Charging tt batteries

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Willowflowage

Willowflowage

Well-known member
Joined
Jan 22, 2018
Posts
79
Location
Ladysmith Wis
  I'm a new 23' 2002 keystone Cabana owner.
I bought two large 6 volt batteries
to power it and a 3100 champion
Invertor generator to top off and run
Stuff here and there.
  My question to get started this spring
Should I just let the generator keep the
Batteries topped off as they drain, by running
The generator connected to the trailer?
    I don't know much about what or
How the campers charging system works.
  Will it get the batteries
Back up to 100% ok? I've read to not
Let them fall below 50%.
  Should I use
A separate car battery charger off
The Genny? How many amps, 2 or 10?
  Or the 12vdc directly
From Genny to the batteries?
Probably simple but just looking
To do it right.
Thanks
 
I'll give a couple quick thoughts that many others here (especially RV Gary, who's a battery genius) will elaborate on:
It's more complicated than just getting your batts to 100%, but I'll say that depending on how depleted your batts are, you'd have to run your Inv/Gennie for hours to get them Equalized (100%, then through a charge step called "bulk", into a maintenance "trickle" charge.

I'll also say, letting your 6V batteries go as low as 50% (6.05V) is as low as you should occasionally take them.  Lower than that can destroy them.

Chime in. everyone!
 
The charging system in that 2002 vintage trailer probably isn't a great one, but it's still almost surely better than direct charge from the Champion. Higher amp capacity and better regulated as well.  If you could identify the converter/charger in the trailer we could be more sure. Usually in that type of RV, the converter/charger is part of the AC/DC load center, so the make & model on that panel is what we need to know.

The Champion's 12v outlet is unregulated 12v (probably more like 13.5-14.0v) and about 8 amps. I can't find a spec on the 12vdc voltage or amps anywhere in the Champion specs or manual, but those values would be typical for that size & type. A typical trailer converter/charger for that year would be more like 35A (peak).  However, the batteries won't accept that much amperage, so the typical charge rate for a pair of 6v golf cart batteries would be around 20-25A initially (battery discharged) and taper off to 3-5 amps as it gets above 80%. That will probably take 2-3 hours, and reaching 100% would be many hours.

If you prefer to use a separate car-type battery charger, definitely select 10A (or more) charging unless those batteries are at or near 100%.

Here is a good source to learn Battery Charge Basics:
https://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html
 
I really appreciate the help and will try and take it all in.
The link is a good tool for me also. I'll try and get some
Specs off the trailer charger soon. I did buy a Battery
Minder Plus 1510 to keep them on for the winter
In the basement. I assume this  isn't a powerful
Enough unit to use in the field from my generator.
Also it sounds like a solar panel can be a good plus
At times, and i'll probably be looking at that soon too.
   
 
A battery minder is a trickle charger, usually around 1-2 amps.  Two 6 volt batteries contain around 200 amp-hours, about half of which is usable without discharging the battery too deeply.

An amp-hour is one amp of current flowing for one hour.

In simple terms, it will take a 10 amp charger 10 hours to push 100 amp-hours into the batteries.  A 20 amp charge rate will do the same job in 5 hours.

Like Gary said, the charge rate will taper off as the battery gains a charge.  Usually it's only practical to refill a battery 80% or so when running a generator as that last 20% takes an awfully long time to accumulate.

That's one advantage to having a solar panel or two.  You can either buy enough solar to cover all of your needs, or run the generator to get the majority of the charge into the battery and let the solar finish off the last 20% or so during the rest of the day.
 
The safest thing for lead acid batteries is just to keep them as close to fully charged all the time as possible (but don't overcharge). I have the Champion and love it. My recommendation is just run the generator as much as you want to, at least 3-4 hours/day, plugged into the rig, and let the converter manage the batteries. Once a month or so, check the water level in the batteries. That's what I do.

