72v, 80v lithium batteries

[new2thiss]

Just wondering if anybody knows the easier route to obtaining a 72v lifepo4 battery, or an 80v lifepo4? I cant seem to find an already packaged battery of this capacity. I dont exactly know how to build them from scratch as I was on hobbyking and that seems to be what that site offers, also I have already a 60v lifepo4 "duct tape" battery and it seems it may be possible to simply add the cells to it but I dont fully understand how to do that either.

Any help would be greatly appreciated.

 

[wesnewell]

In the simplest form you just series the cells together until you get the voltage you want. Easiest would be debatable. HK lifepo4 packs can just be plugged together in series until you get the voltage you want. Headway cells can be strapped together using their terminals. Etc. Regardless of chemistry, they all wire the same.
http://scriptasylum.com/rc_speed/lipo.html

 

[new2thiss]

In the simplest form you just series the cells together until you get the voltage you want. Easiest would be debatable. HK lifepo4 packs can just be plugged together in series until you get the voltage you want. Headway cells can be strapped together using their terminals. Etc. Regardless of chemistry, they all wire the same.
http://scriptasylum.com/rc_speed/lipo.html

So I can pick any pack on hobbyking of lifepo4 and wire them in series?
Is there anything I need to be careful of? How can I tell how many AH it's going to be ? And also how can I charge the battery ? I currently have a 6 Amp charger for my 60v lifepo4 can I use that ?

 

[new2thiss]

In the simplest form you just series the cells together until you get the voltage you want. Easiest would be debatable. HK lifepo4 packs can just be plugged together in series until you get the voltage you want. Headway cells can be strapped together using their terminals. Etc. Regardless of chemistry, they all wire the same.
http://scriptasylum.com/rc_speed/lipo.html

Also if I was going to add the cells to my own battery is that a possibility? Which one off hobbyking would you recommend ?
And can you explain in a little more detail what that entails or if its safe ?
Thank you for your help !

Really appreciate it

 

[dmwahl]

It would help to know the goal of your project and some more details about what you want to do. Increase range, speed, fun, etc. There are also lots of battery building threads on here that should help you a lot.

 

[arkmundi]

Also if I was going to add the cells to my own battery is that a possibility? Which one off hobbyking would you recommend ?
And can you explain in a little more detail what that entails or if its safe ?
Thank you for your help !

Anything is possible, but not recommended. The cells in battery packs need to remain "in balance", meaning they discharging & charge more or less evenly. What makes them go out of balance more than anything is differing internal resistance, a natural phenomena as cells are used and age. Changes in the internal chemistry, lithium plating on the anode & cathode, dendrite formations in the electrolyte, etc. Eventually it gets so bad the cell fails and the battery needs to be replaced. Adding new cells to a pack with old cells will almost certainly lead to balancing issues, which will surface immediately and get worse over time. Even those of us building packs from acquired cells will look for a batch of cells made at the same time, so they will have near identical electrical properties.

 

[new2thiss]

It would help to know the goal of your project and some more details about what you want to do. Increase range, speed, fun, etc. There are also lots of battery building threads on here that should help you a lot.

Forgive me. The end result is speed, I upgraded to 60v lifepo4 from 48v lead acid and the speed is undeniable. Its fantastic. I want to be able to keep up with traffic, and do what I need to do.

Its for my E bike. Not like a bicycle, like a scooter with a body and mirrors etc.. I never know what to call them sorry lol.

 

[new2thiss]

Also if I was going to add the cells to my own battery is that a possibility? Which one off hobbyking would you recommend ?
And can you explain in a little more detail what that entails or if its safe ?
Thank you for your help !

Anything is possible, but not recommended. The cells in battery packs need to remain "in balance", meaning they discharging & charge more or less evenly. What makes them go out of balance more than anything is differing internal resistance, a natural phenomena as cells are used and age. Changes in the internal chemistry, lithium plating on the anode & cathode, dendrite formations in the electrolyte, etc. Eventually it gets so bad the cell fails and the battery needs to be replaced. Adding new cells to a pack with old cells will almost certainly lead to balancing issues, which will surface immediately and get worse over time. Even those of us building packs from acquired cells will look for a batch of cells made at the same time, so they will have near identical electrical properties.

I will definitely do more research, but more or less the end result is 20 amps, and 80v.
I dont personally really want to open this battery and add cells to it I'd rather purchase a bunch of fresh cells and perhaps piece it together on my own if thats what I have to do Im just not sure exactly what Im looking for on hobbyking. I also dont know what kidn of a charger Im going to need because there are alot of chargers on that site and I dont know which one I need or is right for the battery.

 

[r3volved]

http://ex-battery.com has those voltages at high capacity and high output.

 

[new2thiss]

http://ex-battery.com has those voltages at high capacity and high output.

Do you know other good sites where you can buy lifepo4 batteries in those voltages?I have been having trouble finding them online and would appreciate any links, I like that this site sells 86v but I just wish it was lifepo4 and not lithium ion.

Any help is appreciated thanks !

 

[r3volved]

Their LiFePo4 goes up to 72V

Their Liion is pretty awesome! I just went from 48V lifepo4 to thier 72V15ah liion and it's night&day.
Acceleration is ridiculous!!

Quentin can customize size and form-factor for you too. I also had trouble finding lifepo4 in that range and that's why I ended up with liion (I am happy I did - nearly double the battery at half the weight and size of my 48V lifepo4).

Otherwise, you're probably looking at a highV BMS and combining two 36+V. I've seen some headway kits up to 84V as well but never tried myself (heard they were heavy).

 

[new2thiss]

Their LiFePo4 goes up to 72V

Their Liion is pretty awesome! I just went from 48V lifepo4 to thier 72V15ah liion and it's night&day.
Acceleration is ridiculous!!

Quentin can customize size and form-factor for you too. I also had trouble finding lifepo4 in that range and that's why I ended up with liion (I am happy I did - nearly double the battery at half the weight and size of my 48V lifepo4).

Otherwise, you're probably looking at a highV BMS and combining two 36+V. I've seen some headway kits up to 84V as well but never tried myself (heard they were heavy).

Little expensive. Ideally I'm looking for 86v I could go live ion but lifepo4 is double or even triple the life expectancy. Does hr do custom lifepo4 in 86v?

 

[wiredsim]

You need to determine if your controller can handle 72/80 volts before you go ahead and hook them up. You can fry your capacitors and/or mosfets. Take a look at the technical forum to get more info, there are lots of existing threads on it.

 

[dogman dan]

yes, Likely you are flirting with disaster with the 60v lifepo4, which when fresh charged will be quite a bit above the typical 48v controllers upper limit of 63v.

So before you go too much farther, you need to get a higher voltage controller.

 

[new2thiss]

You need to determine if your controller can handle 72/80 volts before you go ahead and hook them up. You can fry your capacitors and/or mosfets. Take a look at the technical forum to get more info, there are lots of existing threads on it.

Im going to get a new controller,
The one I have now is good for 60v and 1500W. I want to get a kelly controller.

 

[new2thiss]

Their LiFePo4 goes up to 72V

Their Liion is pretty awesome! I just went from 48V lifepo4 to thier 72V15ah liion and it's night&day.
Acceleration is ridiculous!!

Quentin can customize size and form-factor for you too. I also had trouble finding lifepo4 in that range and that's why I ended up with liion (I am happy I did - nearly double the battery at half the weight and size of my 48V lifepo4).

Otherwise, you're probably looking at a highV BMS and combining two 36+V. I've seen some headway kits up to 84V as well but never tried myself (heard they were heavy).

Anyone else know of any cheaper 72 + volt lifepo4 pack sites?