Hurricane II: An HP-41C Battery Pack w/ USB

[Hans Brueggemann]

(12-13-2020 01:38 PM)HP-Collection Wrote:  Seems to become a new mass product:
I suggest:

Maybe there is a nice 3D printer where the PCB and the recharging batteries fits perfect, contacts between the batteries and to the calc can be done by old Siemens Gigaset Battery springs (at least that's my best goal)

this. battery pack case is indeed 3D-printed. as for the contact springs, i still have to find a commercial solution. i ruthlessly cannibalized two HP 82120A for the prototypes. dedicated "Automatenstanzteile" at reasonable cost should be viable, though.

[wbvreeuwijk]

Hi Hans,

Cool project and I'd be interested to purchase a few of the populated PCB's.

Regards,
Bas

[Hans-Peter]

Shapeways has a battery case with two tabs. So I used nickel strips like those used for battery spot welding. You can attach the tabs to the housing in your 3D model. They are 10x6mm and 0.5mm thick. About 2mm away from the inside. I think this is the best solution for the contacts. They have enough spring travel.

[Artur - Brasil]

See this:
https://www.hpmuseum.org/forum/thread-12503.html
Best wishes!
Artur

[BobVA]

(12-14-2020 06:57 AM)Hans Brueggemann Wrote:  ...
for an HP-41CX w/ CLONIX,
12000 hours STANDBY and 25 hours RUN.
(typical values w/ 700 mAh ENELOOPs, after 10 hours charging time)

OK - I'm sold :-)

[wbvreeuwijk]

Hi Hans,

I was wonder if there is any update on this project?

Kind Regards,
Bas van Reeuwijk

[Hans Brueggemann]

hi bas,
i have currently two working prototypes on my bench. proto #1 is feeding a HP-41CX plus CLONIX. it is right now commencing a 2000 h stand-by test to figure out as to whether real-life battery drainage complies with calculations. i'm looking for battery droop in mV / day figures.
proto #2 is feeding an early HP-41CL which is serving as (shame!) 4-banger on my desk to figure out how (in-) convenient it is to keep it going in daily usage. also, i need to investigate the accuracy of the charger circuitry and its impact on the "mileage" that you can get out of one full charge cycle.

[Uli]

Moin Hans,

I did not read in your description that you will also offer your development for sale, but if you do, I would like to join the group of interested parties with the desire for 1 or 2 battery storage units. And one would be better than none :-).

Schöne Grüße!

[aurelio]

(03-13-2021 10:33 AM)Uli Wrote:  Moin Hans,

I did not read in your description that you will also offer your development for sale, but if you do, I would like to join the group of interested parties with the desire for 1 or 2 battery storage units. And one would be better than none :-).

Schöne Grüße!

Congratulations Heins for your project, and thank-you for the efforts, the time and the money you invested in that.
Me too interested in one of your jewels (Hope not so expensive at the end, like diamonds)

As Uli wrote "one would be better than none :-)"

[wbvreeuwijk]

(03-08-2021 06:34 PM)Hans Brueggemann Wrote:  hi bas,
i have currently two working prototypes on my bench. proto #1 is feeding a HP-41CX plus CLONIX. it is right now commencing a 2000 h stand-by test to figure out as to whether real-life battery drainage complies with calculations. i'm looking for battery droop in mV / day figures.
proto #2 is feeding an early HP-41CL which is serving as (shame!) 4-banger on my desk to figure out how (in-) convenient it is to keep it going in daily usage. also, i need to investigate the accuracy of the charger circuitry and its impact on the "mileage" that you can get out of one full charge cycle.

Thanks Hans,

As my HP-41CL, needs constant recharging I'm very much looking forward to you making this available to a broader audience. Are you planning to make the schematic available or selling the charging/converter circuitboard?

