smoke alarms on inverter

We've just built an off-grid retirement home and are having problems with smoke alarms that are required by local building codes. Three out of seven of them 'chirp'. They are interconnected and mains powered with individual battery backups on each one. We've replaced all their backup batteries and they still chirp. I doubt that we have almost half of them bad right out of the box.

Our inverter, etc is a brand new powercenter DR2424 from Trace/Xantrex. It runs lights just fine. As almost any inverter would. We don't have any other loads on the system. All appliances are propane so we don't mind the minor constant draw of the smoke alarms.

No, I haven't tested the voltage and frequency the inverter puts out. Simple answer is that I don't have the meters to do so.

Do smoke alarms need sign-wave power? Do smoke alarms need EXACT voltage. Do smoke alarms need EXACT frequency. Suggestions?



Reply to
Don Miller
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Make, model of detector?

Charles Perry P.E.

Reply to
Charles Perry

Trace/Xantrex DR2424 is a "modified sinewave" output inverter which uses 24VDC to produce 120VAC. Modified sinewave is typically a pulse-width-modulated square wave. Because battery voltage can range from 21 to 26VDC, the peak voltage of stepped wave can vary from 137 to 170 volts (since peak of sinewave 120VAC is 170 volts, it starts at

170 volts peak at battery voltage of 26VDC and then drops to 137 volts peak at low battery shutdown at about 21VDC).

This difference of peak voltage might be interpreted by the smoke alarm detector that it is not really getting 120VAC and starts using the battery (which might trigger the alarm letting people know that battery drain is going on).

Just an educated guess.

Nam Paik

Reply to
Nam Paik

There are dc powered alarms. Contact an alarm company. We use these all the time in communication shelters.

Bill Kaszeta Photovoltaic Resources Int'l Tempe Arizona USA

Reply to
Bill Kaszeta / Photovoltaic Resources

problems with

Three out of seven

with individual

backup batteries and

bad right out of

Trace/Xantrex. It

don't have any

don't mind the

puts out.

they are instuments... the output of which is affected by the input..if the input is glitchy... the output will be glitchy... my solution would be to trade in the line powered smoke alarms for battery powered ones.

just cut the wire... glue the new ones to the ceiling. yer done.

Phil Scott

Reply to
Phil Scott

Inverters often need a minimum load to run well, say a light bulb or two. Do the alarms only chirp when all the lights are off?

If you are off grid then this isn't the first problem of this nature you are going to have ... I would first go to Radio Shack and get a $25 meter. Then the problem can be solved logically.

"You cannot control what you cannot measure." -- Lord Kelvin (just another dead white man, he doesn't matter anymore I am told ...)

Reply to
Nicholas O. Lindan

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