Anyone ever replace SI batteries?

[Steve88M3]

My tach is on the fritz and I was reading the procedure on Gustave's site and it freaked me out. I'll deal with anything on the car except electrical problems, so I'm not very confident about doing this. Has anyone ever done it? How difficult is it really?


Cheers.

[Nick-NY]

Its actually a really easy straight forward process. you have nothing to fear, the most difficult part of the replacement is the soldiring of the batteries.

[Reelizmpro]

Yeah it's pretty easy actually. Just make sure you observe the polarity and do a good job soldering the correct batteries in. If you didn't charge them prior to installation, give them some time and they'll charge up after installation.

[jmarch]

I just did it. Nick is correct, the hardest part is soldering the new batteries in. I suggest you unsolder the tabs from the si board and solder them onto the new batteries. Then check the batteries with a multimeter to ensure that you didn't ruin them (you really need to heat them up before the solder will stick). Then reattach the whole thing to the si board.

Good luck!!

[Mick]

I've heard that soldering in a RadioShack battery holder works well. Then you can mount the battery holder and just pop in new batteries.

[Jeremiah]

I did the radio shack pack in my ETA. It worked out very well, plus I wasn't sure if my car was charging the batteries so I didn't want to take the cluster apart again if they went dead.

[Motoechnic2]

My speedo and tach are fine but my temp gauge reads high and if I give the top of the dash a smack it goes to normal. This symptom started after I disconnected the battery for winter storage. Needless to say I use a battery tender now.

So would the temp gauge be a symptom also?

Moto

[Todd black 88]

Temp gauge is usually the first to react with bad batteries. But your problem could also be a loose ground nut on the back of the gauge.

[Motoechnic2]

Thanks...

[s14dan]

It's easier to just swap the board out..I have a spare from a 318is

[Todd black 88]

Holy three year old thread bump batman.

[Gregs///M]

SI board battery replacement can quickly go bad.

I've rebuilt well over 100 SI boards and I've seen many people "try" to replace their batteries only to end up damaging their SI board.

The biggest problem that I see is that people are using the wrong temperature soldering irons resulting in higher temp and damaging the printed circuit board and the electrical traces.

Another issue I see is people not completely removing all of the solder. They then try to pry out the batteries and "take" the soldering pads with them, also damaging the electrical trace as well. With the positive side of the battery, there are two pins so you have a redundant backup just in case you damaged it. However, and more importantly, the negative side only has one pin, therefore if that landing pad is damaged, you or someone like me will have to perform and electrical repair on that solder pad.

So my tips are:

1. Use the proper soldering iron. Fine tip, no more than 700 deg F.
2. You should hold the tip no longer than 10 seconds per joint.
3. You will have to use a solder sucker and solder wick to remove all the solder. As much as possible.
4. You will notice the factory bends the pins. Apply heat after cleanup, and bent the pins straight.
5. Once all pins are vertical and all solder is removed, then pry out the batteries. They should easily come out.

If you find you are not up to the task or do not have the proper tools, contact me and I can perform this rebuild for you or provide an already rebuilt SI board for you.


Good luck!