Using REGEN on Crystalyte CT4840 v2 Controller

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Tanya   10 µW

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Using REGEN on Crystalyte CT4840 v2 Controller

Post by Tanya » Jul 30 2008 11:56pm

I recently read a post by StevenR on how to wire a regeneration switch on a crystalyte 4840 controller.

I have a regen that I use on my tidalforce bike for braking on steep hills. The regeneration doesn't do
much for the batteries but it saves the brakes.

My new bike is a electra cruiser with a rear crystalyte 5304 motor. The rear brakes are weak and the front brakes are practically useless so I have a hard time stopping.

Can I use the wire from the brake inhibits to turn on and off the regen on my 4840 controller? Could anyone draw me a diagram of how to wire the regen?

Tanya B
Joined Wed Jul 30,2008
Santa Cruz ca

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fechter   100 GW

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Re: Using REGEN on Crystalyte CT4840 v2 Controller

Post by fechter » Jul 31 2008 2:18pm

The brake lever switch won't be able to handle the amount of power needed for motor braking.

There are a few options.

I think the simplest way is to mount a lever actuated micro switch to the brake lever or caliper. These switches are available in 15 to 20 amp ratings, which should be enough for dynamic braking.

Here's the kind of switch I'm talking about: ... VER/1.html

On my old Zappy, I used a similar switch that was mounted directly against the brake mechanism on the wheel end (band brake). As soon as I squeezed the brake lever a tiny bit, the switch would close. You might also be able to mount one to the brake lever on the handlebars.

To make use of the actual existing brake switch would require some kind of relay or transistor. This could get complicated and / or expensive depending on your junk pile. The stock brake inhibit switch pulls down a 5v signal from a resistor inside the controller. There is not enough power available at the switch to operate a relay. A relay would need to be powered from the 5v regulator, which feeds the throttle. Even this source is pretty limited and could only operate a small relay.
"One test is worth a thousand opinions"

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StevenR   100 W

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Re: Using REGEN on Crystalyte CT4840 v2 Controller

Post by StevenR » Aug 01 2008 1:28pm

Regen comes on whenever the brake lever is pulled. Wiring from ABS to GROUND inside the controller enables regen so the brake lever triggers it; no other wiring is needed. I put a switch in the wire from ABS to GROUND so I can enable or disable regen entirely but if you want it whenever the brake is pulled, you don't need the switch.

I severall issues with regen.
1. It is ON/OFF. It can be more braking than you need if you just want to slow down a litle.
2. It comes on hard and you need to have very sturdy torque arms in both directions. Even with two arms, the axle will work back and forth and loosen the bolts. I am awaiting an aftermarket arm that may have less slop than the standard C'lyte arms and, if solidly attached to the fork, may prevent this.
3. The power leads from the controller to the motor get HOT. I didn't notice any heating without regen but after I enabled it, they were very hot after a series of fast acceleration/deacceleration runs. This was not normal riding but I was testing how well the torque arms were working so I was accelerating to 30 MPH then deaccelerating using just regen.
Bianchi Alante MTB with C'lyte 5303 Front Hub Motor / Motobecane hardtail MTB with C'lyte 5303 Rear Hub Motor
CT48V35A Controller / method monster 100A100V controller
Schwalbe 26"x2.3" Big Apples / 26" Schwalbe Ice Spiker Pros
Ping v3 48V20aH with 60A v2.5 BMS / Headway 48V10aH BMS used to balance, bypassed on discharge
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Lolo06   1 µW

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Re: Using REGEN on Crystalyte CT4840 v2 Controller

Post by Lolo06 » Mar 04 2014 4:26pm

hello, i need help for understand if i can connect the regen on my crystalyte 48v 40Amp controller is two year old.

i have search and read more on the forum, but with a very desastrous english is so hard to find...

if it can help, some picture !

Lolo06   1 µW

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Re: Using REGEN on Crystalyte CT4840 v2 Controller

Post by Lolo06 » Mar 04 2014 4:30pm

sorry here the picture's

Firedog   10 W

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Re: Using REGEN on Crystalyte CT4840 v2 Controller

Post by Firedog » Jan 06 2020 2:33pm

6 years for a response!

I have several 4840 and 3640 controllers with the same boards as your pictures. They do support regen braking if the solder hole marked Bk is grounded. Applying the brakes will activate the brake sensor switch and cut the throttle and engage motor braking if the speed is sufficient.

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