SI/Dashboard batteries, are these correct?!

Post Mon Feb 06, 2012 9:22 pm

Hi,

My fuel gauge has started acting strange and my rev counter has dies unless i nearly reach the redline, car is a 1987 318i.

read about the SI batteries causing problems and have removed the circuit board and there is a slight leak from the battery.
Is this the correct battery to replace it with:

http://uk.rs-online.com/web/p/aa-rechar ... s/3777911/

Many thanks!

Post Mon Feb 06, 2012 9:47 pm

http://www.e30zone.net/e30zonewiki/inde ... _Batteries

especially this bit:

"However, if the SI batteries have leaked, the entire circuit board will need to be replaced. "

Post Mon Feb 06, 2012 11:06 pm

Thanks for that,
When i say slight leak though i mean slight, its hard to tell if anything has actually contaminated the board and theres only a small amount of dried acid at one end of the batteries

Post Tue Feb 07, 2012 8:30 am

Just get a later board with the lithium batteries

Post Tue Feb 07, 2012 8:38 am

some info here:

http://www.peakeresearch.com/siboard.htm

http://forum.roadfly.com/threads/936872 ... ttery-info

Post Tue Feb 07, 2012 9:25 am

DanThe wrote:Just get a later board with the lithium batteries

These don't suffer from battery problems, unless stored for several years without being 'switched off', but do have a few (non repairable) problems associated with them. The NICd boards are usually 100% reliable apart from the battery problems.
The battery in the link will do the job, but isn't the one I'd use by choice. Although it has tags, they won't directly fit the board, so wire links will need to be added, and there isn't a lot of room for the extra bulk at the ends of the batteries without shorting to other components. A better choice is a shorter (2/3AA or 4/5AA) battery, and NiMH rather than NiCd.

Post Wed Feb 08, 2012 7:17 pm

Ok, i am very confused now after looking at the battery layout...

The batteries are laid out next to each other with positive on one battery neighbouring negative on the other. which looks correct.

The confusion is that the positive on one battery is linked with wire directly to the negative tag on the other battery which is then wired down to the circuit board, this doesnt look right!?

Post Wed Feb 08, 2012 7:42 pm

Simple series connection of the batteries to add their voltage together. 2 x 1.2V = 2.4V.
Same arrangement as the batteries in any torch that uses AAA, AA, C or D cells.

Post Mon Feb 13, 2012 5:47 pm

Thanks, measured the two batteries at 1.2v each, refitted to the car, everything worked fine for a few days with dash loosely connected, went to re-connect it all back and its stopped working and having taken apart again a million times its driving me insane....

When it just stopped working if i hit the dash with my palm the inspection lights flickered, but im getting nothing at all now

Post Mon Feb 13, 2012 6:33 pm

Board needs to go in the freezer for half an hour before you measure the battery voltage.
Check the soldering of the pins of the white and blue sockets to the main circuit board. These joints can crack if someone has been a bit rough with the plugs in the past.

Post Sun Mar 18, 2012 9:56 pm

I tried to reset my Si lights today as per my normal "paper clip"method, but it just won't work....

Believing the SI batteries to be the culprits I took the cluster out and looked at the SI board. This has clearly been replaced as I have 2 x Lithium 3V batteries, each one giving 3.15V on the multimeter...

Does this mean that I have another problem with the board?