Using a ebike battery as a mains power supply

[brucelee]

Hi all,

I've a couple of 12Ah 36v Yose power batteries and was looking for a contingency plan just in case the utility companies can't do their math right (know what I mean?). Seems to me it would have occurred to a few other people and there might already be a thread some where... I'm aware of stuff like this :

WGE 36V DC Power Inverter To 220V AC Converter, AC Socket Car Inverter,500W : Amazon.co.uk: Electronics & Photo but was thinking it looks a bit iffy with a dc-dc converter on the front end. Also concerned about how it would handle start up current on things like fridges and central heating pumps. Anyone mulled this one over?

Cheers,

Bruce.

[Jdsk]

There's a lot of this sort of stuff in the world of caravans. And presumably of small boats. And of survivalists.

Have you done any calculations of how long they would run essential domestic appliances?

Jonathan

[Nearholmer]

Besides emergency lighting, which might be better done using low voltage LED lamps anyway, are you going to be able to run anything worthwhile for any worthwhile duration from a battery with a capacity that low?

[brucelee]

Besides emergency lighting, which might be better done using low voltage LED lamps anyway, are you going to be able to run anything worthwhile for any worthwhile duration from a battery with a capacity that low?

432Wh, fridge/freezer (70W) 6 hrs continuously guessing this would be enough for a couple of days in practice,
Central heating (~40W) 10 hrs continuously
Worst case they're talking about rolling blackouts of 3hrs, with two bats this would easily cover Heating, refrigeration and TV of course.

[brucelee]

There's a lot of this sort of stuff in the world of caravans. And presumably of small boats. And of survivalists.

I guessing these guys use 12/24v, there's plenty of that about but not for 36v.

[irc]

I thought briefly about a backup for CH etc but decided the cost and hassle wasn't worth it.

Preparation we have done is.
Assume it may be longer than 3 hours
Already have battery radio.
Already have power bank for keeping phone charged.
Worth carrying minimum cash in case shop payment systems down but they are taking cash.
Head torches placed in easy to find places up and downstairs.
Two £5 LED lamps bought from Asda
Don't let car tank go too close to empty.

That's it. House will cool down but we have duvets and sleeping bags etc
Assuming blackouts happen during cold windless spell keep a carton of milk outside the back door to reduce the times fridge is opened.
We have a gas hob so cooking and tea and coffee making will continue.

[rjb]

This thought crossed my mind too. I could use my 36v. 12amphr (approx 1/2 kw hour,) bike battery as a power wall with my solar PV. I would need a new hybrid inverter to charge the battery from the solar panels and an inverter to connect the battery to the mains.
Or even just charge up the battery and use an inverter to power stuff locally, anything I could plug in.

[Dingdong]

Would lead acid car batteries not be a much more commercially viable option? In case of emergency?

[Jdsk]

I think that the idea was opportunistic... the eBike batteries are already paid for and available.

Jonathan

[hemo]

Not forgetting any inverter conversion from 36v to 240v will likley lose 15% capacity during the process so in reality one is talking 370wh.

[axel_knutt]

Central heating (~40W) 10 hrs continuously

My Worcester Bosch 28 CDi uses 105W peak,1W on standby, and 6W mean.

I thought briefly about a backup for CH etc but decided the cost and hassle wasn't worth it.

I've got all the bits on my Amazon wish list, but I dare say they'll be sold out within minutes of the first power cut. An inverter, SLA, & charger costing £66 will give me ~10 hours of heating. A caravan/boat battery costs a bit more than it's worth.

Would lead acid car batteries not be a much more commercially viable option? In case of emergency?

They're not designed for deep discharge, a caravan/boat battery would be more suitable.