I have some Nimh eneloop AA and AAA cell, i also have some Energizer D cell 2500mah wich i think are just AA wrap in a D shell
I was using the eneloop charger for my AA and AAA but it charge 2 battery at once but can’t balance them, Im i right?
Now i want to use my new Accucel 6 80W to charge all of these.
I have a balance lead that’s on the way but i read on the forum that you can’t balance charged nimh? is that right?
From what i read here, i should be charging Nimh somewhere between 0.5 to 1C
How many mah should i push in a 2500mah to be charge including loss during charging?
I charged some of my 2500mah D energizer and i put many mah in it. I can’t remember how much mah i push in it, first time i think i push around 1500mah and i shut it off before going to sleep. Now i’m at 2800mah so i think i pushed more then 4200mah in it. I can fell a little heat in the battery and it is now at 1.47V charging at 0.7A. Is this normal?
It seems that the charger stop to charge by itself around 1.5V isn’t it a bit too high?
I find charging over 0.25C overheats the batteries (even eneloops), i use a lacrosse BC700, its a good charger but pricey
There are other smart chargers, eneloop even makes one,
What do you consider “overheating”? Many people, including me are happy with the 0.5C or 1C charge rate from the Sanyo MQH03 charger…. batteries do not get hot or overheat throughout the charge… they just come out warm
Mine were just warm, not hot.
I read somewhere on the forum that too low charge rate could make the charger to overcharge the battery because it doesn’t get the cut off voltage soon enough… is this true? or only for lion cell?
At 700mA the charger shuts down after an hour or so because the batteries get too hot, it has built in temperature sensing
At very low charge rates NiMH chargers can miss the slight voltage drop at full charge that is supposed to terminate charging. This will reduce the life but how much is unknown but chances are they will die from age first unless you let it overcharge for days straight.
Li ion charges very differently, its a different algorithm, you can look up the CC/CV method they use for charging (there is no voltage drop signal on li ion). If you overcharge them they can lose life quickly, overheat or explode, hence any “dumb” li ion charger is a ticking time bomb and should never leave the factory.
Good smart chargers like the Panasonic CC17 pulse at a higher current than the average charge rate. Detection of when the cell is full is reliable through this method.
Were you charging AAAs or AAs at 700mA? In any case, I think there’s a firmware issue or some sort of issue with the charging algorithm on the BC700 because Sanyo/Panasonic chargers do not exhibit this phenomenon even as high as a 1A or 2A rate on AAs… or 800mA on AAAs
The fact the batteries overheat at the 700mA rate and causes the BC700 to go into thermal protection… it’s an issue all right, considering the simple (but smart) Sanyo/Panasonic chargers don’t have this problem, even at higher rates
Sure, charging at a lower rate maybe acceptable if you’re not in a hurry and just charging them overnight. But frankly, I would be unhappy if I couldn’t fully utilize the charger’s capabilities while within the specifications of the cell’s manufacturer
Sanyo MQR06, Sanyo MQH03, Panasonic CC16, and Panasonic CC21
all charge using at least 0.5C rates… MQH03 notably can charge at 1C… all no problems, all no overheating
as a matter of fact, even Sanyo’s USB chargers when charging 1 cell only puts out 850mA and there’s no heat issues either… this is the MDU01 or the E1A “mobile booster”… both USB only chargers