SLROC Forum

Hi All,

I'm told I need a new battery for my 90 ( 200tdi ), I just want to check before I spend the money, only had the vehicle for a few weeks and had noticed that if I left it parked up for a couple of days it wouldn't start, turned over very slow then just clicked.

I thought something might be draining the battery so today I fitted a battery isolator switch , had the battery on charge all night and on checking it the meter said it was fine. Anyway quick run to town about 10 miles and I switched it off and it wouldn't start again, very slow turn over. I have to say the ignition light does not work so I didn't know if it was charging.

I managed to bump start and took it to a mechanic I knew, meter showed it charging at about 12v or just under , he said it should be around 14v, he then put a device on the battery ,( spike in each terminal ) and it showed poor battery, he also said one of the cells was bubbling when he did that and that was the sign of a dead cell.

Another bump start and drove home, when home I switched off and again it would not start again, however about an hour later I went to it and it started this time!!!!

Any thoughts,

Ta

Donald.

Think you have a two fold problem here knackerd batt and alt....

Just had a think about that the knackered batt might be drawing the alt voltage down . Try a new batt first...

Daft question, you are waiting for the glow plugs to switch off aren't you, if I forget (which is frequently) mine is very slow. But it does sound like a duff battery

Hi Dave,

Yes letting glow plugs heat up, it's an easy starter but battery barely turning engine over and then just clicks.

It's strange that after a good run for about 15 mins it won't start after switched off,

I have no idea about electrics and going away for a few days so will probably get a battery when I get back,

Ta

Donald

Agree with aliipod you have two probs. battery and alternator . I would be testing alternator first to see if it's charging battery but sounds like its not .

Hi Piwi,

How do I test alternator ??

Cheers

Donald

Put a volt meter across your battery terminals and note the reading.
Start the engine  and repeat, you ay need some revs to excite the alternator. You should now have a reading of 13.5v. If it reads the same as before, you want to take a reading from the back of the alternator. Black to a good earth poin and the other test lead goes to the output terminal of the alternator the one with the big (hopefully red) lead.
It could be a poor connection on the + or - side.



Just reading up on split charging systems

Some one the other day was on about draining battery liquid then letting them sit upside down for a day or two then refilling them and it was supposedly meant to help your battery work for longer!  allthough i cant confirm this actually works as i have not tried it!

Cheers guys for all your useful comments, the battery reads 12v no matter what the revs are at( liquid bubbling on end cell when large metal prong thing put on to test ) ,mechanic says that's the sign of a fault cell?

I checked the alternator today again reading just under 12v , there are two thick brown wires and a thinner red wire coming from the positive side of alternator but the short thin black wire with spade terminal connection on it is NOT connected to anything Would this make any difference, I am nearly beat here and away tomorrow for a week so I am considering putting it in somewhere .


Cheers

Donald

Large metal prongs - will be a drop test. Even if a battery reads 12v doesn't mean it holds it charge. This test measures the battery discharge rate with a heavy load. If the reading from this is bad, then a sure sign you need a new battery. You can also test individual cells with a hydrometer, it will tell which cell is giving the problem.

 

My  alt, has 2 thick wires & 1 thin wire. There is another terminal unused - I best go check I'm charging 
From your readings, it sounds like your not getting a charge. It could be the diode pack at fault, this is repirable on the alternator.  But near in mind an alternator will struggle to charge a duff battery.

I know in old minis and the like the charging light in the dash was part of the charging circuit, if the bulb blew then it wouldn't charge, don't know it it would be the same in a 90, just a thought as its cheaper than a battery or alternator.

Knuckles,

I have checked the bulb in dash and its okay, problem is it never comes on ?? Even when ignition turned on so it doesn't seem to be wired properly,

Thanks anyway

Donald

You need to fit a battery to start with, then get an alternator from someone on here. that way you know all on the charging side is good and reliable. then find the fault with the ign light on the dash. it might be that someone has disconected it from the alternator so its not on all the time (as it would be with a nackered alternator)
Drew.

If i remember correctly the thin wire on your alternator is for the charging light check to see if there's a break in the wire.