Sorry for this noobie question - I'm rumming a phoniex racer 48 volt with 4 12 volt 20AH SLA's - I use the bike to commute 25 miles each way to work - so far everything works great! I'm considering lifepo batteries and considering the V28's and over volting the system to 56 volts and connect several V28's in parallel. question is how many V28's equal 20AH, Is my quess 14 correct (seems like a lot)- v28 has 3AH * 7 = 21AH - is my quess correct? Thanks
Milwaukee V28 vs. 12v 20AH SLA's
- Thread starter Spanky
- Start date
Your guess is close.
Firstly though, the V28's are not LiFePO4. They are Emoli Li Mn cells. Their actual Amp Hr capacity is more like 2.6.
So for ~ 20Ah @ 56V you would need 16 batteries. 2s8p
Then you have the hastles of trying to charge 16 batteries in any realistic manner. That's a lot of individual chargers or a lot of switching batteries through the chargers.
FWIW, you probably dont need 20Ah worth. I can't remember the range some of the guys have been getting with various number of these batteries but I dont think anyone would be using 16 batts. Most run around 6, or 8. Not sure what range they are getting though as I forget. The Phoenix racer would be a bit of a hog I think. I'm sure someone will pipe in with an answer.
Cheers, HB
Firstly though, the V28's are not LiFePO4. They are Emoli Li Mn cells. Their actual Amp Hr capacity is more like 2.6.
So for ~ 20Ah @ 56V you would need 16 batteries. 2s8p
Then you have the hastles of trying to charge 16 batteries in any realistic manner. That's a lot of individual chargers or a lot of switching batteries through the chargers.
FWIW, you probably dont need 20Ah worth. I can't remember the range some of the guys have been getting with various number of these batteries but I dont think anyone would be using 16 batts. Most run around 6, or 8. Not sure what range they are getting though as I forget. The Phoenix racer would be a bit of a hog I think. I'm sure someone will pipe in with an answer.
Cheers, HB
docnjoj
1 GW
Hey Spanky Welcome! The true amp/hrs is closer to 2.5 under load, so you would need about 8x2 as you surmised. However, the SLAs only give about 1/2 their rated value under load, so you would go a lot further and faster with Lifepo4. pwbset in this group has a lot of experience with those Milwaukee packs.
otherDoc
otherDoc
docnjoj said:
Not as much as some I just talk more. :wink: 25mi each way is quite a commute! It really just boils down to watt hours. Do you have a Cycle Analyst/Watts Up meter to see what you're averaging wh/mi? That would give a good indication of how many V28s you'd need. Each pack is good for a very realistic, real world 70wh. More if you ride easy. Are there any hills? What controller do you have? A 5303 is going to be pretty amp hungry I imagine.
On the flats with almost no pedaling I can do 20mi or so with 6 packs... never really taken it to max distance on the flats yet. A 2s4p 56v/10.4ah setup would probably get you there pretty easily... you'd need to charge to get back maybe. You could get a couple of 3-in-1 chargers and be re-charged in like 2-3hrs. 3 of those and you'd be charged in 45min with a spare slot.
Thanks everyone for the information!
I can recharge at work, but I do have one pretty good hill to climb - about 3 miles (1500 to 2000 foot) climb. I'm running the crystalite 4840 controller. Almost purchased a Ping 48v 20AH until I found out about the not enough AMP's issue for the Phoniex Racer. Kinda torn betwwen the V28's and a Ping 48v 30AH. Does anyone know if the cycle analysist plugs directly into the 4840 controller or are modifications required? Thanks again for all the help!
I can recharge at work, but I do have one pretty good hill to climb - about 3 miles (1500 to 2000 foot) climb. I'm running the crystalite 4840 controller. Almost purchased a Ping 48v 20AH until I found out about the not enough AMP's issue for the Phoniex Racer. Kinda torn betwwen the V28's and a Ping 48v 30AH. Does anyone know if the cycle analysist plugs directly into the 4840 controller or are modifications required? Thanks again for all the help!
Spanky said:
I climb 1,600ft in 3.5mi and it uses most, if not all (depending on peddle effort), of my pack. The other 4mi of my commute is relatively flat and uses <.5ah. Just an FYI. I'm also only 2 in parallel so am punishing the V28s a lot... you'd likely have better luck with 4p or 5p... though that might be offset by the 5303 slurping the amps up that hill... though it's likely quite a bit more efficient doing hills than my 4011 would be. Tough call... if you can get Ping to make you a 30ah I bet it would be fine @ 40a sustained. Probably quite a bit lighter than like 10 V28s also.
