IamRobbie

IamRobbie

Well-Known Member
Ok so the mrs has gone away for a week with the monster in law which gives me some more landy time :D

Been messing around putting in a cubby box radio voltmeter ect...


When my 90 is on (disco 200tdi lump) It sits at 13.8 v, BUT when my 90 is just on the ignition (no pre heat for the glow plugs ect) It only has 1 ignition light on which is the oil light and the battery is being drained fairly rapid....

The battery doesnt drain without the key in, only when the ignition is clicked on... Even with no fans on or anything.


What could be draining it so quickly?
 
wow that is a massive drop.. oh wait.. you haven't actually posted any figures. i vote for cubby box radio voltmeter etc :D
 
Ok would you like me to go take a video?

When i say it drops fast i mean it drops fast lol.. like something is earthing, but if I'm honest when i swapped the engine and cocked the wiring up i never had a battery warning light since then and when driving at night i can see i have a faint battery light on, very faint... hmm

Also does anyone know what the yellow with brown trace wire is under the bonnet???

Mine is cut and a cable runs from there all the way through the 90 to the back left.. o_O
 
Sounds like a poor earth to the engine block. That leads to all sorts of false readings.

I would be interested to know where you connected your voltmeter. Best place is the battery. If you connect it there, you will probably not see any voltage drop.
 
IamRobbie said:
Ok would you like me to go take a video?

When i say it drops fast i mean it drops fast lol.. like something is earthing, but if I'm honest when i swapped the engine and cocked the wiring up i never had a battery warning light since then and when driving at night i can see i have a faint battery light on, very faint... hmm

Also does anyone know what the yellow with brown trace wire is under the bonnet???

Mine is cut and a cable runs from there all the way through the 90 to the back left.. o_O
Click to expand...

ok, saying drops fast isn't helpful, especially as you seem a bit clueless with electrickery. :p

the brown and yellow trace thin wire is your battery warning lamp, you need that connected to make your alt work properly.

do you have a multimeter?
 
Yes buddy i have multimeter. Get the same readings as that when multimeter is on it also Sp00k mate. Got plenty earths on as when the starter motor packed in the other week i added lots more lol.
 
IamRobbie said:
Yes buddy i have multimeter. Get the same readings as that when multimeter is on it also Sp00k mate. Got plenty earths on as when the starter motor packed in the other week i added lots more lol.
Click to expand...

why do you think you have a huge drain?

first measure your battery voltage after it's been off for a good while. you want it to be up near 12.6v. i can see from your vid it's 12v.. which is flat and i'm surprised it turned over. measure the voltage directly on the battery posts.

then fix your alt wiring. go find the thin brown with yellow trace and stick it on the back of the alt to D+.

see if your batt light now works on ignition and goes off when started.

also measure the voltage at the battery at idle without you blipping the throttle you are really making the alt self energise at higher revs).

post back :)
 
Since ive got no mrs at home to moan at me for walking in and out the house ill go check now :)

Ill go check the battery voltage with my multimeter now, I can leave it turned off for days and it will start fine, its only when i leave the ignition clicked on that it drains.

Ill go do them bits now and ill post back.
 
ok so the multimeter reads 12.97 - 13volts at the battery.

touched the broken brown yellow cables together and you were right i now have a battery warning light :D

Cant understand why it is connected to a blue cable that runs to the back of the truck tho

p.s thank you for sorting the battery light out :)

http://s30.postimg.org/y0zyo8nxt/photo.jpg
 
IamRobbie said:
ok so the multimeter reads 12.97 - 13volts at the battery.

touched the broken brown yellow cables together and you were right i now have a battery warning light :D

Cant understand why it is connected to a blue cable that runs to the back of the truck tho

p.s thank you for sorting the battery light out :)

http://s30.postimg.org/y0zyo8nxt/photo.jpg
Click to expand...

you need to wait for the battery to settle down. have a quick measure in the morning.

make sure the yellow/brown cable goes to your alt, discon that blue wire.

the light will come on when that wire is earthed, so it might not be fixed. it goes off when the alt sends up 12v to cancel the 12v going down to it.

you need to do the other tests ;)
 
alright, in the morning ill check the voltage at the battery, then ill turn it on and measure it at the battery on idle..

The reason i blipped the throttle in the vid was because i didnt know if it charged or not unless it had an initial kick up the arse to make it charge.
 
No idea, the optimiser charger i have charges the battery tests it and tells me if its strong or weak, its strong so i don't think its that but i wont rule anything out.
 
Ok this morning I tested the battery which was sat at 12.89v so only dropped .11 overnight but it didn't start so I couldn't check the voltage on tickover. I've put the battery on charge and gone to work so I'll start it up tonight and check it on tickover.
 
12.9V should be enough to start the engine, I thought a fully charged battery was only 12.7V ish??
 
Last edited:
it is...

12.66 V 100%
12.35 V 75%
12.10 V 50%
11.95 V 25%
11.70 V 0%

what type of multimeter are you using, Ive seen cheap ones have error of 1V (my £50 cheapie is 0.2V overread)
 
Guys you cannot check a battery without a load tester or without the battery being loaded, the static voltage can be anything and yet means nothing.

A simple test is for him to turn on his headlights on high beams, leave them on for two minutes and then measure his voltage.
 
Barbados said:
Guys you cannot check a battery without a load tester or without the battery being loaded, the static voltage can be anything and yet means nothing.

A simple test is for him to turn on his headlights on high beams, leave them on for two minutes and then measure his voltage.
Click to expand...

that's not load testing it, that's getting rid of surface charge, which dissipates over time, hence the leave it over night bit.

that's why we can all hook our multis up to the battery without load testing it :)

a load test is when you draw a good amount of current and you are watching to make sure the volts don't go below 9.6v. i think the jobbies the garage use draw half the cca of the bat.

Us cheapo's can just start the engine, this makes the starter motor the load tester as it needs a lot of current.

you also get people discussing whether it is 2.1v or 2.2v per cell. afaik, 2.2 is fully charged and float charged (constantly topped up) and 2.1v is the resting voltage.
 
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