Not sure if i have an issue or not, i bought a couple of Sanyo ur18650fm 2600mah batteries earlier this year, and have used them in a convoy m1 and s2 without issue.
Today was the first time i ran a battery to low battery warning (105C so should be 3V), i usually recharge in the 50-60% drained range, and the time taken usually seems reasonable given the 650mA rating of the charger, and i often check the voltage before charging out of interest and do the mental math.
This time it was 3.06V 5 mins after removal from light, 3.14V after 30 mins. I tossed it on the charger for about 3.5 hours, and it read 3.86V, settling to 3.85V an hour later.
I thought it should be about 80-85% charged, but seems to be about 50% charged
Any thoughts?
I might be missing your point, but if your battery charges up without overheating and maintains voltage it’s doing what it’s supposed to do and is good to go. A good cell will stay cool.
Voltage is only an indication of an approximate estimation of capacity…the only reasonably accurate test would be to run a discharge. Charging is another indicator, but is not a reliable estimate because not all of the current gets absorbed by the battery. Loss could be 30%. All of these factors taken as a whole can give a snapshot of where a cell is at in terms of performance and life expectancy.
Li-On batteries will lose capacity as they age and under use, that’s normal, and depending how they are treated lifetime can be short or extended. They will lose capacity if stored at full voltage…that, and over charging/discharging are the real killers.
The second battery had the same behaviour, fully charging took more then double what it should, so unless there is a charger malfunction the battery would have taken close to 5000mA to recharge 2600 (probably closer to 2400)
The first one took over 7 hours to fully recharge the second is still going and on track to take the same
Seven hours seems about right to charge from 3 volts with an intellicharger anyway.
Nothing scientific, but in charging pack pulls, 2 volts to about 3.5 volts is VERY quick (an hour?). However the climb from 3.5 to 4.2 can be a lengthy one. I am doing panasonic 2900 pack pulls right now, which started at 2.47 volts or thereabouts. At 4 hours, I’m at 3.58 volts right now (just checked). So I bet it’ll take 6-8 hours before I’m through. I also betcha some batteries will take 6 hours and others will take 8, but their performance will be the same as far as I can tell. Like Top Cat’s sagely advice, I wouldn’t worry unless they get warmish, even then sometimes that’s heat from the charger being transferred to the cells and not the cells heating up themselves. Then again, I’m not quite sure what you’re asking.
So I just got a Makita li-ion drill-impact driver combo. When the li-ion pack goes dead, this fancy schmancy charger — with a HUGE noisy fan — takes 20 minutes (that’s TWENTY MINUTES) to fully charge the li-ion pack. Man, that’s fast. I wonder how low the pack goes before it shuts off? Can it really be below 3 volts and then charges it up in 20 minutes to 4.2 volts? If so, I need to mod one of these chargers for my light batteries! Can’t get a reading off the pack pins and the literarture that came with it is absolutely useless.
Fast charging isn’t good for the cells, and will shorten battery life, but the tool batteries use a different high-discharge chemistry that is more resilient… but those packs will last longer and perform better on a slower charge as well.
I don’t think i am making myself clear, the charger puts out 650ma per hour, and to charge 2600ma is taking over 7 hours (650 x 7 = over 4550)
I’ll try this again on a partially discharged battery to see if it returns to normal, these two charges were on fully discharged which i normally never do
