AGM Battery & External Charger

You can think or believe what you want to, but in the real world, any battery that requires adding a lot of water for whatever reason, will be a short lived battery. AGM mite take more abuse, but they will be short lived too if constantly overcharged.

The 7100 is a converter that stays on. The external charger could be one of those which shuts off when it decides the battery is full, so it is no good as a substitute converter. I don't know what the SEC does for that.

I have a 7300 which is still the RV's converter for when on shore power, but I do my battery charging when off grid from generator using external chargers that have better charging profiles than the converter has, but they shut off when done. I have one that does not shut off but stays at 14.8 until I shut it off, so that is no use as a converter either.

The fixed 13.8v of the 7100/7300 converter will only gas off your battery 'water' if you leave it on in hot weather for a long enough time. The correct float voltage depends on the temperature. 13.8v is correct for 50F. Colder than that out, and 13.8v is too low. 80F goes with 13.2v.

Some AGMs specify they are to be floated at 13.8v. What AGM does the OP have?

If you live where you are floating the batts where it is below 50F, all you get by having the three-stage converter is 13.2v which is even lower than the already too low 13.8! You guys all know this but keep telling people they just have to have a three stage converter no matter where they live.

In any case, if you do have 13.8 and you live where you float the batts for a long time above 50F, you just add water to the batts every so often---it is not a big chore---and it is your own fault if you don't do that, not the converter's. :)

One of the advantages of the Lifeline AGM is the fairly high charge rate. I once had a discussion with a Concord/Lifeline battery engineer concerning the daily boost cycle to 14. what ever volts the Progressive Dynamics converter and Morningstar solar controller go through and he indicated this make sure the battery reaches full 100% state of charge. You have an expensive very good quality battery that has very specific needs to live a long and happy life. I will also recommend a Victron or Trimetric battery monitor the only real way to accurately know what is happening.

IF the installer of the AGM specific did not do it I'd "Cut the cord" to the 7100's charger module.. here is how to do that.

Open the power distribution panel, Find the wire that goes from a circuit breaker most likely labeled CONV to the back of the panel. remove and tape it off (or just turn the breaker off and tape it).. That way if the external charger ever fails you can easily restore the 7100s

The 7100 is a low end single stage converter, In fact I'd call it a power supply, It is not really that good at charging batteries since it is a single stage.. However running it in parallel with the other charger very likely will do no damage.. May slow charging a bit is all by "Tricking" the AGM charger into thinking the batteries are fuller than they are.

Quote:
The 7100 is a good converter and will not harm the battery including AGM. It is fixed at 13.8v.
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Wow, I wouldn't talk about wrong info !!
All of a sudden a 13.8 float voltage won't hurt a battery ??
It won't hurt it, until it boils it dry. Hot weather is coming......ya know ?

Very simple,...disconnect the 7100, add a PD 9200, and forget it !!
Worked for me anyway ! :)

Hi,

It is very easy to determine if the "Other converter" is still putting out power. Plug in the RV and unplug your charger. Then turn on a bunch of lights and monitor the battery voltage. Even if it is just a "1/3 - 2/3 - full" led light up on the water panel, you can monitor the battery. If it stays "Full" after a hour of use, or goes from 2/3 to full, then the battery converter is still working. If it drops (and it might take a while to drop the voltage on a large 4D battery) then your converter is not connected.

When I disconnected the converter in one RV, all I did was disconnect one black wire from the converter 120 volt input where it connected to the 20 amp circuit breaker, and install a orange wire nut on that wire. Hopefully some new owner will be able to figure it out - if the electronic charger that I installed ever stops working.

Yes I agree that if you just started the generator, and the charger is putting out a lot of amperage, then the charger can be using more than 500 watts and thus the microwave will overload the generator. The solution is start the generator about 15 - 20 minutes before using the coffee maker or microwave, then the "Peak" charge will be somewhat over by the time you need the microwave. or unplug. Your pick.

Fred.

Lots of wrong info in replies above, sad to say! :(

The 7100 is a good converter and will not harm the battery including AGM. It is fixed at 13.8v. At that voltage it is a slow charger though, for batteries that want 14.x volts to get a faster charge.

The batteries accept charge from any charger with a voltage higher than the battery's. When the several chargers get the battery to 13.8 the 7100 drops out of play and the battery voltage keeps rising to whatever the other chargers can do.

If the solar controller's high set point is 14.4v and the SEC can go to 14.6v then the last charger with the highest charging voltage will be the one that finishes the job when the others have dropped out.

It matters what the brand of AGM is. It will have its own specifications for the correct voltage to charge it. Just make sure the solar and the SEC are set to that and let them all get on with it. No need to disconnect anything.

Yes, the generator can be the limiting factor when using several chargers that eat up its available power.

Shadow Catcher wrote:
It may have been updated for solar, but the Parallax converter is a single stage converter and may not play well with your solar controller. The Parallax put out 13.8V and that can damage your battery. Progressive Dynamics makes a head unit that will play well.
http://www.progressivedyn.com/pd4600_converter_replacement.html

Ok one of my questions is can this stock charger be disconnected or is it integral to the converter? My understanding when I purchased the TT was that it was disconnected and the only operative charger was the outboard SEC. I don't know how to check and see nothing in the documentation.

It may have been updated for solar, but the Parallax converter is a single stage converter and may not play well with your solar controller. The Parallax put out 13.8V and that can damage your battery. Progressive Dynamics makes a head unit that will play well.
http://www.progressivedyn.com/pd4600_converter_replacement.html

Well it does need to be unplugged when using my eu2000i if I want to use the microwave. It does overload the genny when both are running and the charger is going full bore at 30A.

It may be that the internal charger is disconnected. Not certain how to tell without removing the entire converter. I dint find a circuit diagram anywhere for the converter/charger and I don't know if the converter can be used independently of the internal charger.