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Author Topic: Charging tt batteries  (Read 430 times)


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Charging tt batteries
« on: January 25, 2018, 09:25:58 AM »
   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.


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Re: Charging tt batteries
« Reply #1 on: January 25, 2018, 01:06:00 PM »
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!

Gary RV_Wizard

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Re: Charging tt batteries
« Reply #2 on: January 25, 2018, 06:10:28 PM »
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:
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL


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Re: Charging tt batteries
« Reply #3 on: January 25, 2018, 09:54:45 PM »
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.

Lou Schneider

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Re: Charging tt batteries
« Reply #4 on: January 26, 2018, 12:16:18 AM »
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.
« Last Edit: January 26, 2018, 12:18:30 AM by Lou Schneider »


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Re: Charging tt batteries
« Reply #5 on: January 26, 2018, 11:26:35 AM »
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.


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Re: Charging tt batteries
« Reply #6 on: January 28, 2018, 02:52:16 PM »
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. 
« Last Edit: January 28, 2018, 02:54:11 PM by Madcow »


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