What's harder on an LS.... 3 alkalines or 3 rechargeables?

[Orion]

What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

I saw one of the CPF members state that if you use 3 rechargeable batteries with the LS, you may burn it up. I've seen people successfully use 3 alkalines to power their LS with little trouble (with heatsink).

 

[Roy]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

I believe it is because rechargables have a lower internal resistance than non-rechargables, and will dump more current into the LS. Higher internal resistance limits the amount of current the battery will produce. I'm sure the technical types will correct me if I got it all wrong.

In the electric model air plane business, when high power is needed to a motor, NiCd batteries are still prefered over NiMH because NiCd can dump more amps at a given voltage than a NiMH.

 

[Brock]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

It's true NiMH can supply higher amperage at their voltage.

On a side note NiMH's and NiCad's are very similar. Another important reason RC people prefer NiCad's is the weight issue. You can get about 2 times the power to weight out of NiCad's over NiMH's, very important in a model airplane. And less weight in a RC car means more speed and better pickup

 

[snakebite]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

Originally posted by Brock:
It's true NiMH can supply higher amperage at their voltage.

On a side note NiMH's and NiCad's are very similar. Another important reason RC people prefer NiCad's is the weight issue. You can get about 2 times the power to weight out of NiCad's over NiMH's, very important in a model airplane. And less weight in a RC car means more speed and better pickup

<font size="2" face="Verdana, Arial">dont you have that backwards?
nicd has a lower internal resistance but nimh has higher capacity.
weight is nearly the same.

 

[Wim Hertog]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

I think Snakebite is right

 

[Klaus]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

Yup - have to agree on that resistance / weight thing.

Regarding powering an LS with NiCd/NiMhs vs Alkalines - I think the outcome will depend more on the specific LS used than anything else.

I have one LS with an Vf of around 3.25V at 350ma I just tried using an 0.3 Ohm resistor:

3 fresh Alkaline AA´s - 650ma
3 fresh Sanyo NiMhs - 700ma
3 non-fresh Sanyo NiMhs - 450ma

Klaus

 

[carbonsparky]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

I think you have it right snakebite.

Nicads can take overcharging, making them a better choice for the fast charging systems used by R/Cers. They can also source a bit more current than NiMhs.
Some of this is changing so this may not be totally true even now. The newer NiMh batteries and charging systems are closing the difference. Ray-o-vac is supposed to have a NiMh 15 minute charger coming out and the current NiMhs seem to be able to really be able to produce some current.

 

[AlphalphaPB]

Re: What\'s harder on an LS.... 3 alkalines or 3 rechargeables?

For appljcations pulling up to even several amps from an electric motor, I haven't noticed much of a difference between large NiCad and NiMH cells. Real experts in the field of R/C and the like seem to prefer NiCad because of the lower internal resistance, leading to higher amps for a given voltage.
However, for smaller types of batteries, like those in AA sizes, I've noticed a larger difference in internal resistance in NiCad and NiMH cells.