Sunday, January 4, 2015

2015 Update

So..... Happy new year to all!

What's been happening since our last 01/08/14 is the rhetorical question! Well, a lot of driving and a lot of tweaking..........

Overall, the Citroen DSev (74DSEV) has been working a charm. We have covered 480kms. It has consumed about $15 worth of fuel (electricity) and is eerily silent. "Today we did a range-anxiety" test and the BMS alarm came-on at 104kms.

So at 104kms, the BMS warned me to get to a charger. What a great effort without regen. My friends claim 20% improvement with regain, so my car has a range of around 120kms once I switch on regen. VERY HAPPY INDEED. 
But there is more, yes the BMS alarm came-on early as the pack voltage was still at around 87v. A long way from my theoretical 80% equivalent to 77v. 
So what went wrong? In fact it all worked a charm; everything worked as it should have. You will notice that indeed 2 cells (30 & 25) went below this theoretical value of 2.56v per cell and (one in particular got down to 2.41 by the time I covered 1 km to get home), so the alert was sounded. Had I exclusively relied on the controller software which indeed is great but gives the aggregate voltage value, I would have destroyed those 2 cells.
Now, all I have to do is test these 2 cells and maybe 15 and 20 as well and replace a couple of individual cells. Once sorted, the range should increase by a minimum of another 15kms. 
Before I do that, I shall charge and fully discharge the pack a few times to see whether this regulates those cells. Doubt it though. 
If indeed I have to replace these cells, I'll also replace the controller which I have been wanting to do. This will give me 30%+ increase in torque and I'll also create a bit more cooling for the motor which got up to 95c on a 30 degree day. 
The EVWest chill-plate and my 50c cut/in switch to circulate coolant kept the controller below 65c. Great outcome. 
I have an EV Grin spanning ear to ear!

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