09.18.09
Gauges and More Wires
Hi all! Today was spent trying to figure out why my ammeter wasn’t working properly. After consulting with the folks at Electro Automotive (Gary Snyder, Bill Lentfer) we determined that I may have the wrong type of shunt for my system. A shunt is a device which when hooked up to the main pack allows a small amount of voltage to be used for the “calibrated”gauge. This allows me to use small wires to the gauge instead of big battery cables. Since I have regenerative braking I have to have a shunt that allows current to flow in both directions. I am not real sure of the structure of the shunt but I think it runs by Thermal Dynamics, metallurgy and some kind of magic incantation. So once I realized that i was not going to fix that one today, I moved on.
My next task was to hook up the “State of Charge” gauge. This went flawlessly since, I already ran the wires when I made the loom which runs from my relay board to the front of the car. lastly I hooked up the DC/DC converter. This device acts like an alternator on a car, When the key is on it pulls juice uniformly from the main pack and uses it to charge the auxiliary 12V battery. After I got it all hooked up I put my volt meter leads on the aux batt and it read 12.42V, then I activated the DC/DC by turning on the key. When I measured this time it read 13.55V. This told me the DC/DC converter was charging the aux batt. The only pics I took today were of the State of Charge gauge.
