Nihm do they discharge at 3%/per day,or Nicad.Need to make a choice

-- hey (d@j.v), November 13, 1999

Answers

The way I understand it is that NiMH and NiCad batteries are similar in that they both lose their charge fairly rapidly with time. The main differences with NiMH is Cost (they cost more), duration of charge (they have more capacity so they last longer), no memory effect (they can be charged and recharged more times and NiCads). If I remember correctly, NiCads lost their charge at around 1% per day, I was under the impression that NiMH lost at a bit less than that (not sure though).

Personally, if I had the choice, I'd go for rechargeable alkalines. The Renewal stuff has worked good for me. I have some AA's that are still going after 4 years. 2 years powering my Remote Control Car transmitter, a year and a half sitting in a drawer, and a half year playing my CD player at work all day. The nice thing about the Renewals is that they keep their charge, so you don't have to worry about charging before use, like NiMH and NiCads.

-- James Collins (jacollins@thegrid.net), November 13, 1999.

Hi Hey (de hi de ho),

What James said! I've used the Renewal Alkalines since they came out, and they're great.

But ... with the possibility of batteries not being available for a while, come next spring, I've recently started buying NiMH (AA size) batteries and a recharger that will work off 12 volts (solar, wind, car). That's because the Renewals will stop taking a charge after 50 to 200 charges, especially if you discharge them too far -- and they may not be available.

PS: I have hundreds of Renewals, now, and 5 chargers for them. I just ordered 24, AA NiMH's just in case.

-- Dean -- from (almost) Duh Moines (dtmiller@midiowa.net), November 13, 1999.

Renewal batts are a scam on folks who don't bother to do the math. Their only advantage is higher voltage for the few devices (like CD players that don't like the lower voltage of nicads). The manufacturer will even tell you they're only rated for 25 charge/discharge cycles. Not exactly a good long term investment.

We tested these by cycling them at the rate the manufacturer stated was optimum for recharging (discharge rates are important with this alkaline technology). After 20 charge cycles our 1500mah rated battery had become a 550 mah battery and was basically useless by 30 cycles. We tested a set of 4 batts and all reacted the same way. The article is in Home Power issue #41

NiMH batts discharge about 3% a day at 70 degrees and faster at higher temps. Nicads are about 1%, lead acid batts (new) 3-5% per week. The Nicads are usually rated for around 600-700 charge cycles which is the same as NiMH. I'm perfectly happy with my 1100mah Panasonic Nicads bought from Costco last Christmas for $1.50 each. I'm sticking with nicads, they've treated me fine for 15 years.

-- Don Kulha (dkulha@vom.com), November 13, 1999.

My brother in law has had problems with the Rayovac version of "renewal" batteries.

Here is the pertinent text he sent to me regarding the "Renewal" batteries...

I have complained to Rayovac about their power system. I know Jeff was "into" the system two years ago and I followed. My plan was to slowly add batteries all the time and eventually use them for everything.

They system failed .... The cells did not last as long ... they did not recharge adequately ... they did not keep their charge once recharged and kept going dead.

Rayovac is sick of me and is sending a pre-paid postal box for me to put my system and cells in for a refund!

...meanwhile, I have been trying to get away from batteries in general since we seem to eat them like candy at our house. Anything that can be converted to grid power is in process and anything that can be converted to manual or solar is in process also. I'm even considering getting a Baygen radio for Christmas to take with me on "construction jobs" where I want a radio to listen to.

Best regards,

-- Joe (KEITH@noosnet.com), November 15, 1999.

From ccrane.com

NICAD BATTERIES IMPORTANT INFORMATION!

Batteries & Chargers

Nicad batteries can be a great financial and ecological investment if you know a little bit about them.

 New batteries require a few charging and discharging cycles to come up to full power. When you receive your new batteries, charge them overnight. Next, allow them to drain. You can put them in a radio until it shuts off or no voices are heard, or put them in a flashlight until the light is very dim. Then recharge the batteries fully. This procedure should be repeated two more times if you want to get the full output of your Nicads as soon as possible.

 Do not overcharge Nicad batteries. Excessive charging heat will substantially reduce their life span.

 Nicads slowly lose their charge even without use. It is best to charge them up for an hour or so once a month if you are keeping them for emergency use. You can store Nicads indefinitely without ever charging them. If you want to use the stored batteries treat them as new and follow the charging and discharging steps described in the second paragraph.

 Nicads can develop a memory. For example, if they are constantly drained only half way and then recharged they will lose some of their capacity. For this reason it is best to fully discharge them a few times a year so your batteries will retain their full capacity. This can be done safely by putting them in a radio or flashlight, as stated above. However, it is best not to drain Nicads fully. If you have a volt meter bring them down to approximately 1 volt.

 There is one more thing to carefully watch with nicads when you are charging more than one battery at a time. If one of the batteries has a charge much lower than the others the battery that has the low charge will sacrifice itself to benefit the battery with the higher charge. After a few charge cycles the weak battery may permanently lose its full capacity. After many charge cycles this battery may be permanently dead. The way to prevent this from happening is to check your batteries with a tester before and after charging them. Be sure batteries that are low are charged separately until they equalize.

