Some rechargeable N-Cells I have used in my 41c over the years

[Johnboy]

N-cells

All Ni-Cd (usually 150mAh) except the latest "Pickle Power" which are NiMh and 750mAh !!

Cheers,
John

[born2laser]

I've recently revived my 41CV after ~15 years in a drawer, and repaired the card reader. I had great experience with the pickle power ones, they seem to last forever, even with a lot of use (testing) of the card reader

[Johnboy]

Good to know the Pickles are good. I bought 4 of them with the crappy single cell charger from Amazon, then ordered another 8 pickles from Alibaba, but different ones were delivered (Batmax) that are only 700mAh instead of the 750mAh of the Pickles :-(

Cheers,
John

[Dave Britten]

I've used these on my 41 with pretty good results:

https://www.amazon.com/Tectra-Rechargeab...B096FJKDX3

The 4-pack comes with a single charger, so you have to charge them one at a time, but they're not exactly high capacity, so they charge pretty quick. Alternatively, buy two 4 packs so you get two chargers, and have a spare set you can alternate with.

[TallKey]

(04-25-2023 06:27 PM)Dave Britten Wrote:  I've used these on my 41 with pretty good results:

https://www.amazon.com/Tectra-Rechargeab...B096FJKDX3

The 4-pack comes with a single charger, so you have to charge them one at a time, but they're not exactly high capacity, so they charge pretty quick. Alternatively, buy two 4 packs so you get two chargers, and have a spare set you can alternate with.

The positive comment of the pickle cell brand led me to what seems to be a "too low a price to trust." The pickle standard alkaline N90 20 pack is 45 cents US, per cell at (ugh) amazon.

Pickle brand rechargeable 4 N90 cells here for the same price as the tectra.

How do the tectra run-times compare to Duracell or Energizer?

Never used the tectra or the pickle cell brand batteries.

[Chr Yoko]

I am currently using a smaller set of NiMh cells into my 41CL, but they last 3 weeks about....

Pikcell 2/3 AAA 400mAh

Issue is that i usually lose all my 41CL parameters if the cells depleted completely.
Also there is no more "battery low" warning from the 41.
Therefore that is a pretty not so convenient solution.

Those 2/3 AAA are also kind a pain to recharge as they are too short to fit into my multi-charger, so i need to put 3 small round magnets onto their negative pole to be able to charge them under a low current condition (300mA).

Also i had to put some electric tape around each one so they do not rattle into the 41.
Last be not least from time to time one cell is falling below 1V and needs to be put back to life or it would not recharge at all. I then apply 1,5V from a battery or a DC power source between its 2 poles. That issue may also happen with the N types NiMh.

So i just ordered from Ali a set of 8 of those 750mAh Pickel N type NiMh cells.
Thanks for the tip, will see how they behave and report it here.

Best would be to develop a proper NCM Lithium based battery pack including an USB-C charging port and its buck/boost converter to the 41 required 6V.
I saw already such DIY projects. I may look at it also in the future.

[mfleming]

(04-27-2023 08:00 AM)Chr Yoko Wrote:  I am currently using a smaller set of NiMh cells into my 41CL, but they last 3 weeks about....

Pikcell 2/3 AAA 400mAh

Issue is that i usually lose all my 41CL parameters if the cells depleted completely.
Also there is no more "battery low" warning from the 41.
Therefore that is a pretty not so convenient solution.

The smaller 2/3 AAA cells are excellent with the HP28C/S and other clamshells. The flattops reduce pressure on the battery door.

Someone gave an excellent explanation (with diagrams IIRC) of the low battery warning a few years back. In a nutshell alkaline and NiCd cell output voltage declines gradually as the cell discharges but NiMH voltage remains relatively steady before "dropping off a cliff. " Low battery warning time is therefore brief.

I just stick with alkaline N cells since their capacity is superior to rechargables.

[derekamos]

'Some rechargeable N-Cells I have used in my 41CV over the years', & still going strong.
They are standard size, so they fit in the normal battery holder. Available from
BatteryBobs website Thats: https://www.batterybob.com/products/2923...0nm/?bc=no
You would need your own recharger for all 4x at once. Not sure how they would stand up to 41CL power use though.
DA

[m_a_s]

(04-25-2023 06:27 PM)Dave Britten Wrote:  I've used these on my 41 with pretty good results:

https://www.amazon.com/Tectra-Rechargeab...B096FJKDX3

The 4-pack comes with a single charger, so you have to charge them one at a time, but they're not exactly high capacity, so they charge pretty quick. Alternatively, buy two 4 packs so you get two chargers, and have a spare set you can alternate with.

I use the same batteries in my 28S with no issue. But when I tried to use these in my HP-41CL (has the "chassis" of my dear old HP-41CV that works no more) they don't work.

At first I thought it was the corroded battery tab that I had fixed with a whisker of fine wire and some solder. It's the one that contacts the + battery all the way on the end, not the middle + terminal.

Normal alkaline N cells work fine. Even brands I thought are very "sus". After much fiddling and fussing it turns out that the end + terminal doesn't make good contact with the Tectra or any other rechargeable N cell I had on hand (Anvow and Batmax at the moment). My fix was to solder the nipple of a regular alkaline battery's nipple onto it. It really needs the flange.

I ordered some of the 2/3AAA with flat tops to see if that makes a difference.

Attached photo shows the modified cell (right most) above the battery compartment terminals.