A t-105 may have 1350 watt hours, but it's not all available. only about 50% is useable if you are trying to get maximum life. The NiFe has over 80% of it's theoretical wh capacity available without degradation.
Steve Spence
On 11/16/2010 03:47 AM, Eric wrote:
>
>
> Kevin,
>
> I did the math with the data on the link that you provided. One 100Ah
> 1.2V cell weighs 4.9Kg (dry weight?), so 10 dry cells would weigh 49Kg
> which is 107.8 pounds. That battery would be rated for 1200Wh which is
> 11.1 Wh/lb. But the page says that you need to add distilled water to
> make them work, and of course the link doesn't say how much. If a 100Ah
> cell takes only 2 cups of water, then one cell is close to 12 pounds and
> we're back to 10Wh/lb. Looking at the 200Ah cells, they are 26.4 pounds
> dry or 264 pounds for a dry 200Ah 12V (2400kWh) battery. Add water and
> you're probably past 280 pounds or 8.5Wh/lb.
>
> Alternatively, a T-105 weighs 62 pounds (according to Trojan) and is
> rated for 225Ah @ 6V or 1350Wh. That works out to 21.8 Wh/lb. Take two
> in series and you've got a 225Ah 12V battery that weighs 124 pounds.
>
> Are you really sure that size doesn't matter? Lets compare the 200Ah 12V
> NiFe to the 225Ah 12V T-105s
>
> 2400Wh NiFe = 13.2" x 32" x 13.6" = 5745 cu. inches, 280 pounds
> 2700Wh T-105 = 10.4" x 14.3" x 10.7" = 1591 cu. inches, 124 pounds
>
> The NiFe battery is more than 3 times the volume of the two T-105s for
> 10% less rated capacity.
>
> I'm not passing any judgement, just doing the math so that people can
> decide for themselves.
>
> Fair winds,
> Eric
> Marina del Rey, CA
>
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