Dissilussioned with NiMHs

[hunterlar3]

Ok, first of all this isn't really a flashlight related matter, so if I'm violating any rules, sorry in advance.

Here's the problem. I do a large amount of predator hunting in the winter where I rely on a couple pieces of electronics that use AA's. First is a Garmin Etrex Vista and the second is a Foxpro electronic caller. 2 AA's in the first and 8 AA's in the second. A couple of years ago, seeing how much I was spending on AA "coppertops", I thought it would be wise to go the rechargeable NiMH route. I bought a bunch of NiMH 2300mah and latter some 2500mah Energizers. I'm charging them on a Duracell 1hr charger.

The Vista does not like the NiHMs at all. The display works really slowly (if at all) and is sometimes very week. My remedy was to go back to alkaline if I really needed GPS to work.

The Foxpro runs just over a day making 12-16, 15min stands (usage) with Duracell alkalines, but sometimes only 2 or 3 stands with the rechargeable NiHMs. I remedied the situation the same as above by returning to alkalines almost exclusively.

Now, after investing a chunk of money on a couple of dozen NiMhs, I'm spending about the same amount on Duracell alkalines as I was before. I still like the idea of using rechargeables… it really would make sense if I could get adequate performance…but I'm leery of making the same mistake twice.

I know the rechargeables self discharge to some extent and have always put all the batteries on the charger the night before I went out.

I am very tempted to try some Sanyo 2700mah or Powerex Nimhs. I have read good things about these and some not so good things about the Energizers I currently have. Since I can charge right before use, I don't see much advantage to going with Eneloops. I would put more priority on run time than low self discharge.

What is you're your recommendation? Should I invest in a new set of NiHms of higher quality. Perhaps I should get a better charger also. Everything I read seems to point to better performance of NiMH versus alkaline, but my experience hasn't born this out. Maybe I should just stay with what works and keep funding Duracell. My rechargeable Energizers have seen some useful duty in kids toys and such, so that wasn't a total loss.

 

[tarponbill]

My guess is the device electronics is not designed for the lower voltages of NiMH. I found this to be the case with a camera and GPS. The problem is usually more severe with higher numbers of cells. Call the manufacturer and ask.

8x1.5(12v) is far greater than 8x1.2(9.6v) -- both my devices use 4xAA and they cut out after just a few hours use on NiMH when they would go all day with alkalines. You need to stick with devices designed for NiMH, I notice that most new cameras now spec NiMH, as well as many other devices.

The battery brand is not the issue, it's the device power supply IMHO.

 

[scott.cr]

Could be a voltage issue as tarponbill mentioned, but check this out, I've had way better luck with NiCd cells on low-draw devices.

It all started with my Icom IC-R5 portable radio scanner. It came with a pair of NiCds that I outright disregarded. Ran it on alkalines for a while, which was okay. NiMH cells would give awful life. Out of frustration I threw in the NiCds and that little radio will run for months on a charge.

I wonder if it has something to do with QC issues with NiMH or ???

 

[jayflash]

Electronic manufacturers should not be marketing devices that have so little "margin". Other than a, possibly, small difference in cost, is there any good reason to make an appliance that can't operate well, down to ~ 1.0 volts per cell. The simple inclusion of one more cell or a circuit/component modification would cure the problem of electronics running "close to the edge" of their power supplies' limit.

It's high time for all manufacturers to be adopting "green" processes and producing environmentally friendly products.

 

[OpenGuy]

Did your 2300 mAh cells work well when you first got them? There are a lot of comments here about the higher capacity cells going bad quickly even with light use, and my experience is in line with that.

I used some Lenmar 2300 mAh in my digital camera, and they worked like a charm when they were new, but now they're completely useless. I didn't know just how bad they had become (or whether my camera had developed a fault) until I got my new C-9000 charger/analyzer (thanks to the comments on this forum). The Lenmar 2300 batteries are now down to something like 500 to 1000 mAh and exhibiting high internal resistance (and going into the recycle bin as soon as I stop playing with them). My older Rayovac 2000 mAh IC3 batteries are still going very strong (average 1850 mAh).

I also got some new Sanyo 2700 mAh batteries, and after the first charge they all read about 2600 mAh. After the second charge, I left them unused
for two to three weeks, and measured again. Two did pretty well (2400+ from memory) and two had self-discharged a lot (1400 or so from memory), so I strongly suspect they will not last well either.