 At least once a year clean the contacts on your batteries, the electronic device and your charger. A thin black insulating film builds up and prevents proper electrical contact. To clean the contacts use the eraser on a common yellow pencil and gently rub the contacts, followed by a rub with a cotton swab dampened with alcohol.

 No matter how much a manufacturer brags about how fast their batteries will charge, the fact is the slower the charge the better. You can substantially reduce the life span of a Nicad battery by consistently charging at a high rate.

 Dont waste your time and money with lower capacity nicads. Most of the time our nicads provide more power. The power increase with our batteries is generally 60% for AA size batteries and 220% for D size batteries. This is more power than most Nicad batteries found elsewhere.

NOTE: High battery drain situations like a laptop computer, may require special batteries. Though our batteries have more power, they are not able to deliver it as fast as some appliances need it.

When comparing length of service, ours last about half as long as an alkaline, but can be recharged several hundred times or more. The service you will get from other nicad batteries is probably the reason Nicads are not more popular. When fully charged Nicads are only slightly over 1.2 volts.

NICAD CHARGING

Look at the battery. The rating is usually printed on the edge. If the rating is not on the battery you can assume it is 500 MAh (milliamp hour) for a AA battery and 1800 MAh for a D battery. Suppose you have a 850 MAh AA size battery. If your charger is set on 150 milliamps charging should take about six hours. However because of inefficiencies you need to charge the battery for nine hours to be sure you have a full charge. A 4,000 MAh D size still takes about 40 hours including the 50% overcharge at 150 milliamp charge rate. At 70 milliamp a heavy duty D size will take 85 hours to be assured you have a full charge. See our batteries and chargers.

(Note: ccrane.com has its own generic NiCads and I've got several hundred dollars worth of them. They also have the Baygen w/light on sale--didn't notice the price--solar chargers and more.)

-- Old Git (anon@spamproblems.com), November 15, 1999.

The only info I could find on the other batteries follows, but you could e-mail c.crane and ask them.

NICKEL HYDRIDE CHARGER

Comes with (4) AA batteries. Nickel Metal Hydride batteries are almost twice as powerful as NiCad batteries. Best for high use situations because they lose their charge at 30% per month without use. NMH batteries should never be charged in a regular charger because they might overheat and be damaged.

BULK ALKALINE BATTERIES ALKALINE BATTERIES

GREAT PRICES AND QUANTITY

If you buy a box at a time we can give you a nice discount. We tested our batteries against the famous rabbit batteries. We used an electric clock and radio to measure the time they lasted. We only had time for one test. Ours ran the clock 4% longer! Alkaline batteries can be stored two years and still keep 90% of their energy. Store in a cool dry place. Alkaline batteries do not last longer when stored in a refrigerator. Why put a battery next to your food?

-- Old Git (anon@spamproblems.com), November 15, 1999.

Who is the "we" in the following:

"We tested our batteries against the famous rabbit batteries."

"Most of the time our nicads provide more power." (ccrane.com?)

I'm interested in ORDERING these - pls provide a SOURCE!!

thanks,

-- Bill (chicago519@aol.com), November 15, 1999.

Bill, I don't believe any nicad puts out equivalent or greater power than a quality alkaline cell of the same physical size. I'm not sure what Bob (Crane) means by that statement. Seems to me I saw it on their website.

Fact of the matter, you can generally remove more power from a nicad for a given amount of time. Nicads will generally deliver more amps than an alkaline can. This might be what he meant.

-- Don Kulha (dkulha@vom.com), November 15, 1999.

. . . .

Triple-Array 9-volt Solar Battery Charger - Made in the US - Only $35 ($4 shipping) Four-Array 12-volt Solar Battery Charger - Trickle Charges an Auto battery - Only $45 ($4 shipping) Click Here for Solar Battery Charger Page
Don't confuse these chargers with the more common chargers you see advertised for $25. Those are made in China and only have one solar array, so you can only charge 2 batteries at a time. These chargers can charge your 2 AA's, 2 AAA's, 2 C's and 2 D's at the SAME TIME! Or, they can charge multiple 9-volt batteries at the same time. These chargers are hand made in the U.S.A. Need rechargeable batteries? We sell only the best - Nickel Metal Hydride (NiMH). NiMH AA cells cost about $3 a piece, compared to about $2 a piece for Nickel Cadmium (Ni-Cad). www.stpaulmercantile.com/solar.htm Call John tollfree at 1-888-395-1164 or at 651-452-8572 or 651-452- 9242. Best time to call is weekends until 10:30 pm central time, or weeknights 6:30pm to 10:30pm central time.

-- john (john@stpaulmercantile.com), November 16, 1999.

Sorry I wasn't clear. All that info came from ccrane.com.

-- Old Git (anon@spamproblems.com), November 16, 1999.

Oh and I got three 4-battery chargers (all types except 9v) from ccrane--I think for about $15 or $20. Can't remember.

-- Old Git (anon@spamproblems.com), November 16, 1999.