Originally Posted by
Idontknow
thanks for the replies guys,
I'm thinking I don't want something really expensive. So probaly nothing more than 1,000. However, I don't want something that will die or fall apart fast. Right now without any assist I can maintain an average of 10mph for about 40 miles. Otherwise speed really isn't to big of a factor, my biggest worry is battery life. I'd like to be able to go quite aways with the battery. If the battery goes dead during a ride, is it that much harder to pedal?
Asking for 40 miles out of a battery between charges is asking a lot. The best situation for you is going to be lifepo4 batteries. Yes there are better batteries available but the lifepo4 packs require the least amount of knowledge are lighter weight then most and have very good range with min. voltage sag. Personally I recommend not running a battery lower the 80% of capasity but others may tell you 90 or even 90% is OK. When you talk to suppliers or read their BS info use a factor of 50% to 70% of what they claim (10 miles = 5 to 7 miles).
If you choose SLA batteries and I hope you don't they are very short lived and extreamly heavy. When you discharge them you should not exced 50% and they should be recharged ASAP after discharging or they will be damaged futher. Whereas, a lifepo4 pack has minimum effect from waitting to be recharged.
Because of your mileledge requirement consider the posibility to add a second battery pack when looking at your bike. For example the Currie IZip/EZip is sold with 1 SLA battery but you can mounta second pack on the other side of the rack. You can also make you own battery case to mount Thunder Sky lifepo4 battery packs. With a set of these packs you could get a 40 mile range at 15 MPH with strong motor assist for the 40 miles. I know I have this setup but with a lot more modifications.
Bottom line as I told you before it's all in the battery.
Bob