Author Topic: Battery quick charge  (Read 385 times)

Offline Roger

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Battery quick charge
« on: June 02, 2017, 12:05:26 PM »

My car has an Odyssey AGM type battery and I want to be able to recharge it quickly between runs if needed. The company tech tells me that the best rate for recharge of this type of battery is 14.4-14.8v, that’s the bulk or quick charge rate, and to just be sure the battery didn’t overheat. Since a conventional battery charger only puts out 12 volts, I am looking at using a power convertor that takes the 120v AC from my generator and converts it to 14.4v DC bulk rate for maximum battery recharge voltage. Has anyone had experience with something like this or any other thoughts?

Offline denverflatheader

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Re: Battery quick charge
« Reply #1 on: June 03, 2017, 01:27:48 PM »
Roger - you might first check the amp hour rating of your absorbed glass mat (AGM) battery.  Probably 25 percent of the total amp hour rating is the maximum safe charge rate.  Going higher amps to attempt a quick charge might damage your Odyssey.  For example, if your battery is rated 40 amp hours, you’d use 10 amps maximum to charge.  With the charger on, you could check the input line voltage for 14.4-14.8v.

My Optima Red Top is rated 50 amp hour, so my maximum charging amp rating would be 12.5 amps to keep battery safe (e.g. 50 x 0.25 = 12.5).  The higher the charging amps, the faster it charges.

A similar power convertor is my “old” 120V AC battery charger, it has 2 options; 2amp and 6amp.  Today, my battery initially measured 12.32v and I charged it for 15 minutes on the 6amp setting, it went up to 12.75v and with a 30 minute charge it went slightly higher to 12.88v.  Input line voltage from battery charger during 30 minutes went from 13.74v start to 14.11v end.  Alan


Offline Roger

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Re: Battery quick charge
« Reply #2 on: June 05, 2017, 10:14:34 AM »
Thanks for the input Alan. I spoke again today with the Odyssey tech department and learned more about my battery and charging in general. Charging one of their AGM batteries is voltage sensitive, not amperage sensitive like a conventional battery. Tech agreed that with a conventional battery and its high internal resistance that about 25% of the battery’s amp hour rating would be a maximum efficient charging rate. But for an Odyssey AGM battery that maximum charging rate can be as high as 4 to 5 times that of a conventional battery because it has a very low internal resistance as long as there is 14.7 volts or so pushing it. Tech pointed out one of the selling points of their brand was the quick recharge ability with no damage to the product or its lifespan. Can’t say how this affects an Optima battery because the Tech would only speak for their brand of AGM and engineering.

So after taking this all into consideration I’m ordering a power convertor/power supply/battery charger that will take in 120v from my generator or wall outlet and send out 35 amps of 14.6 volts DC current to charge my battery. This is a 3 stage system, starts at 14.6v until fully charged then backs off to 13.6v and then to 13.2 as a battery maintainer. Cost about $100, depending where you shop. Isn’t technology great:)

Offline denverflatheader

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Re: Battery quick charge
« Reply #3 on: June 05, 2017, 03:09:43 PM »
Enjoyed learning the new info.  Pleased to read battery technology continually enhanced.  Odyssey’s setup revolutionary, probably full charge under 5 minutes.