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AGM battery help

Posted: Fri Oct 01, 2010 5:10 pm
by jbates58
hi all.

i have recently acquired a few more batteries to add to my camping setup, from our forklift (it had 4 and only 1 was buggered hehe, 3 for me) anyway, i have had these in the shed charging for a few days now, and my charger ticks off after 41 hours in bulk charging mode. but anyway, a quick Google on the batteries yielded this

http://www.ecopowerltd.co.nz/download.pdf?id=2945" onclick="window.open(this.href);return false;

it says:

The Champion® battery requires a specific “I-E-I” (constant
current-constant voltage-constant current) recharge profile be
used to maximize battery life. Use of a charger with the incorrect
recharge profile will significantly shorten your Champion®
battery’s life and void your battery warranty. For more information,
contact your local GNB Sales Representative.
The following is the recommended charging algorithm for the
Champion® Valve-Regulated deep cycle batteries at 25ºC
(77ºF):
Step 1. Charge at 20 Amps/100 Amp-hours to 2.37
volts per cell.
Step 2. Charge at 2.37 volts per cell until current is less than
2 Amps/100 Amp-hours.
Step 3. Charge at 2 Amps per 100 Amp-hours and a
maximum voltage of 2.55 vpc. Termination should
occur from a dv/dt sensor during step 3 or 4 hour
timer initiated at the beginning of step 2
For temperatures other than 25ºC (77ºF), the following formula
can be used to determine the correct charge voltage.
V corrected = V25ºC – [(T actual – 25ºC) * (.00474 V/ºC)] or
V corrected = V77ºF – [(T actual – 77ºF) * (.00263 V/ºF)]
The minimum corrected voltage for charging is 2.25 volts per
cell and the maximum corrected voltage for charging is 2.50
volts per cell.

is that correct? im currently using a powertech plus MB3606 charger, its similar to a ctek.
shown here: http://www.jaycar.com.au/productView...6&form=KEYWORD" onclick="window.open(this.href);return false;

what are your thoughts people? will my charger cut the mustard? according to the book, it will do up to 230AH, but my batteries seem to be getting really warm. all the other car batteries i charge with it dont get warm.

cheers all

Re: AGM battery help

Posted: Sat Oct 02, 2010 2:22 pm
by Dooley
Well I'd say it's a bit like how you can get nicad/nimh chargers that actually detect cell temperatures and voltages and react and have multiple charging stages and can charge batteries in a short time frame safely.

OR

You can get dirt cheap chargers to find it basically has a resistor and a diode to trickle charge them over several hours with a risk of overcharging and overheating.

In case 2, the battery pack was dead and I would say overcharging did it.

So I think it's a case of if you want to spend extra money to get an expensive charger or if they were free just roll with it and get a shorter lifespan. Up to you.

Although someone more knowledgeable can probably weigh in...