CycleAnalyst Control Board

It has been a while since I installed the CycleAnalyst and I've received a couple of questions about how I built the control board so I figured it was time I documented it. I have gone through a couple of iterations so the one here is the final version. There really isn't much difference between the two versions except that the first one had a reed relay which would turn off the CA's back light when the headlights were off where as this version doesn't switch the back light on and off but instead has a 1Kohm 15 turn potentiometer used to adjust the back light brightness. The other change is that I added a toggle switch to the side of the box the CA is in so I could turn on the CA when the key was off.

[edit: I wanted to have the CA operate without a 12V system under normal charging circumstances which is why I went the route I did. The only time I need the 12V system to work is when driving and when using the manual over ride switch. If you don't need/want to operate the CA without the 12V system a simpler solution might be to hook the CA to the switched side of the main contactor and use a SPDT relay to switch on the CA when charging or with a manual over ride.]

The CA would always seem to record either +0.1A or -0.1A when sitting idle which would increment or decrement the amp-hours faster than reality so I decided to figure out a way to have the CA only come on when the key was turned on or when charging. Since the CA is a high resistance device it doesn't draw much current. I also noticed that the relays in the Zivan charger are rated at 1A at 30VDC and 0.3A at 110VDC which meant that I could likely get by with a 10A 28VDC relay to switch the CA to a pack voltage of 70VDC without any problem. I also figured that if the relay welded shut there wasn't much that could go wrong other than the CA not turning off. In any case, if you use a relay outside of its ratings you do so at your own risk. I'm also blessed with a DC-DC converter from Sure Power Industries which has a switched and unswitched outputs. As far as I can tell it is not an isolated DC-DC converter so both input and output grounds are shared with pack negative. I hooked the coil of the relay to the switched 12V so that when the key is turned on the CA is connected to the pack. So far this has been working just as I want.

Since I don't charge with the key on I needed a way to turn on the CA during charging so I could see the pack SOC without having to fully charge to get to a known SOC. This has been handy when I have had to go farther than the round trip range of my rig. I could just charge until I knew I had enough to make it back home. Fortunately the Zivan NG line of chargers has two auxiliary relays, each with a NC and NO contacts. AUX1 closes the NO contact when the equipment is switched on. AUX2 opens the NC contact at the end of charge. All I did was run a wire from B+ to the NO contact on AUX1, a jumper wire from the C contact on AUX1 to the NC contact on AUX2 and then from the C contact on AUX2 back to the CA. This will turn the CA on while charging and off when it is done.

Zivan NG1 relay connection

I recently had my NG3 reprogrammed with the LiFePO4 profile with the same 69.3V saturation voltage. I also installed another 50A Anderson connector to hook this charger to for those times I need a quick charge. The problem is that this charger is usually mounted on my shop wall so doesn't have the wiring to automatically turn on the CA so I installed the toggle switch to turn on the CA at any time. Since I didn't want another high voltage switch in my dash I merely wired in +12V from the always on side of my DC-DC converter and ran this to the +12V input of my CA control board. Since I didn't want anything back feeding to the rest of the 12V system I installed a diode between the key switched input and the toggle switch. If you look by pins 1 and 2 in the picture below you can see the diode. BTW, since the Zivan chargers are isolated I can charge with both at once for a 55A charge rate!

CA Control board

Note that there are 16 wire locations. I didn't really have to have so many but I wanted to be able to disconnect the CA without having to desolder things or disconnect things back at the source so I took the liberty to also make the CA control unit a convenient disconnect location. Here are the pin connections:

Vertical set

1 – +12V switched with key

2 – +12V manual over ride switch

3 – Speedometer input

4 – Ground from pack negative

5 – Shunt -

6 – Shunt +

7 – Out to Zivan NG1 relays from B+

8 – B+ Pack positive

Horizontal set

9 – CA Back-light

10 – CA Back-light

11 – Speedometer to CA

12 – Ground to CA

13 – Shunt - to CA

14 – Shunt + to CA

15 – In from Zivan relays

16 – B+ out to CA

Pin 1 is connected to pin 2 through the diode. Pins 7 & 8 are connected to each other as are pins 15 & 16. Pins 3, 4, 5, and 6 are connected directly to pins 11, 12, 13, and 14, respectively. The wiper and one end of the 1K pot are connected to pins 9 & 10. Apparently the CA has a constant current LED driver for the back light so it is perfectly safe to completely short out the LEDs or connect a resistor in parallel with them so it doesn't matter which side hooks to pin 9 and pin 10. I found through experimenting that about 600 ohms of resistance across the LEDs would dim them to the brightness I liked for night driving. When they were full on it affected my night vision. [Grin Tech (ebikes.ca) now make a CA which has optional red back lighting which I would definitely use if I had the choice now.] If you look carefully you can see where I drilled a small hole in the side of the box so I can adjust the back-light brightness without opening up the box.

