Battery options for 82143A printer

[Dave Britten]

Does anybody produce a battery pack/receptacle for the 82143A printer (I believe it's the same battery pack as the topcats) with removable cells, like the ones available for the classics and woodstocks? I prefer not to risk series-charging modern high-capacity battery packs in these old machines (to say nothing of how much longer it takes when you've got about 4 times the capacity with NiMHs). And I know you can't run these printers off AC only, so I'd rather strictly use batteries and charge them in a separate "smart" charger.

[twoweims]

I got one from Mark Hoskins on eBay. It is working great.

[Paul Berger (Canada)]

One problem is the batteries used in these packs are sub-C size which are generally flat top batteries, so are not convenient for a pack with removable cells. I have put together a pack using 4 AAA NiMh cells and that works, I could not fit 4 AA cells into the battery pack shell. I also run my 97 from a pack I hacked together from a single cell Lithium "Power pack". The power pack is of the type that turns on the 5V when a load is presented and turns of again automatically when the load is taken away. To charge it I retained the micro USB connector that was provided for that purpose, so charging is convenient. I have also used it successfully in a HP-IL printer. These are things I hacked together, I don't know of anyone who is offering anything like this for sale.

[Dave Britten]

(02-08-2020 03:58 AM)Paul Berger (Canada) Wrote:  One problem is the batteries used in these packs are sub-C size which are generally flat top batteries, so are not convenient for a pack with removable cells. I have put together a pack using 4 AAA NiMh cells and that works, I could not fit 4 AA cells into the battery pack shell. I also run my 97 from a pack I hacked together from a single cell Lithium "Power pack". The power pack is of the type that turns on the 5V when a load is presented and turns of again automatically when the load is taken away. To charge it I retained the micro USB connector that was provided for that purpose, so charging is convenient. I have also used it successfully in a HP-IL printer. These are things I hacked together, I don't know of anyone who is offering anything like this for sale.

I considered the possibility of using AAs, since NiMHs would easily give you as much capacity as the old sub-C NiCds. Flat-top AAs are readily available at Batteries Plus - I have a few for my 25, and my charger has enough of a "bump" at the positive end that it makes contact just fine. I've also got a few 4/5 A cells laying around that would likely work.

But I'd still have to build a holder of some sort, and I'm not much of a handicrafter. I'd probably have to jigsaw something ugly out of a block of wood and fine tune it with the drill and Dremel.

[Paul Berger (Canada)]

(02-08-2020 12:49 PM)Dave Britten Wrote:  I considered the possibility of using AAs, since NiMHs would easily give you as much capacity as the old sub-C NiCds. Flat-top AAs are readily available at Batteries Plus - I have a few for my 25, and my charger has enough of a "bump" at the positive end that it makes contact just fine. I've also got a few 4/5 A cells laying around that would likely work.

But I'd still have to build a holder of some sort, and I'm not much of a handicrafter. I'd probably have to jigsaw something ugly out of a block of wood and fine tune it with the drill and Dremel.

Yeah 4/5 AA would work the space inside a shell for one of the battery packs for your printer is about 85mm, a quick way might be to get 4 single AA holder trim one end on them and glue them into the battery shell to form a pair of end to end 2 cell holders. You can even use the original contact but would nedd to either glue or tape them in place. My pack with AAA cells uses four single cell AAA holders fitted into a shell.

If I was better with 3D print design I might take a shot at designing something, but I am really only starting out.

Paul.

[Dave Britten]

(02-09-2020 12:03 AM)Paul Berger (Canada) Wrote:  Yeah 4/5 AA would work the space inside a shell for one of the battery packs for your printer is about 85mm, a quick way might be to get 4 single AA holder trim one end on them and glue them into the battery shell to form a pair of end to end 2 cell holders. You can even use the original contact but would nedd to either glue or tape them in place. My pack with AAA cells uses four single cell AAA holders fitted into a shell.

If I was better with 3D print design I might take a shot at designing something, but I am really only starting out.

Paul.

Ooh, that's a great idea, I hadn't considered cutting up AA holders and sticking them together. Even better, get a pair of 2 pc. AA holders and stick those end-to-end.

https://www.amazon.com/GFORTUN-Plastic-B...06XW891WK/

There's also a stacked 2x2 holder. I don't suppose that would fit in the battery compartment, would it?

https://www.amazon.com/WMYCONGCONG-Batte...07JMMCMBL/

[mfleming]

(02-09-2020 01:02 AM)Dave Britten Wrote:  There's also a stacked 2x2 holder. I don't suppose that would fit in the battery compartment, would it?

https://www.amazon.com/WMYCONGCONG-Batte...07JMMCMBL/

I have the same 2x2 AA stacked holder, and unfortunately it's a bit too high to fit the battery door over it. The diameter of an AA battery is more than half the height of the stock battery, so you can't really stack them vertically.

