CellLog & rotary switch: switch packs & disconnect

[powersupply]

Hi,
reading about the CellLog, this amazing gadget, I learned that it's best to completely disconnect it if not in use.

Considering that I have up to 3 packs to be monitored, I thought using a rotary switch to be able to switch between the packs and even disconnect the CellLog completely.

Has anybody done this?

I am mostly worried about transitional issues that could cause things like latch ups etc.

What I had in mind:

 

[amberwolf]

I dunno if anyone actually ever did it, but it's been discussed before.

 

[Hillhater]

Might be helpful to correct the title !

 

[powersupply]

Thanks for pointing that out!!!!

Might be helpful to correct the title !

 

[migueralliart]

It doesn't seem like a bad idea. I wonder if a small PCB can be made with three jst inputs and a toggle switch. That'll be a cool little gadget.

 

[powersupply]

Meanwhile I let it sink and first of all I need 9 poles, not 8.

Then I was envisioning me soldering ca 30 wires to that thing.....and it struck me:

Why not use a data switch box? You know, those boxes where you would hook up several pcs to share a printer.
Or better yet, sharing a monitor or serial stuff.

Picture:


I would get rid of the metal case and et voilà: a ready made switch assembly.

But I would still need to find a way to hook up the actual batteries to that contraption....

 

[heathyoung]

You can set them up so they drain all cells evenly - I designed a unit that does this, I use them on my LiPo's on the current bike, they run all the time when the bike is on (they use the +5V from the throttle to turn on) and run when charging (and the HVC output drives a relay when bad things are happening - I had a bad pack and it caught it before the magic smoke and flames escaped when bulk charging).

With the current pack, I havn't had to balance charge since the original installation.

If you are interested, its a pair of Quad high voltage opamps that buffer the input and draw directly from all cells. (Per Cell-Log)

 

[powersupply]

Yes, I've read your posts with the LT1014, very intersting.

Been lurking a while, though it is tough to learn/remember all the things I have to take in.

Thankfully the experienced people here understand that with a kind compassion and don't mind (re-) re-repeating it all for us newcomers.

But yes, I remember seeing your post in that regard, plus the "finished" version.

I still have to understand all that balancing stuff, but ordered a smartBMS and that is next.

In my case, I just wanted to have a simple way to check upon the cell voltages visually and maybe even read out the log. And it will be only used when everything is turned on. And because it will be used stationary, I would power it throught the whole bank (i.e. get rid of the VCC diodes, which probably cause the imbalancing). If there is still some unbalanced draw it would (hopefully) be taken care of through the BMS.

The other reason for my approach is that $30 are $30, and just the thought of mouning several units onto my scooter..

The other thing I concluded after reading about the many mistakes which happen, is that I *really* don't want to plug anything around.

The main power switch will shut off the CellLog, too, via a relay that disconnects the minus (ground) of the CellLog. So even if the rotating switch is connected to one battery bank, there will be very little draw from what I understand.

With recycling a switch box I save myself $60 and the soldering of many wires.

However, I still wonder if there could be any damage to the CellLog by switching from one bank to the other.

What do you think?