CellLog 8S battery monitor and logger - any reviews?

[dequinox]

if you intend to leave the cellog attached to the battery pack then go over to richard's cellog hack thread so you can learn how to hack the power from all 8 cells.

My desired use was for the datalogging/USB feature. It seemed like you could hook it up to a PC and gather cell voltage data, which would be useful for my upcoming laptop battery teardown project.

That would be a shame if it were discontinued. Although it's been pretty quiet since 2013 here's Junsi website - http://www.jun-si.com/Enindex.asp

Maybe drop them an inquiry?

Perhaps, I have to let my wife get over the initial purchase of 1000lb of laptop batteries first....

 

[DrInnovation]

I've been using a CellLog8 for about a year. Today I was setting up a new BMS and for the first time I happened to compare the CellLog with my metered values. to my surprise it was noticably off, both on the overall value and the per-cell.
View attachment 1
28.7 on the cell log and 29.41 on meter. Quite a big difference. Has anyone else seen this type of behavior?

I've hooked i up using a DB9 using an old mouse port and ribbon cables... (It makes for a nice watertight connection that is easy to connect through the batter case:


The setup is TP 3S connectors on the balance plugs connecting in parallel to both the BMS and the ribbon cable leading to the DB9, with the mating DB9 on the outside connecting to the Celllog8 leads. All connections are soldered. (The balance plugs are for connecting 2P, though now it only has 1 pack per connection).

Is it possible that the thinner /longer wires (hence higher resistance) are hence impacting the voltage reading? (there was no instruction limits on installin git).

Or is possible that its caused now because have it in parallel with the BMS lines (before it was straight connection balance leads to DB9 to DB9 to celllog, but I never compared it with the meter).

Also I'm wondering if this might be why I killed some of my lipos, since a few times when I knew I'd need greater capacity for a longer ride, I let it charge until the CellLog said 4.2. The per-cell on the above was as high as 4.24 on the meter cells showing 4.11 on the cell log. (I know its high, but I allowed it to go to 4.24 to test the BMS).

 

[amberwolf]

28.7 on the cell log and 29.41 on meter. Quite a big difference. Has anyone else seen this type of behavior?

Often, when the multimeter's battery is low, it reads higher than it should. Might check that first, but it could be a real difference in accuracy.

 

[DrInnovation]

28.7 on the cell log and 29.41 on meter. Quite a big difference. Has anyone else seen this type of behavior?

Often, when the multimeter's battery is low, it reads higher than it should. Might check that first, but it could be a real difference in accuracy.

Thanks, I had already checked the batteries and they are good.

Left the charger+BMS running overnight with 29.8v input and while the meter shows cells ranging from 4.24 to 4.19 (Still not fully balanced, but I digress). SingnalAB BMS is nominally supposed to balance at 4.2 so the 4.24 is likely about right. However, the CellLog has a high of 4.13, and most cells are reading .10 or .11 Volts lower than the meter. Thus I'm pretty sure it my CellLog or my setup to it. I know I have plugged the cable to the CellLog offset a pin or two a few times.. could that hurt the unit and cause this?

Reading the manual I see it has a "user calibration" mode, a pretty cool idea in its own right as even if it is my setup is causing the problem I can correct for it on the bike setup.
Has anyone used that? The manual says need to do it with 8s.. would it work if I only calibrate 7s? Either way I'll get/check with another meter before I do it, but seems like a nice fix no matter what the cause.

EDIT: Well my above analysis was incorrect, Turns the CellLog8 was fine in its voltage measurement (or at least much closer than my meter). The above statement about balancing from a 29.8v input to 4.24 on a cells etc was bogus because, duh, I had set the moded RS-150-24 meanwell charger voltage using the meter so if the meter was off the 29.8 was overstimated. So I decided to find a way to test the mete and I found nice 5 and 12 volt references at school (\pm 1% claimed) and tested my meter to find it was about 5-8% high, while celllog was within 1%. Adjusted my meter best I could using the two reference values (there is a pot in the meter). Now two cellog is within 2% which is within the margin of error of the "adjusted meter". So lesson learned.. Celllog is well calibrated. RadioShack meters not so much.

 

[Hillhater]

Sorry to revive an old thread, but anybody know a supplier for the 8s logger ?
..either Australian based or shipping to there .

 

[Ykick]

Sorry to revive an old thread, but anybody know a supplier for the 8s logger ?
..either Australian based or shipping to there .

Progressive RC seems to have 8S in stock and their eBay listing indicates worldwide shipping - http://www.ebay.com/itm/CellLog-8S-/301131847789?hash=item461cdb586d

Dale seems to have ‘em at Buddy RC but I’m not sure if he ships down under? Jet him an email?

http://www.buddyrc.com/junsi-celllog-8s.html

Weird, Hobby King only carrying 8m for past several months. 'hope perhaps Junsi has something new and better coming along?

 

[Hillhater]

Thanks Ykick,
That EBay link is ideal...
But yes, it's odd that HK seem to have dropped them ?
Maybe they think their IR meter is a substitute ?.....it isn't !

 

[cwah]

After all these years... isn't there a better or updated version of the cell log?

 

[Ykick]

No logging - http://www.ebay.com/itm/NEW-RC-Model-BVM-8S-1-8-Cell-Battery-Voltage-Meter-LiPo-LiFe-NiCd-Ni-with-Alarm/252213991018?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D37470%26meid%3Dc7533664d8cd4f1789a62c372880e9e3%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D301992460197

 

[cwah]

No logging - http://www.ebay.com/itm/NEW-RC-Model-BVM-8S-1-8-Cell-Battery-Voltage-Meter-LiPo-LiFe-NiCd-Ni-with-Alarm/252213991018?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D37470%26meid%3Dc7533664d8cd4f1789a62c372880e9e3%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D301992460197

Yeah there are few products like this on the market... i tried few that were really poor quality (eg. Medic) with inaccurate cells measurement.

Is this one better? Ideally it would be good to have something able to measure up to 20 cells

 

[jumpjack]

After all these years... isn't there a better or updated version of the cell log?

There is the possibility of connecting CellLog to a tiny WiFi module (ESP8266, NodeMCU) which can transmit data to your smartphone using WiFi:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=20142&start=200

Here you find an article I wrote about it (in Italian):
https://jumpjack.wordpress.com/2017/01/02/collegamento-di-un-celllog8s8m-ad-arduino-o-a-esp8266/

 

[Steve1M]

Alarm port - Connector type??

8M still serving me well.

Please can somebody correctly identify the alarm port connector.
JST-PH??
Some flavour of molex?

Many thanks, Steve

 

[fechter]

I think it's some type of JST connector. You can measure the pin spacing and see if it looks like any of these:

JST connector types