You are not supposed to leave charging cells unattended. Thatās one of the rules of Liion batteries. The few people Iāve heard that charge unattended put the charger in a metal pan and put it outside or in their garage in case it catches on fire. There have been people whose house have burned down because they left it charging unattended.
Maybe Iām being a bit too precautious, but itās easy for me to babysit them. Itās usually charge all my main cells once a week. Iāve got the one C4-12 and 2 Xtar SV2 Rocket chargers. So if I need to charge 4 x 26650 at 3A and 4 x 26350 at 1A I can do it all in one setting.
If you need to charge 8 x 18650, your idea from above sounds good and should reduce the overall charge times. Can your particular 18650 take a 3A charge? Not all can. You can look up your particular battery models data sheet to see all its specs.
I have no clueā¦
On this forum Iāve read 1C is ok, and 0.8C advisable.
All my 18650 cells are 3500 mAh, so with that in mind I bought 2A and 3A chargers.
My LiitoKala 35A 3500 mAh cells arenāt in the list.
Sharing the charging of the Lii-402 (charged a fully-discharged Sony VTC4, discharged to around or a bit below 3.0v) and then set 2A charge rate in Lii-402. Using EBD-USB+ meter to graph the charging:
Same graph (one shows charging time and the other shows mAh charged ā it is measuring the Lii-402 charger, which may not exactly correspond to the charged capacity of the 18650 battery, but should correlate).
(Lii-402 appears to have a high charge terminating current (around 0.45A) when set to 2A charge rate. Although when I checked the battery voltage right after charging, I got a quite exact 4.20-4.21v.
What is odd is that it doesnāt list a max safe charging rate like other brands. Other brands will list a low charge current rate for max battery life, a standard charge current and a max charge current.
For the Panasonic NCR19650GA it appears the highest they recommend is 1.67A. If we look at the Samsung 35E it shows a similar standard charge rate of 1.7A and a max of 2A. If we look at the LG MJ1 it shows a similar standard charge rate 1.7A, but a max of 3.4A. So it really does depend on the specific model and itās chemistry.
You might be able to charge those GAās at 2A and be fine, but 1.5A looks like the safest rate.
Also, I did a bit of digging and it is not known if the Liitokala lii-35A is actually a Panasonic GA. It may be a 35E or even an independent cell that has similar characteristics. Thread is here.
Have you ever discharged them to about 2.8v and then measured the capacity? Weāre they close to about 3200-3300mah?
Sorry I have no way to do an accurate test of any sort.
But even if the cells are really Panasonic NCR19650GA the wrapping is wrong because it states 3500 instead of 3350.
And IF the cell is genuine charging at 3A with my MiBoxer isnāt a smart thing to do, because thatās almost double of whatās safest. While I donāt babysit cells all the time, I do sometimes. On a few occasions I touched them and they werenāt hot, not even warm. So thatās a little good news I think.
Anyway, when time is no issue Iāll charge at 1A. And I must say often time is no issue at all. Even less now because I bought 7 more cells. That vastly reduces the need for quick recharge during the day. But the babysitting them remains a problem.
Is it so that charging at 1A reduces the risk of fire? Or is it more an age related problem? I donāt remember which one but when looking for a charger one description stated the charger shuts down after X minutes no matter how far the battery is charged because of safety reasons.
The wrapper and rating of 3500mah for the GA is still āaccurateā as they measured 3450mah in the labratory. In the real world they can vary a bit. HKJ measured 3350mah, but he started at 2.8v instead of 2.5v or so. I forget the details.
Thatās why I said if you start at 2.8v and get 3200 to 3300 your doing pretty good regardless of the actual cell in the wrapper.
A fire is possible any time, any charge rate, any battery age, etcā¦
As a side note, unless you running your batteries down below 3.2v or so, your not really using all that capacity. I donāt usually run my cells that low so I use the Samsung 30Q. They do more amperage (15A continous), have less voltage sag under load and can be charged at up to 4A. :+1:
Has Miboxer C4-12 been upgraded with new flashware, fixing the C3 Error, restart problem, overcharging, inconsistent resistance measures and with upgraded sliders, etc.? Should I order at Banggood, Gearbest or Fasttech to get the most recent version minimising the risk for any of these issues?
Sorry, but the recent buyers are not going to be able to tell you anything other than they bought it and it works or doesnāt work. They canāt take it apart and see any internal changes or see software changes.
Maybe they can measure the height of the lowest bump on the outboard slider to see if itās been raised slightly?
To get of those other questions answered you need to ask Leo-Miboxer and even he probably canāt tell you what store is selling the most recent version. He might can say who has bought a recent batch, but that store might still be selling an older version.
I donāt think they can fix all the things you mentioned since some seem to be very rare events, but maybe they have made upgrades in a few areas. I think the vast majority of buyers, like myself, have had zero issues. I bought mine in November.
Does Miboxer sell direct? Maybe you can get one of the latest versions from them?
I just wish to have upgraded sliders, on my unit I had to use magnets on negative side to be able to charge 26650 batteries and I donāt like that. All other problems are less important to me as I believe they happen only sometimes or not at all.
I bought C4-12 mainly for charging 26650ās and it was annoying to deal with magnets to make it work.
I still wait for some answer from them, will see if I ever get it.