OF said:
PontiusPilate said:
Anyway I picked up a 4 pack of Maha Powerex 2700 mAh batteries, and an Enercell 15 minute charger. It's now 5 months later and 2 of those batteries are dead and can't be recharged at all (the charger blinks to indicate the batteries are defective), and the other 2 charge but just barely (even right out of the charger I can barely get a hit using them).
Five months seems a bit short for 4 batteries to die like this doesn't it?
I don't think the problem is so much the batteries as the
charger. That charger is made for their battery (which can take the higher charge rate), it's WAY faster than Maha specifies. They call for 'Maha compatible' chargers, which means more like an hour.
High end batteries are a trade off. High capacity, fast charge rates, long cycle life, stable discharge and a bunch of other factors all relate to each other. The 2700 have a modest advantage WRT capacity if used right away (say same day). This is, at best, 10%, so a hit or two. Overall, the 2400s MF uses are probably a better option for most guys. Self discharge is much lower and they seem to stand up to the abuse the box demands on discharge better (longer life span). While the maker says '500 to 1000' cycles, I bet it's really only a few hundred the way we use them.
I'd retire the charger (or get the batteries intended for it), give the dead and dying batteries a decent funeral and get a set of the 2400s to replace them. I think there's a reason MF uses them, and absent a real need for that extra 10% (and being willing to charge just before use) I'd stick with them. They're way ahead of the 2700s by the end of the week....and probably for more weeks.
OF
Hi,
These comments are correct. The Energizer charger attempts to charge the batteries in 15 minutes, which is rather the extreme limit. Energizer batteries make some trade-offs in their design to allow for this to some extent (they are not expected to last as long). For MAHA batteries, such fast charging can work and be used *sometimes*, but it is not really sustainable and not a good idea for regular ongoing use -- hence the shorter battery cycle life you noticed. The
maximum sustainable charge rate for regular usage is a little over an hour (for 2700 capacity batteries). However, to *optimize* for the health of the battery in terms of overall longevity (the maximum number of charge cycles), the ideal charge rate would be around 3 hours or so. Both the batteries and the chargers we ship stock with the Box have a near optimum charge rate -- we believe in the long term. We have had units work just fine in regular usage for more than 6 months with the stock system.
Note, the charge times indicated above reflect a 'complete charge', ie how long it takes to charge a
fully depleted battery -- if your battery is not fully discharged when you put it into the charger, the charge time will be significantly less. This is usually not a problem as long as the battery is at least 1/3 discharged. If you put a nearly completely charged battery back into the charger, the charger might not be able to detect the completed charge state and will thus overcharge (damage) the battery.
Also to be considered are some factors including how hot the battery is when it goes into the charger (do you go directly from the Box to the charger, or are the batteries allowed to rest?), and how hot the battery is when it comes out of the charger. For example, if the battery is still warm from charging (it had just 'finished') and you go directly to using it in the Box, the internal temperature spike in the battery will be higher. Much better is to let the battery cool after charging and before using.
The level of damage to the battery is in proportion to the
maximum temperature event. Getting too hot
once, even if for not so long, is much worse for battery longevity than getting "rather warm" a number of times. A single overheating event can cost several hundred charge cycles -- significantly shortening the useful life of the battery. Since the battery does not "heal itself", it must be expected that even
one event of overheating will significantly shorten the battery life. You may not notice right away, but the damage done to the battery cannot be undone, and it will show up as performance issues eventually. By "too hot" here, we mean hotter than coffee. Damage past that point is very steep: If you let it get to "you cannot touch it" hot, it will be surprising if the battery will do more than a dozen cycles -- its life is essentially over.
Finally, it is to be noted that battery life and longevity can also be shortened by having a habit of forever keeping the batteries in the charger when not in use. This when one takes the battery out of the charger, uses it for a bit, and then immediately puts it back in the charger, where it remains for all time. While it is OK to leave the batteries in the charger for more than a day on occasion, doing so as part of a regular practice also stresses the battery. Several weeks of 'trickle charge' will eventually wear out the battery, since the energy of the charge has to go somewhere. This is one of the reasons we recommend using the LSD type of batteries -- you do not need to keep them in the charger all of the time to have them be useful.
-- Magic-Flight