Ykick
1 GW
http://www.ebikes.ca/shop/ebike-parts/cycle-analysts/ca-sa.html
How an eBiker evaluates a DC charger & battery capacity
- Thread starter Ykick
- Start date
friendly1uk
1 MW
lol@your intent
As an electrician, I feel tarred (by that other thread) and feel it's title inaccurate and is effecting my future chances of work lmao
As an electrician, I feel tarred (by that other thread) and feel it's title inaccurate and is effecting my future chances of work lmao
dogman dan
1 PW
Don't let a member trick you into getting yourself banned from ES. If you have too much fun, you'll get axed before he does. We saw this before with another guy. He nearly took some good members with him.
As moderators, when we see two people in a big enough fight, it's just the practical thing for us to do, to chuck them both.
If you want to watch your charge as it happens, a good wattmeter like a CA can do it pretty good. even the cheap ebay wattmeters can show you when the charger is pushing a lot of watts, and when it's not, even if it's off by 30 watts. But they aren't going to graph it for you.
As moderators, when we see two people in a big enough fight, it's just the practical thing for us to do, to chuck them both.
If you want to watch your charge as it happens, a good wattmeter like a CA can do it pretty good. even the cheap ebay wattmeters can show you when the charger is pushing a lot of watts, and when it's not, even if it's off by 30 watts. But they aren't going to graph it for you.
Ykick
1 GW
CA to measure a discharge cycle for 16S1P Turnigy 5Ah 20C RC Lipo hardcase battery pack. This is a living room setup so 'using an old toaster oven for load. It's much more fun to ride and simply use all of the wonderful CA parameters to calculate Wh/Ah per mile, etc. But, it's icy outside and I'm kinda bored....
Resting voltage was about 66.7 and this capture is moments after connecting the load:
Almost the end, I think it went another few moments before the BMS kicked off but it looks like I actually got labelled capacity. Really amazing to me is the difference in Watts between HV/LV extremes.
View attachment 1
This is a log grabbed from an 8S CellLog which was attached to cells #1-8 for the entire cycle:
The BMS really allowed me to squeeze every Ah between 4.2-2.8V from these 5Ah Turnigy bricks.
Resting voltage was about 66.7 and this capture is moments after connecting the load:
Almost the end, I think it went another few moments before the BMS kicked off but it looks like I actually got labelled capacity. Really amazing to me is the difference in Watts between HV/LV extremes.
View attachment 1
This is a log grabbed from an 8S CellLog which was attached to cells #1-8 for the entire cycle:
The BMS really allowed me to squeeze every Ah between 4.2-2.8V from these 5Ah Turnigy bricks.
dnmun
1 PW
you can see how the cells all jumped back up to 3.7V when the load shut off too. so there is still another 1-2% left in the pouches even when discharged to the 2.8V LVC.
Ya - this goes to the business of open circuit voltage being the actual measurement of state of charge.
The CA V3 calculates the battery internal resistance on the fly as a means to correct the gas gauge icon - since when underway OC voltage is not available. The 'loaded' voltage is corrected by the current and internal resistance to yield an approximation of what the OC voltage would be - the computed voltage is used to drive the icon state of charge.
As a side effect, the battery IR is available in a CA stats display which is a handy indicator of battery aging and general battery circuit connectivity issues. Bad fuse or connector issues cause a jump in the IR since the CA cannot discriminate between true battery IR and wiring/connector resistance.
The CA V3 calculates the battery internal resistance on the fly as a means to correct the gas gauge icon - since when underway OC voltage is not available. The 'loaded' voltage is corrected by the current and internal resistance to yield an approximation of what the OC voltage would be - the computed voltage is used to drive the icon state of charge.
As a side effect, the battery IR is available in a CA stats display which is a handy indicator of battery aging and general battery circuit connectivity issues. Bad fuse or connector issues cause a jump in the IR since the CA cannot discriminate between true battery IR and wiring/connector resistance.
cwah
100 MW
nice discharge curve! cell log is great
Ykick
1 GW
dnmun said:
Actually, they didn't jump up to 3.7V on their own. That charger limits current more on the LV side until the meat of the charge at that 3.7V/cell point. It also tapers down again towards the end. However, I only allowed a short break in between discharge and then switched back over to charge.
Here's the zoomed pic from the Log:
Check the lowest cell - it only bounced up from about 2.8V to 2.95V on it's own before the relatively low Amp charge began.
I think I should let them rest 5-10 minutes next time before firing off the charger? Gonna work up another adapter cable in order to grab all 16 cells on the 2nd CellLog too.
friendly1uk
1 MW
dnmun said:
Not too loud, we will have another one circling with their erroneous test results.
