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Workshop Convenient low voltage source

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Posts: 227

Some time ago I ordered a USB power bank "jump starter" and this week it arrived. The jump cables and croc clips are surprisingly good quality although I doubt I'll ever use it for jump starting. The main reason I wanted it was as a convenient clean 12V source, it is ideal as it can be charged easily by USB and is also a standard USB power bank. There is also an LED torch as is standard on most USB power banks. I thought I may have to butcher the jump start cables but the connector is an EC5 battery connector which is readily available, an inline fuse is required for safety as these are direct output of the lithium battery. Units like this are available from online retailers, I paid less than £20 including shipping. As with all this stuff, never leave it charging unattended and I like to keep it in an old metal tin with the rubber terminal plug in when not in use.

PS: Tonight at Lidl, heat-shrink variety pack £2.99.

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Topic starter Posted : 24/04/2021 10:38 pm
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Posts: 226


Thankyou for posting this.

Last winter, I bought a similar car jump starter with a lithium rechargeable battery inside. It came with plug-in crocodile clips having the same sort of plug as yours. I didn't realise it was a standard type.

I actually used mine to start my car on a cold morning when the car's own battery was too weak. It worked - I was quite impressed. I also thought about using the unit as a portable 12v power supply, but didn't want to chop up the included croc clip lead because it had been useful. After a search on aliexpress, I found a company selling an EC5 plug to car cigarette lighter socket cable for around £2 including delivery, so I ordered one. It arrived in 10 days and worked exactly as I had hoped for. When plugged into the jump starter, it gives a cigarette lighter socket output into which you can plug standard car accessories and power them from the portable jump starter.

I already had an inverter that plugs into a cigarette lighter socket and generates 240v AC from 12v DC. This makes the jump starter into a portable source of mains power (up to 100W) - very handy indeed. Only one minor issue. The first inverter I tried did not work. When I measured the jump starter battery voltage, it was 15v instead of 12 - 13.8v as usual in a car. Perhaps the inverter detected the voltage was out of range and shut down (they normally shut down when the battery voltage is too low). Anyway I tried a different inverter and that worked.

The EC5 to cigarette lighter socket cable I bought did not have any fuse protection which is a bit naughty considering a short circuit could result in a fire or explosion of the lithium battery. I ought to add a fuse to it, and certainly not leave it plugged in unattended. Otherwise I'm happy now that the jump starter has gained extra usefulness.

Posted : 21/05/2021 3:56 pm