Gear for logging C-rate vs Temperature, also capacity

Batteries, Chargers, and Battery Management Systems.
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john61ct   1 GW

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Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Oct 28 2019 10:16pm

branched off from

viewtopic.php?t=102981#p1506203

Would like to collect reco's here for "reasonably" priced testing and data-logging equipment,

let's shoot for altogether well within $500, not counting the target PC and Logview type software producing the final charts.

Chargers like Junsi iCharger and FMA/Revolectrix Cellpro, maybe ISDT are of course one important category.

Another is CC electronic dummy loads, especially those able to go higher than say 20A for true stress testing of sustained high C-rates.

One class I am particularly interested in, is "passive" or pass-through logging hardware, that maybe does not itself create or control the charging energy or discharging load, but simply records the volts & amps data over time, for later transfer to the PC for analysis.

Really hoping to find still-accessible sources for the old-school quality versions of (Japanese?) CellLogs?

For true-capacity testing, I do not like to assume coulomb-counting gear is accurate enough for that, so besides the CC load regulation, the ability to automate and precisely time the lower-current draw-down over, say 3-5 hours is important, ideally more elegantly than using a smartphone to capture photos on a timer.

And finally of course the temperature change logging hardware so the varying C-rate can be correlated with its impact on cell health and longevity.

Obviously this thread should keep a focus on the testing process, so general discussion on different testing approaches, defining related protocols etc is fine.

But ideally the intention here is to build up a comprehensive listing of suitable hardware, and discussions comparing the various units' costs/sourcing, features and capacities.

Extensive sub-topics about the implementation details for a particular piece of hardware could perhaps be split off into a separate thread for each, to keep it useful for us noobs seeking an overview.

john61ct   1 GW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Oct 28 2019 10:20pm

Obviously would be great for members to link to all the important existing threads on related topics, even old ones if they have important still-relevant information.

To the extent such threads get into hundreds of posts long, ideally try to give "the gist" from your POV, what reco's there are still relevant etc, if you are really interested maybe even provide a parsed-out summary, even if you aren't yourself an actual expert that would be a valuable contribution saving others coming across this thread in future Googling, a lot of time.

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DogDipstick   1 kW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by DogDipstick » Oct 29 2019 9:58pm

I use a Powerlab6. Configurable taper to .001A, Safety codes, This is cell level testing I want something to test the entire pack Ah as a whole, reliably and efficiently. Hobby grade charger ( compare to your average high end iCharger)

Anything that gives me a consistent IR read tell me alot. Pretty much everything I need to know, like a Wayne Giles IR meter ( later copied by Revo lol) . I takled to Wayne in a RC groups pm about my Chevy Volt cells, and with an capacity of 15.5Ah, @ 6w/Ah of heat max dissipation, IR of 1-1.2 mOH, they would support 17C, or ~270 amps, theoretically. This is using his calculator made famous on RCGroups.

All you need to know on cell level testing: Voltage, capacity, IR, pack V., it is all datalogged on a spreadsheet in the powerlab for me and later stored on a hard drive. i can do 6 cells at once, 40 amps max discharge with a ten day cycle timeout, 1-99 cycles. Configurable cool downs, SOC map generation, 1-2-3C PID controlled charging, up to 6s or 25v. Its about 200$.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...it will hurt you... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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flippy   1 MW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by flippy » Oct 30 2019 7:52am

first i would be a distincion between single cell tester or pack testers.
Lithium beats liquid dinosaurs.

john61ct   1 GW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Oct 30 2019 9:22am

Reco's and discussion of both categories are welcome.

Lets assume cell level, so just label the pack level gear as such when posting about it.

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by silentflight » Oct 30 2019 2:11pm

I use a West Mountain Radio CBA IV. It is well known, but I'll add a mention here.

The standard version (which I have) only uses the thermistor to shut off charging if the cell or pack temperature goes over a preset limit. It is possible to buy a pro version which upgrades the unit to record the temperature along with the voltage and Ah, etc.

