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May 15, 2017, 09:22 AM
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I'm purchasing an ODYSSEY AGM battery PC1500 (or the Sears equivalent) to power my sailplane winch. On the Odyssey web site they recommend using a charger that can bulk charge at 25 amps or more and includes the following three phases:
•Bulk Phase - Fast charges the battery up to 14.7V and gets the battery to about 80% state of charge.

•Absorption Phase - Finishes off the charge in no more than an additional 4 to 6 hours after completion of bulk charge.

•Float Charge
More details can be found here - http://www.odysseybatteries.com/acce...er-charger.htm
and here on page 13 - http://www.odysseybatteries.com/files/techbook.pdf

This technical document goes into pretty good detail. You can see a summary of the charging profile on page 12 in Figure 6.

Seems to me my PowerLab8 should be able to handle this easily but I don't see any presets for AGM batteries and I've really not learned how to use the more involved functions. Additionally, I've read that AGMs require different charging profiles from old style Pb batteries but I don't really understand what those differences are.

If anyone can share some experience with this it would be greatly appreciated.

Thanks!

Louis


Been selling these and optima's (basically the same identical pure lead thin plate technology) for 25 years.

You are correct that they need both high Amps (no limit), and 14.7V at room temperature for the CC/CV stages of charge. The PL8 does this well. And then very important in cyclic use for a long service life you MUST do the following:
There's 3 options:

1. Terminate at 1000th C based on CAPACITY at the 20 hour rate. (so 0.07A or 70mA on a PC1500. Not sooner.) And with a 8 hour CV time limit. (12 is better but the PL8 doesn't allow that option). This is fine if deep cycled, or topped up. Any state of charge. It ends up full, and is best way for long service life. It takes a long time. No float needed. Which is just as well as the PL8 doesn't have this... If it did, you would set 13.4V for long term storage. Low enough to cause no gassing or plate corrosion and high enough to prevent long term storage Sulfation.

2. As above 14.7V and Max Amps, but terminate at 100thC (0.68A or 680mA on a PC1500). Then go to a 13.6 to 13.7 Float CV voltage which adds the last 1% charge and this prevents the Sulfation from causing rapid deterioration. for 10 hours (fully charged) to a week or so (storage) PL8 cant do float... So this isn't an option.

3. Less easy to get right. Same 14.7V and terminate at 2A. Same 8 hour limit. Then use the TRICKLE which isn't float, but CC at 1A for 2 hours. If voltage exceeds 15.6 terminate. It can do this. But better to do no. 1 above as its kinder! And this is only for deeply discharged batteries.
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May 15, 2017, 09:24 AM
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May 15, 2017, 11:37 AM
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3. Less easy to get right. Same 14.7V and terminate at 1A. Same 8 hour limit. Then use the TRICKLE which isn't float, but CC at 1A for 2 hours. If voltage exceeds 15.6 terminate. It can do this. But better to do no. 1 above as its kinder! And this is only for deeply discharged batteries.

Correction to 3 above. Voltage will climb high at the end with limited current. But at a low enough rate that the recombination can cope. And this is called the fast finishing stage. ONLY for deeply cycled batteries in a hurry. Best use 1. above.


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