Nice choice, what with the transistor testing, 10A current capability and all!
Just be careful with the 200VAC range, one click to much and you are measuring 200uA. This means blown fuse or maybe blow meter.
Cheap DMMs shouldn't be used anywhere near 200V anyways imo.
8) Actually you’d be surprised (disgusted) at prices here. DMMs of any kind aren’t available around here for anywhere near $10, which is one of the main reasons why I’m into budget products from China.
HKJ, I would be very interested in your opinion too on the subject of high quality Li-Ion cells with cheap protection circuits, especially relating to undervoltage protection. To me, undervoltage seems to be one of the most common dangers with Li-Ions, be it from parasitic drain or a very low mode.
Careful.. You were not supposed to tell anyone that you live in Fin.. [Oops, sorry!]
I have not really done any testing of protection circuits, mostly because I do not have any free test equipment to make it on.
Generally I would not expect problems with the protection circuit, it is one chip that contains all the tests and it controls one or more transistors to connect/disconnect the cell. This kind of circuit will be fairly robust.
There is, of course, the risk of a fake circuit, i.e. a circuit that does not do anything, but that would show up when I do the current test.
Another risk is that the circuit manufacturer buys whatever protection chip they can get cheap and might get some with a extra high or low voltage . That would not be a serious risk, but would wear the battery down considerable faster if it is always discharged until protection trips.
Thanks HKJ!
OK, good news about the Panasonic 3400 mAh protected button tops from BangGood: The protection circuit does work, at least for undervoltage protection. I ran one in my Uniquefire UF-X8 on high until the circuitry of the light shut it off for low voltage. Then I put the battery in a Solarforce light with a P60 drop in that ran it even lower until the LED was just dimly glowing. Then it shut off, and I tested the battery, which was at 0 volts. Putting it in the Intellicharger apparently reset the circuit, since it charged it back up again.
This thread gives me doubts
about wanting a headlamp that takes lithium batterys.
I have one of those 4.35V HXY chargers from Fasttech. Since I misplaced my 4.35V cells, it sits doing nothing all the time. The other day I was contemplating it and the thought occurred to me that in theory I should be able to charge any protected cells in it. I finally could not contain my curiosity anymore so I put a protected cell in it. After enough time for a charge I took it out and measured it and it read 4.19V, so I’m assuming the protection circuit in the cell should allow me to use that charger safely to charge 4.2V protected cells as well as 4.35V unprotected cells.
Hi all,
Sorry if this is a dumb question, but what is supposed to happen when a protected battery runs down to 2.75V or so, does it just switch off?( is 2.75V the low voltage cut off point?)
I ask, becaused I was testing 1 of my sanyo 2600’s from banggood, and got it down to around 2.5 V or so, and the light it was in was still glowing dimly… I thought it will switch off the light at 2.75V. I took the battery out of the light to test it, so i did not test it under a load…
Thanks
Anton
By 2.5v the low voltage cut off should have tripped. It disconnects the battery until its recharged / sees voltage coming into the battery. Your protection circuit could be bad. Seiko protection is regarded as high quality. Who knows the quality of protection that added by mystery chinese companies.
What flashlight & mode was it in? Low voltage cut off doesn’t always trip if the current draw is low enough.
Do you know the protection in this battery?
Different protections have different cut off voltage and some of them are below 2.50 volt.
Isn’t below 2.5v more uncommon?
I know the chips can have lower cut offs. Partly, I suppose, I was expressing where the cut off should be, at minimum IMO. Really I like to see 2.8 but it seems they are more fond of 2.5. Its suppose to be just a backup but some people rely on it more then they should.
Jacob A60, high mode. The light coming out is very weak, but it stays on, got nervous, so I switched it off…
First tried to run it down in my Yezl y3, but it started blinking, already at around 3.3 v or so, I assume this is the driver in the yezl doing that…
I have not tested enough to say what is common, but I haev seen protections at 2.40 volt.
You cannot just say that you want a protection on 2.80 volt, it depends on the battery. A 3100mAh battery is fine with a 2.50 volt protection.
Specs on Banggood website say discharge cut off voltage is 3V…
Anyone else checked these batteries?
Do not expect that has any to do with the protection voltage.
My reasons for liking unprotected cells that haven’t been mentioned are, I have an old Zebralight headlight that uses a 16340 cell. The driver in the light seems to have low voltage cutoff set around 2.5 volts. If I use protected cells they turn the light off with no warning at 2.8v leaving me in the dark. If I use unprotected cells the driver in the light gives me a lower level of light so I know it’s time to put in another cell or find another light. I should have sent the Zebralight back when it was under warranty. I also had this happen in an EDC, 16340 host that was getting a new driver anyway when I bumped it up to 3 amps. Protected 16340’s can’t put out 3 amps anyway.
Can you even replace a driver in any Zebralight? I would lose their great UI. I use IMR cells in all my moddifed 16340 lights so no need for protection except for the old Zebralight. I solved this problem by giving that headlight to my wife.