modify circulating pump to run off battery power?

bb12

something i've been thinking about but just looking for advice to see if this is a feasable option?

i have a multifuel stove with backboiler that heats the radiators (also have oil heating)

in the event of a powercut i'm just looking for an option to be able to light the stove for heating at least,but the pump is the issue when the pressure builds up. i have an open vented plumbing system with an overflow tank in the attic.

i was thinking that maybe i could get a connector for the electrical supply to the water pump in the hot press that i could plug out in the case of a power cut and then connect to a car battery or similar, so that the pump would still have power to it and i could light the stove.

i'm not sure of the implications between ac/dc power. maybe ii'd need some kind of inverter? electricity is not my strong poing

is this possible and would it work, do you think?

Mod: MOVED FROM PLUMBING AND HEATING

smuggler.ie

nice idea and i would love to know how-to for myself, however...

How you will mange if your battery run flat and stove is on the full blast?

nearly sure there are 12v/24v DC pumps available, not sure if additional regulating electronics would be required

My stove plumbed to be able to operate on gravity circulation in case of power outage. Output pipe goes up to ceiling, then to the hotpress and retun goes under floor.

John.G

https://www.boards.ie/discussion/2058257280/modify-circulating-pump-to-run-off-battery-power

If you have a A rated pump then power consumption ~ 25W, mine is 16/22W with 10/12 rads, so a 50 to 100w inverter to convert 12V DC battery voltage to 230V AC will/should work OK, even the old type 3 speed circ pump will "only" consume ~ 45W on minimum speed 1, so even a 45AH battery should give 6/8 hrs minimum run time @ 45W comnsumption and 16/18 hrs @ 25W consumption, you are probably only looking at 6 hrs or so requirement anyhow.

2011

Or you could simply use a small generator

serox_21

option 1

300W to 600W 12V to 230V pure sine wave inverter (around 120euro from aliexpress) and a leasure 12V battery(at least 100Ah) I think is the way to go.

The cheap inverters are modified sine wave and won't work with a induction motor. Also motors at startup requires up to 5x nominal power.

If the pump has 45W of continuous power usage then a minimum of 300W inverter is required.

option 2:

change the pump to a DC 12V and buy only the batteries. But I think the pump will cost way more than option 1 setup.

John.G

All A rated pumps are DC, done internally in the pump itself, but may not work from a modified sine wave?, the are soft start, ie they do start up....5W,10W,15W, etc up to their normal running load, at least my 6M Wilo Yonis Pico starts up in this fashion.

2011

https://www.boards.ie/discussion/comment/119427127#Comment_119427127

why would shuch a small circulation pump be on a soft starter ??? A domestic circulation pump is DOL. Where is this soft starter installed ?

If not why not?

Soft starters are designed to reduce starting current, not to improve efficiency. This starting current would be too small to bother reducing

Generally motors are not “A rated”, but now that I google it I see it. In industry we talk of “IE3” or “IE4” etc.

Ubbquittious

I have never seen an off-the-shelf DC circulating pump. Though that doesn't mean they don't exist.

Don't under-size your inverter anyway and make sure to use a pure sine one. Otherwise pump might not even start.

John.G

https://www.boards.ie/discussion/comment/119434242#Comment_119434242

Soft start is probably not technically correct but these pumps are variable speed in all their various modes be it CC ( constant curve), CP (constant pressure) or PP (proportional pressure ) mode and on start up they ramp up slowly to whatever power output matches the micro processor's demand, I've often seen mine overshoot by a watt or two and then return to the required power output. Then, as zone valves or thermostatic rad valves close/open the power output changes.