Car battery jumper packs

That should do the battery a lot of good.

When testing, park the vehicle at the top of a hill so that you can bump start it by running it off down the hill when the jumper pack fails to start it.

[...]

As long as it was recharged within a day or so, it will do it no harm whatsoever.

It's leaving batteries flat for extended periods that shorten their life.

Chris

+1

I've used mine "in anger" for starting vehicles a couple of times, in addition to using them to charge phones, run a tyre pump, and run a satnav after the cigar lighter cable failed.

Planning to keep one in each car, over the winter.

Don't believe that one has 51 Amp-hours for a minute. But they do work, you just have to follow the instructions. Some of us in uk.d-i-y understand the adiabatic equation.

It probably is 51Ahr. It will have a 3.7V 51Ahr battery in it probably at the 10hr rate. That is not the same as a 51Ahr 12V car battery.

On reflection, you could be right. Of course the figure is only meaningful if you state explicitly the voltage at which these amps are delivered.

My similar sized Floureon T3 only claims 18 amp-hours (no voltage stated).

You would effectively have a deep discharge if the above advice was followed and car batteries are not suitable for such use.

"SLI Batteries (Starting Lighting and Ignition)

This is the typical automotive battery application. Automotive batteries are designed to be fully charged when starting the car; after starting the vehicle, the lost charge, typically 2% to 5% of the charge, is replaced by the alternator and the battery remains fully charged. These batteries are not designed to be discharged below 50% Depth of Discharge (DOD) and discharging below these levels can damage the plates and shorten battery life."

and

"Completely discharging the battery may cause irreparable damage."

That's not saying that most wouldn't recover if only left discharged to any real depth for a short period but it's not supposed to be a good idea.

Cheers, T i m

Read again what I posted.

'...until the battery voltage is below the threshold for cranking.'

would not constitute a deep discharge, and would be an order of magnitude safer than testing the jumper pack with the main battery disconnected.

Chris

also there is no way that crocodile clips will take a couple of hundred amps. I once tried to jump start a hot diesel where the battery had died at the end of a long run home, I was using serious jump leads but could not get enough power through those to operate the starter, the battery must have broken internally as it would not accept any charge at all to buffer the starting. I had to put on a fiesta battery to get it going, to park it up till I could get a proper size battery for it.

OOI, how deep a level of discharge would a SLI battery be before it couldn't crank the car it was designed for would you say? 75%, 50%,

25%?

That we agree on. ;-)

Cheers, T i m

[...]

How long is a piece of string?

State of battery? (Age, number of times it had been fully discharged.) Age/condition of starter motor? Age/condition of engine? Type of engine oil used? (Viscosity.) Ambient temperature?

I'm sure there are more.

You would also need to define 'crank'. Modern engines when warm will often start the first time a cylinder goes over TDC on the compression stroke; does that count as cranking?

Chris

My Dad had an old car with a cranking handle. That would start on the first crank ....

So would my A40, I reckon that with no starter load the ignition could give a much healthier spark.

So, what was the last car fitted with a starting handle? I remember my parents Bedford Dormobile having one (arguably not a car though) and their Triumph Herald having one (late 60s/early 70s). Can't recall any family cars after that.

Tim

This was ***very old*** - a 1929 Standard Flying 9 which Dad bought in

1954 ...

1988, 2cv.

Wow. Didn't realise that they carried on so long but I do recall seeing the starting handle hole in their bumpers now that I think about it.

When did minis (original) drop their starting handles?

Tim