I have a mongoose dolomite fat tire bike and I replaced the rear wheel with a 72 V 3 kW motor hub. It is awesome. Has plenty of torque off road and a good top speed of about 44.9 mph. I'm only using 3 multistar 6s 10a 10c lipos wired in series For 72 volts and I'm using XT 60 connectors. Going by the hub motor specs I'm only drawling about 41 A. I did order 3 more batteries so I can get 20 A at 72 volts. I wired two sets of three in series and then parallel those two 72v at 20 A. The E bike is awesome only using 10a of batteries. Once I add 10 more amps of batteries Shouldn't it be even faster and more powerful? Also, Do you think it would be beneficial to upgrade my connectors from xt60 to xt90 as well?
Addind 10 more amps of capacity and bigger connectors
- Thread starter Joecool
- Start date
XT60s should be fine for 41A. Do they get warm?
Of course it wouldn't hurt to use XT90s and they don't cost much.
Of course it wouldn't hurt to use XT90s and they don't cost much.
markz
100 TW
There is a difference between (A) Amps and (Ah) Amp-Hour.
A - Amps is the discharge of the battery, with the Multistar's from Hobbyking you have to take their rating and de-rate it by 25% or 33%.
There is a continuous rating, and there is a max rating. Obviously you don't want the battery to work hard by maxing it out all the time because then your batteries wont last as long.
Ah - Amp-Hour is the capacity of the battery, view it as your "Gas Tank" - How far you can go. That's gotta be viewed a tad differently then a typical gas tank. Lets see if I can word it properly. OK so its not how much gas you put into the tank, but more so on how much you take out. The video of that analogy is in the first half of ElectricBikeReview's video on Youtube of Grintech tour. Where they are standing outside by the bike rack.
Or when they are in the small room, talking about the Satiator charging system.
A - Amps is the discharge of the battery, with the Multistar's from Hobbyking you have to take their rating and de-rate it by 25% or 33%.
There is a continuous rating, and there is a max rating. Obviously you don't want the battery to work hard by maxing it out all the time because then your batteries wont last as long.
Ah - Amp-Hour is the capacity of the battery, view it as your "Gas Tank" - How far you can go. That's gotta be viewed a tad differently then a typical gas tank. Lets see if I can word it properly. OK so its not how much gas you put into the tank, but more so on how much you take out. The video of that analogy is in the first half of ElectricBikeReview's video on Youtube of Grintech tour. Where they are standing outside by the bike rack.
Or when they are in the small room, talking about the Satiator charging system.
Voltron
1 MW
More amphours won't change anything other than how far you go... it won't increase the amps flowing to the motor, unless the batteries were a bottleneck before on delivering power, but would have been getting pretty hot if that was happening.
Re the motor specs, you can't really go by that.. there's not much substitute for directly measuring it under use. When I metered mine my 25 amp rated controller was peaking at 55 amps during hard acceleration, and the would taper back down, but it was an eyeopener watching the meter climb as the throttle got pegged...
Re the motor specs, you can't really go by that.. there's not much substitute for directly measuring it under use. When I metered mine my 25 amp rated controller was peaking at 55 amps during hard acceleration, and the would taper back down, but it was an eyeopener watching the meter climb as the throttle got pegged...
Slightly. With a controller that is giving you 100% throttle (i.e. no winding current limit) adding more cells in parallel will reduce voltage drop during maximum acceleration. This will give you slightly higher acceleration (due to less droop) and a slightly higher top speed.Joecool said:
But it's not like 2 batteries in parallel will give you twice the power; more like 5 or 10%.
Thanks for the fast reply guys. Yes the batteries are getting a little warm that’s what made me think of using a bigger connector for less resistance. You’re right xt90 connectors are cheap and I have plenty of them. The batteries sit on top of the rear bike rack with Velcro and battery straps in the open air. Don’t get me wrong I am very happy with the Hub motor kit. It has exceeded my expectations which is always a good thing. I’ve gotten up to 44.9 mph or flat open tarmac. No doubt when I add 10 more amps of batteries it should easily be in the 50s. I will say all the hype about fat bites not needing suspension is true. That was 26 x 4“ tires soak up every pumping curb I’ve encountered with minimal resistance. Are any of you guys using a fat tire electric bike? I have my psi set at 11. The only problem with that is when I’m going faster and trying to make a turn it feels like it's getting away from me a little. This only happens when I'm on the tarmac. If any of you guys use the SW900 LED display, how do you turn the headlights on and off? I have a 12-84 V 20 W LED headlight attached to the headlight cable but the switch on the LED panel doesn’t seem to turn the light on or off when activated. I could wire in an on off switch but according to the manual the LED panel can control the headlight.Thanks again for your guys fast responses, this really is a great website of information.
Yeah I’m a realist I don’t expect to double my runtime and acceleration and speed just by doubling the batteries capacity. The only reason I’m suggesting that it will be better is because the manufacture clearly states to run it at 72V 20A minimum. Thanks again for the insight.
