Just setting up my field box (newbie who scored some bargains) and was wondering what is the best way to charge the 12V gel cell? Not sure I'd want to try the old car charger but I don't want to buy some special trickle charger if it's nothing more than a standard 12V 300+ mA unit.
Any ideas from the experts?
While we're at it, any suggestions for charging duration and/or other life extending advice? How often do you top it up, or decide when to charge it?
C/10 for 14 hours has always worked for mine.
When the starter starts getting weak, I charge the battery. A standard hobby/garden 12v 7aH gel cell will hold a charge a long time, given our use. Dr.1 Driver "There's a Hun in the sun!"
Haven't been able to find much in the way of useful markings on mine. It's a SLA by Panasonic and quotes a number of voltage ranges but nothing on charging.
A pretty obvious and common sense answer I suspect.
Is a 12V 700mA plug pack OK? It's what the local electronics store suggested, after dismissing their recommendation of a standard car charger........... (I'm not that stupid).
It should list a voltage and amperage. Of not, and it has a model number, check Panasonic online. Dr.1 Driver "There's a Hun in the sun!"
Will do.
From memory, it's in the field box at the moment, it makes mention of
2.5Amps. Surely that can't be the charge rate.
This is exactly what Dr 1 Driver was referring to as a C10 charging device.
700 ma is 1/10th the capacity of the 7 Amp battery, Use it to charge overnight, or around 14 hours as noted.
Hmmm, I have on hand wall charger that is rated 12V 500mA.
Will this one be safe for charging 7A gell cell ? What happens once that full charge is reached ? GC will not accept charge anymore or it is neccessary to pull the plug after some 12-14 hours to prevent damage ?
Indy
--------------------------------------------- Power offline, EMP armed and ready
Most probably not. It sounds like a small hobby-type battery. 2.5 a isn't going to power a starter through extended use. You might consider biting the bullet and buying a 12v, 7 aH gel cell. You might be happier in the long run. Dr.1 Driver "There's a Hun in the sun!"
I charge mine with a 14.5v, 500mah wall wart transformer. Overnight charge after a weekend of flying is just about enough to keep it fully charged.
How big is it? A 12V 7ah will be about 8" X 3" X 4". If it is 2.5a, then it will be considerably smaller than that.
That will work great. What you can do is measure the charge rate after the battery is fully charged. Gell cells like to have a constant trickle charge on them or they go bad. Run the battery down until the starter has problems turning the engine over. Then charge it for about 5 hours and measure the current. Measure the current every hour after that until it reaches its lowest rate. That means the battery is fully charged. If the current is less than 100ma, you should be OK for quite a long standby.
Yes. Just increase the charge time by 7/5.
Help me out here, Red...as the voltages reach equalization, the charging amps drop. Right? You can't leave it on charge constantly, but a couple of hours overcharge shouldn't hurt it. Dr.1 Driver "There's a Hun in the sun!"
Gell cells, like all other lead-acid batteries, like a trickle charge to stay topped up. They will go flat on their own and destroy themselves. Yuasa batteries have the charging currents and voltages listed on them for recharging and trickle (standby).
Look for a "float" charger that's used for keeping batteries charged in lawn mowers, snowmobiles, and other things that are put away for a season. They can usually be found in the auto supply section of discount stores. I bought mine at Wal-Mart.
Morris
refer to =
Chargers
Hitec CG335 Pro 4 - 24 cell or multiple packs + Glowdriver. Hitec CG-340 1-16 cell NiCad & NiMh Robbe Power Peak Infinity 2 (Review) = Sunji 3000 ex Kr. Super Brain 969 Pro - MRC *** Gell Cell Battery Charger Lithium Ion Charger - DIY - SHDesigns - Chargers - How to recycle all those old plugins.
12 Volt SLA Charger - simple circuit PC Power Supply Conversion - Pat Harvey PC Power Supply - convert to power a 12VDC Battery Charger PC Power Supply Conversion (110/230 Vac to 12V )Gell Cells require a Constant Voltage Charge (CVC) regulated at 13.6V a simple DIY is available at =
Guys, don't let those lil' wallwart chargers fool you...
That 12V 500mAh charger is most likely pumping around 15.5-16 volts at around 500 mAH constantly... That's why the el cheapo wallwarts are referred to as "Constant Current chargers... without a regulator, they charge at their full amperage rate whenever they're on...
And they can kill a good battery in short order... 500mA can "boil off" the electrolyte.
The charger to use is a CONSTANT VOLTAGE charger, such as the old Ace "CVC"... This will charge at a preset voltage of say, 13.8VDC and the amperage tapers off as the surface voltage approaches 13.8V...
My CVC maintains at 15mAh once the battery is charged...
Cheers,
Their open circuit voltage may be that high but under load it falls significantly. And, they also don't pump out 500ma continuously. The current output is dependent on the load.
After sealing it away in the field box I rechecked, which I should have done in the first place. SLA 12V 7Ah as it should be.
Tried this 12V 750mA charger today, been over 12 hours and there is no hint of a warm battery (or anything disastorous). The panel battery check shows, if anything, a lesser charge than when I started (no idea what the gauge is attempting to show but I presume voltage).
Tried to get a reading with my multi-meter (VOM) but it's a piece of rubbish and doesn't tell me anything beyond the voltage may be 12V. This reminds me to spend those Xmas gift vouchers on a new meter.
Think I'll take this charger back and get the right one. Stupid store has the proper charger listed in the catalogue (for the same price) but the sales guy obviously didn't know that and probably knows less than I do about electronics.
Standard 12V 7Ah SLA.
I know the type you mean but they aren't common here in Australia as we don't tend to run that sort of equipment or see those climate changes.
No Wal-Marts here but I'll hunt up the local Tandy equivalent.
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