Battery drain

[Dellmassive]

The draw is low enough it's possible to wire directly, and there is some argument this gives the best chance of an accurate voltage reading.

I would however try and add a fuse to the wiring, having seen the inside of a BM2 I'm not really comfortable at the separation as per my post here:

What Have You Done To Your Van Today?

I've had / got stud and nut kits on other cars, makes wheel changing easier.. and adding spacers less hassle if needs be. Thanks for that…. I like’s it! :cool:

www.t6forum.com

After my initial battery testing direct on the battery, I moved my bm2 over to my starter battery additional fuse box, and fused at 2A.

It looks like the bm2 PCB has a soldered fuse, but as you said before the link wires would burn out before any real damage.

Interestingly the ctek battery monitor has a longer fly lead and an inline atc fuse..... But it's not as good as the bm2. My testing showed the ctek monitor had poor SoC firmware logic and was often way off the mark with accuracy.

 

[Dellmassive]

its a good time of years for this stuff. . .

my T6 work van has been sitting around for a while over xmas. . .

and i have a BM2 amongst other monitors. . .

ill get a 15day plot and post here:

the two blips around the 29th and 1st were me opening the van doors and relocking it.

you can see a gradual drop in rest voltage from 12.3v down to 12.1v

but it doesn't drop below 12.0v.


( it will drop below 12.0v eventually after about 3weeks sitting there - but i do have some 3rd party kit fitted that makes it drop a bit faster, ie tracker, alarm system, battery monitors,)


all my other kit is now running from the leisure battery.








...

this was a normal day from 19th dec:

battery was about 12.3v at start,

14.8v charging while driving,

then drops over night to 12.3v.




...

 

[Dellmassive]

and for good measure here is the FOGSTAR 230ah leisure battery. . .

same period. . .


now:




the same last 15 days . . .




and that single day - 19th dec - a normal day.

 

[ginkster]

Similar picture to mine over the same period. Nothing extra draining it as far as I know. It’s an EFB battery and I believe it’s the original so about 4 years old.