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Hey Y’all,
Just when I had grown tired of receiving Roundel only to read about 3 guys driving fast in circles (aka "club racing") or how to add another 100 hp to an M5, I found something useful. The article about the rechargable batteries in the e30 si board going dead from disuse caught my attention. Has anyone else had this experience? If my car sits for awhile, this sounds like an issue I’ll need to address if I want my tach to work properly.
Thoughts?
Sasha
Ex36 wrote:
[quote]Hey Y’all,
Just when I had grown tired of receiving Roundel only to read about 3 guys driving fast in circles (aka "club racing") or how to add another 100 hp to an M5, I found something useful. The article about the rechargable batteries in the e30 si board going dead from disuse caught my attention. Has anyone else had this experience? If my car sits for awhile, this sounds like an issue I’ll need to address if I want my tach to work properly.
Thoughts?
Sasha[/quote]it happens all the time to regularly driven E30’s. There are rechargeable batteries on there and they give up the ghost. The newest ones are 15 years old…
The cluster gets switched and unswitched power and the latter is used to keep the SI batteries charged. As long as you don’t disconnect the battery or allow it to go flat when the car is idle (a battery tender is a good idea for extended parking) the SI batteries won’t go flat. However, the batteries have a finite life and eventually require replacement.
Generally the SI batteries will last at least ten years, provided that you replace them before they leak and damage the SI board. The only advantage that I see to remote mounting the batteries is that your choice in replacement batteries is a bit more open.
I wasn’t clear–when the car is parked for a week or more, I turn the master kill switch off. Otherwise my battery goes dead with some mysterious current drain I haven’t bothered to chase down. So, with this routine, the SI board batteries will go dead, no?
Sasha
Ex36 wrote:
[quote]I wasn’t clear–when the car is parked for a week or more, I turn the master kill switch off. Otherwise my battery goes dead with some mysterious current drain I haven’t bothered to chase down. So, with this routine, the SI board batteries will go dead, no?
Sasha[/quote]Sascha, probably, the capacity of those old batteries to hold a charge is the limiting factor. But dead SI board batts is not uncommon in a daily driver…
Yep, that will cause the SI board batteries to fail.
The simple solution would be to leave the kill switch on and connect a battery tender when you park the car. It would probably be a good idea to see what the parasitic draw is and if excessive find & fix the culprit.
A more complex solution would be to mod the wiring to provide unswitched power that bypasses the kill switch to that pin of the cluster (fused, of course).
jlevie wrote:
[quote]
A more complex solution would be to mod the wiring to provide unswitched power that bypasses the kill switch to that pin of the cluster (fused, of course).[/quote]
rules require that all power is switched except to a fire system or other safety device …
What is the SI board, and where is this battery located?
I always hook up the car to the battery tender after a race weekend since I know I won’t drive it for at least a couple of weeks.
So, as it seems clear my actions will kill my SI board batteries (unless I change my habits soon), what will the effect be?
Sasha
Ex36 wrote:
[quote] If my car sits for awhile, this sounds like an issue I’ll need to address if I want my tach to work properly.
[/quote]
I just replaced my batteries, and while it did fix my SI lights (which I don’t need) it did not fix my dead/jumpy tach.
Scott
Symptoms of a dead SI board can include a dead tach, dead temp gauge, and inaccurate fuel gauge.