charging capacity for larger battey banks

40 amperes per 100-amp hours is a lot.

I have 4x GC2 and a 35 amp converter. Usually the converter is off and the solar does all the charging. NO generator.

MEXICOWANDERER wrote:
40 amperes per 100-amp hours is a lot.

Spot on.

The 135AH Powerwares have a spec of 50A max. 50/135 is 37% per battery. I have two batteries for 270AH and a 50A temp-comp charger which is 18%.

These are replacing a Johnson Controls 31C 100AH which is slightly swollen on both ends. I really hammered it over a year and a half both using and charging it with 50A, or 50%.

HTH;
John

Also have four (wet) 6s, 458AH, and when doing 50-90s with no solar I use 140amps to charge them which is near the limit for my Honda 3000 gen (2800VA to run the chargers) So that is 140/458 = 30.6% charge rate. Takes about 2 hrs 15 min to do a 50-90 that way.

I have been using my PowerMax PF corrected PM3-100 amper plus the non-PF 40 amp VEC1093DBD, but I think I can run the non-PF PowerMax PM3-55 amper now instead of the 40, so if the Honda permits, that will be 155/458 = 33.8% we'll see next time off grid.

Telecomm batteries remind me of an elephant. Stick a fire hose up their nose and pull the trigger and suddenly the definition of "excess" becomes palpable.

Playing whamjam I've seen these guys vent where batteries half their weight gulped and yelled for more. A battery specifically designed for exceeding long life slow discharges and everlasting recharges is going to have some quirks.

If lots of amperage is needed simple, parallel more batteries. Capacity, longevity and wattage all at the same time is available but you ain't gonna like the price. Well you can't have everything...

I have a surplus Telecom AGM battery, rated 147 AH, weighs 105#.

Max charge rate I have ever seen it take is 21 amp/hr. It is big, it is long, it is heavy, and it has very, very thick plates, that are few and far between. It is an acid rich battery, the electrolyte inside has a SG of 1.300.

If you buy one of these cheap for your RV, don't expect it to put out a lot of amps quickly, like for starting a motor, if it won't recharge quickly either. Slow and steady is their nature. So is long life, rated 10 years life.

One caveat, charge them up fully, daily. Do NOT EVER let them sit discharged any longer than is necessary, certainly not long term, permanent damage will be incurred. They need to be charged up pronto.

Respect their design and nature, and they will treat you well, neglect them, and they'll be on the recycle heap of batteries a lot sooner rather than later.

It will be slow going every 7 to 10 days to get them fully charged again, taking .2 amps or less at 13.5-13.6V in my case, but it is critical you do so, especially before storing them away.

This Telecom battery is one of those quirky ones. Take notes, watch what it does when it charges and watch what it does when it stops charging too, while still on the charger... get a RC watt meter in line while charging, and you'll soon enough know exactly how fully charged it is.

Fully charged, and then left to sit 72 hours to lose the surface charge, my battery sees 12.92 to 12.94V in storage, completely disconnected. 1x a week, I turn on the MegaWatt at about 13.52V setting with a 10 turn pot rheostat, and when my RC Wattmeter says I have a charge rate of 0.13 amps per hour rate, I shut the charger off again.

Hi,

I have 566 amp-hours worth and if I've been using load support to run the various and sundry systems in the RV while on a 15 amp supply I do 'see' 80 to 90 amps of recharging.

My Magnum is capable of 125 amps of battery charging. Unfortunately the Magnum does NOT like most gfi outlets, so my back up charging is a PD 40 amp unit with wizard. I've not had to use the PD with the 'new to me' telecom jars.

When on load support I've seen a draw of 114 amps. Voltage stays at about 12.3 under that level of demand.