Author Topic: Rechargable or non-rechargable battery for WH2900 (ws-2902a clone)  (Read 1601 times)

0 Members and 1 Guest are viewing this topic.

Offline fedeviper

  • Member
  • *
  • Posts: 2
Hi, reading the spanish user manual that came with my fine offset it said that the sensor use 2AA rechargable batteries but the english version of the WS-2902a said non-rechargable
 :???:
Which it's correct ??

Thanks
« Last Edit: May 23, 2019, 09:03:55 PM by fedeviper »

Offline galfert

  • Global Moderator
  • Forecaster
  • *****
  • Posts: 6822
Re: Rechargable or non-rechargable battery for WH2900 (ws-2902a clone)
« Reply #1 on: May 24, 2019, 08:36:24 AM »
The WS-2902A sensor array has the following 3 power solutions:

  • Solar panel to power the sensor array during the day and to also recharge a super capacitor.
  • A non-removable super capacitor. This is like a rechargeable battery but it charges much quicker, but it is only good for a shorter duration than a typical rechargeable battery. Its purpose is only to power the sensor array during the night as it will be recharged the next day. On some very cloudy days it may also power the unit during the day.
  • Regular user replaceable AA cells. It is recommended that the user install Alkaline batteries or in very low cold climates it is recommended to use Lithium cells as they perform better at very low temperatures. Do not use rechargeable batteries as there is no benefit. A good Alkaline or Lithium set will last you 2 or 3 years. If you use rechargeable batteries you'll spend more and negate the benefits that you would have gained with Lithium for the price, and with rechargeable batteries you'll still need to replace them because they don't last but 2 or 3 years anyway, and you'll have the aggravation of needing to pull them out and recharge them. So there is no benefit to rechargeable nor in cost nor in performance in cold nor in replacement time nor in ease of being worry free so that it doesn't require recharging. The purpose of these Alkaline or Lithium batteries is to power the sensor array when the super capacitor is not sufficient because of extended days of cloudy coverage where the solar panel cannot recharge the super capacitor.

If you find that you are needing to replace the batteries after only a few months then you probably have your sensor array in a bad sited location of too much tree cover with not enough direct sun. This will also affect your solar radiation and UV reporting. Those trees are probably affecting everything...wind...temp...etc. Either that or you live in Alaska and it is winter and only get 4 hours of daylight and your batteries are being over-utilized.

I live in Florida and I could most certainly get by with regular Alkaline batteries as it hardly ever gets below 30°F but I went through the added expense of Lithium for piece of mind.

If you still decide for whatever (bad) reason to use rechargeable AA batteries know that the solar panel will not recharge them. The solar panel only recharges the internal non-removable super capacitor. The super capacitor is also referred to as a supercap.
« Last Edit: May 24, 2019, 12:39:16 PM by galfert »
Ecowitt GW1000 | Meteobridge on Raspberry Pi
WU: KFLWINTE111  |  PWSweather: KFLWINTE111
CWOP: FW3708  |  AWEKAS: 14814
Windy: pws-f075acbe
Weather Underground Issue Tracking
Tele-Pole

Offline Mandrake

  • Forecaster
  • *****
  • Posts: 1102
Re: Rechargable or non-rechargable battery for WH2900 (ws-2902a clone)
« Reply #2 on: May 24, 2019, 02:09:47 PM »
I would also further add that rechargeable batteries actually have a slightly lower voltage than Alkaline or Lithium batteries and as a result you may well get much less life between recharges and even possibly a reduced signal range from the sensor array.
So in general....don't use rechargeable, more trouble than they are worth for this type of application!
G1ZFO

Ecowitt HP2551A + WH65 Tri-Wing (Wunderground: IGUILDFO67)
Ecowitt GW1000 (Wunderground: IGUILDFO68)
Ecowitt GW1000 (Mk2) test environment driving CumulusMX on a RPi 3b
Ecowitt GW2000 (Test)
Ecowitt WS90 Wittboy - Test
Ecowitt WH51 (x6) Soil Moisture Sensor
Ecowitt WH41 PM2.5 AQM Sensor
Ecowitt WH31 (x8) Thermo/Hygro Sensor
Ecowitt WS80 Ultrasonic Anemometer (pre-prod test)
Ecowitt WH57 Lightning Sensor -test
Ecowitt WH32-EP (SHT35) + Davis 7714 Screen
Ecowitt WH45 CO2/PM2.5/PM10 -Test
Ecowitt WN34 Soil Temp Sensor -Test
Ecowitt WN34 Water Temp Sensor -Test
Ecowitt WN35 Leaf Moisture