D2 flat battery - jump starting.

[mannyo]

Went to start my old D2 this evening and the battery does not have enough power to operate the starter. The interior lights etc. all work.

The car is currently declared SORN and uninsured, so has not been driven on a public road for 2 weeks. Prior to that, its only done short runs for 3 weeks or so.

Once I source some jump leads and a donor battery, how do I jump start the D2. The car is reversed into a parking bay, so it is not possible to get another car alongside to use so I'll have to go direct from a freestanding power source.

Or could I get one of those solar trickle chargers and plug this into the 12V cigarette lighter socket, and leave it there for a few days perhaps.

[HPsauce]

Solar trickle charge won't make any difference, you need a mains one running for a fair few hours.
Can you not get a mains extension lead near enough to run a battery charger sitting in the boot? I've done that before to cars on my driveway.

D2's aren't particularly fussed about flat batteries so I'd borrow a decent-sized one and use it to jump-start if you need to do it quickly.

Ideally get some long, thick jump leads such as AA/RAC use and start it from a car with the engine running. 6m seem to be readily available and the car is about 5m long.

[mannyo]

The car is outside, but yes I can easily get mains power to the boot of the car as long as its dry that is. I may buy a halfords charger, they do several. I guess I need to disconnect the negative lead whilst charging.

I want to get a trickle charger anyway, as I want to update the MMI on my D3 and it seems recommended to hookup a trickle charger.

[HPsauce]

Originally Posted by mannyo

I guess I need to disconnect the negative lead whilst charging.

Not really, I've never bothered.
With most chargers you do need to connect (positive first) BEFORE turning them on.

As for dry weather, I just run a long extension out of a window and up over the boot lid at the rear so no connections are exposed. Making sure that the cables are looped downwards so that any rain runs off externally, not into the boot or through the window.
Being careful I then put the socket of the extension on top of something like a box so that it's high up in the boot and there's no chance of water creeping in.
Best place to take the cable in is either bottom corner, there's enough gap.

Or if you have a ski hatch up under the bottom of the rear door (back end, or between front & rear doors ) and through the hatch.

[Dezzy]

You'll be able to get her in neutral Manno and drag her out a bit. If not i have used a jumper pack to start my old girl before, that you'd be able to get in the boot.

[mannyo]

I've purchased a charger, hopefully it will do the job. I won't know until the weekend, since I am not at home where the D2 is.

[mannyo]

I think I need a more beefy charger, the one I have only outputs just under 1 amp. its been on the D2 from 10am this morning, and at 3pm the car will crank but will not start. it turns over, then it almost catches, keeping on the starter it almost runs but the battery runs out of oomph.

Looks like I have a recurrence of the problem I had in July 2012 when the car was left for 4 weeks, where its going to need a lot of cranking to start. Thats fine with a fully charged battery, but its cold and the battery really needs to be fully charged.
http://forum.a8parts.co.uk/showthread.php?t=5101

I have a petrol can for the lawn mower, so next time will add some directly to the car just before trying to start, as per that thread.

She is back on the charger again, I'll leave it charging until late this evening and then resume in the morning. I cannot leave the mains cable trailing out through the front door all night.

Jump leads might work, but I don't want to use the D3 as the donor car because (1) its just had a new battery and (2) the risk to the D3 electronics is just too great to chance it.

[B@fink]

5 hours is probably not long enough to put anything like significant charge into a such a big battery (esp with only 1amp!!!!) you might not need a beefier charger as it's putting charge into the battery, it might just need longer to get a near flat battery on its feet. Hopefully with the extended charging time you are giving it it'll spring into life.

[HPsauce]

Originally Posted by B@fink

5 hours is probably not long enough

DEFINITELY.
We're talking about 100Ah batteries here (or thereabouts) and charging efficiency is way below 100%.
I'd GENUINELY allow a whole WEEK non-stop with that charger.

[ainarssems]

Originally Posted by HPsauce

DEFINITELY.
We're talking about 100Ah batteries here (or thereabouts) and charging efficiency is way below 100%.
I'd GENUINELY allow a whole WEEK non-stop with that charger.

^+ What he said.

5 hours @1A is 5Ah at 100% efficiency(actual varies greatly depending on several variables 0-92%) Let's say you got 80% efficiency, that's 4Ah - less than what you get in scooter battery. Considering it was still operating lights it probably had 5-10% charge in it so after charging it was 10-15% and you probably need 20-25% to start the car. For a good battery of that size (95AH) you expect 12+ hours @10A to go from 10% to 90%. Good battery with low charge level will charge at 80-90% efficiency but it will drop as battery gets more charged. If you have full battery efficiency will be 0% as you will be putting in current but charge will not be increasing, you will just use energy to split water in H2 and O2. Bad/damaged battery charge efficiency can be considerably lower.

Question is if the charger is 1A only or battery is only taking 1A in.

I have several power supplies around he home- laptop, NAS and others around the home at 12V ranging from 2A to 7.5A which could be used to charge battery at faster rate if my battery charger went down. They would not charge it to 100% as idle voltage is only 13-13.5V but they would probably get it up to 70-80% and at 7.5A they would get there a lot faster then 1A charger. So have a look around the house you might have unsuspected suitable hardware lying around.