Strange BM1 battery monitor problem.

[lumphammer]

When I press the illuminate button on the BM1 display panel the charging current goes up from around 1 A to 5A as indicated on the display. This is with the charger running. I thought it might be the charger, but similar effect found when off charge, current changed from 2.5A discharge to just over 0.5A charge.
What concerns me is the fact that anything changes when pressing the "Illum" button rather than the respective current levels.

Anyone seen this effect? Any suggestions as to what might be causing it?

 

[Richard10002]

When I press the illuminate button on the BM1 display panel the charging current goes up from around 1 A to 5A as indicated on the display. This is with the charger running. I thought it might be the charger, but similar effect found when off charge, current changed from 2.5A discharge to just over 0.5A charge.
What concerns me is the fact that anything changes when pressing the "Illum" button rather than the respective current levels.

Anyone seen this effect? Any suggestions as to what might be causing it?

Id guess that pressing the illuminate button is making some undesired connections on the circuit board. How old is it? If out of guarantee, I'd be tempted to tell NASA what is happening and ask for their advice. They might replace it for you, or take it in for a fix.... or they might not... but worth a try?

 

[pcatterall]

When I press the illuminate button on the BM1 display panel the charging current goes up from around 1 A to 5A as indicated on the display. This is with the charger running. I thought it might be the charger, but similar effect found when off charge, current changed from 2.5A discharge to just over 0.5A charge.
What concerns me is the fact that anything changes when pressing the "Illum" button rather than the respective current levels.

Anyone seen this effect? Any suggestions as to what might be causing it?

Ahh!! I had very similar problems with mine. When pressing the illum button the charging rate shot up, I also found I could not null the charge level using the process described in the hand book.

I found manky connections were the problem, in my case they were at the shunt terminals. The whole thing was rusty and the little connections on the block were corroded through and just broke off.
A cheap fitting in my opinion but I was shot down on this site for being foolish enough to fit it in the engine bay ( where the batteries are)

 

[Kylora]

I've also experienced abnormal readings when the illumination was on, though I can't now remember which reading was off.

Anyway the fault was a poor connection in the fuse holder. A quick clean up and all was well again.

Ash

 

[Yngmar]

Had the same. It was poor connections everywhere (fuse holder, crimped fittings, choc block under the nav table), as the wires weren't tinned and had corroded.

Best to make up entirely new wires and put them in, matching the length of the original ones as closely as possible.