Mouser has a 2x2 AAA holder that is 24.5 mm square, which is almost exactly the height of the stock battery. You would need to attach clips to the battery wires to connect to the contacts in the compartment, and maybe add a strip of foam to the cover to keep the holder from rattling around in the battery compartment. The cost of the holder was only a little more than a dollar.

The capacity of an Eneloop AAA rechargeable is 750 mAh while a generic subC NiCd is 2500 mAh, so operating life would be much less. Four short AA batteries in a cut-down 2-wide by 2-long holder might work, but I'm sure the capacity would less than the subC and would be a bit of a pain to charge the short AA battery outside the holder.

How about using a modern charger on a rebuilt battery pack outside the printer? Mark Hoskins has something like that for the Classic 3-pack.

[Dave Britten]

(02-09-2020 02:34 AM)mfleming Wrote:  I have the same 2x2 AA stacked holder, and unfortunately it's a bit too high to fit the battery door over it. The diameter of an AA battery is more than half the height of the stock battery, so you can't really stack them vertically.

I suspected that was probably the case.

(02-09-2020 02:34 AM)mfleming Wrote:  Mouser has a 2x2 AAA holder that is 24.5 mm square, which is almost exactly the height of the stock battery. You would need to attach clips to the battery wires to connect to the contacts in the compartment, and maybe add a strip of foam to the cover to keep the holder from rattling around in the battery compartment. The cost of the holder was only a little more than a dollar.

The capacity of an Eneloop AAA rechargeable is 750 mAh while a generic subC NiCd is 2500 mAh, so operating life would be much less. Four short AA batteries in a cut-down 2-wide by 2-long holder might work, but I'm sure the capacity would less than the subC and would be a bit of a pain to charge the short AA battery outside the holder.

What was the rated capacity of the original battery pack? Modern NiCd batteries seem to roughly double those from the '70s, and NiMHs are about quadruple. Woodstocks can run for a crazy long time on a pair of AA NiMHs. So AAAs might not be that far off the original spec, actually.

When you say "short AA", are you referring to flat-top cells, or something else? I've got a charger that handles flat-tops just fine, and has spring contacts on the negative end, so it can handle anything ranging from just a hair longer than an N, all the way up to a LiIon 18650 (and possibly longer).

(02-09-2020 02:34 AM)mfleming Wrote:  How about using a modern charger on a rebuilt battery pack outside the printer? Mark Hoskins has something like that for the Classic 3-pack.

I could certainly live with that, if such a charger is available for the Topcat/printer batteries.

[mfleming]

I was thinking of the 4/5 AA batteries mentioned by Paul. Even flat-top AAs would be too long to fit the compartment. A 4/5 cell would likely fit where an AAA cell would go in a charger. Might be worth looking into further if a suitable holder can be found (most 4 cell holders seem to be 4 side by side).

Good point about battery life, particularly if you can quickly replace exhausted cells with fully charged ones.

[Hans-Peter]

My solution has a 3000mah LiPo single cell with low voltage protection. A small charging module with a micro USB connector and a 5V step-up DC converter with a low quiescent current.

You can use 2-3 single cells in parallel, but with exactly the same capacity.

           

The first variant was also with 4 AAA cells and a small wooden beam. I still have to look for it to take a picture.

Hans-Peter

[Dave Britten]

Alright, I cracked open the old pack and had a look around. AAs definitely won't fit, but flat-top sub-C NiMHs are available from Batteries Plus. 4/5A are the same length, but smaller diameter.

The pack is built in a typical series layout, and the cells soldered/welded together at the tabs, so nothing fancy at all. The contacts both attach to the same end of the pack. I think I should be able to pop the contacts off, glue them to the inside of the plastic shell, then just put in 4 sub-Cs, perhaps with a thin piece of foam tape at the end of the pack without the contacts to add a little bit of spring tension, and some foil in a few places to make sure the positive ends of the flat-top cells make contact.

