PoolBuster charger - PLEASE help with correct identification

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T

tphaggerty

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LifeTime Supporter
Jun 27, 2007
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Poughquag, NY
Anyone out there with a PoolBuster - can you please tell me what your charger output voltage and amperage is. Thanks!

Background info - I have a PB Max with the "old style" 1 hour charger. This charger is outputs 8.4V, 500mA for one hour on a timer, then switches to a trickle charge of 8.4V, 125mA. After one season, my original battery wouldn't charge. After buying a replacement that didn't work well either and getting help from the manufacturer, I would up with 2 "new" battery/motor packs and a new "trickle" charger. However, the trickle charger doesn't work and I'm not 100% certain it is the correct charger for the PB. It is a 14.4V output, 100mA charger. I am worried that this high a voltage, even at trickle, is killing the batteries. I could just buy a new charger, but the price is pretty ridiculous for a wall wart. If I can get the info from other PB users, at least I can tell if I have the right charger or not.

Thanks for any help!
 
Re: PoolBuster charger - PLEASE help with correct identifica

Well, strictly speaking, a trickle charge means charging the batteries at one tenth of their rated capacity for about 12 to 14 hours. In other words, if your batteries are rated 3650 mAh, you would trickle charge them at 365 mA for about 12 to 14 hours. Quick charge is usually 1 hour at the rated capacity, in this case 3.6 amps for one hour.

Depending on the battery chemistry they may or may not be tolerant to overcharge, NiCd are more tolerant and NiMH are less. The different chemistries also indicate differently that they're fully charged, NiCd actually drop in voltage and this drop can be detected by the charger logic allowing it to turn itself off. NiMH also drop in voltage, but by a tiny amount, more difficult to detect, so the smart chargers often use a thermistor to monitor battery temperature, a fully charged NiMH will be warm to the touch and start venting. So-called smart chargers incorporate these features (and a charge current equivalent to the battery capacity).

That's why you can't really mix smart chargers, a NiCd charger has a peak-voltage detection that's different than a NiMH charger (and NiMH *may* also monitor cell temperature).

It's not so much the charging voltage that's important but rather the charging current. Trickle chargers are simply constant-current circuits (the internal resistance of the cell actually changes during the charge cycle). I've just now built a trickle charger for 2 1.2 v 2650 mAh batteries, the charging current is 250 mA, the input voltage is from a 9 vDC unregulated wall wart and gives 8.6 volts at the terminals, and the power transistor will dissipate in heat the difference between the wall wart voltage and whatever voltage is required to yield 250 mA.

So it's not just a wall wart, there's a bit of circuitry in there. If they build 'em right.

(The note on these Duracell AA NiMH cells simply say "Standard charge 270 mA for 16 hours". I didn't have the correct resistor in stock to hit the target but it's close enough.)

So if I were you I'd look at the capacity of your batteries and get a trickle charger that's close to one tenth of their capacity (for a 12 hour charge) or a smart charger rated at their capacity (for a one hour charge). In my opinion anyways quick charging is a bit rough on the batteries. The battery chemistry and capacity determine the charging parameters.

Best regards,
 
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