Backup power for the water pump?

[saveasteading]

If the power was to fail, the water pump would not work. (Water comes from a distant well, by gravity, to a tank, and then is pumped, with the opening of a tap causing the pump to fire up.) Torches will provide light but water is needed. Is there an easy way to power the water pump?

A generator would be over the top, and would either be running unnecessarily or cycling on and off every time a tap was opened.

A battery seems like the answer. Enough power for a couple of days perhaps, so it could either be trickle charged by solar or wind, or simply on the mains. It would need some intelligence to cut in and out.

I'm thinking this must be a standard thing and doesn't need reinventing.

[Conor]

UPS for a computer?

 

How often does your power go out? Am I the only one who's power only goes off like once every 5 years, for a few mins?!

[JohnMo]

Why not look at from a slightly different perspective. Instead of an electric energy store why not a water store if you have enough space. An accumulator with a pressure switch to control the pump. The accumulator goes between pump and house can be quite big, reduces pump cycles and provides a reservoir of pressurised water 

[ProDave]

Lots of rural properties around here with private water and the best systems I have seen is a borehole pump to charge a large accumulator controlled by a pressure switch.  Even without the pump (during a power cut) there will still be 200 or more litres of pressurised water in the accumulator.

 

 

[Huckleberrys]

I have a borehole filling a 1000 litre break tank which is then pumped into the house. If power goes off there is a 1000litres of fresh water I can access but the best option I would do is then run a extension lead to my battery and it's emergency socket!

[saveasteading]

  On 23/09/2024 at 18:20, Huckleberrys said:

extension lead to my battery and it's emergency socket!

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Probably all we will do.

The discusson has been helpful. We will need to make it foolproof though. Perhaps a plug  that can only go into the mains or the battery, with some warning tag on it.

A worthwhile battery seems to be about £300.

OR put up with the inefficiency of a generator running.

[JohnMo]

Fool proof - As at @ProDave says, zero input required for a couple of days. Zero electric needed either.

[saveasteading]

  On 23/09/2024 at 19:06, JohnMo said:

Fool proof

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But £800 plus labour, and a lot of space, which isn't available.

[SteamyTea]

 

  On 23/09/2024 at 08:40, Conor said:

Am I the only one who's power only goes off like once every 5 years, for a few mins

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No, I think in 20 years my power has been off 3 times, only once for over half an hour. And I live in a very windy place.

[ProDave]

  On 24/09/2024 at 14:35, SteamyTea said:

 

No, I think in 20 years my power has been off 3 times, only once for over half an hour. And I live in a very windy place.

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Anyone on overhead lines and with trees nearby can get power cuts in a storm, and our record was 5 days before reconnection.  When our fault only affects a few houses it gets pushed to the bottom of the pile when there are lots of faults affecting more people.

[Iceverge]

I trialed an inverter coupled to the car battery a few years ago to power the house. A car alternator can be 100A at 14v so 1400w. Plenty for most stuff.

 

 

It was only a cheap square wave inverter.

 

It worked perfectly for everything with a built in rectifier like TVs and phone chargers. Same for resistive loads like incandescent bulbs, it even made a fair attempt to boil the kettle.

 

However it was not happy with inductive loads like the hob and it didn't play well with LED bulbs. 

 

I sent it back and got one for these. 

 

 

I still think a better pure sine wave inverter and quick connectors to the car battery like @markocosic suggested might be a good idea. Maybe add a leisure battery and just charge that from the car a couple of times a day. 

 

 

 

 

[JohnMo]

I was just using this initially 

 

https://hyundaipowerequipment.co.uk/p1-p10000le-7-9kw-9-8kva-recoil-electric-start-site-petrol-generator-powered-by-hyundai?absrc=Google&abid=&abcampid=20457680345&abgroupid=&gclid=Cj0KCQjwxsm3BhDrARIsAMtVz6OdU063Hh0q_OXZ9cG9n3YoyecXIdDMUai4B6yBIx4tceC0UWEQsz8aAmiLEALw_wcB&abkwdid=&tw_source=google&tw_adid=&tw_campaign=20457680345&gad_source=1

 

Ran whole house, including LED lights, induction hob and ASHP and borehole pump. Just add a mains change over switch.

[Dave Jones]

https://www.ebay.co.uk/p/133932680?iid=276577545350

[markocosic]

  On 25/09/2024 at 07:47, Dave Jones said:

https://www.ebay.co.uk/p/133932680?iid=276577545350

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Good shout @Dave Jones - probably far better kit than fleaBay / Alibaba special inverters and can notify of an outage at more rural properties.

 

- Any idea what the standby usage of such units is? (to maintain batteries in a charged state)

 

- What internal voltage do the run on the DC side? (is it viable to run them from a 12V car? if yes up to what size?)

 

- How do they handle nasty loads? (motor start; induction hobs etc that might go from zero to hero or otherwise abuse the output stage)

 

I may add a used UPS to the Xmas list. 🙂

[markocosic]

Looks like the bigger rack mount units are pure sine rather than modified sine: