Update on the minature charger I bought awhile back..

[Uncle Willy]

When I charged the batteries and put them in the 250 they showed four bars on the battery indicator. Strangely, after about two hours the indicator dropped to two bars - but it has been on two bars for about 25 hours now and shows no indication of dropping, so apparently this is the nature of these batteries. They are supposed to last four times longer than alkalines so we will see. If the battery indicator is still sitting on two bars after another 25 hours then I'll know my money was well spent.

Bill

 

[tigermoth]

Hi bill that is the way they seem to run,on your next charge they will run longer,the only thing is when thay do go flat it happens very quick but hey 30 minutes on charge in the cigeret lighter and your back in there,I use these batteries in my tourch,gps,and radio and they go for ever,,,The mag will be posted on the 12th and I hope it finds you ok. Bazza

 

[DavHut]

From what I know, NiMh, and other rechargeables like Nicads, suffer an inherent fault of their own making which is, they never fully charge to the rated 1.5v. However they will hold something less (1.2-1.3V) for a long time, and continue to supply current at that voltage.

How long? It depends on current draw of the circuit. Slow, steady consumption is best, which describes metal detectors to a tee. Short, fast bursts of current draw, like in camera's, drain them faster.

Will you get 50 hours? I personally doubt it, but that is possible.
Temperature, and storage also are factors. There is probably a chart that accompanies the batteries and it should tell you what to expect.

One thing that I CAN say about the ones Ive used is this:
DO NOT leave them on the charger once they are charged, unless it has an auto shutoff. This will shorten their life dramatically. Most of the $10 battery/charger "package deals" at WalMart don't have tihs feature, so watch it.

 

[FrankG]

Hi Bill,

That is normal behavior for NiMh batteries, you'll get used to it. I always use rechargeables and they DO last a long time but the total time depends on the power of the particular rechargeable you use. A 2400 milliamp hour (MaHr) battery has twice the power of a 1200 MaHr battery.

What you are observing is the effect of NiMh voltage at full charge compared to Alkalines. NiMh rechargeables generally charge to approx 1.36 volts per battery while fresh alkalines are a full 1.5 volts so a fresh set of Alkalines gives you 4x1.5=6v total while the NiMh give you 4x1.36=5.52volts total. So with NiMh, you start out approx .5 volt lower at full charge compared to alkalines. There is also some variation in NiMh performance from different battery manufacturers as well.

Now For the ACE battery indicator... I did some measurements when I first got my ACE and learned that each line on the battery indicator corresponds to about .4v reduction in battery voltage. This is why you are starting out "down 1 bar" or if you happen to start out full it will drop a bar pretty quickly. But now you're on the sweet spot for the battery and they will last very long at each level before dropping down another bar. Even when you have NO bars left, your batteries still have lots of charge (perhaps 4 volts left)and the detector works just fine and DOES NOT under perform (I don't know for how long). I say this because I've run it down like that a few times just out of curiosity.

I can't can't in hours how long they will last because it depends on the MaHr rating of the battery. I use 2700 MaHr rechargeables and they last and last and last. I've never measured the time in hours because who cares? They are rechargeables and all I care about is whether or not they'll get me through my next outing. I generally just recharge them or swap them out when I'm down to 1 bar remaining so they don't die on me.

Hope this was more informative than confusing.

 

[Uncle Willy]

Think mine are 2300's. The maker claims they will last four times longer than alkalines. Never used rechgareables before but thought I'd give this charger a shot and so far it seems to be working out. Should save a ton on batteries but I always got my alkalines at discount prices - like 48 for $10.99 at Costco and 36 for $5.99 at Harbor Freight.

Bill

 

[Uncle Willy]

Thanks bud.

Bill