Battery charging issue

[FEDforum]

From Zane Andrews:

We’ve been playing with the FED3 you gave us and there are some issues with the battery - it doesn’t appear to be reloading but functions fine when connected to power (just using a USB USB mini cable to a power outlet). We have different mains voltage here - 230V vs 100/120V in the US. Could that be affecting the recharge of the battery?….I figure replacing the battery is one solution.

Response:

I don't think the 220 vs. 110V will matter.  Does the yellow light on the Feather go on when you plug in via USB?  If so then the charging circuit is receiving appropriate power.

One idea: are you turning FED3 off before plugging in to charge?  I don't know if I mention this somewhere on the Hackaday but the FED3 should remain *ON* when you charge it.  The power button literally cuts the contact to the battery, so needs to stay on to charge.  I designed it this way for simplicity of the build but it makes this issue a bit confusing.  I may change this in a later version as it causes confusion about charging.

[zane andrews]

OK - we sorted it out. Thanks Lex - Key is to make sure system is on before charging and then ensuring yellow light on PCB is illuminated once connected to power.

[Mathias V. Schmidt]

Hi all, is there any update or other suggestions how to improve the battery charging on the devices? Our experiences so far are that some devices seem to not charge at all, although we connect them at the USB while they are running and the yellow light on the Feather is on. Others seem to be charging, but very slowly (even not fully charged over night). We use normal chargers that usually work with phones etc. Any other suggestions? Thanks! In the future we plan to mostly charge the batteries externally and just replace charged with empty ones, but for now we still need to charge the batteries while they are in the FED3s.

[Lex Kravitz]

Hi Mathias,

The yellow light turning on suggests that you're getting appropriate power to the charging circuit, so I think your chargers are good.  If the batteries are not charging at all I would suspect it's the button being off or the battery itself going bad.  You mention the buttons are all on, can you check that to make sure that's true?  If you have a bad battery you should be able to confirm that by putting it into another FED?  I'd start there and make sure you get any problematic batteries out of the mix.

Four other ideas :)

1) The battery is 4400mAh and the Feather charges at 100mA, so it theoretically will take 44 hours to completely charge one from dead.  Have you tried leaving it plugged in for 2 nights?

2) External chargers aren't a bad idea, we use these to keep spare batteries topped up: https://www.adafruit.com/product/1304

3) You could make sure the problematic FEDs aren't draining power for some other reason - can you hook them up to a current meter like this? https://www.amazon.com/Eversame-Multimeter-Chargers-Capacity-Banks-Black/dp/B01D9Y6ZFW  At standby, with a pellet in the well they should be drawing ~20mA.  If it's a lot higher than that you might need to troubleshoot what the cause is.

4) (Longer term solution) I am talking with the Open Ephys Production Site (https://www.oeps.tech/) about them building and selling FEDs.  They are making some changes to the PCB to simplify manufacture that include removing the button and putting a power switch right on the PCB.  This will also eliminate this issue of FED not charging unless the switch is on.  We hope to have this arrangement completed by the fall, and they expect to sell complete circuitry for not much more than building it from scratch.  I'll keep you posted!  

-Lex

[Antonio Benci]

In response to the FED charging issues...

1: Lex is correct in detailing that the battery takes almost 44 hours to fully charge from a flat state. The Feather charge current is only 100mA.

2: The idle current (measured against two units) varies between 10-20 mA.

3: The run current when the motor is operating is >>250 mA. Ensure that during charge periods the motor does NOT run.

4: The yellow charge LED will be fully on when the battery is connected and charging. Check out https://learn.adafruit.com/adafruit-feather-m0-adalogger/power-management

5: There is a mod (idea, not tested or implemented) which requires a change to the FED main board which will resolve the battery charge issues. It negates the Feather charge circuit. It also requires a slightly different USB connection.

Cheers all.

--
You received this message because you are subscribed to the Google Groups "FEDforum" group.
To unsubscribe from this group and stop receiving emails from it, send an email to fedforum+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/fedforum/c5e6110e-050d-4d61-a679-30ceed236304%40googlegroups.com.

--

-- 

ANTONIO BENCI                 

Electronics Manager / Senior Technical Officer
Safety Officer, Monash Instrumentation Facility
Member, Safety Officer Network Steering Committee 2017-2019

Monash Instrumentation Facility

Monash University

26 Research Way, BLD40/G62

Monash University VIC 3800

Australia

T: +61 3 9905 3649                     

M: +61 (0)414 924 833

E: nino....@monash.edu

monash.edu

[Mathias V. Schmidt]

Thanks all, that info helps a lot.

Best,

Mathias

To view this discussion on the web visit https://groups.google.com/d/msgid/fedforum/CALa47uf_1rz7Ap45-XoNdZjzui6EHjBikf%2BkLcM3SW6c2ckpjQ%40mail.gmail.com.

--

Mathias V. Schmidt, PD, PhD
Max Planck Institute of Psychiatry
Research Group Leader "Neurobiology of Stress Resilience"
Department of Stress Neurobiology and Neurogenetics
Kraepelinstr. 2-10
80804 Munich, Germany
Tel:+49-89-30622-519
Fax: +49-89-30622-610
email: msch...@psych.mpg.de

twitter: @MathiasVSchmidt
Home page: http://www.psych.mpg.de/1496026/schmidt_m

                    https://sites.google.com/view/schmidtlab/home

Pubmed: http://www.ncbi.nlm.nih.gov/sites/myncbi/collections/public/1zyx89XrdcgVQr9Uicjdr1ckj/?sort=date&direction=ascending
Google: http://scholar.google.de/citations?hl=de&user=cH0myrMAAAAJ



This email may contain confidential and/or privileged information. If you are not the intended recipient (or have received this email in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this email is strictly forbidden.