Wired up

This is what the box looks like wired up. Note the large zip tie on the bundle of wires. This is to provide strain relief on the connections in the box. It seems to work well. Also, if you look at the lower left corner of the picture you can just see a zip tie going through the corner of the box. There isn't really any where to mount more things under my dash so I suspended the control box from opposite corners using zip ties. The box doesn't bounce much at all and doesn't pull on the wires.

The speedometer input comes directly off the wire feeding my main digital speedometer. I did have to put a 22nF capacitor at the C6 position on the CA board. Note that I have CA rev 2.2. When I would get to 48-50mph the speed would start jumping around erratically and eventually just go to 0. Changing the capacitance of the RC filter would filter out the controller noise. When I was going over 50mph I could let off the throttle and the speed would be rock solid. As soon as the controller was asked for power the speed would go weird again.

Rear Wheel Bearing Modification

I have two Gizmos and both have the same issue with rear wheel bearings. I assume that any Gizmo with a belt drive would have the same issue. I believe that due to the tension required in the belt, the weight on the rear wheel, loads due to acceleration and regen, road shock, and the narrow R12 bearing outer surface the aluminum cannot handle the pressure. I believe that it actually cold flows slightly allowing the bearing to start to move and continually rounds out the hub. On both Gizmo hubs the inner seal was warn down to the metal support due to the bearing slopping around as the wheel turned. It also caused a lot of noise.

As a proof of concept I took a pop can and cut a strip of aluminum just long enough and wide enough to slip into the groove made by the bearing. This worked just fine for about 50 miles and showed me that the noise was caused by the bearing movement. (Ok, for you physics types like me it was actually hub movement on the bearing but relative movement none the less.) Since this worked I decided to use a harder material so I bought some brass sheet and repeated the process. On the second try I finally got the piece made to fit and everything was fine for a while. Then one day I noticed that the outer seal was working out of the hub. Later it was even further out. Finally I took the wheel off and the seal just pulled out easily. What I found was that the brass sheet was working its way out from around the bearing and pushing out the seal. Time for a different approach.

Since the inner, belt side, wheel bearing also wears out quite fast I thought I would like to install a tapered roller bearing on each side and gain an adjustable bearing, more bearing surface, a wider outer race surface, and longer bearing life at the expense of a little more friction. The problem I ran into was that I couldn't find a bearing with the dimensions I needed. The aluminum hub would have to be machined out and the aluminum may not have enough strength to keep the outer race compressed. I confirmed this with a couple of knowledgeable bearing people. I then went to Waite Specialty Machine Inc. in Longview, WA and talked to Keith Warring. Keith is an awesome guy and knows his stuff. I took in one of the hubs to show him what the issue was. I explained what I had tried and what I had found about bearing options. He suggested that a steel sleeve be inserted and that two bearings be installed on the belt side. They regularly sleeve motors and other applications where the bearing seat has rounded out too large to properly hold the bearing. For these types of applications they machine the hole just slightly smaller than the sleeve then they heat the outer piece and freeze the sleeve and insert them. When the two are at the same temperature they create an interference fit where the sleeve won't move. They also cut and faced the spacer that goes between the bearings and installed the bearings so the hub was ready to go.

Note the extra piece between the bearing outer race and the hub. The picture below shows a different angle where you can see the sleeve.


The outer bearing where the castle nut goes did not show any signs of wear. In fact, the inner wheel bearing on all three wheels seems to be the first one to go. I believe this could be due to the fact that the shaft flexes a fair amount so those bearings don't get the same road shock.

The cost of all of this was a little over $500 for two hubs. As with much machining the setup cost is quite high so doing two hubs at once was much cheaper than doing one at a time.

The other issue I've had with Gizmo bearings is that the inner seal seat, the collar on the shaft, had rusted and then wears out the seal rapidly. I was able to sand down the collar, the metal is quite soft, and install a speedy sleeve which is a stainless steel sleeve that goes over the seal race to gives a good surface for the seal to ride on. These are not cheap! One cost me over $40 but I'm sure it was less than replacing the axle or the entire rear swing arm. I'm actually suspicious that the collar that the seal rides on were damaged first by a bearing failure which would lead to premature seal failure and then dirt and water damage. Inspect those bearings and seals regularly.