I used to charge my batteries regularly so I would have charged batteries just in case I needed the camera, but often did not use them for long periods. I'd also recharge them all (also on the Duracall 1 hr charger) a day or so before planned photo events to ensure they were all at top capacity.

That appears to have been the wrong thing to do, so now I'm keeping Eneloops in the camera for the unplanned photographs, and storing the older rechargeables mostly discharged. When I'm planning a long photo day, I'll recharge these a day or two in advance, to avoid cycling the Eneloops until the older ones die.

My main issue with NiMH is the degradation in battery capacity and internal resistance over a relatively short time, not the fact they self-discharge a little (say 10%) in the first month. If the Eneloops hold up, I'll buy them exclusively in the future.

 

[Windscale]

Yes, the first thing you must do is to find out from the menufacturers whether your appliances can take Nimhs. If the answer is in the negative, then you need go no further and have no choice but go back to alkalines.

If the answer is positive, you will need to invest in a better charger. I was shocked at the results when I refreshed my batts in a Maha 9000. 1-hour chargers are never very good except being fast. They may indicate a full charge but in fact the battery is only charged to just over 50% capacity. Whereas, I never got under 90% when using the Maha.

My current practice is to refresh batteries in the Maha once after the same have been recharged in my GP 1-hour charger 5 or 6 times.

Finally, I do have some old style 2300 and 2600 GPs, but my main ammo is now eneloops. LSD is a very good thing as I have been quite frustrated by batts discharging themselves. I have never looked back since.

 

[barkingmad]

Try some 'low self discharge' Sanyo Eneloops - they have replaced alkaline batteries in almost everything I use.

 

[hunterlar3]

I was reading the GPS thread and apparently some people get satisfactory performance out of NiMHs. When I bought the Foxpro there was an opptional NiMH battery pack available at additional cost. At the time I decided to forgo the extra expense thinking I could get some later that where better than the no name brand that they offered anyway. I was probably wrong there.

So, reading the replys, I gather that NiMHs deliver a slightly lower voltage than alkalines, at least at low current draws. I gather that they can, however, tolerate more demanding current draws better than alkalines. I don't see anyone recommending running thier Mag85 on 9 Coppertops.

In summary, you're saying that the 2 applications I'm concerned with are voltage sensitive and intollerant of the voltage drop that NiHM batteries deliver in use?

I think I'll order 8 Sanyo 2700's and give them a try. If they don't work well either...I give up.

Maybe I could try 3 Li Ion 14500s and jump across the empty cell slots. Just kidding, the Foxpro was way to expensive to go experimenting like that.

 

[fishx65]

If you don't have one, I would pick up a nice digital multimeter to check your cells. I picked up a Craftsman 82140 on sale for around $15.00 and use it all the time.

 

[Eugene]

I had a similar issue. Old digicam that was hard on batteries. Would buy new batteries and they seemed to work ok for a few charges then the camera would take few and fewer pictures.
I would charge my batteries and take them fresh off the charger to get any kind of decent use out of them. I ended up going back to alkaline and Lithium for a couple years. We bought a newer camera in Feb of 2006 and I still had the same issues, the NiMh just wouldn't run it as long as a alkalines.
I made two changes:
First I bought a set of Sanyo Eneloop and popped them in and they worked as long as a set of alkalines so it seemed the cameras worked fine when the batteries were nice and new.
Second change I made was buying a nice MAHA charger. After a few charge cycles the batteries still seemed to work fine so I took some of the older NiMH I had and started using them in a baby monitor. They would last 2-3 days and I'd drop them in the maha on the slow setting. then they started lasting about 5 days. Then after a couple more cycles they would go 10 days. Now they run 2-3 weeks compared to the alkaline that would last about a week and a half in that same baby monitor.
So my overall issue was the poor chargers. I was buying the off the shelf chargers from retail stores like walmart and radio shack.
I've now recovered all my old NiMH batteries, some dating back to 2001, a good charger makes a world of difference. The only issue then is traditional NiMH will self discharge so thats why I switched to the low self discharge like Eneloop so I don't have to charge all my batteries right before a trip to make sure they don't self discharge, I can charge them whenever and let them sit, this way i don't need to worry about fast charging to have them all fresh.
Buy one decent charger and one new set of batteries and test them a few cycles like I did.

 

[Eugene]

I was reading the GPS thread and apparently some people get satisfactory performance out of NiMHs. When I bought the Foxpro there was an opptional NiMH battery pack available at additional cost. At the time I decided to forgo the extra expense thinking I could get some later that where better than the no name brand that they offered anyway. I was probably wrong there.

