Author Topic: SI board battery (Read 9551 times)

Froos · « **on:** August 10, 2016, 03:01:36 PM »

Well it happened they are fried (no si lights, no revs meter or econometer) so opened the cluster. Just want to be sure
1) is the mAh that important? All rechargable nicd nowadays are 1850 mah or higher.
2) can any AA nicd rechargable batteries be used?
Thanks a million

DesktopDave · « **Reply #1 on:** August 10, 2016, 04:45:09 PM »

I'd go ahead with any mA/h rating. It's the voltage and charging tolerance that's important, and none of that has really changed in 30 years.

If you solder in a battery pack, definitely go with the AA size. If not, I'd strongly recommend the replacement cells with solder tabs. A pack doesn't fit that space very well. I'm also not sure if the NiCd cells are wired parallel or serial - I believe the later Li cells are serially-wired.

Froos · « **Reply #2 on:** August 10, 2016, 05:02:14 PM »

Thanks for that!
So will solder these up as soon as they are charged, was planning on reusing the tabs
(First pic its the glue thats nasty, old batt didnt leak)

Froos · « **Reply #3 on:** August 15, 2016, 08:11:14 AM »

Ok so i replacedthebatteries with fully charged ones, checked fuses, nothing no revs no consumtion movement...
Also noticed that the led strip for the si lights is not present!!... However revs worked fine before so the missing led have no influense....any thoughts? Also anybody got a spare led light thingy?

colin86325 · « **Reply #4 on:** August 15, 2016, 11:02:01 AM »

It can sometimes take a bit of use to charge the batteries, but you said yours are fully charged, so i don't know what to say.

Froos · « **Reply #5 on:** August 15, 2016, 03:47:06 PM »

Yeah either is damaged it while soldering or something else broke since its old....
My car used to be an 318 with an M40. The check light in the middle was factory blocked off. Im wondering since the si led were missing maybe in the eu this was an option on entrylevel e30s? Because the stomp code trick will also not work without the center check light. To be honoust the cluster doesnt look like it has been opened before, all the screws were correct ie no board damage from wrong screws....

Anyhow, just ordered a new cluster from ebay, lets see how that turns out. Was also shocked that in like 5 years or so all clusters are now 100� or more!

Froos · « **Reply #6 on:** August 22, 2016, 01:13:05 PM »

New cluster works like it should, lights revs and temp work agsin..

DesktopDave · « **Reply #7 on:** August 22, 2016, 09:31:55 PM »

I've seen a few boards with burned traces too. Maybe one or two. Soldering onto batteries can also damage the internal leads beneath the caps.
I've also seen a few guys replace the soldered batteries with a wire harness extension into the board that runs down to a battery holder in the kick panel area.

Froos · « **Reply #8 on:** August 24, 2016, 06:33:23 AM »

That sounds smart, but once the batteries leak the board is fried

Froos · « **Reply #9 on:** June 01, 2017, 03:57:24 PM »

So the "new" si board batteries are dying....after a hot day the service light is flashing, no revs meter movement. Econometer was acting just before that....so either an external battery holder is going in or this:
https://www.amazon.com/BMW-Board-1984-1985-1984-1987-1986-1987/dp/B00UCE5F18
Anybody any feedback on that new board?

DesktopDave · « **Reply #10 on:** June 02, 2017, 07:29:59 PM »

I've heard good things about boards like that in the E28 community, but I'm not sure that Amazon version is the same though.

Are the replacement NiCD/NiMH cells still holding 1.2 VDC? You're sure they're wired the same way? Some E30 SI board batteries are wired in parallel, not serial.

Froos · « **Reply #11 on:** June 08, 2017, 02:24:18 AM »

Hi dave! Yeah i understand that some board dont even charge the batteries...i have to open it up to see what is going on and ill report back

Froos · « **Reply #12 on:** June 12, 2017, 04:58:20 PM »

So im getting error 1234 speed signal loss, this might also be caused by the si board

Froos · « **Reply #13 on:** July 19, 2017, 04:25:19 PM »

Just to follow up on this. I got a new car battery and the malfunctioning econometer and errors are gone. If you have these errors might be worth checking and buying a new battery

Author Topic: SI board battery (Read 9551 times)

Froos

SI board battery

DesktopDave

Re: SI board battery

Froos

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Froos

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colin86325

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Froos

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Froos

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DesktopDave

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Froos

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Froos

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DesktopDave

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Froos

Re: SI board battery

Froos

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Froos

Re: SI board battery