Boiler/Heat Back-up

The basic electrical equation applies:

Amps x Volts = Watts

1.7 amps x 120volts = 204 watts

204 watts / 12 volts = 17 amps draw on the battery

The amp - hour capacity of the battery will determine the run time.

HOWEVER, remember as the battery discharges, the voltage output will drop which will cause the amp draw to increase. If it exceeds the rated full load amp of the motor, an overload condition will result, possibly burning out the motor. So, keep a close check on the voltage output of the battery.

g scott

Dear Sir,

We are dealing in Electrical Heat Tracing System for maintain the temperature.

As you are using boiler for your plant so if there is any requirment so kindly provide me the enquiry for same.

Thanks & Regards

Ashish

919350645260

An off-the-shelf UPS will do this job.

There is a problem with the accuracy of the 1.7 amps. If the boiler has a blower plus a pump and relay, how many amps total.

If there is no blower and the name plate on the pump states x amps, those are probably startup amps rather than continuous amps so you need to tell us the continuous amps total rather than start up amps.

The inverter must be sized for startup amps. The battery must be sized for continuous amps.

~20Amps@12VDC

how
much run time per charge?

RUN time?-Well ,how long do you need to use the Inverter? Recharge time will dsepend on

1. How many Max. Amps you can push into the Battery &
2. How long you will use the Batt. to run the Inverter

Here's some additional info:

Inverters are usually rated in watts, not amps.....I suspect the inverter in question is a 300 watt inverter, which is a rather small one. It may handle a 204 watt load provided the inrush current lasts for only a "split" second, otherwise the pump motor may not come up to speed, which will certainly overload the inverter.

Not knowing exactly what the 1.7 amp circuit entails, but assuming that it is just the pump motor and relay (relay would draw maybe 0.2 amp), the pump would draw 1.5 amp. This indicates a very small electric motor, something in the neighborhood of 1/8 hp or less. These little pumps circulate water in small hot water heating systems. It is very unlikely that the boiler uses a blower. Most of the burners in residential boilers are atmospheric type. However, the new condensing, high efficiency boilers do use a blower.

Usually the name plate motor ratings includes Voltage; Phase; LRA- locked rotor amps, which is the instanteous draw on motor at startup; FLA- full load amps, which is the amp draw when the pump is fully loaded. A clamp-on ammeter will verify the amp draw.

There are small gasoline powered emergency generators, 1000 W or so, that would provide a more reliable back-up and also provide for a couple of lights, etc. Hope this helps.

g scott

The motor in the pump will present a problem. The initial turn-on surge of motors is in the range of 5 to 10 times the motor's steady state current. The surge is brief, maybe up to 1 second for a small motor, but a 300 watt inverter will not support even that brief surge.

Not only will you need a higher rated inverter, but also an inverter that is rated for a motor load. Check here for some technical info:

http://www.theinverterstore.com/faqs.html

Good luck. In the future I will be putting my well pump on battery backup, and may even use solar to recharge the batteries in case the grid goes down for an extended period of time (no electricity - no water!). I already found out that the conversion can be $$$ because my needs will be over 1 KW. Still researching.

Jim