rechargable batteries?

[wendy]

Does anyone use rechargeable batteries in your primary light? I've decided to try it, got the NiMh AA's. I use them for my digital camera and have been happy with them. I am just so tired of having to buy batteries all the time. Any expereinces with them you want to share? I'll be using mine next week in TAG, so I'll repost how that went.

[bsignorelli]

We (several peeps in LRG) use the rechargeable NiMH 2500mAh batteries (only becuase the 2700's weren't out a few months ago) in our Apexes. With the current regulation on the light we're getting 12+ hours of caveable light per set of batteries.

We looked around (candlepower forums mostly) and came to the conclusion that the MaHa POWEREX brand batteries were top notch with average ratings higher than other brands. That link will take you to Thomas Distributing which has served us well and came reccomended from those geeks on candlepower.

Several of us also got one of the MAHA smart chargers that will charge your batteries as long as it takes to do so as opposed to a lot of the others that charge for X number of minutes or at a higher rate (higher rate of charge shortens the life of the battery).

Anyways....depending on the light you choose to use you may not get as big of a benefit out of the rechargeables.

[hank moon]

Sanyo are the best NiMH. I think the Powerex AA currently in production are made by Sanyo (however, the Powerex AAA are not). My experience with the older Powerex: very spotty QC. If you can get the Japan-made Powerex, go for it. Otherwise, go Sanyo.

P.S. Thomas-Distributing is an great retailer. Very good customer service, prices, etc.

[Steven Johnson]

I've been using Energizer NiMH (2500 mha I think) in my PT Apex.

On a full charge, I got about 8 hours of runtime, running almost exclusively on the 4-led "high" mode (with occasional brief use of the 3W spot).

I had a set of Powerex before them which worked well too, but after several years are starting to poop out earlier and earlier -- think they're reaching the end of their useful life.

So, yeah, NiMH work well for me. (Though in cold caves I suspect life would be degraded and Lithiums would be better, if I understand the chemistry... but I rarely go in cold caves, so someone else has to comment here.)

[bsignorelli]

There was a thread on the candlepower forums about how Sanyo is the maker of the vast majority of NiMH batteries....their batteries are just rebranded (like so much else nowadays).

The difference in brands is QC issues on a particular line. A higher quality product run gets sold as one brand whereas the walmart/energizer variety may be a lower standard.

Interesting chart from the CPF showing the differences in testing various brands of batteries.

I got about 8 hours of runtime, running almost exclusively on the 4-led "high" mode

We've been getting 12+ out of them running on mostly 4-high but doing common sense things like 4-low for crawls and turning it off if you are stopped and don't need your light on. This is also a liberal use of 3-high for spotting across the big rooms...on one trip recently we had some old timers pointing at corners/ceilings in the room and asking the Apex guy to look over there b/c they had never seen that ceiling before :)

but after several years are starting to poop out earlier and earlier

NiMH batteries have a "memory" just like other rechargeables...though not nearly as bad as NiCad. Your batteries might could use some reconditioning...find someone with a battery charger than can drain them completely and then recharge them for you. A couple of cycles like that might breath new life into them.

[bsignorelli]

Battery University was a website I turned up just now when reading the CPF that tells a lot of info about the who/what/where/when/why's and how's of batteries.

[hank moon]

I've been using Energizer NiMH (2500 mha I think) in my PT Apex.

Many recent Energizer NiMH AA are made by Sanyo. Look on the - terminal; a small "HR" indicates Sanyo manufacture.

[erebus]

I had a Maha charger. It worked well until it suddenly quit. I suspect it was my habit of leaving it plugged in to the car power outlet. Apparently it's bad to start the car with the charger plugged in. Had bad luck with the Powerex batteries (maybe the 'old' ones). Most of them are dead now. No problems with the Panasonic NiMh batteries or chargers, or with the little black fold-up chargers that Radio Shack sells.

My information is that NiMh batteries do not have any of the memory problems common to NiCads, but I'm no expert.

[bsignorelli]

I suspect it was my habit of leaving it plugged in to the car power outlet. Apparently it's bad to start the car with the charger plugged in.

