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Topic: Basic battery question

Posted By: Marlynmik on 06/02/10 12:35pm

Do I have to disconnect the battery when the TT is connected to electricity? What does a battery disconnect switch do? I see this as a common "mod".


2010 Dodge Ram 1500 5.7L V8
2009 Keystone Hideout 27SLE


Posted By: pianotuna on 06/02/10 12:39pm

Hi Marlynmik,

No, and probably it is a bad idea to do so. Battery disconnects are mainly used when an RV is going to be in storage. They are to prevent parasitic loads from discharging the battery bank.

Marlynmik wrote:

Do I have to disconnect the battery when the TT is connected to electricity? What does a battery disconnect switch do? I see this as a common "mod".



Regards, Don
Full Time in a Kustom Koach Class C 28'5", 256 watts Unisolar, 875 amp hours in two battery banks 12 volt batteries, 2500 MSW watt inverter.


Posted By: mgbogue1 on 06/02/10 12:43pm

No, you don't want to disconnect the battery when hooked up to shore power. In fact, some converters require the battery to be in the circuit for the 12V side to work.

A battery disconnect is used to isolate the battery, normally when the TT is not in use. It keeps the small, parasitic loads (smoke detectors, CO detectors, etc) from draining the battery over time.


Posted By: JFG on 06/02/10 12:50pm

No... some of your rv systems work off 12 volt only, not ac... like slides, some lights, water pump... keep battery connected


Fred



Posted By: Marlynmik on 06/02/10 12:57pm

Ok so I don't have to worry about the battery being too charged? All this RV stuff is SO overwhelming! This forum can be scary for a newbie


Posted By: pianotuna on 06/02/10 01:01pm

Hi Marlynmik,

That would depend on the converter. Do you know the make and model? If so post it here, along with the total number of amp-hours in the "house" battery bank.

Marlynmik wrote:

Ok so I don't have to worry about the battery being too charged? All this RV stuff is SO overwhelming! This forum can be scary for a newbie



Posted By: 2inAlabama on 06/02/10 01:13pm

With your late-model TT, you probably have a "smart" converter which should not overcharge your house battery. But I would check it out just to make sure that you know what you have.


Just DH & DW



Posted By: bikendan on 06/02/10 02:52pm

Marlynmik wrote:

Ok so I don't have to worry about the battery being too charged? All this RV stuff is SO overwhelming! This forum can be scary for a newbie


you do have to worry about overcharging, if you have an older convertor.
since you have a 2010 trailer, you should be fine since it should have a 3-stage converter.


Dan- Firefighter, Shawn- Musician/Entrepreneur, Zoe- Faithful Golden Retriever(RIP), 2007 Chevrolet Avalanche LS, 2007 Rockwood Roo 23SS w/Equalizer and Prodigy, and 5 Mtn. bikes and 2 Road bikes



Posted By: Pokey2 on 06/02/10 03:21pm

Marlynmik wrote:

All this RV stuff is SO overwhelming! This forum can be scary for a newbie


Yes. But it can offer you so much help, and there are lots of folk here ready to offer it.


Posted By: pianotuna on 06/02/10 05:11pm

Hi,

It is possible to overcharge with a modern converter--but you really have to work at it. It may probably be safe to plug in for a week at a time.


Posted By: opnspaces on 06/02/10 11:28pm

Marlynmik wrote:

Ok so I don't have to worry about the battery being too charged? All this RV stuff is SO overwhelming! This forum can be scary for a newbie


As Pianotuna states it is possible to overcharge the battery but you probably would have to leave it plugged in for an extended period of time.

Are you planning to plug it in that long or just for the occasional weekend to week long trip?


1996 Suburban 4x4. 350, 4.10 3/4 ton
2005 Jayco Jay Flight 27BH
1986 Coleman Columbia Popup.


Posted By: wbwood on 06/03/10 03:22am

I have a question related. WE have a camper in storage has been there for couple months now and we did not disconnect the battery. I guess there is a good chance that it will be depleted when we pick it up in a couple weeks. How long will it take for it to charge up via connected to the tow vehicle? We will have about a 4 hr drive home with it and wondering if that would be enough to charge it up? If not, what's the best way of charging it up when we arrive home? Disconnect and take home and charge it with a battery charger? We didn't realize that we should of disconnected when we left. Will the campers electric charge it as well when we are at a campsite and plugged in?


Brian
2013 Thor Chateau 31L



Posted By: pianotuna on 06/03/10 07:08am

Hi wbwood,

Very little in the way of charging will happen from a tow vehicle unless the wire in the charging path has been upgraded in size to say #4 wire.

If it is a fairly new RV the best way is probably to plug in the the electrical system to 115 volt power. It may take up to 168 hours to completely recharge the batteries.

If it is an older RV then get a charger such as this one (or similar):



Charge the battery bank up, then follow that by a "recondition" cycle (that takes 24 hours).

wbwood wrote:

I have a question related. WE have a camper in storage has been there for couple months now and we did not disconnect the battery. I guess there is a good chance that it will be depleted when we pick it up in a couple weeks. How long will it take for it to charge up via connected to the tow vehicle? We will have about a 4 hr drive home with it and wondering if that would be enough to charge it up? If not, what's the best way of charging it up when we arrive home? Disconnect and take home and charge it with a battery charger? We didn't realize that we should of disconnected when we left. Will the campers electric charge it as well when we are at a campsite and plugged in?



Posted By: wbwood on 06/03/10 10:04am

Don it's a brand new camper...


Posted By: Marlynmik on 06/03/10 11:34am

opnspaces: just weekends/week here and there. Otherwise it won't be plugged in.

How long can it NOT be plugged in? We may go a month max without using it (though I really hope not to have to go that long between trips) Then all we need to do is disconnect before parking it for the winter?


Posted By: pianotuna on 06/03/10 12:42pm

Hi Marlymik,

That depends on the type of battery chemistry. Standard flooded batteries may self discharge at up to 1% per month. If they are AGM that can be as low as 1% per month. Current wisdom is to charge at least once per month.

I'd look into a modest solar system.


Posted By: pianotuna on 06/03/10 12:44pm

Hi wbwood,

Thanks! Then the converter may likely be a good one--but it is still prudent to check, and not entirely "stupid" to know what is in your RV.

wbwood wrote:

Don it's a brand new camper...



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