Battery Light Issues

Battery died just before christmas....before it died the battery light on the dash would stay on....at half brightness from when you first switch on the ignition. Got around to putting a new Numax battery in today and started first time.....the problem is that the battery light still remains on at half brightness after starting the engine.....the battery light remains on while the engine is running with no flickering on or off.......my Landrover is a 1990 200tdi 90. Any ideas what the problem is ?.........Cheers.

I would guess the alternator is playing up. Have you connected a voltmeter (multimeter type) to see what voltage you are actually getting when the engine is running? It should be between 13.5-14.4V.

electrics are not my bag sorry.......would you connect the volt meter between positive and neutral on the battery terminals?

yes

Yes.

A battery in a good state of charge should read about 12.5V with the engine off. When you start the engine the voltage will usually only rise very slightly but then a couple of seconds later when the exciter circuit cuts in (you may have to blip the throttle slightly) you should see the voltage rise to between 13.5-14.4V. As you have already replaced the battery, anything less would initially indicate a fault with the alternator. Again, anything over about 14.4V will also show an alternator fault and will quickly cause battery damage.
The reason it started first time today was that the new battery while possibly not being fully charged, certainly had a decent amount of charge in it however if the alternator is faulty it will soon discharge again. Would have been worth checking the alternator first as the old battery might have been ok after all.

Thanks for the indepth reply.....much appreciated and easy to follow. I will check out the alternator tomorrow.....if its found that the problem is here could i still use my old battery and set up a two battery split charge or would i need two batteries of the same age/power.....thank you.

split charge no probs. just make sure sure your old one charges and holds it ok. both mine are starting to pack in now

G

The voltage you r getting might be ok, i had a similar prob, i was getting 13.6 volts, battery was fine, and the warning light was glowing gently indicating that it was drawing current to excit the alternator in to working,

well long story short i traced the fault to the diode pack, i was told ther was a phase down .

new alternator and its sorted, only buy a decent alternator the cheap crappy ones only last a year or so.

I cheated i bought a new pully for mine as there a bugger to crack the nuts.
Mines is a 98 300TDI

I had the exact same issue with mine (td with 200tdi fitted). Turned out to be a knackered ignition switch. Recently put a new one in and all is as it should be.