Charging the batteries with converter?

TMfor4ofus · 01-12-2017, 03:16 PM

We recently were fortunate enough to get a 2011 TM 2720. I'd like to know how effective is it use the converter to charge the batteries?? I'm assuming its all original and so how good is the converter at charging the batteries. Is it a smart or multi stage charger? It seems like after a night its charged up good. I found out it has 2 - 6v GC batteries. I was happy to see that and the date stamp says 7/15 so fairly new? We got a Westy 2400i Gen and I was wondering if I should go and buy a good 3 stage charger and power that off the Gen or is the converter sufficient? I only have 30w of solar which was okay for our 1 Gp 24 battery in our popup. If I keep them aimed at the sun and they actually get the batteries charged almost all the way on a good day if they werent discharged too much. The 30w solar is pretty useless on a cloudy winter day. I may upgrade the solar and so don't want to spend $$$ on a charger. ??
One more question is should I disconnect the batteries when sitting for even a couple weeks? Just pull the Neg terminal?

**Bill** · 01-12-2017, 08:21 PM

Congratulations on your new-to-you TM! You will love it.

As to your questions, I first need to ask if there is some reason behind these specific questions. Are you having some problems? Has someone suggested a problem?

The TM's built-in converter contains a battery charger that is very good at charging your battery. There should be no reason to consider replacing or augmenting it. It is a smart charger, which will keep your battery up very well under normal conditions. Where it fails, in my opinion, is in keeping your battery properly charged during long periods of non-use. If you put your TM in storage for a couple weeks, and leave the converter/charger powered up, it may tend to overcharge the battery a bit. For that reason, it is often suggested that if you put the trailer in storage for more than a few days, you should unplug shore power, disconnect the battery from the entire trailer, and just let the battery sit there. Some people disconnect the negative terminal - I disconnect the positive terminal. Either will work.

The real reason for disconnecting is to prevent the trailer's "phantom loads" from discharging the battery. Phantom loads can pull your battery down in only a few days, so if you plan to leave the trailer for more than that, it is a good idea to simply disconnect the battery. On the other hand, if you plan to leave the trailer in storage for a really long time - more than a couple months, say - it is a good idea to keep a "battery maintainer" on the battery. You can use the forum's Search tool to find discussion of the Battery Tender, for example.

As for powering the converter from shore power vs generator power, they are absolutely the same. No reason to do one over the other.

Bill

LoveToCamp · 01-12-2017, 09:12 PM

I am biased, but I do use solar to keep my batteries charged. I have 2 12v deep-cycle batteries (110 aH each). I initially had one 100w solar panel, which was good much of the time, but during a week of rain most of every day, the batteries didn't fully re-charge daily.

So, I put a second 100w panel on the roof, and now I have full power every afternoon, even when camping in the winter (November and December, once in January). They are just mounted on my roof, so they are not aimed at the sun.

My opinion is that 200w of solar will keep your batteries charged, unless you camp in heavy tree cover. However, I have camped under tall, seemingly thick, Ponderosa or Lodge pole pines, and even on cloudy days, I have never been at less than a full charge by evening (usually by 1 or 2 in the afternoon). Others may say fixed panels are not good, but I have used them for 5 years, and am very happy with them. I don't own a generator, and we boondock for up to 9 nights (I work, so have not gone longer).

Enjoy your TM!

TMfor4ofus · 01-12-2017, 09:41 PM

Okay thanks for the info guys. I have noticed after just a few days left alone the charge has dropped quite a bit so I either plug it in our hook it up to the solar panels on our deck above the trailer once a week. The puny 30w solar only does good if its a bright sunny day and I have them leaned toward the sun. Then it will get to about 13.4V at best for 5-6 hours now. So two things: I'll disconnect the batteries after this weekends trip. We are in a hook up site for 2 days so it should be charged good when we get home. Also look into upgrading the solar. Good to know the converter has a smart charger. It does seem to charge it up well after one night. Thanks Again.

Padgett · 01-13-2017, 08:05 AM

Agree with Love plus the caveat that when in the grove I connect a little float charger. Otherwise I would just remove the batteries and keep on a board in the garage when home.

BrucePerens · 01-13-2017, 09:09 PM

you should unplug shore power, disconnect the battery from the entire trailer, and just let the battery sit there. Some people disconnect the negative terminal - I disconnect the positive terminal. Either will work.

I am dubious that this is a good strategy, because the battery will self-discharge, and when it gets low enough, that will further damage the battery.

We don't really know yet what the converter's float voltage is and how often it might try to do an equalization charge. The temperature of the battery is also at issue. Measuring the float voltage and looking where it's stored would tell us if there is much of a chance to overcharge. It is also possible to carefully measure if any electrolyte is being boiled off over the winter.

If you don't want to run extended science experiments, a float charger that has internal temperature compensation, such as the NOCO Genius G750, might be the easiest solution, at $30. NOCO claims that that all of their chargers are temperature compensated, since it's cheap to do this is plausible. 750 mA is enough to take care of parasitic drains, so you can leave everything connected if you make sure all of the loads are turned off.

flipflop · 01-16-2017, 03:47 PM

I think a 2011 will have the WFCO WF8955A 3-stage converter in it (there's a label on it). I did some research about the 8955 and the specs are Stage 1 = 14.4vdc, Stage 2 = 13.6vdc, Stage 3 = 13.2vdc. http://wfcoelectronics.com/product/wf-8955-55-amp/

The WFCO 3-stage seems to still be the industry standard, but it does differ from a Battery Tender device which is 4-stage. The 4th stage is every 21 hours it jumps from the Stage 3 voltage to 14.4vdc for 15 minutes to prevent battery plate sulfation.

You could replace the OEM 3-stage with a Parallax 4-stage
http://www.bestconverter.com/Boondoc...955_c_196.html

For solar I'm finding the 85W factory does a decent job even in intermittent sun to keep the DC systems going. Flat panel on streetside rear roof. The pic is right now in full sun most of the day.

It was up to 13.2v earlier, in weak/intermittent sun it was holding at 12.2 or so.