thermostat without battery

strange I've only ever put 1 new set (2 in total) in ours - duff batteries? ebay it:>)

JimK

Don't know the answer, but there must be something wrong with 'stat/battery. My Drayton RF3 has 2x2AA batteries in (1 for 'stat, 1 for RF, I assume) and they last for 3 - 4 years; even after that, the voltage is about 1.4 and each of the 4 cells will run a clock for 6 - 9 months.

bimetals are more reliable

NT

Well, Honeywell and Sunvic models all require batteries.

Drayton have hardwired versions.

e.g.

You might also check Danfoss Randall and Myson ranges.

Don't think you'll find a non battery one with a digital display. These aftermarket ones have to be universal - it might have to switch mains or low volts, and may not have a neutral available for a power supply to get the power for the display and electronics. And, of course, the power to the sat is removed when the system switches off at night.

The problem with yours is it's wireless. My wired programmable one had a battery life of approx two years.

Provide the name of the thermostat - I guess someone will have one the same. As others have said, I suspect poor batteries.

Horstmann. But wired rather than wireless. A wireless one *must* use more current. And may also use a more expensive type of battery like a PP3. AAs give the best value.

A decent wireless one should give more than 3 months battery life. My Honeywell CM927 is still running fine on the original pair of Duracell AA's after 2 years.

Thanks folks. I will see how long the current Duracell batteries last. It's annoying though that a device which has a mains supply (not my wireless thermostat) needs a separate battery at all.

I explained that. Quite logical if you think about it.

You need a 3 core cable from the boiler to the stat.

Andrew

Thanks folks. I will see how long the current Duracell batteries last. It's annoying though that a device which has a mains supply (not my wireless thermostat) needs a separate battery at all.

Whenever it needs to switch it has to transmit a radio signal to the receiver. This takes significant power.

Is there an option to turn off the display to save battery power?

Hi,

Some of the Honeywell radio stats can be set to 80% duty cycle when reception has been lost. Read the manual to set this.

andyv wrote:

Perhaps check on the thermostat to see if there's an option for how often it transmits? Not an expert on thermostats but quite a few remote sensors have such an option. If its transmitting every 20 sec it'll use a lot more power than every 5 min.

On Thu, 04 Feb 2010 17:46:31 +0000 (GMT) someone who may be "Dave Plowman (News)" wrote this:-

Not in the least logical.

Some programmers are fitted with rechargeable batteries which will keep them going for a considerable time. A thermostat could have a similar arrangement, but it would cost a little bit of money to fit the transformer and so on. If mains is available from time to time then this keeps the battery charged. Otherwise fresh cells need to be inserted.

What makes it worse is that some manufacturers, go to the naughty step Horstmann, produce s***ty equipment which cannot be powered by rechargeable batteries, as within a week or two the thermostat is whining that the battery is discharged. I used to like their equipment, but this has turned me right off them.

Rechargables are 1.2 volts and most will 'self discharge' over a few weeks - Look at Sanyo ENELOOP - these do not self discharge. I have had some in my camera for about 6 weeks - previous rechargeables would be flat by now.

On Thu, 4 Feb 2010 21:06:21 -0000 someone who may be "John" wrote this:-

I know.

The same batteries will operate remote controls for months, so self discharge is not as great a problem as some think.

usually use alkaline batteries and these are good for about 3 years (maybe more).

I believe rechargeables with their 1.2v are more suited to a higher discharge device where a normal alkaline probably only gives 1.2 v anyway - when subjected to a high load.

Incidentally - Eneloop batteries come ready charged.

All those add considerably to the cost and size. You then have the problem that it will no longer work on a low volt switching circuit without first providing a mains supply to it.

Common with most things. Rechargeable cells have a lower voltage. Adding an extra cell would get round this in some apps. If you designed the device to still work at the sort of voltage a rechargeable can still give adequate current it wouldn't warn of low batteries with alkalines.

My Horstmann programmable batteries lasted over 2 years which I found acceptable. Rechargeables might well fail not long after this - so don't really give a true advantage. Since the mains would be removed when the system shuts down at night (unless you re-wire things) they would be cycling at least once a day. And 600 cycles is more than many rechargeables can manage.