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
--- In
electricboats@...,
Kevin Pemberton
wrote:
>
> Eric,
>
> According to this page batteries supplied by
Ironcorebatteries
>
100Ah weigh almost 100lbs
> for 12v pack. T 105 6v about 67lbs. No problem
discharging NiFe to 80%,
> big problem discharging the T 105 to 80% over the long
haul. Was two
> optima blue tops. 120 lbs for 100Ah when large
discharges a re not
> figured in. Where is weight a problem?
>
> mount in wood mount because fumes are non corrosive,
can be mounted
> anyplace if vented outside. Size becomes no problem.
>
> And yes I see the weight problem with anything other
than batteries
> easily distroyed by over charge or over discharge.
>
> Kevin Pemberton
>
