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Trek 7500 conversion, with split battery

Little-Acorn

100 W
Joined
Oct 15, 2009
Messages
130
Some pics of the project. I ordered a 48V 20Ah battery from Vpower.hk to be made in two pieces, so I could mount it as shown. They basically made up two 24V 20Ah batteries and wired them in series, with BMS taps as appropriate and a 48V BMS and charger. Works great so far. Bike is somewhat tailheavy, obviously - this idea might work better on a front-drive ebike. But with a 265# fat slob like me in the saddle, a few pounds here or there just don't seem to matter much.

View attachment 5
The bike so far. Might put Schwalbe Big Apple 29'er tires on it to smooth our the jarring 30mph ride caused by the Continental Ultrasport 116psi front tire.

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trek7500_motor_freewhl00.jpg
48V 1000W motor from daoji666 in China. Right-side battery half is just above. Also with 11-32 7spd freewheel from Pat Winston of http://www.sdelectricbikes.com - nice for pedaling at 25mph.

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trek7500_battmount00.jpg
Mounted on Home Depot technology 2" x 1/8" extruded aluminum angle. The bungee cord and rubber bands will be replaced by aluminum clamps when I get the Schwalbe tires on it.

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trek7500_rearview00.jpg
Split battery allows for lower center of gravity, and leaves the rack available for groceries. Also easier to swing the leg over when mounting/dismounting.

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trek7500split_handlbar00.jpg
From left to right (roughly): Rearview mirror, left gearshift trigger group, headlight (below hbar), WattsUp meter temporary mount, Trek speedometer, right-side gearshift trigger group, thumb throttle. Original brake handles are on there somewhere too - Trek provided much better ones than those miserable power-break handles.

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trek7500_kckstd00.jpg
Nice two-leg retractable kickstand from Crow here in San Diego. Similar to a motorcycle kickstand, but lighter. Now the bike won't fall over when I step away from it. A GREAT addition.

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Another nice thing about that kickstand is that it's sturdy, and very adjustable. And when it's down (or up) it's possible to turn the pedals forward or backward, thru their entire 360-degree sweep without hitting anything, unlike the standard one-leg kickstand found on nearly all bicycles.

:D

The reason there's a block of wood on the ground next to the front wheel in these pictures, is because I've adjusted the kickstand to be slightly longer than sometimes necessary, so that it still contacts the ground even on uneven ground. One result of this is that, on completely flat ground (like a cement driveway), with a bike as tailheavy as this one when no one is aboard, the kickstand lifts the front wheel about 1/8" off the ground. And the handlebars naturally turn all the way one way, making for lousy-looking photos.
 
Put something on the outside facing side of the batteries. When bikes fall over, the battery may get a torn pouch and be a real hassle to fix. Coroplast is popular, like used on political signs and real estate signs. I made a box for my new ping from the top of a plastic storage box. Just anyting but raw duct tape vulnerable to damage.
 
dogman said:
Put something on the outside facing side of the batteries. When bikes fall over, the battery may get a torn pouch and be a real hassle to fix. Coroplast is popular, like used on political signs and real estate signs. I made a box for my new ping from the top of a plastic storage box. Just anyting but raw duct tape vulnerable to damage.
Good idea, dogman, thanks!
 
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