Hi all,
(also posting on DC404)
I just had to replace a laptop battery, which prompted me to ask some
questions about how you maintain your batteries of various types. In
this context, I'm talking about electronics and personal equipment not
exposed to foul weather. This would exclude vehicle batteries.
I'm interested in three types of batteries:
- Lithium Ion / Lithium Polymer (laptops, cell phones, tablets, etc.)
- Nickel Cadmium / Nickel Metal Hydride (cameras, AA cells, AAA cells, etc.)
- Lead Acid / Sealed Lead Acid (security systems, hand held spotlights,
ups's, etc.)
I'm interested in three parts of the battery lifecycle:
- Initial Prep
- Routine Usage
- Refreshing Old Batteries
Here is my understanding for each type.
For Lithium Ion / Lithium Polymer:
- Starts aging as soon as it's made. Doesn't have a memory effect in
the traditional sense. Deep cycles help kill the battery (slowly).
- For smart batteries (most of them), the digital battery level gauge
can get confused and misread the battery.
- Initial Prep - Charge fully. Discharge until device cuts off. Repeat
a couple of times. This calibrates the digital level gauge.
- Routine Usage - Generally don't fully discharge. Charge early and
often. A few times per year (say 4 - 6), do one or two full discharges
and recharges to recalibrate the digital level gauge. This will affect
when your equipment cuts off, for example.
- Refreshing Old Batteries - Once the capacity is gone, it's gone.
After a period of time, the battery must be replaced, usually around 2-3
years. An analogy I read once said it's like adding rocks periodically
to the bottom of a bucket, so it hold's less water.
For Nickel Cadmium / Nickel Metal Hydride:
- Some of this data comes from a Maha Energy instruction sheet for a
NiMh / NiCd battery charger. Because they're so finicky, I'm happy to
say I'm using almost none of these now, except in one camera.
- Has memory effect. Partial charges can reduce capacity. Deep cycles
can help the battery.
- Initial Prep - From the sheet "New batteries and those stored for
extended period become chemically deactivated. Battery forming is a
charge - discharge - charge cycle which forces a full charge into the
battery at a very slow rate. This process activates the battery. In
some cases it needs to be repeated two or three times." Apply a forming
charge initially.
- Routine Usage - Charge before use due to self discharge. Use fully
and charge fully when possible. Avoid partial discharge and recharge
when possible. (Hard to do.) Refresh once every 10 cycles (see
below). Apply forming charge once every 30 cycles.
- Refreshing Old Batteries - A refresh involves a charge - discharge -
charge cycle. You can try this three times. After this, you can try a
forming cycle, which happens at a much slower rate. If capacity doesn't
improve each time by 10% or so, battery probably needs replacing.
For Lead Acid / Sealed Lead Acid:
- Doesn't have a memory effect in the traditional sense. Deep cycles
help kill the battery (slowly).
- Initial Prep - Charge fully then start using.
- Routine Usage - Charge before use due to self discharge. Partial
discharges and recharges should not be harmful. Occasionally, a few
times per year (say 4 - 6), discharges to equipment cut off then
recharges are probably a good idea for testing purposes.
- Refreshing Old Batteries - I've heard this can be done, but have never
had any luck with this. Lead sulphate crystals (I think) accumulate and
decrease capacity. Substantially reduced capacity batteries probably
need replacement.
These sites have some cool data:
http://batteryuniversity.com/
http://www.mahaenergy.com/FAQ-C9000/
I'd love to know your experience and opinions on these issues.
Sincerely,
Ron
--
(PS - If you email me and don't get a quick response, you might want to
call on the phone. I get about 300 emails per day from alternate energy
mailing lists and such. I don't always see new email messages very quickly.)
Ron Frazier
770-205-9422 (O) Leave a message.
linuxdude AT techstarship.com
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