Have I Messed Up Again?

[racecar 0]

Having just received my latest purchases mail order and read the instructions that I don't think I saw on the on-line sales page. The charger is an Ansmann ACX-1 which states that it's for 7.2v 1400-3000 batteries both NiCD and NiMH. The two batteries I bought with the charger are rated as 3300 NiMH capacity. Simple question what will happen if I plug those two batteries onto the ACX-1 charger, will they only ever get to be 3000 capacity or worse still will they end up being useless as they aren't getting a full charge.

Looking forward to your response.

Andrew

[Eddystone 1]

Hi Andrew, I think you'll find the charger works fine - the ACX1 is a Delta Peak Detection charger so it should keep on charging until it senses the voltage drop associated with a fully charged pack. If your battery packs are just getting warm when the charger cuts out then thats a good sign that they are fully charged. Modelsport UK list this charger as suitable for up to 3500mAh batteries which should help settle your mind.

[racecar 0]

Thanks for that. Modelsport was where I bought it from, I was going to send it back to them if it was not suitable.

Andrew

[terry.sc 19]

The charger works fine with your batteries, but it has the 3000mah limit because it has a 90 minute timer built in as a safety feature. This limit means the charger sometimes switches off before the batteries are fully charged if the batteries are fully flat when you start charging them. If the battery pack is cold when the charger switches off restarting the charger will top up the battery to make sure it is charged.

[chrisland 0]

hi i have the same charger and when i got mine in the advert online it said can charge batterys from 1400 -3000 but i got a 3300 battery with it ,i to was going to take it back or ring the shop but i looked at the charger and on the front it says for batterys 1400-3500

have a look at the front of the charger and it will say they same

[bigoggy 205]

wish i hadnt read this forum. i just checked my charger and found out its only rated up to 1900 nicad, and most of my batts are 3000 nimh. will i have damaged them?

[HunterZero 84]

wish i hadnt read this forum. i just checked my charger and found out its only rated up to 1900 nicad, and most of my batts are 3000 nimh. will i have damaged them?

No, you've probably just been undercharging them. Again, your charger probably has a safety timer, that would stop charging after about 1 hour or so if it hasn't detected a peak, depending on what rate it fast charges at. If it doesn't have a timer, then it's probably been detecting the peak OK.

Only real ways to damage batteries are to overcharge or overdischarge them. If you had overcharged the batteries, you would have known about it. Pack would be too hot to touch, and could possibly be hissing as it vents.

The issue is that a charger designed only to do NiCD might not be able to reliably detect the delta peak in a NiMh, which has less voltage drop at full charge. Most quick chargers charge at 3A, which is fine for NiMh, but you would have to continuously check the pack and stop the charge when the battery gets very warm.

At 3A, it should take approx. 80-90 minutes to charge a 3000mAh pack.

- James

[bigoggy 205]

its been charging at 2.5 and takes about hour and half. so it looks like i got away with it

[terry.sc 19]

wish i hadnt read this forum. i just checked my charger and found out its only rated up to 1900 nicad, and most of my batts are 3000 nimh. will i have damaged them?

Highly likely. Your nicad charger detects the voltage peak when nicads are fully charged, and lets the peak fall a little before it switches off. NiMhs have a much smaller peak and should be switched off as soon as the peak is reached. This overcharging will cause a heat build up in the cells, which if it's bad enough will cause the cells to vent, releasing the contents and reducing its capacity. There have been many cases of the soldered together 4200mah racing packs literally exploding when they are accidentally overcharged as the soldering damages the safety vents.

Definitely worth investing in a new charger.

[bigoggy 205]

asked for overtime at work to buy one