This is a question for Mugen battery owners. I just bought the Mugen 3800 mAh battery for my X5. It is a little bulky, but WOW does it hold a charge.
I followed their instructions about initially charging the battery for 12 hours, and then doing 3-5 complete discharges (though I did pull it out and recharge when it got to just below 10%, since the Axim's warnings and blinking red lights make me nervous about falling into a hard-reset). It has been difficult to get it to discharge over the course of a whole day -- I tried upping the processor to full power, turning off the power savers, running video streaming over wifi non-stop. Even still, it takes the whole day!
Their instructions say that the batteries should NOT be left idle in the charger for more than 24 hours.
In other discussions in this forum, people said that the Dell cradle will not overcharge a battery, and recommended leaving the unit in the cradle whenever it is not in use -- charging everytime it goes below 90% and also not worrying if it is left there for a few days.
Here are my questions to the gurus:
And after the initial charging-discharging, should I be charging this every night, or whenever I'm near the cradle? Would I be harming this battery by leaving it in the cradle more than 24 hours? If so, am I be harming my standard Dell battery by doing this? (right now, that dell battery has been in the charger for days).
I charge my mugen 3800 every time I'm near the cradle, and every night to boot. I seldom get below 75% charge. (I too worked hard to try to discharge my mugen when I first got it -- it's not easy!) My now spare Dell battery sits in the charger nearly full time, although I occasionally use it just to use it.
I don't think it is the cradle that keeps the battery from overcharging, but rather it is the batteries themselves which have circuitry to keep them from overcharging.
My understanding agrees with yours, that it is that it is best to keep these batteries fully charged.
Is the Mugen battery a Li-ion? If so you should NEVER completely discharge the battery. Li-ion batteries will last much longer if their charge is kept as high as possible. Letting it get below 30% frequently will significantly reduce the life of the battery. Here is a quote from the following link.
Quote:
"Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.)
Short battery life in a laptop is mainly caused by heat rather than charge/discharge patterns."
The Mugen is li-ion. The company says to discharge it completely 3-5 times when new. They say this gets the battery to achieve its full stated capacity.
After the initial "breaking-in" they say only NOT to leave the battery in the charger idle for more than 24 hours.
My understanding is that li-ion battery life is also based on the actual age of the battery. Wish an expert with real science would let us know what is really going on.
All Consumer LiIon batteries (other than coin-type) have circuitry in the battery itself, to prevent overcharging under any circumstances.
LiIon batteries are actually quite dangerous commodoties and the only way they were allowed into the Consumer market was to include this circuitry.
Quote:
From First Link: The charge cannot be terminated on a voltage(Which is what the Axim's green light is indicating).The capacity reached at 4.2 Volts per cell is only 40 to 70% of full capacity. For this reason you need to continue to charge until the current drops, and to terminate on the low current. (Which is what the Battery's Sensing Circuitry is sensing, and then doing).
It is important to note that trickle charging is not acceptable for lithium batteries. The Li-ion chemistry cannot accept an overcharge without causing damage to the cell, possibly plating out lithium metal and becoming hazardous.
That advice to do full discharges seems like superstitious nonsense... unless it's for some reason needed to set the counter in the battery. That's something which is mentioned in Mr. Klaatu's linked articles, though I'm not really clear on whether the counter referenced is the battery's information as sent to a device-based chart/percentage indicator, or if it applies only to batteries with some sort of external indicator of charge you can just look at. There seem to be a couple of grey areas on those pages, but generally they are very clear.
I've just started the ordering process from a Canadian company, and hope to have one of these big babies strapped to my X5 within a week, so this interests me great deal. Hope I don't make the wrong decision, come initial charging time!
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