Charge rate specs AGM

[tecnodave]

I have recently scrounged a bunch of CD Technologies VRLA batteries.

The manufacturers charge rate spec is a bit baffling to me:

"C/5 @ 20 hour rate @ 25deg C."

I'm assuming that they are talking about the discharge rate for the 20 hour constant discharge

So: 5/5 .....1 amp??

Or maybe more like high flyer suggested C20/.025   2.5 amps. With max current C20/.035   3.5 amp

These are standby batteries that have a high discharge rate but apparently a slow charge rate


Model TEL-105-FS

109 a.h. @ 20 hour rate

These are from the Long Duration Series. Phone company backup batteries.

Dave

[SuperTed]

Hi
i'd think they mean (1/5 of c20) amps  = 109/5   = 21.8 amps max up to 14.4 or 14.8v per 12V battery
Cheers

[Westbranch]

go here.... and have a thorough read       http://www.cdtechno.com/pdf/ref/41_2128_0212.pdf

to be found here  http://www.cdtechno.com/resource/support_doc.html   

I'll try to dig in but the value they are posting IMHO is for a GT charger tat can pump out constants Amps.

I use an EA of 5 with the WBjr on a 900Ah 24 V setup

[tecnodave]

im concerned because some of the batteries audibly vent at charge rates above 3.5 amps, apparently they have been abused, the best set will accept sustained 15 amp charge rate, with 4 batteries in series using settings from rolls-surrette battery manual for VRLA , in any case they have been abused....3 banks in parallel driving a 10 kW powermax inverter. (or whatever the name of that Chinese inverter that everyone seems to smoke).he had one smoked one there....charged by 2 FM-80's

WB,

thanks for that lead, I downloaded it into my battery library. It seems that that they recommend charge rates up to C/5 or C/4 for fast charging with voltage limited to 2.4 v.p.c.

Dave

[mike90045]

1) Generally, those are disposable telcom batteries,  they get cycled 3 or 4 times and then get replaced.  They are not deep cycle batteries and will fail after a couple hundred deep cycles, just designed to keep a telcom center working until the generators get running.

2) if you are getting venting from them, you are overcharging and loosing electrolyte (H2o as H & o2 gas)  each vent episode damages them more