Field Charging Problems

[ARAM SCHLOSBERG]

To recharge batteries at the field, at the suggestion of Dave Acton a number of years ago, I purchased a portable automotive Jump Starter. It happens to be made by Vector – 300 Amps 12 Volt DC, model VEC0105.

Recently, I’ve discovered that I’m unable to charge my 2S LiPoly batteries above 8.05 Volts when the voltage of the Jump Starter falls to about 12 Volts. The Jump Starter is trickle charged at home, and the AC-DC current chargers typically measure a DC 13-15 Volts. A fully charged Jump Starter reaches about 13 Volts. And as long as its voltage remains above 12 Volts everything is fine. I’ve also tried to directly power my Lipoly chargers from the 12 Volt outlet in a car, but since it is really 12 Volts, the problem persists.

Maybe my Jump Starter is fatigued and should be replaced with a new one. Another possibility is that my LiPoly batteries (2S Hyperon, 1.5 Amps) have developed higher internal resistance over time.

Have others run into similar problems? Are there other alternative to field charging?

[DAN BERRY]

I used a 12 gel-cell last year. Same as I use on my starter box.

[ARAM SCHLOSBERG]

Dan,
Not sure what a “12 gel-cell” actually is. How many Volts and Ampers does it have?
Had a 12 Volt large bulky battery, but it never seemed to work with any of my LiPoly chargers.

[DAN BERRY]

12 volt. Probably 6 amps? Same thing almost anybody with an electric starter has.

[rivers]

Some lipo chargers are not very tolerant of low input voltage. I have 3 chargers with input specs as follows:

Hyperion 5S; DC input 12V – 15V
X-Peak 3S; DC input 11V – 15V
FMA Cellpro 10S; DC input 10V-16V

I use an automotive 17 amp-hr booster for power as well as my car battery outlet. No problems most of the time, but occasionally the Hyperion charger will display a low voltage warning. If so, I put more charge on the booster (at home) or switch to another charger. It’s the amp-hr rating that determines the capacity of a booster unit or a gel cell. They are all 12V lead acid batteries.

An alternative is a deep cycle marine battery. This is another type of lead acid, same size as an auto battery, but built for longer lasting discharge.

[ARAM SCHLOSBERG]

Dick,
So it seems that my automotive jump starter has fatigued out.
What 17 amp-hour automotive booster do you use? Any suggestions for a deep cycle marine battery?
Thanks!

[rivers]

The 17 amp-hr battery I use is shown here: http://www.tooldiscounter.com/ItemDisplay.cfm?lookup=BOOES2500 .
I got from Richard. It’s really a high current starting battery, not a deep cycle, but it works okay if kept fully charged when stored. I took off the cables and clips to make it lighter.

To do it again I would shop for a deep cycle battery… about 20 or 30 amp-hr, sealed, and as light as possible. Note that some deep cycle batteries require a special charger.

I agree that your automotive booster is probably failing, most likely from too many deep discharge cycles.

[REYNOLD MAZZOCCO]

Try Harbor Freight http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96157

For $80 you get an inverter and compressor along with the 17AH battery. They have cheaper if you forgo the bells and whistles. They also have a 24AH jumpstarter.

Rey

[ARAM SCHLOSBERG]

Thanks Dan, Dick and Rey!

Ended up buying a Deep Cycle Gel battery from West Marine with a 31.6 Amp Hours with 500 discharge cycles. It also required getting a specialized charger (as a standard plug-in 12 Volt charger of a conventional automotive jump starter no longer works). I tossed the battery in the trunk and headed off to the Nats and it did its job recharging Lipo batteries.

Probably the only disadvantage is its weight – 24.2 Lb, as compared to 10 Lb of a standard automotive jump starter. Since chargers can’t be transported by plane – whatever their weight – it add a wrinkle to contest beyond the driving range. But this is getting far ahead of the curve…..

[Author]

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