E30 Zone

OK my rev counter is not working again plus the service lights are playing up!!! So I'm presuming SI board / batteries?
However I replaced the batteries about 8 months ago with new ones....the car does not get driven that much could it be the batteries again? More likely the board i think although it looks like new...
Will any SI board do or do I need the specific one for my car?
For information it's a 325i 1987 and the board has the lithium non rechargeable batteries fitted..
Many thanks for any info!!!

Could well be the batteries, if you don't use the car much...

How old were the batteries when you last replaced them? Lithium batteries usually last years, but as with most batteries, they have a 'shelf life', and if left sitting around, they will eventually self-discharge.

Ordered the batteries from German eBay as that's the only place I could find them!!! I checked the voltage before I fitted them and it was good?
Like you say they could be 50 years old and knackered!!!

Correct batteries are available from CPC in the UK.
Are you sure you fitted the correct type? There is more than one kind of Lithium battery - some rechargeable and some not

My E28 is doing the same. What batteries do I need?

Lithium type: http://cpc.farnell.com/varta/6127601301 ... nsku=false

NiCd replacement. Note that the tags won't fit the circuit board, so short wire links will need to be soldered to the tags: http://cpc.farnell.com/varta/5511920101 ... nsku=false

Also note that the replacements need to be the same type as the original. You can't fit lithium in place of NiCd or vice-versa.

Thanks for the help guys, I'm going to try some new batteries and hopefully that will sort it!
If not can I just get a different SI board and try that or are they model specific? Also could I put a board with rechargeable batteries in? or would I have to stick with the lithium non rechargeable?

The batteries are all rechargeable, have to be if you think about it. The wiki may help you, see http://www.e30zone.net/e30zonewiki/inde ... _Batteries

Either type of board can be fitted. They are completely interchangeable.
E30s were first fitted with the NiCd board, but throughout production, the later lithium board was introduced.
When the batteries on the original NiCd boards began to fail, they were initially replaced by similar boards, and then by the newly introduced lithium boards, but the faulty ones weren't thrown away - they were repaired and reissued, so eventually it was totally random as to which type you got when the board was replaced.
A replacement lithium board can be identified from an OE one by the presence of a large orange arrow sticker, pointing at a three pins and a jumper clip near the batteries which acts as an on/off switch. OE versions have a small wire link instead. The reason for this is to prevent the lithium batteries discharging while sat on a dealer's parts shelf.
The NiCd batteries are rechargeable, and can be replaced by equivalent NiMH types. The batteries constantly power the SI board circuits, and are constantly charged by the car's main battery, and ultimately the alternator, to prevent them going flat.
The lithium batteries used are NOT rechargeable, and no charging circuitry is fitted. The SI board circuits are powered by the car's main battery, and for most of its life, the lithium batteries just sit there doing nothing. Power is only drawn from them to power the SI board volatile memory when the car's main battery is disconnected, or the board is not fitted to a car. Once they are discharged, they cannot be revived, and need to be replaced.
In short, if your car has the type with the NiCd/NiMH batteries, and they are in good order, there is no problem in leaving the car for extended periods with the main battery disconnected, but if you have the lithium type, doing this will eventually kill the batteries.
Some crude testing and estimating suggests the batteries will last for a total of three or four years powering the board on their own.

Thanks Brian you've been a great help as always....one last stupid question does it matter what engine is fitted or can also board from 318 go into a 325?

One board for all E30s (except the very early stuff with two red SI LEDs). Different engines are catered for by a coding plug which fits to the board from the outside of the cluster.