[mfleming]

I like the approach Hans-Peter suggests, because once built you can recharge the pack without opening it. Your idea corresponds to what I did with a Classic pack rebuild. I used 3 AAs with copper strips to bridge between batteries and the the original contact strips to bring out power. Everything was snug enough within the battery case that pressure kept the batteries in good electrical contact with the metal parts. I could recharge within the calculator, or disassemble and recharge the batteries separately.

If you give it a try with subCs be sure to mark where everything goes. Easy to reassemble in reverse order and get the wrong polarity at the contacts!

~Mark

[Hans-Peter]

If you want to charge the NiMh batteries in the case, you need a serial charger like this

https://de.aliexpress.com/item/400028332...b201603_53

or like this

https://de.aliexpress.com/item/400003838...b201603_53

Hans-Peter

[Dave Britten]

(02-11-2020 06:41 AM)mfleming Wrote:  If you give it a try with subCs be sure to mark where everything goes. Easy to reassemble in reverse order and get the wrong polarity at the contacts!

~Mark

Oh yes, I quadruple-checked the polarity of the terminals, and put a small label inside the battery compartment indicating + and -! I will similarly label the inside of the battery pack shell.

This morning I quickly spliced some alligator clips onto a 4xAA battery box so I could clip it to the battery terminals and at least test the printer with an outboard battery pack. The printer seemed to work just fine, but I noticed that the Battery light would come on with any activity. I figure this means one of three things:

1. The batteries I stuck in were a bit low/worn (they're Rayovac Hybrid low-self-discharge, and I topped them up a couple months ago, but they're a few years old)
2. The rather light-gauge 5" of wire from the battery box to the terminals was causing some voltage drop under load (likely)
3. The Battery light simply doubles as an "activity" light on this model (doubt it, but you never know)

I do like how it's significantly quieter than the 82240 wireless printers, though! It's just a shame it can't be plugged into a DM41X.

[Dave Britten]

I stopped by Batteries Plus this morning and got a set of 3400 mAH sub-c NiMHs, and the printer works great. I still need to do a little finishing work on the battery holder, but I'll try to upload some photos when I'm done. Turns out it's really easy to modify a Topcat battery pack to accept removable cells, once you've dealt with the hardest part: getting it open without cutting yourself. So now I've got one less excuse to avoid buying a 97, I guess.

[Dave Britten]

Here's some photos of the converted/rebuilt battery pack:

https://imgur.com/a/K14ZXhD

It's really simple to do. The hardest part is opening the pack, because you need to use a sharp utility knife to get the halves apart. If you have a chain mail or thick leather glove, I highly recommend wearing one on the hand holding the battery pack so you don't cut yourself badly. Alternatively, hold it gently in a bench vise. Another option is to use a knife to get a good start, then tap the halves apart with a chisel.

Once it's open, use a knife to separate the soldered/welded batteries contacts, taking care not to mangle the actual y-shaped battery terminal assembly too badly. With the old batteries removed, you'll hot glue that back into the pack by putting a moderate drop in between the two contact openings along the center spine. The two plastic halves of the pack are identical, so don't worry about getting them mixed up. They fit together when rotated 180 degrees.

For the end of the pack that bridges the pairs of batteries together, I just folded some aluminum foil to a good thickness. Use a piece that's much wider than the pack, so you can fold the ends in and make it thicker where the batteries make contact. I put some very thin foam mounting tape behind the contact points to hold the bridge in place, and offer a tiny bit of pressure.

After that, just drop in 4 sub-C NiMHs, place the other half of the plastic shell onto the pack, and put the whole thing in your printer/Topcat. When it's time to recharge, pull them out and stick them in a charger.

[mfleming]

Nicely done! I received a dead rebuilt battery pack that used the same technique for bringing out the contacts. Never occurred to me to use a spot of hot glue to hold things in place inside the case, but I'll give it a try next time. Thanks for the tip.

[Dave Britten]

(02-16-2020 01:50 AM)mfleming Wrote:  Nicely done! I received a dead rebuilt battery pack that used the same technique for bringing out the contacts. Never occurred to me to use a spot of hot glue to hold things in place inside the case, but I'll give it a try next time. Thanks for the tip.

Yeah, it worked great. At first I was wracking my brain trying to figure out a good way to secure the leads, thinking I'd need to attach them to the other half of the shell and slide the batteries in underneath the floating contacts, and then I realized, "Oh duh, glue it to the spine..." You just have to do it fast enough that the glue doesn't harden before pressing the contact strip into place, i.e. you want it nice and flat against the spine so it doesn't prevent the batteries from sitting deep enough in the tray. Trim any excess glue that comes out from underneath using your preferred knife.