I’m replacing AA rechargeable batteries that are 1700mAh with ones that are 2000mAh. Am I right to assume that the since the mAh is just the storage level of the battery, that I’m not going to blow up the charger, batteries, device or my house by doing this?
This is going in a cordless rechargeable mouse.
Thanks.
You are correct. The mAh is just a capacity rating of the battery that tells you how long the battery will last with that much draw. (i.e. a 2000mAh battery will last for one hour on a constant 2 amp draw) No special consideration needs to be given to the charger used as they charge at a constant rate. The only difference will be in the time it takes to charge.
Thanks so much!
Well their are a few chargers out there that just charge the batteries for a set time, regardless of the state of charge. If you use much higher capacity batteries they might not fully recharge.
Those chargers are mainly older types, most modern chargers will do fine, but if your charger is much older then your 1700mAh batteries then it may be one of these.
That must have been dangerous. Overcharging batteries can be a fire hazard; most (name-brand) chargers that I’ve come across have an overcharging circuit. They simply charge until full voltage is achieved and then either shut down or trickle charge. This was especially important with older NiCd and NiMH batteries because they could explode, catch fire, and/or melt if overcharged or if one of the cells went bad, preventing the current from flowing to the next cell in the series.
Remember that ‘exploding’ batteries that we hear about at Li-ion, due to high energy densities, I don’t recall a Ni-mh or NiCd battery catching fire, though I’m sure it happens. The chargers I speak of were mostly used for NiCd, but they were also made for Nimh (I have one, it does a 5 hr charge regardless, bought at the time that 1550 mAh batteries were the norm). I assume it will use a current that too low to produce a fire, but the batteries always got hot at the end of the charge cycle.
No problem, although recharge time will be slightly longer. Now, if you went from 2000 mAh to 1700 mAH there might be a problem if the charger was set up to charge 2000 mAh batteries. Conceivably, the batteries could charge too fast. Even there, though, the difference between 1700 mAh and 2000 mAh probably isn’t enough to worry about.
I’ve overcharged some NiMHs before now and they got mighty hot, but didn’t melt down, explode or catch fire. What’s more they enjoyed a long and successful life, though I don’t encourage anyone to emulate my stupidity!