Query for W-8681-Solar/WH3080

[JohnF]

Hello.
First. Is there any reason why I cannot use rechargeable batteries other than alkaline ones in the transmitter, ie.e NiCD or NiMH?
Currently, my transmitter has no batteries in it and yet my indoor sensor is locked to the DCF clock. No other data is coming from the transmitter.
How come? (My solar panel unit has been returned for replacement so I removed the batteries from the transmitter)
TIA
John

[AllyCat]

Hi John,

Firstly, those rechargeable batteries only have a nominal voltage of 1.2 volts (compared with 1.5 for Alkalines or 1.7 for non-rechargeable AA Lithiums) so you might get reduced transmitter range. But another reason is that they have rather poor self-discharge characteristics so can go flat in 6 months to a year even with little or no external drain. Of course they should be alright if they're being continuously recharged by the solar cell (but I'm fairly sure the FO version I tested wasn't actually charging the cells). If you want to use rechargeables, I recommend the "low leakage" NiMH type (sometimes known as "hybrid" or "pre-charged"), available under various trade names such as Eneloop, Infinium and "Good to Go" (7dayshop.com), etc..

Are you sure the clock is "locked" to the DCF clock, the only way to tell is the icon on the LCD (even assuming FO have implemented it properly)? The internal crystal will retain time accuracy for months or years, just as it does for the versions without a RCC.

Cheers, Alan.

[JohnF]

Thanks Alan. I thought I could rely on you to provide an in-depth reply.
I recently bought an 'intelligent' battery charger which can charge batteries in various modes so I think I'll try non-alkalines. Unless I buy another battery charger for the alkalines!
The icon for the DCF station was showing ON on the screen although it has gone off now. Strange.
Thanks again
John

[AllyCat]

Hi John,

Certainly DON'T get an alkaline battery charger. The general view (confirmed in Which? magazine this month) is that ALL alkaline batteries (whether they claim to be rechargeable or not) can be recharged, but only to a very limited extent. If they're repeatedly "topped up" before much power has been used then they may give some extra life, but if they're allowed to fully discharge then they become useless (even the so-called rechargeable ones). So rechargeable alkalines might work quite well in a solar charged unit (but didn't in my FO 3080).

AFAIK the DCF receiver only operates for a short period each night (and immediately after the batteries are installed) and I guess the controller might wait for several missed signals (i.e. days) before switching off the icon.

Cheers, Alan.

[JohnF]

Thanks again Alan.
The 'intelligent' battery charger I purchased recently will not charge alkaline batteries - it says so in the instructions.
So from that I know alkaline batteries need a dedicated charger. From that observation and your comments, the solar panel must be quite happy to charge alkaline batteries AND other types . That is fine with me. I have quite a collection of rechargeable batteries and will sort out the type you recommended.
Regards
John

[colinpb]

Hi Alan

Just to clarify, are you saying you use low leakage NiMH type e.g Eneloop or Infinium in your WH3080, as opposed to rechargeable Alkaline as supplied by FO?

As an aside, the DCF signal on my WH3080 can come and go at any time during the day. From another manufacturer’s product manual apparently transmission reception problems can be down to weather conditions, and this appears to be the case with DCF on my WH3080. I've also found that it's not only the transmitter that needs careful siting, so does the console. Edge on to signal is OK for most data, but both DCF and solar transmissions need to “see” as much of the back of the unit as possible. The solar transmission for some reason is fussier than the DCF on my WH3080.

Colin

[AllyCat]

Hi Colin,

No I'm not currently using NiMH batteries in the 3080, but I certainly wouldn't buy rechargeable alkalines. The situation with "my" 3080 (which is actually located some way away at a friend's house) is that the the low battery symbol came on within 3 months of installation and the (supplied) rechargeable alkalines were indeed "flat" (and subsequently seemed reluctant to take any charge). As a "quick fix" I put in a pair of standard alkalines and performed a few tests.

There appeared to be two "faults", the current drain seemed to be excessive (a few mA) and there was no "charging" current when the PV cell was in daylight (which together would explain the batteries only lasting 3 months). So currently we're waiting to see how long the replacement batteries last, but (since the solar data is fairly useless in its current location) I will probably swap out the 3080 for a spare 1080 and then do some proper "bench tests" on the 3080 to see what faults (design or manufacturing) that it may have.

