Thursday, 31 July 2014

Power loss Issue & A lesson in logging trip data from your Soliton!

I drove to work on Tuesday (29th July) of this week and as I left immediately began to lose power in an intermittent fashion, not total power loss, The contactor did not cut out but it seemed as if the throttle was cutting back, Slight panic ensued as I began to think that a dead cell might be rearing its head but after pulling over and checking all voltages everything seemed normal.
I cast my mind back to the previous day and remembered that I had left my headlights on after arriving at work only for an hour though before a colleague told me so and I rushed back up to the car park to switch them off, Also I had driven home fine with no power loss issue that evening and so although it seemed unlikely I stuck the 12v lead acid (only around 3 months old, so essentially brand new) on a 2A trickle charge and left for work in the Deep Fat Fryer (The Diesel) that eve I tested again, same issue, power cutting out intermittently jerking the car around as it tries to “fly stop fly stop” etc.
A little more thought on the previous days and I remembered that we had just had a lot of rain and my car sits outside in it after it’s nightly 2-3 hour charge, so my mind got to thinking that some water had got in somewhere and was causing this issue, A few emails to Steve and he ran me though the “pre-flight” checks to try and track the problem down, Although I had already sort of ruled out the 12v I was still not entirely convinced so I left the 12v disconnected from car and charged overnight.
Next day (Wednesday eve) I checked the 12v all seemed fine and during my emails with Steve he asked me to check the logs, Logs? I asked and he seemed surprised that I was not already logging data, a little more reading and sure enough I have completely missed out on a very simple way to log your trips using a laptop and an Ethernet cable and running the Solition’s Datalogger a very simple command line data logging app that pushes the data coming out of the Soliton to a laptop via Ethernet and stores it in a simple text file, a brief search on this and I found an app called EV Trip viewer by “bhayman AKA Bryan” that imports these files and displays them in a human readable format (save all the dicking about in excel you would need to do otherwise), Cheers Bryan.
I had already looked into another Android based app called “EV Dash” by “Evlowrider AKA Pete” which involves setting up a WIFI router in the car and using an android phone or tablet to connect to the router and then capture data that way, however I could not get my dumb old android pad to connect to a router on the 169.254 range so I dropped the attempt for later pickup.
So using this newly found data logging capability I ran a test up the road and sure enough on reading the data in EV Logger it appeared that the throttle was cutting out intermittently, So seeing as I had only recently (since the rebuild) implemented the LVC I assumed that it might be the cause and went about removing the LVC loop from the throttle, and sure enough things returned to normal, well minus and Low Voltage cut-out safety for protecting the cells!
I have a couple of weeks holiday booked starting next Monday so I hope to get a few more treats implemented, such as, reinstating the LVC once the fault is found and fixed, finally fitting the Charge Analyst as my fuel gauge, removing the charger and trying to isolate it from the car chassis to avoid those electrifying moments when I forget the car is plugged and charging, maybe if I get time I will update the firmware on the charger as well.
But in the meantime and basking in the warm glow of another problem solved for now, I leave you with this juicy screenshot of my trip to work this morning, I particularly like the section when I am not necessarily sticking to the speed limits on an open stretch of clear road with no other cars in sight, where you can see the amps drop off as despite my “leadfoot” the power required to push the car at full pelt drops back as I attain top speed ;-) Sweet!

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