HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 24, 2009, 04:10 PM
Registered User
SteveM732's Avatar
United States, OR, Beaverton
Joined Feb 2008
1,976 Posts
Quote:
Originally Posted by write2dgray View Post
Then most in the RC community have never considered or heard of a BMS.
Then why do you leave us to guess what it is?

Based on context I'd guess BMS = Battery Management System, a device that monitors your battery and keeps it from over discharge and keeps it properly charged.
SteveM732 is offline Find More Posts by SteveM732
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 24, 2009, 04:35 PM
Registered User
Joined Oct 2009
63 Posts
Quote:
Originally Posted by SteveM732 View Post
Then why do you leave us to guess what it is?

Based on context I'd guess BMS = Battery Management System, a device that monitors your battery and keeps it from over discharge and keeps it properly charged.
You got it Most BMSs have LV/HV cuttoff circuits built in and a cell balancer circuit as well. That way, a "less intelligent" charger can be used.
gumpee is offline Find More Posts by gumpee
Reply With Quote
Old Nov 24, 2009, 05:15 PM
ProgressiveRC
write2dgray's Avatar
Seattle, WA
Joined Dec 2006
1,997 Posts
Yep, you got it - a battery management system. Purely an oversight and not out of spite I assure you .
write2dgray is offline Find More Posts by write2dgray
RCG Plus Member
Reply With Quote
Old Nov 24, 2009, 10:10 PM
iCharger
junsi's Avatar
Joined Mar 2007
1,087 Posts
Quote:
Originally Posted by Doctorbass View Post
Hello Junsi, i'm from the Endless sphere forum ( crazy powerfull ebikes gang)

http://endless-sphere.com/forums/vie...p?f=14&t=12815

We really love your cell log8 and would be interested to know if it is possible to make a new release of it woth up to 24s ?

Something like.... that:

Hello Doc,

Thank you for your great support and appreciation of our products, and your nice picture.

Maybe we will have a forecasting of the market situation before we decided to make it up to 24s. If there is a great demand of 1000 units or more at you, we will be glad to have a cooperation with you. More detail or requirements you can send to our email: szjunsi@163.com or harrief111@hotmail.com.

Thanks.

Regards,
Junsi
junsi is offline Find More Posts by junsi
Reply With Quote
Old Nov 25, 2009, 01:13 AM
Registered User
Joined Oct 2009
63 Posts
Quote:
Originally Posted by junsi View Post
Hello Doc,

Thank you for your great support and appreciation of our products, and your nice picture.

Maybe we will have a forecasting of the market situation before we decided to make it up to 24s. If there is a great demand of 1000 units or more at you, we will be glad to have a cooperation with you. More detail or requirements you can send to our email: szjunsi@163.com or harrief111@hotmail.com.

Thanks.

Regards,
Junsi
You should have seen the buzz out on the ES forum when Doc first posted this picture. It may not have been a thousand posts, but it was a level of enthusiasm to behold, none the less. Every tree with with a million flowers has to bloom with a modest few in its youth.
gumpee is offline Find More Posts by gumpee
Reply With Quote
Old Nov 26, 2009, 08:12 AM
Registered User
toddiebandit's Avatar
Tönisvorst / Germany
Joined Jul 2008
3 Posts
Quote:
Originally Posted by junsi View Post
Hello Torsten,

As for your improvements 1st, actually you need only select as shown in Pic.1.
The 4th, you can consult CellLog manual P8, which I also shoot screen as shown in Pic.2.

Regards,
Junsi
Hi,
thanks for the reply...and sorry to check this forum not so regularly.

For my suggestion 4.Lowest Voltage this is a different than what is implemented.

At the moment the valuse which are shown in the screen are ACTUAL cell data. My wish goes to the direction Lowest voltage oder the whole Time Cell log is switched on.

So when you have flown the battery you can quickly recheck if the voltage has droppe below a certain value, over the whole flight time.
At the atual implementation you only see tha actuals plus the logged ones. But this can only be checked after transfering the data to Logview

The first I have to recheck, but I suppose it is not working in the way you suggested.What i want to have is that I can log more than one cell to one logfile and CellLog is attaching the data to the actual log file. You mention a feature in Logview so that you can select more than one transfered file...but I have only one...

Is this more clear ?

BR
Torsten
toddiebandit is offline Find More Posts by toddiebandit
Reply With Quote
Old Nov 26, 2009, 09:24 AM
SpeedEBikes
speedebikes's Avatar
Joined Sep 2009
33 Posts
This is an update to this previous post. All is now well regarding my celllog-8. After the failed upgrade attempt yesterday, I tried again this morning. I noticed that although my celllog was flashing a blank screen and clicking it was still recognized as a USB device by my pc. It took two attempts of connecting and disconnecting the celllog. The first time I got the same results as yesterday, but the second time the text quickly changed to "upgrading" and it completed successfully. BTW, from yesterday to today there was a new release so I'm now running V207. But I don't think the firmware revision had anything to do with this as the problem appears to be between my USB interface and the upgrader.exe software.

