log 12s cell voltages??

[izeman]

i use a bms for my 12s4p lipo battery. but still i'd like to know which cells sag most under load. but i don't get this data from a passive bms with no output. and the CA shows total pack voltage only.

so i could connect the logging celllogs from HK https://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9282

but you have to open the battery box, connect them, reset them, after the ride you have to remove them, connect to your pc, import values and analyse. not very comfortable.

i'd like to use something like an arduino and log the data and maybe output it over bt to a smartphone/tablet.

those little monitors have an output and should be able to communicate with an arduino: FrSky Lipo Voltage Sensor FLVS-01

third solution would be to reactivate/buy a new smartbms from bmsbattery they can output their data as well. but a) those are sh*t and b) i have a good working (analog) bms from bestechpower which is much more reliable.

any other ideas? or maybe ready to use solutions? there are so many ppl working on similar things but most of them do much more than i need, or are never finished.

 

[dnmun]

you can use the cellog 8S model and download the data later. if it is a 12S then just use the first 6 channels on each one, and use a 7 pin plug so the top two are unconnected and then connect the ground of the upper cellog to the top of #6. i solder the plug leads to the underside of the BMS pcb where the sense wire plug is soldered onto the pcb.

 

[izeman]

thanks dnmun. i know that, and this was option #1, which i already mentioned - but which is not prefered as you have to install/deinstall those celllogs every ride as they drain (uneven) power from the battery. and opening the battery compartment is something i don't want to do that often.
i'd prefer some wireless data transmission to a (android?) phone.

i don't even need to solder to the bms as i have two spare jst-xh plugs for
a) balance charging with a bc168 charger if necessary
b) connecting some monitoring device - but this should be temporary only

these are my balance boards meant for 4p (with 6x 6s connectors)

image property of osh-park

 

[izeman]

i forgot to mention that i read somewhere that those cell-logs transmit live data over usb all the time. the main difference between the 8s and 8m is, that the 8s has some memory and a usb port. but the data port inside should be the same and available on the 8m as well (of which i have several at home). so it would be nice to connect an arduino to the data port(s), collect the data, save it to sd card and transmit it to a smartphone over bluetooth. of course you still would need to cut the power to the cell-logs if the bike is not in use.
what do you think? maybe there is some one with deeper knowledge of those loggers.

 

[athlon]

AFIK cellogs unbalance the pack only for cell 7 and cell 8 , becuse cellog take power from the fist 6 cell.

If you use une cellog every 6 cell you can leave them connected

 

[major]

i forgot to mention that i read somewhere that those cell-logs transmit live data over usb all the time.

Be careful with that. I think the USB are not isolated from the cells they monitor. I fried the USB port on a laptop using it while connected to the battery. Since then, I always disconnect the CellLog8s from the battery before I connect the USB to the computer. I'd certainly check before I connected 2 CellLoggers to any one device, computer or anything else.

http://www.tmenet.com/products/lithium-charger/xtrema-balancer Has anybody tried this device? A friend lent one to me and I can't get the software to download to connect to the computer. It looks like an interesting product and may do what you seek.

 

[izeman]

Looks like a nice product. How does out come that I've never heard about it in do many years, as it's on the market since 2007!!
I'm also not sure if it's do easy to let an Arduino communicate with it.

 

[docnjoj]

I've heard of Tejera but can't remember if it is in relation to model aircraft or full size ones. Anyone know cause his products look neat and not overpriced. Kool!
otherDoc

Eureka! Model aircraft smoke systems!

 

[jumpjack]

Any progress with this projects(s)?
I need to monitor a 16s and a 20s pack.
Which are the serial pin of the CellLog I should connect too through a level shifter?