Hi guys, quick question for you. Sometimes the car will startup straight away, other times it needs a good 5-10secs of cranking. Had a look at the alternator and it reads 14-14.1 (measured from the back of it) which seems in the right ball park but measure the battery and it shows 13.5-13.6, this seems a bit low to me. What do you reckon?

Thanks

Edit: 98 4.6hse

If you are getting 14 - 14.1V at the alternator, but only 13.5-13.6V at the battery than that suggests to me that either your +ve cable from the alternator, or the earth straps from the engine block/suspension strut to the battery are corroded internally and that's giving you a voltage drop.

If you have a '98 GEMS, then check and see if you have a direct +ve cable from the alternator to the battery terminal. Earlier ones had a cable from the alternator to the starter, and then a single +ve from the starter to the battery. So you're cable length for the charging circuit was stupidly long, and fairly open to contaminants, especially if you have an oil or coolant leak that drips around the starter.

I think later GEMS models had an additional +ve cable direct from the alternator to the battery fitted - if you don't have this, then it's worth adding one.

You can check the health of the +ve/ground wires by switching your multimeter to millivolts (mV) and measuring between the alternator +ve and the Battery +ve terminals first, and then the engine block and battery -ve post with a decent load on the electrical system (headlights on, AC blowers up etc) and the engine at around 2000rpm.

Ideally you should see no more than 130mV on ANY of them. (so no more than 130mV on +ve, and no more then 130mV on the engine block to battery -ve) If you do, then the cable is faulty. You can narrow down the ground side by measuring from the engine block to the ground point on the suspension tower, and then from the tower to the battery -ve terminal.

There was a LR TSB ages ago which had these figures in it - but with new +ve/ground wires you can get the voltage drop down to about 30mV.

It's also worth checking the ground points etc and cleaning them and the battery terminals up to make sure they aren't causing any voltage drop issues too.

Hope this helps.
Marty

Hi Marty,

Many thanks for your advice. Mine lloks like it has a +ve from the alternator - starter motor - battery. Couldn't see the starter motor side but the battery and alternator side the cable looks ok. The ground, however, looks in pretty poor condition so that will need replacing. Juding by all the corrosion it's been festering for a while.


Any Advice on where to get a replacement? Would halfords be a good place or on oline shop? Don't mind if it's a few days as I'm waiting on some lpg bits to arrive.

Also, whilst I was having a look I found the lonesome connector. No idea what it's for. Can't find anything that's missing a connector. It's on the loom behind the ecu box

Thanks for the help and I've going to have to pick your brains about adding an additional battery, inverter, extra power sockets etc.

thanks
mick

EDIT: can't work out why image aren't displaying, using imageupload

If you don't have a direct connection from the Alternator to the battery +ve then I'd be looking at adding one at some point. From memory, there was a TSB on adding one on earlier GEMS vehicles...

Whilst the cables can look ok - it really needs to be measured with a multimeter to see what the actual voltage drop is along the cable - the ends of the cable can look fine, but you can get internal corrosion which isn't visible, but yet creates more resistance in the cable, and more voltage drop - again meaning not as much charge getting to your battery.

The pictures showed up in the email notification I got about the thread - so saw the state of that ground one... it does look a bit crusty!

You can get generic earth straps that are made up - which will be easy enough for the one from the suspension tower to the engine block.
From memory, the one from the suspension tower to the battery -ve includes the battery terminal and another ground point half way along. You could either get a second earth strap to run in parallel, or you can probably order an actual Land Rover one, which will have the proper connections on it, so it's a direct replacement.
The part number for the cable from the -ve battery terminal to the first ground point and on to the suspension tower (up to VIN WA410481) is: AMR3424, superceded by AMR6655, superceded by YTB101150. So any of those part numbers should work (I presume you have a GEMS vehicle? If Thor - let me know and I'll get the part number for that...)

If they are stupidly expensive, then an auto electrical shop should be able to make one up. I ended up making my own, as I was installing a split charge system at the same time, and bought a set of hydraulic crimpers to do all of my cable terminations. The only thing I would recommend with getting them made is get the biggest size possible, given how hungry P38's are for power!

You might get away with cleaning up the end of the ground cable from the battery with some sandpaper, and a thin coat of dielectric grease, and see if that improves things. The strap from the suspension tower to the engine block should be easy enough to replace with a generic one though.

Hope this helps... Feel free to pick my brains about split charge systems and all that.. can post pics of my install if needed.

Cheers,
Marty