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Replacement batteries?

Discussion specific to Fine Offset and similar rebadged weather stations
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clarets7
Posts: 2
Joined: Sun 15 Feb 2015 6:06 pm
Weather Station: Fine Offset (Watson W-8681-SOLAR
Operating System: Windows 8
Location: West Yorkshire

Replacement batteries?

Post by clarets7 »

Hi, I've got Watson 1080 (? well maybe) that was bought for my 60th birthday just under 6 years ago. The batteries are no longer holding any charge, so I was wondering what people have replaced them with? Mine has the solar pod, and the batteries say they are 1.5V Alkaline rechargeable. Would ordinary NiMh rechargeables be ok or is the voltage too low?

Mapantz
Posts: 864
Joined: Sat 17 Dec 2011 11:55 am
Weather Station: Davis Vantage Pro2
Operating System: Windows 10 x64
Location: Dorset - UK
Contact:

Re: Replacement batteries?

Post by Mapantz »

They would probably work fine, but it's overkill to use NiMH's in a weather station as they're more suited to use in high power devices.
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Super-T
Posts: 843
Joined: Tue 09 Sep 2008 3:37 am
Weather Station: wh-1081
Operating System: Weather Laptop - Windows 10 Pro
Location: Auckland, New Zealand
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Re: Replacement batteries?

Post by Super-T »

NiMh voltage is too low.

I am trialing 1 x Lithium 3.6Volts AA with a dummy battery as well but then again I don't have a solar pod doing the recharging. Anyone know if the lithiums will stand being charged by the solar pod voltage?

Using a spare transmitter and base station for the trial.

Lots of power available and hasn't blown up the transmitter with the 3.6 volts, yet.

clarets7
Posts: 2
Joined: Sun 15 Feb 2015 6:06 pm
Weather Station: Fine Offset (Watson W-8681-SOLAR
Operating System: Windows 8
Location: West Yorkshire

Re: Replacement batteries?

Post by clarets7 »

I was toying with the idea of using an old phone battery, but not sure again if the recharging circuit in the pod would deal with that very well, but anyway they are too big. I've got a couple of NiMh batteries in at the moment, only been in 12 hours, in the dark, voltage is 2.72V. It is working but the receiver is only in the same room! Are replacement batteries not available anymore, same type as the original?

AllyCat
Posts: 1078
Joined: Sat 26 Feb 2011 1:58 pm
Weather Station: Fine Offset 1080/1 & 3080
Operating System: Windows XP SP3
Location: SE London

Re: Replacement batteries?

Post by AllyCat »

Hi,

It might depend if it's just a "charging" Solar Pod (WH-208x ? ) with I believe no "electronics" or a "Solar Data" Pod (WH-308x) which has a voltage regulator.

IIRC the "charging" voltage from the WH-308x Solar Pod is around 3.0 volts (a 3.3 volt low quiescent current regulator feeding through a Schottky diode to prevent reverse leakage), which is marginal even for the original "Rechargeable" Alkalines. The battery manufacturers' recommendation is that these should never be allowed to fall below 3 volts. But there's almost no difference between "ordinary" and "rechargeable" Alkalines (a misnomer if ever there was one), so you could just replace them with reasonable quality normal (primary) Alkalines.

If you do want to use rechargeables, then a pair of AA NiMH is probably the best choice. The final charging voltage for NiMH tops out at around 1.5v per cell and that little PV panel is not going to give enough current to damage them. The only issue is that the "Low (Transmitter) Battery" Icon might come on, (if that irritates you) and the wireless range might be a little reduced. Other possibilities are a pair of NiZn AAs (nominally 1.6v each) or a singe LiFePO4 (Lithium Iron Phosphate) with a dummy (short-circuit) both in AA profile, which also gives nominally 3.2 volts. But I certainly wouldn't expect a 3.7 volt lithium cell (whose charging should top out at 4.2 volts) to be satisfactory in long term.

Cheers, Alan.

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