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Looking for NiMH AA cell recommendations

My Duracell AA cells get quite hot in my Annsmann charger, but I think it is quite normal. My Vapex 10AH D cells get really hot… sometimes too hot to handle comfortably. The charge rate is 600mAH and they take 20 hours to charge. :grinning:

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For charging, discharging and refreshing my Eneloops I use a Kraftmax BC-4000 Pro and I am highly pleased with both of them. The Eneloops get only a little bit warm (charge current 200 mA).

73, Alfred, OE5AKM

After reading this: https://gizmodo.com/are-ikeas-7-rechargeable-batteries-actually-pricey-ene-1823204061 and watching few youtube movies I decided to buy LADDA’s from IKEA. I’ve been using them since early 2018, tested them after few charge cycles and they were better than the specs says so i think its a good option to give it a try.

73’s Darek LB1DH & SQ9X

PS. I also got this charger from IKEA its very small and can be used with standard USB Cellphone charger, perfect for abroad trips.

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I use these in my FT-817 and my Garmin GPS. Very reliable and cost effective.

I haven’t used AA Ni-Mh’s for SOTA or anything else for several years now but when I did the self-discharge rate was 0.5% per day. That was measured simply by charging and capacity testing directly after charging, then after various resting intervals. These were ‘Powertech’ 2,700’s bought from Strikalite. Knowing the self-discharge rate (which I thought surprisingly high) enabled the application of the correct amount of ‘tickling up’ required directly before a SOTA expedition.

The longest living AA’s I had were Saft Ni-Cad 500’s bought about 1983. The last two or three of a batch of 20 lasted until approx. 2005.

I have been using AAA Alkaline for GPS use for many years now because they reduce the workload of preparation and spare cells can be left in a pocket or rucksack for longer periods.

Thanks for the recommendations on this useful thread. If I ever need any more rechargeable cells they will be Eneloop; a make I’d never heard of until now.
John G4YSS

To continue this…

I read that deep discharging NiMH cells and fully recharging and using them can restore the low self discharge ability. I discharged all my old AA cells slowly by using them to power a LED headtorch, then recharging them and leaving them for a week before use.

The results on the 1st pair were poor. After 1hr20 in my GPS I got a low battery alarm. OK it was cold but not Baltic, about -2C on the summit, -5C with windchill. I switched the GPSoff during the activation and fired it up 1hr45 later and used it for another 1hr30. When the low battery alarm sounded, it was showing 1 out of 4 blobs on the charge guage. When I got back to the car it was showing 3 out of 4 blobs. I left the GPS on in the shack where it had some GPS coverage looking through the window. It ran for a total of 22hrs before the GPS shutoff.

That’s not bad TBH. Now a stationary GPS is still doing the GPS RX and navigation stuff but the rest of the navigation facilities run infrequently. i.e. when you are moving, it updates tracklogs every second or so. But stationary this drops down to every few minutes. So 22hrs mainly stationary can be guestimated to probably 17-18hrs use in the field. That is what I used to see. Charge up batteries, get 3 weeks use of the GPS each weekend before charging. What was annoying was the battery charge meter jumping about. Anyway, I’m repeating this test with the other cells I have.

On the way back from this activation, I called in to my nearest Ikea and picked up some LADDA 2450mAHr cells and a USB powered twin AAA/AA charger. Last year I realised how much of my SOTA walking depended on the GPS I used and looking at the new models, I didn’t like any of them. So I watched eBay and found another one which was mint and used but missing accessories for £35. I have the LADDA cells in that and I’m running a comparison of the new cells versus the old ones.

Last night, 2100Z I put a freshly charged pair of old cells in one GPS and a new pair of LADDA cells in the other. This morning at 800Z (11hours later) the GPS with LADDAs shows 4 blobs and the other shows 2blobs. I’ll update this thread when I get more data, but on a statistically valid test of 1 pair out of the box, the LADDAs look rather good!

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I am following this thread with interest.
As an aside LADDA translates from Swedish to CHARGE in English; so now you know, hi!

They’re especially good in torches - hence the expression “the charge of the light brigade”

:rofl:

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21hr30 after starting the test, the GPS using the old cells has shutdown. It powers up but immediately starts complaining the batteries are no good. Each cells measures 1.18/1.19V on load. Trying to turn on the backlight gives an error “batteries too low for backlight”. The other identical GPS using brand new LADDA cells is still showing 3 out of 4 blobs on the charge scale and the cells measure 1.24/1.26V on load.

I think at this point I should consider the obvious conclusion, a randomly selected pack of new cells from the hundreds on the shelf in the store contained 2 cells of enormous capacity in comparison to 2 cells which are 7-9 years old.

For interest, I’ll see how long these new cells can power the GPS but probably there’s no point proving the old cells are tired and ready for the recycling bin.

The LADDA cells ran the GPS for a total of 27hrs before the low battery alarm was sounding along with the insufficient power to run backlight alarm. The cells showed the classic NiMH voltage pattern at sitting around 1.2-1.25V for most of their discharge time. I’ve got them in the USB charger now, they are slightly warm. The charger says it charges at 245mA so it should take about 14-16hrs to charge these cells up.

£5.95 for 4 from Ikea.

Your GPS seems to handle “low battery” very well, maintaining the essential functions for as long as possible - just for interest, which is it?

I have a Garmin eTrex 10 which runs on 2 AA cells, but I haven’t yet run them right down to see how it handles that. Probably a good experiment to do. Maybe today, as I’ve just ruled out a possible activation on the grounds of road conditions…

Garmin Vista HCx. I bought it in 2008 and it was pricey ISTR. Then I bought another “used but mint” example in 2017 (I think) as a backup. The backup was a steal at £35 as it turned out it contained a microSD card with some more detailed UK topo data on it than I had. Which was nice.

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