newbie battery/charge questions

While not exactly your scenario, this thread may be helpful: http://tab-rv.vanillaforums.com/discussion/comment/24852#Comment_24852 (found by searching on vampire draw).

Nolagringa, do you have a battery cut off switch installed?  If not, just pull the fuse at the battery.  Either of these will eliminate phantom draw down of the battery.  Depending on how discharged your battery is to start will determine how long it takes to recharge.  The converter in the TaB charges slowly.  You may be better served by hooking up a smart charger either continuously or in advance of a trip.  

@nolagringa, Either some good holiday reading, or a good start to a "wish" list for your T@B. Sounds like you're on your way to a lot better understanding of not only your new (to you) trailer, but your needs as well. If you haven't already checked, you might want to see what the AMP Hour rating is on your battery, it's also referred to as reserve capacity. If the previous owner replaced the battery, you might have an up-grade already.

nolagringa said:

@Michigan_Mike recommended plugging in "occasionally" for three solid days ... I wonder if this is once a month or so?  That makes more sense to me than keeping it plugged in all the time, but my knowledge of batteries is limited.

Hi Marie,

If you do have an "on/off switch" that allows you to isolate the battery from the trailer wiring you can plug your trailer in lets say, every one or two months and as needed to replenish the battery.  Here in Michigan where the temperatures drop below freezing during the winter months, I normally give my batteries (on my lawn tractor, pontoon boat, T@B, etc.) a full charge in the fall and they remain this way until spring time with no issues.  I don't unhook the batteries on my pontoon boat, the lawn tractor or my trailer and they survive the winter months.  By giving them a full charge in the fall this minimizes any freeze up issues and this is something I have been doing for over 25 years now and with success.  

On your T@B you could easily monitor the battery voltage occasionally (with the battery isolated from the trailer's electric circuits) and plug it in occasionally (every two months or as needed) for 2-3 days, check the voltage reading and you should be fine.  If you have a wet cell style deep cycle battery you do need to check the water level and replenish any water lost via use/charging/heat, etc. with distilled water as this will help the battery maintain a good charge rate and extend the life of the battery as long as you keep the voltage level above 12 volts DC.   I do use a battery tender (I have a couple here at the house) as needed as this floats the charge on my batteries and eliminates the need to constantly monitor and plug the trailer in to shore power.  

And depending on how your trailer is wired and whether or not you do have an on/off switch for the battery you will want to verify the wiring (and the battery charge rate), as plugging the trailer in to shore power may not charge the battery if it is "completely isolated" via an on/off switch from the trailer's electrical circuit, so it's important to verify how the battery is wired into the trailer circuit, to measure the battery voltage when you are (a.) plugged into shore power (b.) unplugged from shore power (c.) and when using the on/off switch.  

It is also important to note that after a battery has been fully charged and has been unplugged from a charger or lets say the trailer's electric converter, the voltage reading will tend to dissipate (lower) some and show a lower voltage read after 2-3 hours once the battery plates cool down some and the charge across the battery plates levels off.  You will see this type of voltage fluctuation when using a solar panel to charge the battery or when you disconnect a solar panel from the battery charge port.  This is a normal phenomena and is really nothing to worry about as this does happen.    

And if you are not familiar with the way your trailer's electric circuits and battery are wired it is probably best to have a seasoned individual check these areas out for you, or take your trailer in to a nearby RV repair center and consult with them about the circuits (to verify the wiring) so that you are able to keep the battery charged and maintain it properly.  Camping World techs normally will talk to you and may perform visual inspections & tests for you free of charge if you ask them beforehand.  Most business people with integrity want to help others out without charging them a bundle, but on the flip side we have also seen where some entrepreneurs with less than honorable (and with unscrupulous) intentions did so in a manner that took advantage of people who were not knowledgeable in these areas.