Battery Testing With Maynuo M9812 - Page 1
Forum section: electronics / testgear

author: MotoDan
author_rank: Contributor
timestamp: March 23, 2018, 08:03:50 pm
content: Hello all,I recently bought a Maynuo M9812 DC load and am trying to do some battery capacity testing - specifically for lithium coin batteries. The manual shows a time limit range of 1 sec to 16 hrs, but I can seem to find a way to change this value. Ideally I would like to go beyond 16 hours since a CR2032 for example has an approximate capacity of 220mAh @ 2mA. This equates to around 110 hours.So far I really like the M9812. Hoping someone else has done some battery testing and knows of a way to change the cutoff time.

author: BillB
author_rank: Unknown
timestamp: March 23, 2018, 10:31:02 pm
content: I've got the ITech 8511+ which I thought would be similar enough to help, but looking at the M9812 that does not seem to be the case. (ITech goes to 99999 seconds)Maybe they are using a 16 bit number for the seconds timer, which would limit you to a maximum of ~18 hours?

author: ovnr
author_rank: Frequent Contributor
timestamp: March 23, 2018, 10:40:59 pm
content: The Maynuo loads are not very appropriate for the task. My M9712 set to 0.5 mA CC reads 0.2 mA - while actually taking 1.6 mA. Set to 500 mA, it takes 501.2 mA. So there's a mostly fixed offset, and at very low values it'll just completely ruin any hope at an accurate result.I doubt there's anything that can be done about the time limit.

author: MotoDan
author_rank: Contributor
timestamp: March 24, 2018, 10:36:14 pm
content: What about setting the time limit? The specs show 1 sec to 16 hrs, but not how to set the timeout.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 24, 2018, 11:37:42 pm
content: I’m interested in one of these units, so don’t mind me taking a seat in the thread.

author: georges80
author_rank: Frequent Contributor
timestamp: March 24, 2018, 11:43:11 pm
content: I think to use the battery test mode in a useful fashion (i.e. to collect the discharge curve data and then export to csv etc) you need to be using their software package and the USB/Serial dongle. I have a home made isolated dongle and their software is pretty reasonable.In the battery mode you can set time limits and sampling rate etc to log the discharge curve.cheers,george.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 24, 2018, 11:49:23 pm
content: Quote from: georges80 on March 24, 2018, 11:43:11 pmAre you referring to using software versus using the device on its own? If so, I gather using the device together with home grown software would be viable too?

author: georges80
author_rank: Frequent Contributor
timestamp: March 25, 2018, 12:05:44 am
content: ^ Maynuo software. It's pretty reasonable for what it is. The battery mode works just fine and I have used it to get Ah ratings of various li-ion cells at differing load currents (10's to 100's of mA draw).cheers,george.

author: Macbeth
author_rank: Super Contributor
timestamp: March 25, 2018, 12:15:12 am
content: Maynuo uses the MODBUS protocol vs SCPI. Doesn't matter if you use the OEM software. If you need to DIY then there ishttps://github.com/MetalPhreak/pyMaynuoto help you out.The 9 pin D sub is not RS232 but TTL. Not isolated either.

author: MotoDan
author_rank: Contributor
timestamp: March 27, 2018, 03:02:51 pm
content: Thanks for all the comments. I decided to download the Maynuo M9700 software which allowed me to run my battery test without a time restriction.