I realize now that I need to invest in a better solution for recharging batteries, primarily AA's in a series of four.

What does the forum recommend for charging capacity, (mAh?), I have seen numbers like 40,000, 2,000 etc. Need some refresher on that.

I would prefer solar charging but will settle for car and then wall for last resort.

I realize I will recoup the investment over time. Interested in make/models for my purchase and what to avoid.

Read here:

Charger Comparison
NiMh Battery Shoot Out
NiMh Shoot Out Part II

I'm interested in this too. Currently, I'm leaning towards the Maha Powerex MH-C9000 WizardOne Charger-Analyzer, mostly because it takes 12v input, so I can hook it to my car, a solar panel, or plug it in at home.

Maha c9000 is a good charger, for a smaller more bob friendly the c401fs is good too.

I read a report (put out by NASA) a few years ago in an amateur radio magazine that battery memory is for the most part a myth. It only happens in situations where the battery is charged and discharged the same rate every time. It said this happens in only 2 situations, with satellites in space (because they are on a never changing orbit) and with backup devices that charge batteries at a given time every day. Like emergency lighting and battery backup units. For the normal situation a person puts a battery through they get more then enough discharge and recharge variance to not have any kind of issue with memory.



I know this is the internet and someone will say this is not so, you can say the sky is blue, and someone reading it on the net will tell you it’s another color.

But I have never seen memory problems and have used a lot of batteries.

I've read the same thing Bob. But even though it's not true "memory", a battery still improves in internal resistance and capacity by cycling it a few times if it's been dormant for awhile. I used to fly electric R/C planes, and the amount of power available is very noticable. You can tell when a battery isn't performing very well quite easily, either you don't get the climb performance you're used to, or your flight time is cut short.

Apple documentation is very biased, they are going to make lithuim ion look best since thats what they use.
The average consumer grade lithium ion MTBF for cycles is 300. NiMH and NiCad are 500-1000. They do make Lithium ION that have higher cycle counts but those are more $ than any of us can afford. likewise there are NiMH that never make it to 100 cycles (energizer 2500mAH on their crappy 15 minute charegrs for example).
Cycles are a full charge to a full discharge, if you run the battery down only half way and charge it back up then thats only 1/2 a cycle.
Remember that Lithuim ion also loses 10-20% of its capacity per year no matter if its used or not. Now before you say my 4 year old laptop has a lithuim ion battery and it still works, battery life is determined when the max charge is aroun 80% of new so that battery may still take a charge and last a couple hours but at 80% its considered old by industry standards.
Rememeber one battery isn't the best for everything. Lithium ion has the best power to weight ratio, but is also the most expensive and has the shortest lifespan. the old NiCad is best for something that is always on a small trickle charge like those solar yard lights since it is the most tolerant of overcharging.
So when your choosing gear and batteries to power it you have to keep these things in mind, after 3-4 years factor the cost of a replacement battery into that GPS or camera if its lithium ion powered since you'll be down to the 80% capacity mark. Thats why I prefer AA powered over the lithium ion powered, besides eliminating the need for the dedicated charger and being able to swap and borrow batteries I can also go at least twice as long before needing battery replacement. I have some old Sanyo 1600mAh NiMH's from 2000 and 2001 that have just now reahed the 80% capacity mark and are now in kids toys replaced by eneloops in my important gear.

Good info with a good explanation.

I have one. It's good, but a bit bulky, and the UI could be better.

I doubt mine will ever pay for itself as it is quite expensive and I don't throw away many rechargeable batteries. I wanted a fancy one anyway.

The mass market chargers emphasis speed, and so tend to high charge currents which let the batteries get hot, which is bad. The high-end ones tend to have lots of features and be expensive. I don't know if there's anything in the middle, that's cheap and basic but doesn't hurt the batteries. Ideally it would have independent channels and terminate based on voltage rather than a timer, but you don't really need LCD displays, the ability to set charge current etc, or a lot of the other bells and whistles unless you just like gadgets.

Charging current partly depends on the capacity of the battery. The manual for the Maha C9000 advises against charging below 0.3C or above 1.0C, where C is the capacity of the battery. Within that range lower is better for the battery but takes longer. Higher currents tend to over-heat the battery, which is less of a problem with good ventilation. Lower currents make it harder for a smart charger to detect when the battery is full.

AA Eneloops have a capacity of 2,000mAh, so the range is 600mA to 2,000mA. AAAs are around 750mAh so the range is 225mA to 750mA.

I would suggest using 0.5C, or half the capacity. That's 1,000mA for AA and 400mA for AAA. The C9000 defaults to 1,000mA.