Ni-Cad vs Ni-Mh vs Li-Ion

[Renamon]

I am needing to get some new batteries for a few radios of mine, so I was doing some research on the different battery chemestries. This is what I have come to understand...

Ni-Cad: Most difficult to damage, easier to "repair" (recondition), generally output at terminals stays the same as battery depeletes, performs best under temp extremes. Memory effect. Not damaged by totally/over discharging.

Ni-Mh: Higher capacity & lighter than same-sized Ni-Cad, output drops slightly as battery depletes. No memory effect. Cycle life. Reconditioning not as effective. Totally/over discharging can damamge/kill battery.

Li-Ion: Lightest of all three when comparing identical capacity, does not handle output cuttent spikes as well (TX'ing), most expensive. Battery life based on cells, not cycle life. Cannot recondition. No memory effect. Totally/over discharging can damamge/kill battery.

Am I right/wrong? Please give me your 2 cents.

[escomm]

www.batteryuniversity.com

[Astro Spectra]

Motorola has a 24 page Power Point preso on this choice called 'Battery Presentation Outline'.

From the summry slides 19, 20, and 21:

If you operate your radio for 10, 12 hour shifts or more
If you use your radio indoors or warm climate
If you don’t mind purchasing special chargers
If you want to “virtually” eliminate memory effect
If light weight is an important factor
If price is no factor
Use Li Ion

If you operate your radio within an 8 hour shift
If you need a wide operating temperature range
If your users overheat batteries during charging
If you can “live with” memory effect
If you want the greatest value
Use Ni-Cd

If you operate your radio for 10, 12 hour shifts or more
If you use your radio indoors or warm climate
If you utilize recommended rapid chargers and follow charging procedures
If you want to “virtually” eliminate memory effect
If you don’t mind paying slightly more (per watt hour) than a NiCd for your battery
Use NiMH

[MTS2000des]

In my experience, NiCD's are the best value IF you use your radio heavily everyday (discharge to LOW BATTERY) and fully recharge OVERNIGHT (regardless of rapid charge GREEN indication), a GOOD QUALITY (keyword being GOOD QUALITY MATCHED CELLS) Nicad battery will last YEARS before it becomes unusable. Nicads also have a long shelf life IF PROPERLY stored. IIRC, 5 years for 90 percent capacity (not talking about self-discharge here, talking about fresh cells unused from the factory). Memory effect can be eliminated by periodic conditioning and sometimes bad batteries can be brought back to life by various methods. Good quality NiCD's can go a couple thousand charge/discharge cycles if you treat them right.

Lithium Ion batteries are great for high capacity mAH's, lightweight, and solid voltage/current out to the point of discharge. No memory effect.
However one big point is that LiON batteries lose capacity the older they get REGARDLESS of how much use they have. A brand new 2 year old LiON battery may only have 75-80 percent capacity left depending on the quality, storage and discharge state. a 5 year old LiON battery may be half gone before you even charge it. They don't like high or low temperatures. When their life is over and the "chip" inside says their done, that's it. Not to mention they usually cost more. High rate of self discharge the older they get.

NiMH is supposedly an "environmentally friendly" version of NiCD. similar characteristics and performance, but unlike NiCD's which can last years if used daily, NiMH usually yield far fewer charge/discharge cycles than NiCD counterparts.

These are from my personal experience. I prefer NiCD's whenever possible.

[AL7OC]

The sub arctic take on batteries- if you live on the Bayou, then this doesn't much matter...

My experience with Li-Ion batteries is that they don't do well in the cold in Alaska. I have to keep the radio or batteries inside my coat in the winter to keep them warm. They also seem to deteriorate at a constant rate whether you use them or not. The old plan of buying a bunch of extra batteries to have around as spares doesn't pan out with Li-Ions. They gradually fade away their own.

The NiMH cells do a little better in the cold, and have a longer shelf life than the Li-Ion cells. You still have to keep them warm in freezing weather or their voltage drops.

Our old SP50s had NiCd batteries, and they retained charge for quite a while and seemed less sensitive too the cold. I carried 2 spares in my SAR pack year around, and the pack stayed in my van. That meant -40 in the winter, and 80s in the summer. I used them in rotation, and they lasted for years.

Anyway, that's my battery experience in an extreme environment.

-Pierre

[RadioSouth]

Besides being cheaper up front Motorola claims NiCads are capable of more cycles than NiMh or Li-ion. I use almost all NiCads except for the couple of Li-Ion I have for a couple of small radios, can't beat the size and weight of Li-ions when it matters but it does cost you a lot more to obtain this.

[Tom in D.C.]

Where did you get the idea that a Li-Ion battery can't be reconditioned? It's done all the time using the Motorola Impres system.

[escomm]

Where did you get the idea that a Li-Ion battery can't be reconditioned? It's done all the time using the Motorola Impres system.

Hi Tom, it's not necessary or possible to recondition a li-ion battery, per se. The Impres charger will calibrate the battery so the fuel gauge is more accurate, but the negative voltage process involved in battery conditioning has no effect on Li-Ion because it doesn't form crystals like nickel based chemistries will

[Tom in D.C.]

Jeff,

I was going by the wording of the Motorola Impres charger brochure, to wit:

Manual tracking and recording of battery use are a thing of the past. IMPRES uses a unique communications protocol to facilitate adaptive reconditioning – the charger evaluates the details of the battery’s usage pattern to determine the optimal reconditioning interval. This automated process works to diminish memory effect and optimize the cycle life of the battery and maximize talk time.

Regards,

[mr.syntrx]

The partial discharge then recharge usage pattern considered bad for other chemistries is what works best for LiIon.

[escomm]

Jeff,

I was going by the wording of the Motorola Impres charger brochure, to wit:

Manual tracking and recording of battery use are a thing of the past. IMPRES uses a unique communications protocol to facilitate adaptive reconditioning – the charger evaluates the details of the battery’s usage pattern to determine the optimal reconditioning interval. This automated process works to diminish memory effect and optimize the cycle life of the battery and maximize talk time.

Regards,

Yeah, agreed, Motorola is not doing us any favors with their marketing hype on this one. It works great for Nickel based. Even made a comment to the planner about "reconditioning" li-ion at the last dealer expo and he just chuckled and said "yeah, I know"