? for those that know electric

darwin

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May 26, 2008
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3,350
Would 3 of these batteries be powerful enough to let a 350watt hub motor go 50 miles etc.? They're 12 volt and 18ah apiece. Hook them up to get 36v plus they're deep cycle batts. From the size 3 could mount easily on a rear rack. My bike had a 19.2ah 52v battery and it would go 37mi using throttle only w/minor pedal assist down to a 20% charge. How would 3 of these SLA deep cycles compare? Lots of electrics use 36v systems. https://www.batterysharks.com/12-Volt-18-Amp-Deep-Cycle-Battery-p/12V-18AH-DC_b12-18.htm?msclkid=1c3efc99921b1ee29f74a0215427daa1&utm_source=bing&utm_medium=cpc&utm_campaign=1_Shopping_PLA&utm_term=4582489588120547&utm_content=VandAH
 


Joined
Jun 29, 2017
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The thing about lead acid batteries is they are extremely heavy. With only 350 watts, that motor is going to have to haul about 35-40 pounds of lead plus the weight of the rider. I have 4 12v 18ah deep cycle batteries and a 1000 watt motor and I average about 22 miles before my batteries are run down at 30% charge. Mounting them on the rear rack also effects stability I would put them in saddle bags next to the sides of the rear tire for more stability.

With lead acid once they are run down about 50%, the voltage starts to dip too much under load and the motor controller starts to hit the low voltage cutoff and you start to loose power with the motor cutting out. I would say if you really took it easy with the throttle maybe 25 miles. I have a wattage reader on mine and I only use about 23 watts per mile but as soon as they are around 50%, my motor starts cutting out. The weight of the batteries would be too much for 350 watts and it'll have to work twice as hard. I would stick to lithium if you can as the voltage doesn't dip nearly as bad as lead acid. Plus, even at 250 miles on my odometer, I am already starting to loose range they just don't last long.
 
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JerboaJohn

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Jul 29, 2018
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1,272
battery tech is not up to what we need yet. so sad,, a car can go 300+ miles on electric but then they can all the weight they need of battery
 

bike4life

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Mar 19, 2018
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529
battery tech is not up to what we need yet. so sad,, a car can go 300+ miles on electric but then they can all the weight they need of battery
I’d suggest tailgater engine 750w at harbor freight mount to rear or trailer. Salvage a microwave transformer to step the 120 to 36 and then buy full bridge rectifier to convert the ac to dc (10 dolla). Give infinity range and lots of power. The microwave transformer must have both windings removed and ratio the step down about 3:1
 

Frogslayer

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Jan 20, 2019
Messages
789
I have 3 lead acid batteries 12amphour and a 500 watt hub. With no wind, not much pedaling i can go 15 miles at 50 to 75 percent throttle, cruising around 20mph. I don't experience any funny happenings when the batteries get low but my kit works with SLA. I'd guess you would not have much voltage sag at all with a low draw motor like a 350 watt. Insane these days when one legit battery cost as much as 2 or 3 China girls. I was told not to go lead acid as well but made my own decision to try it out and am happy with the results and cost. I use lithium batteries in my rc toys so I'm not scared of them or anything, just didn't want to fork out more 💰 than the bike and hub combined on what is essentially a consumable part of the whole set up.
 

bike4life

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Mar 19, 2018
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529
Where is Tesla wireless power when we need it? Would have been so sweet to bypass the battery all together.
i heard about this tesla wireless power, is it myth. was he a genius. doesnt wireless power deminish with 1/ distance^2 so it wouldnt be effective?
 

bike4life

Active Member
Joined
Mar 19, 2018
Messages
529
Would 3 of these batteries be powerful enough to let a 350watt hub motor go 50 miles etc.? They're 12 volt and 18ah apiece. Hook them up to get 36v plus they're deep cycle batts. From the size 3 could mount easily on a rear rack. My bike had a 19.2ah 52v battery and it would go 37mi using throttle only w/minor pedal assist down to a 20% charge. How would 3 of these SLA deep cycles compare? Lots of electrics use 36v systems. https://www.batterysharks.com/12-Volt-18-Amp-Deep-Cycle-Battery-p/12V-18AH-DC_b12-18.htm?msclkid=1c3efc99921b1ee29f74a0215427daa1&utm_source=bing&utm_medium=cpc&utm_campaign=1_Shopping_PLA&utm_term=4582489588120547&utm_content=VandAH
look, recall simple physics equations and find out how many watt-hours it takes to go x-mph for y miles, to find this, use a biking calculator that does calories like for fitness folks. Then convert calories to watthours or just find one that does watt hours. Then see if your batteries wh matches that by multiply VoltsxAmps.
 
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