NiMH batteries for battery extender

[Anonymous]

I use the Rayovac 15 minute charger and 4 of the I-C3 NiH 2000 mAh batteries in a battery extender power pack. On extrnal battery power, the battery icon is green for Power on-line and the charge light goes off when the internal battery becomes charged. This is with the back light at full brightness and the Linksys wireless card connected to the network. The charger kit comes with a wall charger and a car cord.

[Anonymous]

Rayovac 15 minute NiMH battery rechargeable kit. Charges 1 to 4 AA or AAA Rayovac I-C3 batteries in 15 minutes in your home OR car. Also charges regular NiMH and NiCd rechargeable batteries overnight.

http://store.yahoo.com/bestbrandsclub/ra15niresy.html

[Foxdie]

Somehow I think batteries that are recharged that quickly will fast develop a memory effect

[Anonymous]

Somehow I think batteries that are recharged that quickly will fast develop a memory effect

Please explain, how does this happen?

[Foxdie]

Imagine a battery like a car engine.

If you keep the engine running slowly (at low RPM) the engine will run like that for a long time and not do itself damage

If you keep the engine running fast it will wear itself out eventually, doing itself damage and also creating a lot of heat.


By using a charger that charges a battery faster than 5 hours you\'re guaranteed to wear the life out of the batteries.

[Anonymous]

Imagine a battery like a car engine. By using a charger that charges a battery faster than 5 hours you\'re guaranteed to wear the life out of the batteries.

Rayovac must not have heard your analogy between between battery chemistry and engine rpms.  

The new Rayovac 15-Minute Rechargeable System— the only one of its kind to offer an unprecedented battery charging time of 15 minutes or less—has been chosen by Popular Science magazine to receive a “Best of What’s New” Award for 2003.

http://www.rayovac.com

[tumnus]

I didn\'t think NiMHs suffered from the memory affect nearly as badly as NiCads. The only thing I would be worried about would be the batteries and charger burning my house down. I find NiMHs are almost too hot to handle after a 2 hour fast charge. I could see them turning into a night light or radiation heater with a 15 minute charge :shock:

[Anonymous]

The battery charger has a fan that cools the batteries as they charge. The batteries get warm to the touch but not at all hot. The cooling fan runs only for the I-C3 NiH batteries.

[tumnus]

Ah, so it doubles as a convection heater

[Foxdie]

I could do with one of these rayovac chargers then, my office is badly insulated

[Anonymous]

LOL

[Anonymous]

I though these were 1.5 volts nominal. So potentially much higher on full charge ?

I\'ve measured standard 1.5 V AA 4 packs in battery extenders and they have shown over 7.3 volts when fresh. Getting a little on the invalidate warranty side for my liking...

Zuber

[gawth_slacker]

quick charging any of the rechargable batteries will cause them to develop a shorter life span but is more difficutl or takes more quick charging sessions with the NiMH and Lithium Ion rechargables than the NiCD to shorten its life span.  In the business field, this is called planned obsolecence and is intended to shorten the life of the product as to get the consumer to purchase more of then increasing the products sales...quantitiy over quality...just a bit of explination.  Also, the charge for a NiCD will have a longer shelf life than the NiMH which has a longer self life than the Lithium Ion, but Lithium Ion back towards the NiCD tend to have a longer life span due to the chemical memory that tends to develop in the NiCD\'s. :-)

[gawth_slacker]

In short, if you dont \"need\" to charge them that quickly, save yourself some money and charge them properly over a longer period of time.  slow charge.

[Anonymous]

gawth_slacker:

if you dont \"need\" to charge them that quickly, save yourself some money and charge them properly over a longer period of time. slow charge.

I-C3 NiMH batteries are designed to quickly charge. You cannot charge them slowly. These are powerful batteries that do not have an inconveniently long charge time. If you need to charge batteries slowly, save yourself some money.  

Zuber:

I\'ve measured standard 1.5 V AA 4 packs in battery extenders and they have shown over 7.3 volts when fresh.

Good that you caution against using ordinary carbon-zinc or alkaline batteries. Some have designed power supplies with a power diode to drop the voltage into a safe range. NiMH cells do not need a series diode, because the voltage is lower than the ordinary batteries. 4 I-C3 cells in series with full charge measure 5.7 VDC.