Thursday, September 8, 2011

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 ( 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.


Andyj said...

Hey Giz,
Here's a thought if you want the CA on while driving and charging.

The supply line to the "on" switch has a diode and another facing diode to the charger socket.

This way it will be on with the switch or on while charging to watch the reverse count yet the line will not bypass the on switch.

ign sw --<|--T--|>-- Charge skt

Lets hope this works :-S

Gizmo said...

Hi Andy,

I'm not sure what problem you are trying to solve. I already have it working where it is on when charging and driving. The diode I have in the unit is to keep +12V from back feeding into the rest of the 12V system. If you are talking about a diode in the line from the battery then it will affect the voltage readings. Maybe I'm not following you.

Andyj said...

Two facing diodes.

Yes it will reduce the total voltage readings of the total pack by 0.6V, either way between charge and running.

However, you won't need to mechanically switch the CA on. It will be on when you start up and also come on as soon as you plug in and switch on the charger.

no matter, just a thought :)