I've read that you shouldn't have anything electronic plugged in when you start the car (cell phones, gps, etc) due to the possibility of surges.

But also...I wonder how the heat that builds up inside a car in the summer affects the charger? I know my cell phone manual says to not leave the cell phone in the car due to the heat. Previous observations with a thermometer sitting in my air vent showed internal temps of 140+ degF.

My information is that NiMh batteries do not have any of the memory problems common to NiCads, but I'm no expert.

Google for it but stuff I've read says they have a lot less of a problem than the old NiCad's but the problem is still there.

That Battery University link has an article called Memory: myth or fact? that talks about this.

[NZcaver]

I've been using Energizer NiMH (2500 mha I think) in my PT Apex.

On a full charge, I got about 8 hours of runtime, running almost exclusively on the 4-led "high" mode (with occasional brief use of the 3W spot).

Ditto - at least 8 hours. My Apex indicator lamp is still green after 9 hours of caving plus a couple of hours around the campfire yesterday. I wouldn't be surprised if the same batteries survive another full day of caving. Great batteries - fantastic headlamp!

I started using AA NiMHs about 4 years ago, and now they are in almost everything I have that runs on batteries. Regardless of whether they have a "memory" or not, they will of course eventually die. But I have noticed one factor that seems to kill them pretty quick - rapid chargers. Several times I have used other people's rapid chargers, and every time it has led to that set of batteries soon losing their full capacity. So now I only slow-charge my NiMHs (like overnight).

[wendy]

I've been using Energizer NiMH (2500 mha I think) in my PT Apex.

On a full charge, I got about 8 hours of runtime, running almost exclusively on the 4-led "high" mode (with occasional brief use of the 3W spot).

Ditto - at least 8 hours. My Apex indicator lamp is still green after 9 hours of caving plus a couple of hours around the campfire yesterday. I wouldn't be surprised if the same batteries survive another full day of caving. Great batteries - fantastic headlamp!

I started using AA NiMHs about 4 years ago, and now they are in almost everything I have that runs on batteries. Regardless of whether they have a "memory" or not, they will of course eventually die. But I have noticed one factor that seems to kill them pretty quick - rapid chargers. Several times I have used other people's rapid chargers, and every time it has led to that set of batteries soon losing their full capacity. So now I only slow-charge my NiMHs (like overnight).

that's good to know about the slow chargers, as the charger I have takes about 16 hours to fully charge.

I'm just looking forward to not having to keep buying new batteries all the time.

[NZcaver]

I'm just looking forward to not having to keep buying new batteries all the time.

...and doing your part to reduce the number of spent ones that end up in landfills... and leach into the groundwater.

[fuzzy-hair-man]

I have ordered my charger and will be getting some batteries as soon as it arrives
I previously wasn't going to rechargeables because of bad experiences with Ni Cad batteries and memories and short and unreliable battery life.

My PT Apex with a battery life that I can't use on a normal duration trip and the newer NiMH batteries has meant that I am going to re-try rechargeables.
I figure this way I have the ability to start every trip with full batteries and don't have to try and wear down a set of alkaline batteries over several trips.
There is also the pleasing 'green' and $ aspect to it

[Steven Johnson]

But I have noticed one factor that seems to kill them pretty quick - rapid chargers.

I have a charger (I think it's a Maha) that can flip between a fast and slow mode. I normally use slow (~8 hours for a full charge, worst case) for those reasons, but it's good to have fast available just in case

[potholer]

From reading around I did when building a charger some months ago, supposedly the best charging regime for NiMH cells is a smart charger capable of fully charging the cells in 1-2 hours, but stopping (or switching to a very gentle and time-limited trickle charge) as soon as the cells are charged.
However, some of the sites saying that do seem to be marketing smart chargers, so may not be entirely free of bias.

With a (fast or slow) non-smart charger, it's probably worth checking at some suitable interval for cells on charge starting to get warm, if environmental conditions allow an increase in temperature to be reliably determined. Cells getting warm tends to indicate charging is complete or nearly so.