WH24 power supply / batteries type

[Tomasz Lewicki]

I would like to ask if anyone still uses the HP-1001/1002 (WS-1001/1002) station with the WH24 external sensor. I am having trouble finding the right batteries for this sensor. I know it is old equipment, but maybe someone will be able to help me.

I got the station from a friend who bought it in 2015 and didn't use it because he couldn't install it (he lives in a multi-story apartment building). I got it in 2023 and started using it in the spring of 2024. I found the original manual here -> https://fccid.io/WA5WH24B (April 2013 version). The Polish distributor's manual is from January 2014. It contains an important note that is not included in the original manual about powering the WH24 with 1.5 V ZnMn rechargeable batteries: "The outdoor sensor can only be used with the special ZnMn rechargeable batteries with a rated voltage of 1.5 V included in the set." Since I didn't have any, I used regular 1.2 V NiMH rechargeable batteries, but they quickly died during the cold spell, which is not surprising. That's why I used 1.5 V lithium batteries. They worked for almost two years, give or take a few weeks. But now I have to replace them, which brings me to my question for WH24 users - what kind of batteries should I use? There are no longer any 1.5 V ZnMn rechargeable batteries on the market, but there are NiZn batteries with a voltage of 1.6 V. Will these be suitable? Should I go for lithium batteries again? The thing is, access to the external sensor is very difficult and I can't easily replace it if something goes wrong. 

[michael.k...@gmx.at]

Afaik you could simply use NiZn, which won't fully charge in this station. Also, the low battery warning will most likely not fit when this cell is being used. I'd give it a try. Also, you might not want to put fully charged NiZn cells into your device.

But absolutely no guarantee you won't ruin the station.

[Tomasz Lewicki]

Thanks, so I'll try.

[Tomasz Lewicki]

I ordered NiZn rechargeable batteries. I don't think I need to worry about damaging the station due to overvoltage, because - as I checked on the only AA lithium battery I have on hand, which has been sitting around for two years - the voltage on it is exactly 1.79 V. So 1.6 V, even when fully charged, is unlikely to be a problem. I'm more concerned about charging.

wtorek, 3 lutego 2026 o 09:20:11 UTC+1 michael.k...@gmx.at napisał(a):

[michael.k...@gmx.at]

Try a supercap instead of a battery and measure the end voltage. The end voltage should be roundabout the same with the supercap and rechargeable batteries. It shouldn't exceed the maximum end voltage of the battery to be used, and high enough to store enough energy. Given the charging/discharging curve of NiZn Anything between 1,6V and 1.85V will more or less fully charge the battery without harming it. If under 1,4V it is empty and the voltage will dramatically fast so the low batt alarm really might not work as one might expect it. 

[Tomasz Lewicki]

"Supercap" means supercapacitor? I don't have any... And my knowledge about electronics is near to zero :)

According to low battery alarm - I'didn't noticed it on display before so the death of lithium batteries was sudden and unexpected :| 

[michael.k...@gmx.at]

OK, then just go for it and give it a try :)

[paul.ba...@gmail.com]

For about a year I used Zithion and Ausmann Li-Ion batteries, with good success. They incorporate a voltage controller in the AA that helps for both charging and discharging. The "apparent" discharge while unused is very low, 5-15 %  per month. and the output voltage is very stable while in use. I measured 1.54 V.  This stability is important for stations that are voltage sensitive , generally for Pressure or humidity that are not well compensated (I use a Irox PC2 station, aka Honneywell 923).

Only drawback, they are expensive,  but their prices are dropping regularly.

[michael.k...@gmx.at]

But you can't charge these batteries via their terminals, can you? They have USB-C charging connectors.

[paul.ba...@gmail.com]

You are right. This may be useful in some cases as for me, or a major drawback in others. Sorry for the imprecision.   Paul

[Tomasz Lewicki]

I will do that. Unfortunately, the station is difficult to access, and I am waiting for good weather to get there. I will let you know in a while how the cells are doing.