Re: [Electric Boats] Picking batteries

If you read battery chemistry engineering books, you would know that
Nickel based batteries have a peukert of virtually 1.00. I do not
"parrot", I do research and practical experimentation. I've lived off
grid for 6 years, and have over 25 years in electronics. I resent the
implications otherwise. My calculator is accurate.

Steve Spence
Renewable energy and self sufficiency
http://www.green-trust.org
http://arduinotronics.blogspot.com/

On 11/14/2010 03:36 PM, Myles Twete wrote:
>
>
> *>*A Peukert exponent of 1.00 means that there is no Peukerts effect at
> all and that the battery will deliver the same amount of energy at any
> discharge rate. I would guess that the Peukert's exponent for Nickel
> Iron batteries is higher than 1.00
>>Eric
>
> No doubt. References online claim virtually no Peukert effect for any
> of the Nickel chemistries including NiCd, NiZn, NiMH.
>
> I'm sure he just was parroting these. Worse, the weblink he offered
> drawing folks to his personal Peukert calculator page does not provide
> any support for the 1.0 Peukert exponent claim.
>
>
>
> From the brief looking I've done, I'd guess that the effective Peukert
> exponent for NiFe is below 1.05, and once you're down that low, unless
> you're drawing high-C loads, I don't think you have to worry much about it.
>
>
>
> I think the major beefs against NiFe batteries are:
>
> · Cost
>
> · Relatively high self-discharge rates
>
>
>
> And those weigh enough against them that we don't appreciate the
> uber-long life of them. Charge/discharge inefficiency isn't much of an
> issue for many of us, but high initial cost and self-discharge rates are.
>
>
>
> -Myles Twete
>
>
>
>

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