lithium battery (lifepo4) for motorcycle - Fuel Economy, Hypermiling, EcoModding News and Forum

johnathanf1lm · 05-05-2014, 12:40 AM

Hey i was wondering if anyone on here has actually used one of the new lighter lifepo4 batteries on there bike and if the bike is a older bike or a newer one. and how well it acts/ runs/ charges. i know about the starting in cold issues, that's why my bike has a kick start along with electric start

FastDemise · 05-12-2014, 05:31 PM

I have made my own batteries out of A123 18650 cells. Works great for me. I have no bms or any safety measures. I just pick out of a pile of cells and check the internal resistance of the cells and group them accordingly. I have done around 6k miles (7months) on my last battery which is just a 4s4p (4Ah) battery. My 1984 CB650SC starts immediately and all my lights are noticeably brighter.

I have never experienced a cold start problem. During the winter here in Oregon we had some 20 degree days and I was still riding my motorcycle no problem. Rode to College and it start right up no problem after sitting in the cold for hours.

I have no experience with the store bought batteries but I much prefer making them myself. A lot more fun.

johnathanf1lm · 05-12-2014, 10:30 PM

Whats the weight of your 4s4p battery? My main reason to do this is to reduce weight so I can increase my sprocket size without a lag in the starting off really.

FastDemise · 05-12-2014, 11:17 PM

I don't have a scale to measure the weight. It's really small compared to a 14 Ah lead battery. About half the height and 1/4 the weight is my guess, if not more. It runs on my 650 without any problem and starts so quickly due to just having 4p gives me around 80cranking amps (20C) nominal with peak at (30C) 120 amps. I build a larger pack of 4s8p and it was enough to start my Jeep Cherokee just as quickly as the Optima (1000cca) battery. So it's likely a 4s4p can still be made smaller to a 4s3p or even 4s2p. Only reason I have not made it smaller is I worry it won't have the capacity to keep the headlights on for more than a hour. Wish I could be of more help.

johnathanf1lm · 05-13-2014, 12:01 AM

No you were very helpful. I would build my own but im too much in love with my bike so I would rather not test my luck or rather blame the maker not myself for a issue. At least ik it wont kill my electrical system.

PaulB2 · 09-26-2014, 01:32 AM

Someone please explain the jargon to me. What is "4s" and "4p"? Are these cells the same size as AA's? How do you connect them together?

FastDemise, I live in Hillsboro too. I'd like to take a look at your work if you are available for that.

redpoint5 · 09-26-2014, 04:45 AM

I'm running supercapacitors only on my bike. 6x 400 farad capacitors wired in series. The generator is capable of maintaining 12v at idle, so I haven't had any electrical problems. If I was stuck in traffic for a long time, I might not have enough juice to run the cooling fans for very long, although I haven't run into this scenario yet. The weight is about 1 pound.

I also have a 4.2Ah LiFePo4 battery (4s, 1p) from Hobbyking. Haven't used it on my bike because I'm so happy with how it's going with just the capacitors.

I'll build a hybrid supercap/LiFePo4 battery to replace a car battery once one of them dies.

If you have any interest in the LiFePo4 battery I purchased, or the supercapacitor I'm using, visit this thread.

Quote:

Originally Posted by PaulB2

Someone please explain the jargon to me. What is "4s" and "4p"? Are these cells the same size as AA's? How do you connect them together?

4s means 4 cells in series, and 4p means 4 of the 4s batteries wired in parallel, for a total of 16 individual cells.

4 of the 3.3v cells need to be wired in series to raise the battery voltage to 13.2v, which is about what a standard lead-acid battery is.

To get enough amperage to run the starter, 4 sets of the 4 series cells are wired in parallel.

The cells are larger than AA. Cells are generally soldered or spot welded together.

FastDemise · 09-30-2014, 04:57 AM

Quote:

Originally Posted by PaulB2

Someone please explain the jargon to me. What is "4s" and "4p"? Are these cells the same size as AA's? How do you connect them together?

FastDemise, I live in Hillsboro too. I'd like to take a look at your work if you are available for that.

Awesome, just PM me and we can work out a time to meet.