I was very interested to read how somebodies older pack was spending 80% of it's charge time CV charging when he used a high CC rate.
We can't ban them. Ykick is in the union, and krackers is too funny. I might go and have a look at Grease for this summers holiday. I think it will be equally as entertaining.
There are many useless tradesmen. Often the grading system is 40% for a pass, 60% for a merit and 80% for a distinction. So you can be an electrician if your wrong 60% of the time when doing your absolute best to answer questions you did already in you mock exam. Thus I'm not really interested if someone has their papers or not. Only insurance companies are. It is the same with going uni. It's just a financial statement. It don't mean your any good.
cal3thousand
10 MW
friendly1uk said:
What other thread are we talking about? I missed this one
EDIT: Nevermind. I found it. What a hoot. Long live the CA!
Ykick
1 GW
Damn, modded my JST parallel adapter to run both CellLog 8S and had a nice discharge/charge graph of all 16S. Unfortunately, inadvertently deleted one of the log files so will have to rig it up and do another pass.
However, in the meantime I wanna throw this image up which shows the Bestechpower D245 BMS cutting off when cells reached about 4.25V. Trouble is, after sitting for around 30-50s, it kicks back on and continues to bulk charge with seemingly no HVC protection. Once it got up to around 4.27V/cell I terminated the charge and scratched my head. Good thing I wasn't "relying" on this BMS to prevent an overcharge condition.
The charger used is a 3A 60V SLA which floats up to over 68V. I was under the impression the BMS would cut-off @ HVC and remain cut-off. Obviously, not the case....
However, in the meantime I wanna throw this image up which shows the Bestechpower D245 BMS cutting off when cells reached about 4.25V. Trouble is, after sitting for around 30-50s, it kicks back on and continues to bulk charge with seemingly no HVC protection. Once it got up to around 4.27V/cell I terminated the charge and scratched my head. Good thing I wasn't "relying" on this BMS to prevent an overcharge condition.
The charger used is a 3A 60V SLA which floats up to over 68V. I was under the impression the BMS would cut-off @ HVC and remain cut-off. Obviously, not the case....
friendly1uk
1 MW
The HVC on a bestech is 4.28v +/- 0.05 meaning 4.33v is within spec. It's the reason I won't use them.
HVC should never happen though. It is fault protection. It's not balance threshold. Which for a bestech is 4.2v
Just for anyone still scratching.. The board trims down cells if they pass 4.2v and will stop charging if they reach 4.28v which is a sign the board has inadequate balance current for the batteries state of play.
HVC should never happen though. It is fault protection. It's not balance threshold. Which for a bestech is 4.2v
Just for anyone still scratching.. The board trims down cells if they pass 4.2v and will stop charging if they reach 4.28v which is a sign the board has inadequate balance current for the batteries state of play.
Ykick
1 GW
Pack is 16S1P 5Ah 20C Turnigy Hardcase. 4qty, 4S bricks series wired using all stock plugs. (don’t wanna bugger any warranty that may exist from HK?)
2 independent CellLogs running side by side.
Channels 1-8 discharging roughly 1C:
View attachment 2
Channels 9–16 discharging roughly 1C:
CA discharge screenshot:
Upon ODDV (discharge finished) allowed cells to rest and stabilize for about 10min. Continued...
2 independent CellLogs running side by side.
Channels 1-8 discharging roughly 1C:
View attachment 2
Channels 9–16 discharging roughly 1C:
CA discharge screenshot:
Upon ODDV (discharge finished) allowed cells to rest and stabilize for about 10min. Continued...
Ykick
1 GW
Fired off charger:
Channels 1-8 Charging roughly 1C:
Channels 9-16 Charging roughly 1C:
CA Charge screenshot:
Rested about 3 min and reconnected load to burn off a little charge so the cells don't sit around @ 4.2V.
Channels 1-8 Charging roughly 1C:
Channels 9-16 Charging roughly 1C:
CA Charge screenshot:
Rested about 3 min and reconnected load to burn off a little charge so the cells don't sit around @ 4.2V.
Ykick
1 GW
emmetbrown
10 W
If I could only afford that professional equipment I could log my 18650-packs, too.
Oh stop, my charger does logging, too.
Just have to find a software for that for Linux.
friendly1uk
1 MW
Ykick said:
So if someone set a pack level lvc of 3.33v per cell, a cell would be just touching 2.8v at cut-off. This happened on both packs tested.
That right?
dnmun
1 PW
i have a toaster oven just like that one. mine is prettier but it was also from the dumpster. it even had the metal tray with some aluminum foil still on it. i never had a toaster oven before. now i recognize i don't really use it either.
