Charging Last Year's LiPo

To know if there is any hope, you need to describe what is happening.

What does the charger say when it terminates the charge? It shouldn't be saying "charge complete." There has to be an error message on the charger.

LiPolys don't peak, so they can't false peak either. They charge to a very specific voltage level of 4.2 Volts per cell.

How many cells are in the packs? Are you using the correct settings on the charger? What is the voltage that the charger charges the packs up to? What is the voltage that the charger discharges the packs down to?

Could you have run them down past the 3.7 volts per cell? If so, weep over them and give them a decent burial.

Morris

I told the charger that but it just said "charge complete"

Two

The charger directions are scanty, and the batteries came with none. The batteries say "no more than 400mA" so that's what I've set the charger to.

I think that's the problem -- the charger set it's discharge voltage to

Ah well, off to buy shiny new batteries.

No necessarily. I left a pack plugged into a wahttmeter for several adys. Voltage 0. But no real current draw - less than a few mA.

Surprise surprise, they charged up as normal although I started out very carefully, at very low current until they were over 2.5v per cell. Pack (etec1200) flies as well as it ever did, took 1180 mah to charge...

They still have a little power you can power your night flight lights. You do have a night flyer don't you? :) mk

Tim- I don't think there is anything wrong with the charger, as 3 V/cell is a conservative cut-off level. Many ESC's let them drop further than that. 2.8 V/cell seems to be the most common, though some go to 2.6 V. I think it's a good choice not to mess with them if they are not accepting a normal charge. IIRC the packs sold initially by BA don't have voltage taps, so unless you want to brave peeling the wrap and exposing the cell terminals, there's no way to check each of the cells. What the heck can you do with a 4C 400 mah pack anyway? A current of

Abel

It's for a GWS 180-size motor that draws about 1.8 amps on full throttle

-- so I was running it with a smaller prop, and being careful not to peg it. They didn't have the 600mAh 2.5A batteries when I got these -- that's going to be the replacement.

The _real_ problem is that I built the plane for the 110mAh NiCd packs that no longer seem to be available, and there isn't anything else in that form factor. The battery compartment is a bit constrained, so I can't just throw anything in there.

------------------------------------------- Tim Wescott Wescott Design Services

Batteriesamerica still has the 1/3AA 110 nicad reciever packs for sale at 10.95 each. Did they tell you they don't have any in stock?

I wouldn't trust a receiver pack to have high discharge rate batteries in it -- and I recall being very happy with the idea of a 400mAh pack. That's about all I remember from a year ago.

Batteriesamerica now has a 350mAh 1/3AA NiMH flight pack for about $10 _more_ than their 600mA LiPo -- I'm buying one of each to see which will fit, and how I like them.

------------------------------------------- Tim Wescott Wescott Design Services