Recommanded NiMh battery cells for HP82162A

[Gene]

Ah, thanks Bob... I was hoping for NiMH batteries, not Nicads, but I was not specific. My fault!

Any USA sellers using cells other than nicad ?

[Neve]

(09-26-2017 09:55 PM)Gene Wrote:  Anyone have a link to someone selling these 82162A compatible batteries on the USA TAS ?

I don't recall having seen them. Of course having stated that... I'm sure there must be dozens of sellers! :-)

TIA

(09-26-2017 10:33 PM)rprosperi Wrote:  http://www.ebay.com/itm/Battery-for-HP91...2270869464

I have recently bought stuff from him. Very nice guy. These are Ni-Cd cells, but he told me a coupe of days ago that he will be having new Ni-Mh packs ready in a week or so for $24 each. Hope that helps.

I personally ordered 4800mA Sub-C cells from Germany and will be rebuilding my original packs.
I should be receiving them early next week or later this week.

PS:I don’t have an external host link to post pictures, otherwise I would post the stuff I’m building or rebuilding.

[brickviking]

(09-27-2017 02:51 AM)Neve Wrote:  PS:I don’t have an external host link to post pictures, otherwise I would post the stuff I’m building or rebuilding.

I can recommend imgur.com for hosting, if you're prepared for the fact that you then don't (solely) hold rights to your images. However, I've had no problem with the images I've hosted there. And an image embed is really easy to do here, simply click the "Insert image" icon up on the editor toolbar when you write up a message.

Oh! I forgot, this is my hundredth post! Yay!

(Post C)

[Sadsilence]

(09-27-2017 02:51 AM)Neve Wrote:  I personally ordered 4800mA Sub-C cells from Germany and will be rebuilding my original packs.

Capacity of 4800mAh in a Sub-C cell? That is a dream value and little bit unrealistic. I would doubt any offer above 3000 - 4000mAh, depending on type (LSD or not) and high current capabilities. At least I would check capacity on arrival. Do you have a source link?

[Neve]

(09-27-2017 08:34 AM)Sadsilence Wrote:  

(09-27-2017 02:51 AM)Neve Wrote:  I personally ordered 4800mA Sub-C cells from Germany and will be rebuilding my original packs.

Capacity of 4800mAh in a Sub-C cell? That is a dream value and little bit unrealistic. I would doubt any offer above 3000 - 4000mAh, depending on type (LSD or not) and high current capabilities. At least I would check capacity on arrival. Do you have a source link?

4300 mAh, sorry. Here’s the link to what I ordered:
https://www.reichelt.com/fr/fr/Cellules-...ARCH=sub-C

[Sadsilence]

Thanks.

Funny. Cell name and cell label says 4000 mAh, advertising text says 4300 mAh. Both values are above average. 3500, 4000 or 4300 does not really matter as long as all 4 cells in pack have nearly the same capacity.

[Neve]

(09-27-2017 10:21 AM)Sadsilence Wrote:  Thanks.

No Problem.

(09-27-2017 10:21 AM)Sadsilence Wrote:  Funny. Cell name and cell label says 4000 mAh, advertising text says 4300 mAh. Both values are above average. 3500, 4000 or 4300 does not really matter as long as all 4 cells in pack have nearly the same capacity.

Yes, I guess you’re right. I noticed that as well. What is the average normal mAh value for these Ni-Mh cells?
Anyways, even at 4000mAh I’m sure they’ll work just fine for a very long time without having to recharge. Which is good since I only have one HP charger for all my devices.

I also ordered rechargeable N cells for my second HP41CX.

[Neve]

(09-27-2017 06:35 AM)brickviking Wrote:  I can recommend imgur.com for hosting, if you're prepared for the fact that you then don't (solely) hold rights to your images. However, I've had no problem with the images I've hosted there. And an image embed is really easy to do here, simply click the "Insert image" icon up on the editor toolbar when you write up a message.

Oh! I forgot, this is my hundredth post! Yay!

(Post C)

Thank You, and congrats!!

[Dave Frederickson]

(09-27-2017 10:29 AM)Neve Wrote:  I also ordered rechargeable N cells for my second HP41CX.

Where did you find rechargeable N cells? The quality of the cells in the U.S. is iffy.

You found some adapters as well?

[Dieter]

(09-27-2017 03:36 PM)Dave Frederickson Wrote:  Where did you find rechargeable N cells? The quality of the cells in the U.S. is iffy.

Felix Europa... ;-)
It seems that the well-known GP50NH is no longer available. But here is an alternative.

(09-27-2017 03:36 PM)Dave Frederickson Wrote:  You found some adapters as well?

You can even get a complete set with four cells, four N-size-adapters and a suitable processor-controlled charger, cf. here. A similar solution has been suggested in earlier threads on this subject.

Dieter

[Neve]

(09-27-2017 03:36 PM)Dave Frederickson Wrote:  

(09-27-2017 10:29 AM)Neve Wrote:  I also ordered rechargeable N cells for my second HP41CX.

Where did you find rechargeable N cells? The quality of the cells in the U.S. is iffy.

You found some adapters as well?

http://www.conrad.fr/ce/fr/product/25517...ggest=true

http://www.conrad.fr/ce/fr/product/65100...ionarea=01

Will be receiving them tomorrow.
Didn’t buy the adapters, though. I’ll use some bolts.

[Didier Lachieze]

(09-27-2017 06:41 PM)Dieter Wrote:  You can even get a complete set with four cells, four N-size-adapters and a suitable processor-controlled charger, cf. here. A similar solution has been suggested in earlier threads on this subject.

I've got one of these sets (4 cells, adapters and charger) from this shop thanks to your earlier suggestion. Great value.