So, reading the replys, I gather that NiMHs deliver a slightly lower voltage than alkalines, at least at low current draws. I gather that they can, however, tolerate more demanding current draws better than alkalines. I don't see anyone recommending running thier Mag85 on 9 Coppertops.

In summary, you're saying that the 2 applications I'm concerned with are voltage sensitive and intollerant of the voltage drop that NiHM batteries deliver in use?

I think I'll order 8 Sanyo 2700's and give them a try. If they don't work well either...I give up.

Maybe I could try 3 Li Ion 14500s and jump across the empty cell slots. Just kidding, the Foxpro was way to expensive to go experimenting like that.

Saw you replied while I was typing my thread so I'll rehash, buy a good charger to start with, your problem sounds exactly like mine where the charger wasn't fully charging the batteries.

I also recommend low self discharge so you don't have to try and charge them fast to keep several sets ready, you can charge it your leisure or slow charge overnight.

 

[Sub_Umbra]

Two things in your post struck me. Like others, I would also recommend a better charger. The best cells on earth will perform only as well the charge put to them and their life expectancy will also be somewhat linked to charger quality.

I also noticed that you described using the cells in cold weather. The performance often quoted for NiMH cells is only attainable in a much narrower temperature range than NiCads. When you're outside of the Goldilocks zone (not too hot and not too cold) NiCads may be a better choice for the performance you need.

 

[Power Me Up]

If it's the cold conditions that are causing problems, it'd be worth trying Eneloops - Sanyo made a big thing of them working a lot better in cold conditions compared to other NiMh cells...

 

[johnny13oi]

Yeah I would try the Sanyo Eneloops or the RayoVac Hybrids. They are low self discharge so they should last longer over the span of a weeks.

 

[hunterlar3]

The Energizers, both 2300mah and 2500mah, never gave me satisfactory performance, even when they were new.

They are occasionally used in extremely cold weather, although not always. They also see warmer conditions inside the truck in between stands. I don't think the cold was the issue, I just don't think they ever delivered the required voltage. The charger may be a problem. I will probably order a Maha charger if I decide to give another brand a try.

It is rather aggravating to have the caller cut out 2 min into a stand on a fresh set of rechargeables. I start cussing under my breath and dig in the pocket for the hand calls. Also, GPS only serves a purpose if you can read the display.

 

[Power Me Up]

I'm not sure which version of the Etrex Vista you're using, but the first GPS I ever had was a Garmin Etrex Legend - had a monochrome screen and only 8MB of memory for maps. The Etrex Vista that was available at the time was very similar to the legend - basically the same except for some added features - from memory, it had a barometic altimeter and extra memory for maps.

My Etrex Legend ran fine on Energizer 2100 NiMH cells, so I'd be surprised if your Vista couldn't run on NiMH cells as well - unless it's a lot older. It even had a setup option to tell it that you were using NiMH cells - Main Menu->Setup->System->Battery. The options that were available were Alkaline, NiCad, NiMH and Lithium.

First check to see if your unit has the option to select NiMH cells - if so, you can be pretty sure that it's capable of running on them. You could also try running the unit on NiMH cells under normal conditions just to rule out the possibility that the cold was affecting them.

Hard to say with your eletronic caller, except that if your GPS was having problems due to cold batteries, it was probably also being affected as well... Could you also try it in normal temperature conditions with the rechargeable batteries as well?

 

[hunterlar3]

Yes, I think the Legend and Vista are the same except for some internal extras. I just checked and I don't have a different battery option. It does have a normal and battery saver option. Its on battery saver. I think that just turns off the electronic compass. I've had it 4 years or so, so maybe they've updated them since then.

 

[Power Me Up]

My Legend would be about 4 years old as well, so maybe yours is just a bit older than mine... They've certainly updated them over the years - perhaps it's time for an upgrade?

 

[wakibaki]

Buy some torches to use the NiMhs in. Resign yourself to using alkalines for the other devices. It could be worse. You get more torches.

w

 

[Hans]

My Legend would be about 4 years old as well, so maybe yours is just a bit older than mine... They've certainly updated them over the years - perhaps it's time for an upgrade?

Actually, I've been using NiMHs in all my Garmins over the years, starting with the GPS 12. Whenever there was a problem it was due to a bad set of NiMHs.

Hans