Eneloop Pro AA specs

[6PTsocket]

I have an old Isotip 60 (minute charge)soldering iron. The original batteries are a 2 cell pack of 4/5AA's. Full charge detection is an old fashioned thermal trip on the end of the pack. I only use the iron occasionally and leaving it plugged into the stand on trickle charge is a waste and bad for the battery. With low discharge cells available I am looking for alternatives. An 18650 is out because I would need a buck converter to go from 3.6 to 2.4. There is definitely not enough room for that and a charge control board. There are 2.4 volt LTO lithiums but no off the shelf control boards. That leaves low self discharge NiMh Eneleloops The Eneloop Pro AA is 2250mah, though less at high discharge rate, and my old 4/5 C's wre only 1300mah.  They hold most of rheir charge for two years.It comes down to max charge and discharge currents. The iron draws 4A at 2.4 volts per tests on a power supply. I can only find limited info on these cells, mostly consumer stuff on how long it will run your camera or flashlight. I found one third party data sheet that tested it at 5 amps but nothing official. For charging I have a Tenergy NiCd/NiMH smart charger that uses the Delta method to detect full charge and offers me 0.9 or 1.8 amps charge rate. Normally I would be under 1C with 1.8 but I know nothing about these cells and they expect you to use their charger. Since the cells will be buttoned up in the iron and I already have a charger I want to avoid any problems before I buy them. Any thoughts. Thanks

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[Audioguru]

You do not say where you are. Are your cells 80% the length of a normal AA? I have never seen such a weird size.
In North America Energizer and Duracell have been selling their copies of Eneloops for a few years and guarantee that they hold a charge for one year.
Energizer AA alkaline are 2300mAh and Duracell are 2500mAh.
Energizer shows poor performance at 4.6A and Duracell at 5A.
What do you expect, they are small batteries.

[David Hess]

It might work if you disable the trickle charging which will damage the NiMH cells relatively quickly.  I actually think it would be better to use a 18650 cell if you can regulate the charging voltage; the extra voltage applied to the heater will not matter if it uses PTC regulation which I suspect is the case.

[floobydust]

Eneloop Pro BK-3HCC datasheet goes to 5A discharge, others to 4A so not a prob.

[6PTsocket]

Eneloop Pro BK-3HCC datasheet goes to 5A discharge, others to 4A so not a prob.

I got no response from Pannasonic but I did get a response from Tenergy, who makes a similar product as well as the NiCd/NiMH  smart charger that I already own. I was told that their cell could supply 4A for short periods of time but would heat up the cell and shorten it's life if allowed to run too long at that current. They said their cell was really built to run at 1C or less. For longest life,  they reccomended I use the0.9amp rate on my charger but could use the 1.8 ano settings if in a rush. The bottom line is that I am pushing the cells. They said my chsrger was totally compatible with their cell. It does have trickle charge but with the low self dischargeof these cells, I would not leave it on the chsrger. I would just full charge it and put it away for the next use.

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[6PTsocket]

It might work if you disable the trickle charging which will damage the NiMH cells relatively quickly.  I actually think it would be better to use a 18650 cell if you can regulate the charging voltage; the extra voltage applied to the heater will not matter if it uses PTC regulation which I suspect is the case.

PTC regulation? I had the heating element tip on a power supply. More voltage equalled more current. I am not willing to experiment with expensive tips to find out what they can take. I also noticed that a wire running between the old battery and the case had melted a groove in thr case. The old NiCd must have run pretty hot, too. I sure don't want to see what happens at 3.6 volts.

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[Pirateguy]

you may want to ask somebody at http://www.candlepowerforums.com/

those flashlight geeks take their batteries very seriously, and there's some people on there
that i would consider expert.

[6PTsocket]

you may want to ask somebody at http://www.candlepowerforums.com/

those flashlight geeks take their batteries very seriously, and there's some people on there
that i would consider expert.

I consider customer support at  Tenergy to be expert. When you go with advice from the net it is a crap shoot. I have a pretty good handle in what is available and what is do able. I'm going with the Eneloops or the Tenergy equivalent. LTO cells and supporting circuitry are not that popular. Things may change. They can be charged at 5C.but not that many devices can't run under 3.6 volts so the need for a 2.4 volt lithium is limited. The capacity is also less. The biggest small cell I saw was 1300 mah.but they can sure charge fast.

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[floobydust]

I had an Iso-tip a long time ago and it seemed OK but short battery life and the tip gets trashed/broken in the toolbox. So I went to butane.

From a wattage point of view, I wonder if 10W is really usable? Poor connections at the tip or on/off switch always gave less power.
I thought Dave was not impressed by the USB-powered soldering iron TS80 low power: https://www.eevblog.com/forum/blog/eevblog-1114-new-ts80-usb-soldering-iron-review

[David Hess]

It might work if you disable the trickle charging which will damage the NiMH cells relatively quickly.  I actually think it would be better to use a 18650 cell if you can regulate the charging voltage; the extra voltage applied to the heater will not matter if it uses PTC regulation which I suspect is the case.

PTC regulation? I had the heating element tip on a power supply. More voltage equalled more current. I am not willing to experiment with expensive tips to find out what they can take. I also noticed that a wire running between the old battery and the case had melted a groove in thr case. The old NiCd must have run pretty hot, too. I sure don't want to see what happens at 3.6 volts.

I never had a problem with mine as far as the NiCd batteries.

PTC means positive temperature coefficient.  I thought the solder iron tips used a PTC element for heating to roughly regulate the temperature.

[Pirateguy]

rejecting a potential source of data for lack of prestige is not the mark of a strong mind.

good luck, snowflake.

[bc888]

Poster HKJ posts to Eevblog, Candlepower and Budgetlight forum. http://budgetlightforum.com/forum/batteries/rechargeableHis testing and reviews are topnotch, I'd search all of his info to start with. The link above will get you started and confirm that his info is good. BLF is a great source for Budget Flashlight info, and batteries are a good part of that. More here: http://budgetlightforum.com/forum/batteries/rechargeable

Although I agree with Pirateguy that more info is often better than less, that seems kind of a rough way to note it.

Good luck!

rejecting a potential source of data for lack of prestige is not the mark of a strong mind.

good luck, snowflake.

[helius]

PTC means positive temperature coefficient.  I thought the solder iron tips used a PTC element for heating to roughly regulate the temperature.

Isotips are not regulated. They get hot when you press the button and get cold when you release it.
Same concept as a Weller gun, actually, but DC rather than AC.