[Hans Brueggemann]

(03-15-2021 04:23 PM)wbvreeuwijk Wrote:  As my HP-41CL, needs constant recharging I'm very much looking forward to you making this available to a broader audience. Are you planning to make the schematic available or selling the charging/converter circuitboard?

i'm thinking to make all design files freely available to the hpmuseum community for private and non-commercial use.

from your post today it sounds like you actually know what a soldering iron is. ;o)
i haven't fully finalized testing yet, but results look promising so far. so, if you don't mind DYI assembly and would like to give it a test drive, drop me an email, and i'll be sending you the preliminary design files.
it would be really great to have somebody else testing it before releasing the final version into the public!

[rocket.scientist]

(03-15-2021 04:46 PM)Hans Brueggemann Wrote:  

(03-15-2021 04:23 PM)wbvreeuwijk Wrote:  As my HP-41CL, needs constant recharging I'm very much looking forward to you making this available to a broader audience. Are you planning to make the schematic available or selling the charging/converter circuitboard?

i'm thinking to make all design files freely available to the hpmuseum community for private and non-commercial use.

from your post today it sounds like you actually know what a soldering iron is. ;o)
i haven't fully finalized testing yet, but results look promising so far. so, if you don't mind DYI assembly and would like to give it a test drive, drop me an email, and i'll be sending you the preliminary design files.
it would be really great to have somebody else testing it before releasing the final version into the public!

Hans - I'd be interested in participating as part of this beta test as well. Let me know if that is an option.

Thanks!

-Pat (KG5YPQ)

[Hans Brueggemann]

thank you for your kind offers (e-mail wise and via this thread), gentlemen!
i will come back here once i have sanitized the documentation.

[dmh]

(03-20-2021 06:48 AM)Hans Brueggemann Wrote:  thank you for your kind offers (e-mail wise and via this thread), gentlemen!
i will come back here once i have sanitized the documentation.

Hi, just wondering what the rough timeframe is for this and if it will be a purchasable product?

Just looking into options as the N batteries in Australia are expensive!

Thanks

[Siegfried]

This sounds very interesting. Getting rid of N cell alkalines would be great indeed. Looking forward to this being released even if I don't know if I will be able to recreate it.

[MeindertKuipers]

I was wondering if there is any news about this nice project.
I had to rebuild one of my own LiPo solutions for my HP41. Stupidly I used a 1000mAH pack that did not have protection built in (salvaged from a USB phone power pack), and it became undercharged and is now a bit thicker than it used to be. I have found little charger boards with the protection built in and now testing another 1000mAH pack. Running in my CX for over 15 hrs now. My other pack with a 500mAH LiPo (which has the built-in protection) is now still running in my 41CL at 15+ hrs.
Still puzzled about how to implement support for low BAT, maybe Hans can shed some light here, so I am very curious about his design.

[Hans Brueggemann]

Q1A in the schematics tracks the eneloop voltage and proportionally controls the output voltage by steering the voltage divider R5, R6: the lower the eneloop voltage gets, the higher the feedback voltage at the FB pin of U2 gets.
thus, the output voltage of the battery pack is tracking the three eneloops almost exactly to Vout = 3 x Veneloop + 1 V. hence, for fully charged eneloops, Vout becomes 3 x 1.43 V + 1 V = 5.30 V, while for fully depleted eneloops, Vout = 3 x 0.9 V + 1 V = 3.7 V, which is also the threshold of the BAT indicator.

meanwhile, the HP-41CX w/CLONIX that i'm using for the standby-duration test is starting to collect cobwebs and has clocked approx. 6500 hours of "idleness". total voltage on the three eneloops is still over 3.7 volts and the calculator does power on without the "BAT" indicator coming up.

so, just to confirm, the project is still alive. since march i'm using proto # 2 on a daily basis (HP-41CL) with lots of card reading every now and then (you know, basically every single time when YFNS has left the building. again.), and so far i'm pretty content with its endurance.

for those who are interested in a ready made product: this is probably not going to happen. however, i'll be sharing the design files beginning next year.

[MeindertKuipers]

This is really great info, thanks for sharing! And pretty smart as well.

[Amithlon]

Brilliant stuff. put me on the list for further info STL files, kits or whatever.