Re: Coach Batteries
Reply #14 –
Food for thought.
Foretravel built a correctly matched system to ensure a long reliable life.
Gels can only be charged at 1/5th C. 20% percent of the battery bank amp hours.
125 amps from the charger. 160 from the alternator which went through the isolator and then charged both banks plus its internal losses which required cooling fins to vent the heat from the unit.
No equalization was needed for the gels and no equalization mode was in the oem inverter/chargers as it was not available or needed.
Adding AGM batteries requires perfect charging habits so you do not lose capacity from long term not reaching the full SOC.
if I were to change my gels to AGM's for the additional 38 amp,hours then available I personally would use the lifelines for their sole ability to be equalized and have the sw 2812 set to the correct lower charging voltage they require.
Plus they take a charge 20% faster because of their better internal construction.
So instead of a 160 amp alternator and our combiner I could change it to a 20% higher amp unit and use the lifeline benefits better.
This of course needs long term testing to see if a non lifeline AGM loses much capacity in actual normal rv use.
The difference in price and the extra capacity may or may not turn out to be as material in use if the batteries at five years are now less capacity than similar gels meaning your gen run time if not on a power pedestal goes up.
There was a reason it seems that Foretravel equipped every uni whatever exactly why they did.
Separately I receiving my ME-ARC50 today. I actually do not need it currently but if I store the coach indoors in the future the solar system can no longer keep up the batteries.
If the coach then is plugged in an the charger turned on both the ME-RC50 and the arc unit run the battery banks down 20% prior to reinitializing the charging regime.
The RC is not adjustable. The ARC can be programmed up to 99% SOC to turn on the charger side.
Prevents needlessly cycling the batteries from 100% to 80% then back to 100%.
My guru buddy has large buses with 6-8 gels in the system and if you happen to be at the 80% part of the charging cycle when you start using the coach the the loss of that many amp hours is noticeable.
Especially in float mode and the last 15% recharge of capacity takes much longer than bulk charge from 60% to 75%
If on travels from pedestal to pedestal or runs the gen always when using the coach these differences may not apply or be noticed.
We are dry campers a lot and long term owner type people so a decrease of battery capacity at some future time would have me equalize my system if possible or replace the batteries earlier than may otherwise have been needed.
Takes 15-20 cycles on a battery to get full capacity.
I would measure their capacity at that point and maybe annually there after just to get a baseline and see how my charging setup is doing.
I know. A lot of work. Too many old days in flooded cell battery coaches with single stage battery boiler chargers to not try to eliminate any issues.
The technology exists now where before it did not. Plus the knowledge.
Last step for me is a temp controlled alternator to not overcharge both banks at 13.5 volts in hot weather.
Magnum noticeably adjusts its voltage depending on the temp. Alternator does not.
I have seen perfectly charged and not overly discharged batteries last 15 years or more.
Plus in between the capacity was higher for use
Topic: Coach Batteries