I agree you should never use the DC output from any inverter generator, including the champion, unless it's an emergency jump start situation or something. The output is not regulated. Let the converter in the rig do it's job, or buy a separate 120v to 12v dc three-phase battery charger to plug into the generator if you want to.
 
I mentioned this in another thread.  Just do the job that the TT OEM didn't and install a Xantrex inverter charger.  The Xantrex HFS 2000 provides 2000w of pure sine wave AC when on batteries alone, and will charge batts at a rate of 55 amps when hooked up to shore power or generator.  I can have four 12v Group 31 batts fully charged back up in 2-3 hrs when hooked up to shore power or gen set plugged into the shore power port.  The Xantrex is a multi stage charging unit that does things properly.  While it is charging, it also passes thru AC from the shore power or generator at the same time, and is not limited to the 2000w AC output it provides when on batteries alone. 

They can be had for about $800 and are extremely reliable and long lasting.  Probably best to have a RV shop do the install properly unless you are very comfortable with electrical wiring systems. 
 
I finally dug the camper out of mothballs. We still have over
A foot of snow here. My charger is a Parallax 7155. It says
It's dc output is 55 amps at 13.6 volts DC. Will this get me close to 80 % in a couple hours of generator running? I'm planning on replacing light bulbs with LEDs and should be low usage for the most part. Little water pump and fan use.
Bought a cheap shunt type meter to keep an eye on my voltage in the trailer.
Along with a fluke meter. If I find the right deal I'll grab a suitcase type solar panel with charger/converter if needed.
Hoping my needs can be met from 60-80 percent
With the Genny for a couple hrs a day or less.
 
Cannot guess if a couple hours will be enough without knowing where you started from, i.e. 50%, 20%, etc. But probably yes.  The 7155 can produce more charging amps than the your battery bank can accept, so the batteries are what really determines the time.

Two 6v batteries will contain 210-230AH of power, so if you have to replace half of that, you need to get 105-115 AH back in. That's two hours at a steady 55 amps, but the battery cannot and will not accept that high a charge rate.  It might take 35-40 amps for a brief period, but it will quickly fall off to less than 20A and after an hour its probably down under 10.  A more  sophisticated multi-stage charger will do a bit better in the first 45-75 minutes, but the overall time isn't going to decrease by more than 5 minutes or so.

Going from 50% to 80% means putting in 30% x 230 or about 69 AH. That ought to be achievable.
 
Willowflowage:

My question to get started this springShould I just let the generator keep the Batteries topped off as they drain, by runningThe generator connected to the trailer?
Click to expand...



If I understand your post correctly, you are just asking what to do to get started, correct? After that, do you Boondock, or will you be on Shore power in commercial campsites?


If you will have Shore power every couple of days, the onboard inverter will probably bring your batteries up to full charge overnight.  Depending on how much power your unit uses in 24 hours, you may be able to go a day or more without having to plug in at all.


What sort of camping do you intend to do?

 
I really appreciate everyone educating me here.
I have been trying to camp every chance I get the last six weeks. All with no shore power. Ten days in a row one time. I'm pleased to report that the power I used is minimal, but my generator was great to top me off and occasionally run the microwave just cause I could. Changed my light bulbs to LEDs which cut a bunch. Also a couple motion sensing solar lights and some battery operated lights, some rechargable, really make power use low. The water pump and furnace fan used the most but an hour or less brought me up from about 12.3 to 12.7 vdc each day. Really only more like every other or third day. Also I had a cheap 7 watt solar panel give me a noticable bit of juice on sunny days. I'm sure when the price is right I'll pick up a 100watt or more panel some day and may skip the generator all together a lot of the time. Also it looks like my fridge pulls  a few tenths of an amp. But not a worry. I also rigged up a battery box with three small motorcycle batteries to charge cell phones,flashlights ect. Even had the luxury to watch TV/DVDs with a 16in 12v I bought for $120. It takes about 2amps.
Happy camper so far.
 
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