[Dieter]

(09-27-2017 07:08 PM)Neve Wrote:  Will be receiving them tomorrow.
Didn’t buy the adapters, though. I’ll use some bolts.

More important than adapters: be sure to use a decent charger, i.e. a processor-controlled device that can be set to low charging currents, here 200 mA or less. That's a crucial point.

Dieter

[Joe Horn]

One thing that surprised me was that flat-top NiMH N cells (no "nipple" on the + end) work perfectly in the HP-41. When I ordered mine, I didn't notice that they were flat-top cells, and was dismayed when they arrived, only to be delighted to see that they work great as-is.

[Dieter]

(09-27-2017 07:52 PM)Joe Horn Wrote:  One thing that surprised me was that flat-top NiMH N cells (no "nipple" on the + end) work perfectly in the HP-41. When I ordered mine, I didn't notice that they were flat-top cells, and was dismayed when they arrived, only to be delighted to see that they work great as-is.

The four contacts in the calculator as well as the four springs in the battery holder are the same for each of the four batteries. So if these work fine for the flat minus end they should also be fine for a flat end at the plus side. ;-)

Dieter

[rprosperi]

(09-27-2017 09:50 PM)Dieter Wrote:  The four contacts in the calculator as well as the four springs in the battery holder are the same for each of the four batteries. So if these work fine for the flat minus end they should also be fine for a flat end at the plus side. ;-)

I assume Joe was referring to the fact that the flat-top cells are shorter, yet the springs are still strong enough to maintain contact, but I'll let him confirm for sure.

Joe - note that with flat-top cells, you should 'stretch' the springs in the holder a bit to ensure they're tight, else when the machine gets bumped or horror-of-horrors, dropped, you may lose momentary contact. This rarely will lead to mem lost for the 41's RAM, but it can cause the clock to reset - this is exactly what happened to me, and took a while to figure out.

[Hans Brueggemann]

(09-25-2017 03:26 AM)Neve Wrote:  Now, I have rebuilt the HP41 battery pack a coupe of days ago.
It was originally delivering 5.8v. Now it shows 4.94v. Even after 10h or so (I guess...) of charging it doesn’t go back up to 5.8v. Is this normal? I guess it would be since the original charger was not designed to charge Ni-Mh batteries.
...
On a side note, I also read that the charger is just a transformer. No electronics inside. The electronics inside the pack is what regulates the charging cycle. Do I understand this right?
If this is the case, can it be modified to charge faster and/or more efficiently? If so, how?

Thank you.

the internal charger electronics of the battery pack is basically a simple voltage regulator with resistive current limiting. hence, no real constant-current charging in here. it is that very voltage regulator that limits the fully charged voltage to what you did measure. and, yes, by limiting the voltage to a lesser than feasible level, the battery pack will never live up to what the batteries are capable of. that's a known given with this particular battery pack.

[rant on]
seems that hp got their good reputation (during the heydays of their pocket calculators, that is) by whatever product they manufactured, but for sure not from what they did in the range of battery charging. that area always seemed to be the demilitarized playground where they would unleash their cost-saving punks unto the designers.
[rant over]

so, yes, back to topic: if you know, what you are doing, then there is a slight room for improvement of charge current and end-of-charge voltage to adopt the battery pack to modern NiMH technology. is it worth the effort? depends on your personal use case. my use case is "infrequent use w/o card reader", which means that the battery pack dies ever so often by self-discharge, rather than real usage. so, my answer is no.

[Joe Horn]

(09-27-2017 09:59 PM)rprosperi Wrote:  

(09-27-2017 09:50 PM)Dieter Wrote:  The four contacts in the calculator as well as the four springs in the battery holder are the same for each of the four batteries. So if these work fine for the flat minus end they should also be fine for a flat end at the plus side. ;-)

I assume Joe was referring to the fact that the flat-top cells are shorter, yet the springs are still strong enough to maintain contact, but I'll let him confirm for sure.

Correct.

(09-27-2017 09:59 PM)rprosperi Wrote:  Joe - note that with flat-top cells, you should 'stretch' the springs in the holder a bit to ensure they're tight, else when the machine gets bumped or horror-of-horrors, dropped, you may lose momentary contact. This rarely will lead to mem lost for the 41's RAM, but it can cause the clock to reset - this is exactly what happened to me, and took a while to figure out.

Good suggestion!

[Neve]

(09-27-2017 10:46 PM)Hans Brueggemann Wrote:  so, yes, back to topic: if you know, what you are doing, then there is a slight room for improvement of charge current and end-of-charge voltage to adopt the battery pack to modern NiMH technology. is it worth the effort? depends on your personal use case. my use case is "infrequent use w/o card reader", which means that the battery pack dies ever so often by self-discharge, rather than real usage. so, my answer is no.

If I know what to change and/or replace, I would definitely do it.

[Neve]

Ok,

So I received both the rechargeable N-Cell yesterday along with a charger which I’ll be using with bolts. They work awesome in both my HP41’s. They power the card reader very nicely almost without showing signs of weakening. After 30 or 35 passes, they still read 1.345v/cell. Well above their 1.2v rating.
I also received the Ni-Mh 4300mAh power cells to rebuild the HP82162A and HP82143A power packs. After disassembling both packs and using the original long V-shaped terminals, I wasn’t good enough to have them fit inside the case. They just needed to be soldered a bit closer and tighter to each other. I’m sure someone with better building skills will do a better job (that was my first attempt). The first one didn’t look so good, but worked just fine. Anyways, they both work like a charm, and are placed without the original cases (I’ll keep those for a later rebuild, eventually.)
PS: BTW, 4300mAh is written on them. I should take pictures and post them.