----
I ran the upgrader program that came on the disc with my celllog-8. I clicked the "Donwload" button and a window opened with a list of updates. In the list I found a recent V206 file for the cellog which I selected.

I clicked the "Download" button for that and a message appeared at the bottom of the window "connecting" and the screen of my celllog started to flash. Then the cellog screen went dark. The text changed to something like "connecting again" and my cellog started flashing again. The the text read "device not found".

My celllog screen continued flashing. I waited a bit and then unplugged it. Now whenever I plug it back in my celllog just flashes a blank screen and makes a little clicking sound.

How do I reset/recover my celllog? Do I have to return it for repair/replacement or is there a way to fix it myself?
speedebikes is offline Find More Posts by speedebikes
Last edited by speedebikes; Nov 27, 2009 at 11:34 AM.
Reply With Quote
Old Nov 28, 2009, 01:57 PM
SpeedEBikes
speedebikes's Avatar
Joined Sep 2009
33 Posts
Doc Bass and others interested in these for ev use, here's the solution I've been using.

I considered wiring the alarm outputs to my controllers 'ebrake' cutoff to mimic the behaviour of a BMS which cuts power. But I realized that I don't actually like that behaviour. I want to know my batteries are nearing depletion but I want to voluntarily cut power not just have it cut out by surprise. But if you do go with the power cutoff approach, a point in favor of the celllog over a BMS is that a BMS switches the main battery power and that switch adds resistance, heat and is a potential failure point. To make it robust and efficient means added weight, bulk and cost.

So I find the idea of an alarm very appealing.

But the internal alarm on the celllog is weak. You can hear it from maybe 15 feet away in a quiet room, but on a bike/vehicle at speed or in city traffic you may not hear it. And if you enclose the celllog for weather protection the problem is even worse.

But I found a very easy solution. For about $5 you can get a super loud piezo buzzer from Digikey, part # 102-1643-ND. This buzzer will operate on something like 3-30 volts ac or dc. Volume and current draw go up proportionately with voltage. I run 6s lipo packs, 7s li-ion packs and 8s life packs. These buzzers work great with all of them. All one has to do is wire the buzzer in series with the alarm output of the celllog (think of it as a switch) across the entire pack. If one was using an 8s lipo or liion you probably want to wire across only 7 cells to avoid pushing too much voltage through the alarm. You might also choose to use fewer cells if you find the alarm is too loud. I don't think wiring across a subset of cells is at all an issue for pack imbalance as the alarm only draws a few milliamps and shouldn't ever be on for too long. Any solution to pack balancing, even if rarely used should suffice to correct for this.

I typically run two to four packs in series with a separate celllog and alarm on each. The per cell voltage alarms are all non latching. That means as you roll on the throttle and cell voltages sag under load you will start getting alarms tripping as you approach depletion. Ease off the throttle and the alarm stops. You can set the voltage levels that will trip the alarm to dial in the amount of warning you get before the pack is truly done.

I really like the redundancy of having an alarm on each pack. I can clearly hear each packs alarm. If one pack is a little weaker than another I can hear it trip first or find a throttle level that will trip one but not the others. I like the idea that if a celllog fails or an alarm fails there is almost no impact as I still have power and I still have the protection of the other pack(s) alarms. And I know to investigate if I can hear one alarm but not another.

There are alarm triggers for high and low cell voltage which most everyone will want to enable all the time. There is also a trigger for max cell voltage difference. I like to set this one fairly tight such that if any cell is dropping in voltage more quickly than normal I will know. I use packs made from cell blocks wired in parallel and then in series. If a single parallel connection fails then that cell block will deplete faster and sag harder than the other cell blocks and the cell difference alarm will alert me to that fact early before the pack is run down.

However if you have an old pack with some weak cells you probably want to set the difference alarm high enough to not trip with your typical operating useage. The celllog's logging feature is really handy for this. Record your typical useage, dump it to your PC and then check out the graphs. You'll easily be able to spot which cells have high IR and/or low capacity. For big packs made of lots of paralleled cells it then becomes pretty easy to tack on an extra cell or two where needed to create a better behaved pack.

I put both the alarm and the celllog inside my battery cases to protect them from weather. Also, I don't like the idea of having long balance taps with all the small delicate wires extending outside the protective confines of the case. Small delicate balance wires have the advantage of being self 'fused' in that they will blow readily in the case of a short. To run long external balance taps one will likely want to use heavier wire each individually fused adding complication and expense.

So in summary, I love using the celllog8s on EVs. Even though I sometimes run 24s I don't really want a single 24s celllog.

My biggest issue right now is that there isn't good auxiliary parts support for these units. I can't find prewired JST XH-8 pigtails, extensions or Y adapters. Also, the alarm wires are exceedingly delicate and I have broken one of the alarm wires off from a connector and I don't know how to get more alarm wire pigtails either. You can buy the connectors and terminals for these from Digikey, which is what I've done, but wiring them up is challenging and tedious.

Someone had asked about latching alarms. The pack voltage difference alarm is for the delta between the pack's minimal and maximal recorded voltage for the duration the celllog has been powered on. Thus once this trips it stays on until you unplug the celllog.

