E-Bikekit.com 36v 10ah LiFePo4 Battery

[PeteCress]

I got my e-bikekit today and installed it on a old bmx looking single speed small tube 26" frame. I went with the 9ah battery, so far so good. After I put a some more shallow cycles on it I will check the range. I have 1.5" tires at 60 psi and I am hoping for 15 miles but only time will tell.

What are the outdoor temps where you live, and will you be running the battery under a CycleAnalyst?

If you're in the forties (F) or lower, I'd be interested in hearing how many AH you get out of the battery in real-world use.

So far, my highest from the same make/model has been 8 AH at about 52 F. Some have said that I must have a bad batt, but I'm still not so sure bco the temperature factor.

 

[maydaverave]

I got my e-bikekit today and installed it on a old bmx looking single speed small tube 26" frame. I went with the 9ah battery, so far so good. After I put a some more shallow cycles on it I will check the range. I have 1.5" tires at 60 psi and I am hoping for 15 miles but only time will tell.

What are the outdoor temps where you live, and will you be running the battery under a CycleAnalyst?

If you're in the forties (F) or lower, I'd be interested in hearing how many AH you get out of the battery in real-world use.

So far, my highest from the same make/model has been 8 AH at about 52 F. Some have said that I must have a bad batt, but I'm still not so sure bco the temperature factor.

I don't have a watt meter, bicycle analyst, or even a bicycle speedometer I live in florida so it gets up into the seventies still this time of year. I haven't run out of juice yet and I have gone at least ten miles on a charge. I want to get a little bicyle odometer, that and how long it takes me to charge my battery should give me a good ah aproximation. I got the 3.5 amp hour charger and so far the longest time before the green light came on is a little over two hours so that would be around 7 ah

 

[Ypedal]

Alrighty... it's COLD out here in the maritimes..

(-13) degrees Celsius = 8.6 degrees Fahrenheit !

I just put the 10ah pack outside to chill and will discharge it on the same 8amp load in a few hours from now.

 

[Ypedal]

In the shade, ground temps on the garage floor :

(-12) degrees Celsius = 10.4 degrees Fahrenheit

 

[Ypedal]

My front yard.

 

[Ypedal]

Neighbor's truck, notice the layer of salt covering the side, the chromed chopper is NOT going out in that stuff.... :|

 

[Ypedal]

pack freezing up for the last few hours.

 

[Ypedal]

Pack surface temps at start of test

(-4.4) degrees Celsius = 24.08 degrees Fahrenheit

 

[Ypedal]

35.6v , 3.7ah, still going..

 

[torker]

Brrrr. We are supposed to get some more of that white stuff Wed-Thur.-Fri. here.. Question, I remember the first pack from ebk you did a few mods to. Is this cyl. pack 9 ah totally stock ? Do the power leads look beefy enough? Or do you think there is room for improvement?

 

[Ypedal]

34.7v --- 6.2ah

both the 10ah prismatic and the 9ah cylindrical packs i have arrived with the older connectors, and i have modified both to use Andersons on discharge bypassing the fuse and keyswitch.

At 8 amps those would not matter all that much, but at 20 amps it does.

All current ebk packs come with andersons now. And the laser etched logo instead of the stickers and shipped properly ( hazmat ). If you get a stokemonkey setup the pack comes with Neutrik connectors !

 

[Ypedal]

BMS trip , lights turn off, i bundled up and went out there with my IR thermometer, pack surface +6~8 celcius depending on the spot.. so the cells generate enough heat even when it's this cold to warm itself up .

Results :

 

[Ypedal]

oh, and since it's only science if you can repeat it.. i plan to charge this afternoon and leave it in the garage overnight, repeat the test tomorrow morning. :wink:

edit : and then recharge in the cold to see what i can put back in .

 

[torker]

Awesome, thanks. Good to know they are upgraded and ready for plug and play with the 20 amp infineon. Time to save up Do you think the 9 ah would hold up if I upped the amps on my infineon to maybe 30 or is that pushing it, would it constantly trip the bms?

 

[TPA]

edit : and then recharge in the cold to see what i can put back in .

Yea, then let them warm up and see if the voltage increases with temperature.

 

[PeteCress]

Here's an interesting page that speaks to, among other things, storage of a lithium battery.

Contra-intuitively, it seems that storage at full charge is not the best way.

The way I read it, 40% charge is best for storing the battery.

viz: http://www.batteryuniversity.com/parttwo-34.htm

 

[Ypedal]

That article mainly refers to Li manganese and cobalt that both charge to 4.2v and run down to 3.0 as a function of state of charge.. Lifepo4 is a different animal, and yes, similar rules apply imo regarding storage in partially discharged state it's too complicated to explain to the masses who don't understand or have the presence of mind to fully charge before their first ride from storage periods and can't figure out why they only got 5 miles down the road.

Lfp fully charges at 3.65v and settles down to 3.3v with the slightest of load applied, operating range 3.1~2.7v depending on the load, draining a lfp pack to 40% would only be done using a CA meter or equivalent because of the flat discharge curve.. vs Limn or LiCo you can drain the cell from 4.2v ( full ) down to 3.7v and leave it there for storage.

Personally.. i keep all my packs fully charged and ready for use. all chemistries. my 20ah LiMn packs are going on 4 years and showing their age, but still going .

 

[PeteCress]

Personally.. i keep all my packs fully charged and ready for use. all chemistries. my 20ah LiMn packs are going on 4 years and showing their age, but still going .

After reading all the threads I've read so far I'm coming around to thinking that, unless I do something aggressively stupid, at my age my battery is going to outlive me.

To wit:

• Conservative life estimate = 1,500 cycles = 1500*7AH = 10,500AH
• 4AH per day, 90 days per year = 360AH per year (planned use is only in winter months)
• 10500/360 = 29 year battery life
• 29 years from now, the world won't even know I ever existed.

OK, make it more conservative: divide the battery life by 2.

Now we have, in round numbers, 15 years.

Maybe I'll live that long, maybe I won't... and if I do, maybe I'll be a drooling idiot by then...

 

[Ypedal]

Update.

Pack no.4 from the previous page, this is a 10ah prismatic cell pack that had a dead BMS, It has been sitting for quite some time on the workbench so today i finally had time to charge it ( no BMS ) then ballance it using voltphreaks single cell chargers. Hot off the press fully charged.

Discharge results = 9.9 ah ! 8)

 

[torker]

Bump, Ypedal, any new info? Probably colder than us by far. I've managed about 10 mi. on my mt. bike build Hope to hear about durability of the cyl .9ah pack. Think it will take the rigors of lots of dirt roads with some rubber in the mounting scheme? My pack is in the triangle so it doesn't get a severe beating from the hardtail anyway.

 

[Ypedal]

Very much still in the works !

Weather has been all over the place out here, real mess, sub zero freezing one day and rain the next, i need a cold weekend so i can keep the garage door open and charge/discharge with some consistency..

I really need 36 hour days for a few weeks lol...

 

[karma]

hay ypedal any updates on the lifepo4 battery?

 

[Ypedal]

Other than it was used this past weekend and still pumps amps, no...

But on that note, into the garage it goes.. Right Now !

 

[Ypedal]

Alright.. time for an update ! ( I"m late on delivery of this update , but here it is none the less ! )

It's march 27, and the pack has been in the cold garage for over a week, last night it was :

(-12) degrees Celsius = 10.4 degrees Fahrenheit



And this afternoon it got as warm as :

(-5) degrees Celsius = 23 degrees Fahrenheit

So i took a picture of the weathernetwork before i took off on the ebike !

 

[Ypedal]

My chilled little friend..