Ykick
1 GW
dnmun said:
dogman dan
1 PW
FWIW, two cellogs, even the expensive type, are not that expensive.
I just have the cheap ones, so I'd have to sit there watching them, but still very interesting to watch the charger finish and the bms start working on them.
And of course, you have to have the plugs for them installed on the pack. I keep thinking I need to do that to my allcell pack, voiding its warranty. It's a dilemma when you have a 2 year warranty.
I just have the cheap ones, so I'd have to sit there watching them, but still very interesting to watch the charger finish and the bms start working on them.
And of course, you have to have the plugs for them installed on the pack. I keep thinking I need to do that to my allcell pack, voiding its warranty. It's a dilemma when you have a 2 year warranty.
999zip999
100 TW
Dogman with different points of view the discussion can and should get lively enough to get a pluse and maybe the brain see a new light. Let us not live in the dark. So Watt's up ? Lol.
markz
100 TW
amberwolf said:
What cable do I need to hookup to the charger?
Cycle Analysts always log trip data to the serial channel at either once or 5 times per second. Common practice is to use a Cycle Analogger to capture this live data for later analysis, but the Analogger really doesn't interact with the CA in any way - it's just a serial data logger. For bench testing with a CA, the data stream can be captured using any device that can receive data in 9600baud, 8bit, 1 stop bit, no parity format.
So - a laptop or PC can be pressed into service to capture battery test data using the standard CA USB programming cable. The available FDTI drivers present the USB communication as a serial port on the platform of choice. For Windows, the USB port appears as a familiar com port.
Any serial data capture program may be used, but puTTY is an old standby terminal emulator/SSH client - sort of like the old Windows XP hyperterminal app on steroids.
If you want to give puTTY a try - here's the Windows setup steps:
(blue steps are for subsequent use after initial installation)
)
This will generate a data log like this:
The columns are described in "5.10 Serial Data Port" of the V3 Guide, but for the purposes of battery tests, the first three columns with Ah, V, A data are interesting. CA V2 data is similar but lacks some columns unique to the V3 (e.g. temperature). The resulting puTTY log file can be imported into Excel or Open Office (free) and manipulated or plotted as spreadsheet data.
It's neat that the CA is spewing out this data all the time anyway - so might as well grab it....
So - a laptop or PC can be pressed into service to capture battery test data using the standard CA USB programming cable. The available FDTI drivers present the USB communication as a serial port on the platform of choice. For Windows, the USB port appears as a familiar com port.
Any serial data capture program may be used, but puTTY is an old standby terminal emulator/SSH client - sort of like the old Windows XP hyperterminal app on steroids.
If you want to give puTTY a try - here's the Windows setup steps:
(blue steps are for subsequent use after initial installation)
- Download and install the windows installer puTTY 0.63 here.
- Download, unzip, and install this canned session profile by double clicking the ".reg" file and accepting the scary warnings.
View attachment 1 - Plug in the CA programming cable (assuming that you have previously installed the drivers...)
- Launch puTTY
- Select the CA-V3 profile and press "Load"
- Check the com port is correct
- The canned profile is configured to log files into C:/_LOGS.
Either:- create the directory
- change this under Session/logging (select in left pane) or
- ignore this (no logging occurs if the directory doesn't exist)
- If you made changes to the configuration, press "Save" to update the session profile
- Press "Open" at bottom of window
- Power up the CA
If enabled, the CA data is logged to C:_LOGS/putty.log
)This will generate a data log like this:
The columns are described in "5.10 Serial Data Port" of the V3 Guide, but for the purposes of battery tests, the first three columns with Ah, V, A data are interesting. CA V2 data is similar but lacks some columns unique to the V3 (e.g. temperature). The resulting puTTY log file can be imported into Excel or Open Office (free) and manipulated or plotted as spreadsheet data.
It's neat that the CA is spewing out this data all the time anyway - so might as well grab it....
- This technique may also be useful for bench motor tests. In that case, see "6.9 Displaying Wheel RPM" of the Guide to see how to configure the CA so the Speed data ("S" column) displays motor RPM instead of ground speed.
markz
100 TW
amberwolf said:
The manual is crap, bad english. IMAX b8 plus, looks like a cell phone plug on the side.
I was scrolling through the HobbyKing site, found a bunch on a search line of "USB"
I was going to take a picture of whats on the charger, until I realized my camera usb cord fits in the controller port. I will download LogView and rock from there.
I tell you, installing this logview in linux ubuntu is a trip back to msdos days. "cd, make dir, cd .."
Atleast its a step by step instructions, I am kind of winging it though, jumping back and forth, probably not in order. Im just follow the introductory stuff at the start. Will be cool to get graphs rocking.
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