Need Advice On Battery Charger Voltage Settings

[shields]

We have a 1997 Monaco Dynasty with 50 amp electrical service. Our inverter/charger (original equipment) is a Heart Interface Freedom 20 (2000 watt capacity) which allows limited adjustments for charging voltages. Having just replaced our house batteries with two new Lifeline 12 volt AGMs, proper charging settings seem important. However, the adjustments provided by the charger don't match those specified by the battery manufacturer.

The battery manufacturer recommends bulk charging at 14.2 to 14.4 volts, and float charging at 13.2 to 13.4 volts. The closest I can get to those with the dip switch settings on the charger are:

a. Bulk charging at 14.3 volts (3 hours) followed by float charging at 13.8 volts; or

b. Bulk charging at 13.9 volts (1 hour) followed by float charging at 13.3 volts.

I don't want to replace the inverter/charger unless necessary, but we also don't want to damage these expensive new batteries by over-charging or under-charging. The coach is not plugged in while stored, so I've tentatively set the switches to match option "a" above figuring that we won't be on the float charge voltage very often.

Does anyone have any better or other ideas? Thanks so much!

Tim

[desertdeals69]

I would install a new xantrex full sine wave inverter, 2000 or 3000 watt. The charger has the settings that your batteries need.

[RVerOnTheMove]

While the 14.3V will not hurt your AGM's, I think the 13.8V float is too high. I would settle for the 2nd option as the 13.3V float is right in range and the batteries will still charge just fine at 13.9.

You might do as you are now while parked for an extended time but I would use the second option anytime that you are going to occupy the coach.

Otherwise, the current inverter should handle all of your needs.

[desertdeals69]

One of the reasons I suggested a change to a full sine wave inverter is with all the current crop of electronics, modified sine wave is tough on them. The other reason is you can set the charge rates the mfg recomends.

[RVerOnTheMove]

Since the current inverter is working well there should be no reason to replace it. The claims that a MSW inverter is "tough" on electronics has no real foundation. I have used the Heart 2000 (458) MSW inverter in my coach for over 10 years without a single inverter related incident. That includes my household refrigerator, old analog TV's, newer LCD HD TV's and now the current crop of LED LCD TV's. Convection/Microwave oven, DirecTV hardware, Hughes satellite internet modems, computers, coffee makers, Linksys and WiFi Ranger routers, household lamps, etc.

The only thing that I can prove does not work well with a MSW inverter is a 120V clock (the clock on the coffee maker as an example).

With all of that understood, if this unit dies and I MUST replace the inverter I absolutely would replace it with a pure sine wave but I see no reason to replace a perfectly good unit.

[shields]

Thanks for the input Gents.

I've also contacted the inverter/charger's manufacturer to see if they have any solutions to the charging voltage dilemma. No word back from them yet, but I'll let you know if anything useful arrives. In the meantime, the battery manufacturer suggested using option "a" (14.3 volts for 3 hours, followed by a float of 13.8) and NOT leaving the coach plugged in during storage. Their thinking seems to be that the higher voltage for bulk charging will get the batteries close to capacity and the slightly over-charging on the float will not hurt the AGMs if they are not connected on term during storage.

It's not an optimal solution, so I'll keep searching for a solution that does not involve the out-of-pocket expense of a new inverter/charger.

Once again, thanks for your feedback and suggestions. Your help is most appreciated.

Tim

[wolfe10]

Tim,

If not better solution comes along and the inverter/charger is the only thing left on in the coach, while stored with 15 amp service, go to Home Depot, etc and buy a 20 amp timer. Set it to come on 1 hour a week-- a little more frequently of you have a lot of electrical loads on the batteries.

That will keep the batteries up without your having to plug/unplug, but not have them constantly overcharged.

[shields]

Brett,

Thanks for the suggestion. If a better solution doesn't surface soon, I'll head for Home Depot for the timer. Happy travels!

Tim

[dickandlois]

Tim, have to go along with Brett on this one. I have many of the new toys installed in the old coach (We do like the way it works for us) and have not to date run into any problems with the newer type equipment running on the modified sine wave output.

The old inverter / charger did need a new control board and that helped some charging issues and brought the inverter back to life.

Rich.