I've been looking at the auctions of this ebay seller (pingbattery) with LiFePO4 batteries. I need a 48V pack for my 350Watt Crystalyte 408/4011.

The 15AH with shipping is around $500, the 20AH with shipping is around $700. It seems to me that the 15AH is the better deal and I have the money for it now, but that extra 5AH is maybe worth spending the extra $ to get.

Could anyone post some kind of numbers as to what kind of mileage you would get out of these batteries? I know that's variable depending on a lot of factors. Given a flat road, windless day, test run kind of scenario, what's some real world approximations of what these batteries can deliver in terms of mileage?

Thanks in advance for any info on this.

I don't know your bike or these specific batteries. I do know that in my experience using lead, NiMh and lithium - the later tends to provide slightly better range for same AH as lead/NiMh. In other words if you're getting 10 miles out of 10AH of lead chemistry, probably only need 7-8AH of lithium to go the same distance.

My very efficient Panasonic drive unit 250-350W averages around 10 miles on 3-4AH. When I add my 13Ah NiMh pack I go 20-30 miles easy. I'll venture a guess your 408/4011 should be good for 1/2 what the Panasonic can do - depending on how much you pedal. That extra 5AH might buy you another 5-10 miles. 15AH should be good for 10-20 miles but that is just a guess based on a couple years riding electric bikes.

i have ping's 48volt 10ah, and its more than enuff. i have gone over 20miles no problem. if you never used lipo before your in for a shock :)

cheers

I'm just going to make some guesses about what conditions you're dealing with.

aerodynamics: similar to mountain bike or hybrid
weight (bike+rider+cargo): about 180-200lbs
pedaling?: no
normal cruising speed: 18 mph
battery: 48V15Ah
EDIT: hills: some hills but nothing terribly steep or long

Your range will be something like 35+ miles.

Double the weight, and range will likely go down by ~35%
Go ~23mph and range goes down by 30% compared to 18mph. Go 28mph and range goes down 55-60% (!) compared to 18mph.

Your range will be something like 35+ miles.



35+ miles!!! That would be excellent. I'm stoked. I bought some NIMH D cells 3 years ago, put them into PVC tubes to make a 48V pack. It's been very educational but less than effective transport. From the sounds of it the lithium phosphate batteries are great for this application.

It's all about the (usable) watt hours. Watt hours = amp hours times volts.

For SLA's the usable watt hours are far below the rated watt hours unless you are using a 10 watt motor or something.

For nickel or lithium, rated watt hours and usable watt hours are pretty close to the same thing.

My pack is LiFePO4, rated as 240 watt hours, good for something like 12 miles. 48v15ah=720 rated watt hours, 3 times as much as what I have.

Can a normal sla battery charger be used on lifepo batteries?

well at first everyone was saying no. you can but at the price for lifepo4 thay supply you with one to go with
the warranty.