the forward roof vent you will find a small black switch. It is a master switch for controling the two forward lights. I guess the idea is to leave both lights on at the fixtures themselves and then be able to turn them off and on with the roof vent switch. That way you don't have to climb over the bed to reach them. Sort of like a house that has a receptcle wired to a switch by the front door so that you can control a table lamp from that switch. Pretty trickey huh?

Bob

RockyMtnRay · 05-27-2005, 02:45 PM

Quote:

Originally Posted by BrianG

Hello,

I recently bought a 2720 and have several questions on charging.

How long does it take to fully charge my TM batteries from my home and can I overcharge the batteries if I leave it plugged in for too many days?

Time to fully recharge depends on how many batteries you have, what size they are, how discharged, and in what condition. With the standard 6300 series converter (roughly 8 amp output on the battery charge circuit), it will take around 12 to 15 hours to fully recharge a new but fairly depleted single Group 27 RV/Marine battery (the "normal" battery installed by most dealers). The somewhat smaller Group 24 will need around 10 to 12 hours. If you have two such batteries, the time will be doubled. If you have a pair of 6 Volt Golf Cart batteries, it could take as long as 30 to 40 hours to fully recharge them.

Yes, if you leave the trailer plugged in for more than the time needed for full recharge...and no appliances, lights, etc. are being used...then yes you can overcharge the batteries.

**Caver** · 05-27-2005, 05:47 PM

When you continue to charge a liquid electrolyte lead acid battery it outgases hydrogen and oxygen or simply - it uses water. This really isn't a problem as long as you add distilled water before the plates are exposed. Regardless of your charger if you leave it connected you should check the water level at least once a month until you see how much water is being used. I purchased a filler bottle that automatically adds water to the proper level so it only takes a couple of minutes to top off the batteries.

Since I leave my solar charge controller on all the time, I'm often charging the batteries after they have reached a full charge and I have to check them monthly during the summer months. When I checked the water level after leaving the TM in the driveway all winter the levels were only slightly lower than normal. The low sun angle and some shading by the house helped to reduce the period of time each day during the winter months that the batteries are receiving a substantial charge.

If you have a sealed or AGM battery then this is not a good approach and it requires a charge controller that will reduce the charge as required. The problem in an RV is that there are often loads present when the batteries are being charged and the charge controller has no idea about the load conditions so any approach that attempts to figure out the battery state of charge is a compromise.

Enjoy your TM! Ray

**B_and_D** · 05-27-2005, 09:31 PM

Yesterday I went out and bought a portable battery charger at WallyWorld. It's one of those that you can use as an emergency jump starter (but it's AC, not the ones with its own battery, wanted one of those too, but maybe next trip to WallyWorld). The charging amps are 60 for jumpstarting a drained car battery, and then 10/30 for "quick" charging.

I don't like to leave our batteries hooked up while we're at home because they drain with the "phantom" loads from the detectors, etc. Supposedly this charger will charge your batteries a lot quicker than plugging in the TM and using the converter.

I have a spare group 27 battery that we bring with us and also two Trojan 105's that are mounted to the front. I tried out the charger on both of them (i.e., the group 27, then the two 105's). When I hooked them up to the charger, the batteries were about 70 - 75% (according to the charger meter) and they took about 10 minutes to charge to 100%. I would like to spend some time this weekend using the batteries and the charger (and comparing the readings on the charger with my digital voltage meter) to see how quickly this little charger really works.

So far, it seems like a good investment, but I'll let you know what I find out this weekend. Since we're not going anywhere, we just might "camp out" in the trailer. As a matter of fact, I sleep so well out there that I just might sleep out there tonight!

05-27-2005, 10:38 PM

Thanks for all the responses. My wife and I are really enjoying our TM but are rookies at this so we appreciate this type of forum.

Brian

**B_and_D** · 06-04-2005, 09:05 PM

I've now had several opportunities to use this new battery charger.

Last weekend, I kept running the 9" color TV/DVD combo on and off for 40 minutes at a time until the batteries were at about 12.2 volts. They took about 4 hours to charge up with this battery charger. At first, it charges very quickly, up to about 70% (said it was at 50% when I started), and then it took the rest of the time to get to about 85%, and then the rest of the charging went pretty quickly.

Got another opportunity to use it today, when my daughter drove herself to school to take her SAT's, and called us from the school parking lot asking if there was some "special way" to turn the key to get the car to start. She had left the lights on and the battery was so dead that I couldn't jump start it with my car, even after charging the battery for about 10 minutes with the jumper cables. I took the battery out and brought it home, charger said it was at 11.1 volts (DEAD!) and the charger took about 3 hours to charge it up to full charge. We took it back, hooked it up, and were good to go.

I am very happy with this purchase and will bring this little charger along with us on all of our camping trips. Next thing I want is one of those yellow portable jump starters that don't require a trip home to charge up your battery for 3 hours before you can get a dead battery going.

The only downside to the charger I bought is that it says it's not recommended to slowly charge larger 12V batteries at the 2 amp rate...says it's only good for smaller batteries, lawn mowers, etc.?