To me the solar charging is looking more like a liability than a feature. A pair of (non-rechargeable) Lithium AAs should run the external module for at least 3 years (by which time other "maintenance" may well be required), but I've seen no reference as to whether it is "safe" to charge these from a solar cell (but I'd be prepared to risk it). A potential problem with all NiMH cells is that they only deliver 1.2 volts, so the "low TX" icon may be permanently lit (thus giving no warning of imminent data loss) and the transmitter range might be reduced (it isn't wonderful at its present location anyway).

I don't know if the 3080 has any specific design faults or if it's just unduly complicated (or badly manufactured). IMHO the solar charging, UV sensing and perhaps even the RCC are mainly "marketing" features of little practical value. Personally I'm having quite a lot of "fun" diagnosing all the issues (with several FO systems), but as a "plug and play" system they seem to be a nightmare.

Cheers, Alan.

[colinpb]

Hi Alan
From what I've read I’m dubious about rechargeable alkaline batteries, particularly their apparent proneness to leakage. I would have preferred to use standard lithium batteries. The money invested in the solar charging could have been better invested in getting the Solar and UV side right. Additionally I suspect the display console isn’t as robust as it could be. Since the unit moved from 100% memory used into over writing previous data, the 10 minute logging has had occasional blips. This has happened three times in the last 2 weeks, each occasion was no greater 3 lots of 10 minute log points. Instead of 10 minute increments, I've seen logging periods stamped 14, 26 and even 48minutes! Though looking at the data, I suspect they are 10 minute stamps but with the wrong time. I've also had two glitches with the 24 hour rain display on the console, the value suddenly changing from correctly showing 24 hour total to showing weekly total! I’m also wondering with the loss of transmission of solar data is the console. At most once a day, sometimes once every two days I lose data for up to 40 minutes, no specific time of day. Checking cumulus logs there was one time when I lost data for two 10 minute slots, then got data for one 10 minute slot, lost it again for another 10 minute slot, then it came back and was fine for two days. Over 5 weeks I've lost about 5% of solar data this way.
To summarise; the solar side is great for getting sunshine hours (thanks Steve) but if I was FO I would immediately dump solar charging, and supply two good quality lithium batteries instead. With Google the problems people are getting stands out like a sore thumb, this must be having a negative effect on sales. I would also dump DCF outside Europe, only the 3081 to the UK. The problems with DCF reception in the UK is adding to the negative reaction to the WH3080.
Although it's only been 5 weeks, so far I still pleased with my 3080. I too am having “fun” diagnosing the glitches!

Colin

[AllyCat]

Hi Colin,

The reason I haven't returned the 3080 (yet) is because apart from the "minor" defects, i.e. not charging the battery, useless UV calibration and marginal radio reception (mainly when the PC is plugged in), it seems to be working quite well (at least compared with others). The lack of solar charging may actually be a benefit so the only real issue is the 3 months that the supplied batteries lasted. Maybe they were/are rubbish or perhaps the solar unit has a fault whch drains the batteries too quickly.

With two microcontrollers (there is a second in the solar unit) and numerous ways to "reset" the system (remove batteries, press the reset button on solar unit, unplug solar cable, etc.) it took me a considerable time to get it synchronised and correctly reporting all data. For a significant time it was draining too much current from the batteries, but that may have been the RCC initialising the clock. So at the moment the jury is out.

Note that in the 3080, FO appear to have changed the calculation of the (previous) "24 hour" rain total to "1 day", so it now resets at midnight (Cumulus of course displays both values).

If I decide to fit a rechargeable battery (to use with solar charging), I will probably get a "3.2 volt AA rechargeable Lithium Iron Phosphate battery" (available up to at least 600 mAhr and NOT the same as 3.7 volt lithium polymer cells) together with a blank (short circuit) in the second position. These cells are sold for (some) "solar garden lights" because they have the correct voltage and very good characteristics for over-charging and thousands of discharge/charge cycles (the technology is also used for electric traction applications, etc.). But note that cheap solar garden lights employ a single, small NiMH cell and a voltage up-converter to the 3+ volts required for a white LED.

Cheers, Alan.