They also sell a version which tests up to 100V, but it is still limited to between 100W and 150W depending on current flow during discharge. A 500W dummy load is available as an option to increase that limit.

http://www.westmountainradio.com/produc ... ts_id=cba4

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DogDipstick   1 kW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by DogDipstick » Oct 31 2019 7:51am

silentflight wrote:
Oct 30 2019 2:11pm
I use a West Mountain Radio CBA IV. It is well known, but I'll add a mention here.


http://www.westmountainradio.com/produc ... ts_id=cba4
My Powerlab6 can export to Western Mountain CBA format for using their graphing programs. :) Good stuff.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...it will hurt you... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Nov 03 2019 9:49am

From @docware thread

Li-ion cells cycle ageing viewtopic.php?t=103092

ZKETECH EBC-X0510 (8 channels)
true 4-wire fixture BF-2A
electronic load Maynuo M9712
DMM GW Instek GDM-8351
thermometer Omega HH 520, K thermocouples



BYqSXt8Z   100 W

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by BYqSXt8Z » Nov 06 2019 10:06am

Doesn't hit all the points, but for 10$ of parts I log charge / discharge cycles at up to 20A discharge, 5A charge, and accuracy is pretty good, reliability is excellent.

I'm not quite done yet, but the latest version is far more robust and quick to assemble. I still need to figure out how to better fan mount than hot glue...

It can run as a data logger for x loops, or simply give a readout at the end with impedance calculations, capacity, and voltage stability after 24h. I've designed the board to allow for optional modules like the microsd one. I currently use 2 different firmwares, but only so the rotary indexer / button can be optional and save an extra $. Really it could (and does) have mode selection at startup.

I decided to remove the temp sensor last minute because it was too difficult to implement a proper probe with good contact on a wide range of batteries. Instead, I plan on logging ambiant temperature and use that to adjust capacity in my analyses.

Lastly, load is modularish, so a cc digital load could just be plugged into the output instead of a resistor, but that would mean having preset parameters on the digital cc load, or adding control circuitry and code.
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DogDipstick   1 kW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by DogDipstick » Jan 21 2020 12:40pm

So I am actually doing this, for well under the 500$ that John specced above. Building my own High power Hivgh current "Grinspector"...

All parts in hand. Ready to datalog. Lol. Whoohoo. Building this month.

viewtopic.php?f=14&t=104336
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...it will hurt you... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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DogDipstick   1 kW

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by DogDipstick » Jan 21 2020 3:09pm

john61ct wrote:
Oct 30 2019 9:22am
Reco's and discussion of both categories are welcome.

Lets assume cell level, so just label the pack level gear as such when posting about it.
Have you seen this John? I have one and am going to try to see some way to datalog the wifi signal off of it...: I'll report back later.

Wifi 40$ Chinese "Battery Monitor".... Pretty sophisticated lil guy... for 40$. Its tiny.. an bright. The 300A hall sender looks like it is about 20mm across, and built from high quality CNC machining and is potted. Wifi data transfer and relay triggering. Gee you dont even have to touch the HV battery under test. Lol.

https://www.ebay.com/itm/Wireless-Batte ... 2749.l2649

Thoughts?
Read your battery bank like a fuel gauge.
Battery Status At A Glance.
Charging status indicator, looks like a smartphone.
Combines many functions in one, Dual display
Voltage (V), Current (A), Capacity (AH)
Power (W/KW), Energy (KWH)
Temperature (C), Working Hours (H)
By turning External device/Relay on and off, it can control external devices, such cut off Power input.
Trigger external Relay (Not included) when the reading reach preset value.
[OVP] Over Charge Voltage protection
[LVP] Over Discharge Voltage protection
[OCP] Over Discharge Current protection
[NCP] Over Charge Current protection
Come with a Through-hole Current transformer, it doesn't require shunt.
The current sensor can be placed on the Positive or Negative side of power.
Reverse polarity protection.
Doesn't require isolated power, self-powered 6-80V.
Nondestructive installation, it is very easy to install.
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Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...it will hurt you... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Jan 21 2020 3:38pm

For read-only logging right?

Those based on an external shunt will give more flexibility.

A small 100A one gives higher resolution.

Swap in the 200, 500 or even 1000A one when needed.

I think the Victron protocols are ready published for FOSS integration, their BMV-712 also can control a contactor.

Maybe the BT BMSs can also be adapted.

But I don't believe any of these actually regulate the load to keep it precisely CC as voltage sags, to me doing that over a wide amps range is the real challenge.

There are some great threads on this topic over at the RCgroups forum, but in that context 50A is considered a high rate, 20A range more the norm.

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Jan 22 2020 6:39am

posted links in the other more active thread
viewtopic.php?t=104336

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Re: Gear for logging C-rate vs Temperature, also capacity

Post by john61ct » Jan 23 2020 1:50pm

New thread targeted at Grinspector
viewtopic.php?t=104380

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