Finally, in my wishlist of features for the celllog it would be nice to have a way to query what tripped past alarms such that when one looks at a celllog after the alarm is over, one can readily see what it was about. Perhaps one of the 3 different view screens could be used for this purpose or a 4th view screen could be added that would show past alarms. It would also be good to be able to see info about alarms in logview when looking at exported logs.
speedebikes is offline Find More Posts by speedebikes
Last edited by speedebikes; Nov 28, 2009 at 02:20 PM.
Reply With Quote
Old Nov 29, 2009, 11:04 AM
Asks too many questions
natterjak's Avatar
Berkshire, UK
Joined Nov 2005
474 Posts
Logview version?

Does anyone know if celllog is compatible with Logview v2.5? I have downloaded and installed Logview but can't get it talking with the cell log device. The only ports it offers are some bluetooth ports and com15 CP210x USB to UART Silicon Labs, so I have selected com 15 as I assume that's the one.

No luck though. Any tips?
natterjak is offline Find More Posts by natterjak
Reply With Quote
Old Nov 29, 2009, 08:03 PM
Registered User
Melbourne, Australia
Joined May 2006
6,407 Posts
Just got my CellLog and started to play. As I so often find to be the case, things are so much smaller in real life than they appear on the Internet!

It is a very compact and neat unit with an excellent display. I better read the manual before going much further.

I did have a brief initial play. The second time I connected it to a 3S lipo the display came on all upside down! After disconnecting and reconnecting it was back to normal.
kgfly is offline Find More Posts by kgfly
Reply With Quote
Old Nov 30, 2009, 02:05 AM
ancora imparo
jj604's Avatar
Melbourne, Australia
Joined Jul 2005
6,779 Posts
Neat, speedebikes. Why didn't I think of that?

I think you do have to calculate the end point you want from the starting voltage that you observe then set the pack voltage difference so it's not all that convenient for those "quick and dirty" moments but it is still a neat trick.

John
Quote:
Originally Posted by speedebikes View Post
Someone had asked about latching alarms. The pack voltage difference alarm is for the delta between the pack's minimal and maximal recorded voltage for the duration the celllog has been powered on. Thus once this trips it stays on until you unplug the celllog.
jj604 is online now Find More Posts by jj604
Reply With Quote
Old Nov 30, 2009, 10:42 PM
SpeedEBikes
speedebikes's Avatar
Joined Sep 2009
33 Posts
Quote:
Originally Posted by jj604 View Post
Neat, speedebikes. Why didn't I think of that?

I think you do have to calculate the end point you want from the starting voltage that you observe then set the pack voltage difference so it's not all that convenient for those "quick and dirty" moments but it is still a neat trick.

John
John, it's actually not that complicated if you consistently charge to the same voltage. The celllog only draws a few milliamps, even less if you take advantage of the screen blanking feature just added in the latest firmware. I plug my celllogs in after charging and just leave them connected until the next balance charge. Though I use my batteries pretty much every day. There's also a new sleep mode, but I haven't tried it. But if done right, it might work for those who let their batteries sit unsused for long periods.

Beware though that if you use more than a 6s pack that the celllogs as shipped will only pull power from cells 1 through 6 and thus slowly cause an imbalance. Junsi posted (in this thread I think) how to mod a celllog to make it pull power from all the cells.
speedebikes is offline Find More Posts by speedebikes
Reply With Quote
Old Nov 30, 2009, 11:03 PM
JUNK RADIO
Flazo's Avatar
USA, NY, Queens
Joined Dec 2006
3,136 Posts
can you add a watt meter?

thanks
Flazo is offline Find More Posts by Flazo
Reply With Quote
Old Dec 01, 2009, 01:41 AM
ancora imparo
jj604's Avatar
Melbourne, Australia
Joined Jul 2005
6,779 Posts
Ah,we are talking about a different use. My addition of the latching relay was for when the CellLog is used to monitor a high current discharge into an external load and cut off the battery when the end point or storage level is reached. The load of theCellLog itself is irrelevant in that application. See the thread at:

http://www.rcgroups.com/forums/showthread.php?t=1131817

The delta for the pack min and max could be used instead of a latching relay to avoid the cycling when the load disconnects and the pack voltage recovers.

I'll put a note about the idea in the other thread in case anyone wants to use it.

Thanks again.

John
Quote:
Originally Posted by speedebikes View Post
Beware though that if you use more than a 6s pack that the celllogs as shipped will only pull power from cells 1 through 6 and thus slowly cause an imbalance. Junsi posted (in this thread I think) how to mod a celllog to make it pull power from all the cells.
jj604 is online now Find More Posts by jj604
Reply With Quote
Old Dec 01, 2009, 05:39 AM
AJH
AJH
UK
Joined Jul 2004
87 Posts
Display Program

For reasons I don't understand, my PC and LogView won't play nicely together, so I wrote my own simple display program. In case it's of use to anyone else, here it is.

Note I have no affiliation with the manufacturer, other than being a customer.

AJH
AJH is offline Find More Posts by AJH
Last edited by AJH; Mar 18, 2011 at 06:13 AM. Reason: Added screen grab
Reply With Quote
Reply


Thread Tools