Bongo Fury

Went to clarks village this morning and in the bad weather drove with the lights on, we saw some floods and snow on the hills.

After a shopping trip of a couple of hours went back to the car to find the lights still on and the battery flat.

Now rather than going round the car park asking if any one had some jump leads
we went to find a garage to get some so we would always have a back up, nearest shop 15 min walk and we were told they shut a 1 so it was 12.30 and off we went got there at 12.45 they shut at 12.30
walked back ready to phone the AA, knowing I had a leisure battery and willinton kit trying to work out what I could do to connect the leisure battery to the starter without a jump lead.

Popped the bonnet and looked at the set up and noticed the terminals were 1 inch apart accross the split charge relay.

so I got the wheel brace and shorted the terminals while my wife and boss turned the key.

Started first time

so a car with a flat battery was started with a wheel brace, and never called the AA

much respect .

Next you will be telling us you removed the wheel nuts with jump-leads

Interesting. My split charging relay for the LB is not a voltage sensing one, so just switches with the ignition. I've considered changing it for a sensing type, but the situation you have just described makes me think I'll keep it as is. As long as there's enough juice to flip the relay, she'll start off the LB if I (or more likely, my two year old) leaves the lights on.....

Well done though - very resourceful!

If you do the above, use the L/B to charge the S/B via the SCR, then do WAIT for as long a possible for the charge to transfer across. The SCR is released (if wired correctly) when the ignition switch is moved to the Starting position, if it didn't the fuses between the L/B and S/B would both blow!

A candidate for the most ingenious Bongo repair prize?

I was a bit bothered by the fuses blowing but with willintons 50 amp inlines I thought it worth a try.

the smaller 30 amp supplied by some others I have seen may not do so well

i did simialr to this when had to pick up a bongo from the back of beyond, stopped in a little fuel station just as the guy closed up and left so had bongo with dead battery and no tools, so drove the other bongo nose to nose, went round the back of the garage and aquired er i mean found an old piece of shelving and length of fencing wire, and proceeded to fashion a set of bear grylls style jump leads lol, few sparks and the wire got hot, but got it started lol happy days! so lesson learnt, ALWAYS carry a tool set or at minimum a decent multitool!!

Julian

Only having automatics for over 35 years, I rarely leave home without my jump leads ..

I seem to help more people than myself though ..!!

My jump leads live under the bonnet, and I successfully used my (admittedly 135Ah new Energy Bull LB) to start the car after I left sidelights on and flattened the SB. However, I seem to recall the SB didn't want to turn the engine much just after connection via jump leads, but improved rapidly to give cranking, though still a bit sluggishly (but the TD starts in an instant so no big deal) and I thought that even with the best LBs, its not what they are intended for (pulling high amps) and it can't be the best way to treat them (even though some claim to be dual purpose). So, apart from Geoffs comment on blowing fuses, I think with hindsight that if it happened again I'd try connecting the LB to the SB (in parallel, of course!) and then leave it for a few minutes so the LB could act as a charger for the SB, then see if the SB could manage a quick crank with jump leads disconnected, so that LB was not at risk of having cranking amps pulled out of it.

I'd be interested to get Geoffs thoughts on this, as he is the guru methinks.

Yup that is the way to do it, just use the L/B as a "charger", if that won't do it then bypass all the fuses and relays with a direct connection from +ve terminal to +ve terminal, it won't improve the life of the L/B but it will most likely get you started!
The "problem" with starter motors is that they are series wound motors, this means they can generate a massive amount of torque at very slow speeds, but at the cost of massive currents, for the few milliseconds it takes to get the motor (and engine itself) turning the current can be up in the many 100's of Amps (hence the very high Cold Cranking Amperage rating on S/B batteries) it is these currents that will do in the L/B and anything connected between power source(s) and motor and the reason that the Starter motor and leads to it aren't fused the only device is the internal contactors to switch the power within the motor itself.

g8dhe wrote:Yup that is the way to do it, just use the L/B as a "charger", if that won't do it then bypass all the fuses and relays with a direct connection from +ve terminal to +ve terminal, it won't improve the life of the L/B but it will most likely get you started!
The "problem" with starter motors is that they are series wound motors, this means they can generate a massive amount of torque at very slow speeds, but at the cost of massive currents, for the few milliseconds it takes to get the motor (and engine itself) turning the current can be up in the many 100's of Amps (hence the very high Cold Cranking Amperage rating on S/B batteries) it is these currents that will do in the L/B and anything connected between power source(s) and motor and the reason that the Starter motor and leads to it aren't fused the only device is the internal contactors to switch the power within the motor itself.

Superb explanation as ever Geoff. All us LBers to note methinks.