E30 Zone

I know this has been covered previously - it probably need to be in the wiki.
I need to replace the batteries on my SI board.
What batteries are best (Ni-Cad or Lithium)?
Should I wire them in or buy a little plastic battery cradle and mount it near by (think I read that on a post on here?).
Are a special type of battery required - specs please.
TIA

You can't choose which type of battery to use - they are not interchangeable, and have to be the same as already fitted (although NiMH can be used in place of NiCd). If they are the lithium type, they are unlikely to have failed anyway.
Batteries are available from electronic component specialists, such as CPC/Farnell or RS Components over here, and in the case of the NiCd's are simply AAA sized batteries with solder tags welded to them. I use 2/3 size AAA NiMH batteries to get a little more room around the ends of them. There must be equivalents in your part of the world.
External battery holder is a US thing; one of many strange ideas they come up with! Can't see the point for something that is going to last around ten years.

http://australia.rs-online.com/web/

I installed a remote holder and would definately recommend it. It does not realy take any longer than putting the batteries in the normal place and costs next to nothing. Be optimistic and assume you will still be driving your car in ten years.

I am Sydney, I just used NiMh recargables from Jaycar Electronics.

Millsand wrote:I installed a remote holder and would definately recommend it. It does not realy take any longer than putting the batteries in the normal place and costs next to nothing. Be optimistic and assume you will still be driving your car in ten years.

I am Sydney, I just used NiMh recargables from Jaycar Electronics.

Thanks, any tips for doing the job?
Where /how did you mount the battery carrier?
Is the old battery easy to remove?
Cheers

what you should have done in the first place


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

Follow these instructions http://www.pelicanparts.com/bmw/techart ... teries.htm

When you get to the part about soldering out the old batteries be very careful. Touch the solder iron on the tabs on the other side of the circuit board to the batteries and wiggle out the battery tabs. Don't let it get too hot and don't spread solder everywhere. Inspect the circuits to ensure your new battery holder is the same polarity and same series/ parrallel as the original (let me know if you don't understand what this means as the explanation is long winded). Solder the two wires from the battery carrier into the appropriate spot that the old battery tab came out of.

Make sure your new batteries are the same voltage as the ones you took out.

My battery carrier sits just near the ECU on a drop of glue, connected to a 0.5m wire that goes the the SI Board.

Millsand wrote:Follow these instructions http://www.pelicanparts.com/bmw/techart ... teries.htm

Follow these at your peril. They are riddled with mistakes! Not unusual with these US articles.

I couldn't get the Wiki one to open for some reason so I used the Pelican Parts instructions. I had no problems with this one but I have used some of the others that had errors.

Working on this one today - have some tabbed Ni-MH batteries.
A couple of novice questions ( ).
1. The old varta batteries I removed had two tabs on each of the negative terminals and one on each of the positive. Do both negatives need to be hooked up or is one just to hold the batteries in place (doesn't appear to have a link on the circuit board)
2. The photo below shows two SI boards I have (picked up a spare cluster last year for the temp gauge. They are quite different (although both appear to be 3 red type) and one has Ni-Cd and the other Lithium. What gives? Is one of these more preferable?:?

poolnoodle wrote:Working on this one today - have some tabbed Ni-MH batteries.
A couple of novice questions ( ).
1. The old varta batteries I removed had two tabs on each of the negative terminals and one on each of the positive. Do both negatives need to be hooked up or is one just to hold the batteries in place (doesn't appear to have a link on the circuit board)
2. The photo below shows two SI boards I have (picked up a spare cluster last year for the temp gauge. They are quite different (although both appear to be 3 red type) and one has Ni-Cd and the other Lithium. What gives? Is one of these more preferable?:?

the top board is a replacement board and newer than the one below. You will note that at the end of the batteries is a black plastic 2 pin slide on connector with a third pin off to the side. When these boards were new (in parts store) the batteries were disconnected by having the connector over the centre and currently exposed pin. Stopped battery draw while in storage.

I would repair this board rather than the older one.

Regards
Greg

So are these lithium batteries rechargeable?
They look a bit more difficult to replace than the older ones - not much room

The lithium batteries are not rechargeable, and current is only drawn from them when the board is disconnected from the main car battery.
The NiCD ones, on the other hand, power parts of the board in normal use, and are constantly charged by the car.
The NiCd batteries cause problems because when they fail, they tend to go short circuit, thus loading down the power supply to the other instruments, notably the tacho and temperature gauge. Although the NiCd boards often fail because of this problem, it tends to be the only thing that goes wrong with them, so, as long as the batteries are replaced before they leak, these boards can be considered very reliable
The lithium boards, on the other hand, tend to develop odd minor problems, that I neither know the cause of, or the cure. The most common of these oddities is that the tacho needle jumps up off its stop after the engine is stopped.
Only dealer supplied lithium boards are fitted with the removable jumper link. Factory fitted ones have a small wire link near where the jumper pins fitted. If you place one of these boards (or a cluster containing one) into storage for any length of time the link should be cut.

Thanks Brian, it is all becoming clearer. I have been running the lithium board in the car for the last 12 months or so (bought from US) and it worked fine to start with but is now playing up (including jumping needle as you mentioned).
The Ni-Cad board is the original from the vehicle and appears to be in good condition (no sign of leakage or damage to board) other than the batteries being cactus. The tabs on the new batteries I have bought (Ni-MH 2000mA, 1.2V) have different tabs to the originals - how would you fir them in this case - short 0.5mm wires? How do you fix them to the board?
TIA

The ones I use have different tags. Use short wire links, as you say.

willnz wrote:Use a dab of silicone to stick them to the board.

Wouldn't recommend ordinary silicon rubber! It releases acetic acid as it cures.
Not the kind of thing you want trapped against the print on a PCB!
There is a special silicon rubber available for use with electronics, or hot melt glue is a better solution.

Just a big thanks to those who helped here - got it all working properly today with the Ni-MH batteries...Brian and Will you are legends