Sunday, April 30, 2017

Water Pump Replaced!

As mentioned previously, I discovered my car making more noise than normal and found out the water pump was not performing up to par.  This however only seemed to be an issue when charging on L2.  It seems the motion of the car which creates airflow thru the radiator, etc. was enough to prevent a lot of heat buildup.  After several long jaunts, the top of the PDM was completely cold to the touch. There was not even the slightest hint of heat.  Fast charging also did not affect temps at all including the motor temps. In fact, the motor temps dropped several degrees during fast charge sessions.

But charging on L2 means standing still and you could feel the warmth building in less than 15 mins. While waiting the few days for the replacement pump to arrive, I decided to do a test so went to local Harbor Freight in Lacey  to get their $18.99 Infrared Thermometer and was thwarted! They didn't have it. Only the $27.99 version. Well, as luck would have it, I was working near the West Tacoma Harbor Freight so went there the next day and despite being a much bigger store, they also only had that option.  I decided waiting for an online order wasn't going to work so I just bought it and found out at the register it was a 20% off sale that day so it only cost me $22 and change. It was so nice of Harbor Freight to recognize my dilemma and split the difference with me!

Now that I had tools, it was time to experiment! It was VERY hard to resist the urge to stop at Tacoma Mall for a free charge but it was all in the name of science, right!

To reduce outside influences, I let car sit in garage with hood up for 2 hours to acclimate and it did a good job with PDM case registering 62.5º with garage temp at 61.8º  with probe roughly 44" off the ground.

My EVSE is a Clipper Creek LCS-30P @ 24 amps plugged into 30 amp dryer Socket installed specifically for charging. (My dryer is actually inside the house)

Since I had the thermometer, I measured literally everything.  The J-1772 handle went from 63.0 to 70.5º during the test, the EVSE brick went from 73 to 102º F.

The test ran 2 hours and measured every 30 mins plus or minus one minute.  For the PDM, I measured the highest temp from top and then on the side around the seam.  With minimal water flow, the temps did have a bit of a range to them but less than I expected. The heat was conducted rather well.  During the test, the garage temps dropped to 58.7º by test end.  As luck would have it, LEAF Spy came out with an update that provided several temps as well but didn't really go off as expected but motor temps were available.

The top PDM temps    were;  62.5, 76.0, 85.5, 87, 92.7.
The side PDM temps   were;  NA, 83.0, 91.5, 95.0, 100.0
Motor temps logged from LS; 73, 93, 99, 102, 106


A few days later, I went to Puyallup Nissan and got the pump replaced and Aaron McAfee did verify a broken blade that hampered operation.  I declined a fast charge (cause I wanted a low SOC for a good test) and took it home.  I didn't have the time to wait the two hours because of an early work schedule the next day so let it sit an hour.  To help cool things off, I left the garage door open for most of that time.

This test ran 2 hours and 44 mins. (Basically to bed time) The garage temps started at 58.6º and finished at 61.5º at 8:23 PM.  I was less regimented with my time checks since it was mostly around the normal day to day stuff I needed to do but started at 5:39 PM and checked at 6:07, 6:42, 7:28 and 8:23.

Top PDM;  67, 75,  82,  84,  88
Side PDM; 68, 80.5, 85, 92, 97
Motor LS; 81, 84, 93, 99, 104  

So the results? Well, I should have collected more "before" data to really make a conclusion but at the same time, I was unsure of how much abuse the system was willing to take and didn't want to push my luck.  But if we take this one off data, it appears the max temps don't change much. But one BIG change is the "non scientific" test.

The pump outlet hose I could literally squeeze nearly completely flat with the defective pump. There was barely a sense of movement then. But now, it was all I could do to compress the hose a few millimeters.  The hose was full with pretty good pressure and you could easily feel and hear the water moving.

Now it still amazes me how cool the entire system remains while driving so I guess the radiator is really doing its job!

Sunday, April 16, 2017

Water Pump Dead=DOA? Not In A LEAF!

Normally I only charge just before going to bed. Its one of the last things I do and normally do it while I am brushing my teeth.  But the other day, I had a planned light day and had about 40-50 miles of range so didn't plug in that night.   But as life normally does, I had decided to do something with my time off that was a bit of a drive so I plugged in at home.

After about 2 hours, I went to the garage to retrieve a food item and noticed a faint high pitched squeal.  It was so faint, I couldn't tell where it was coming from but eventually determined it was the car.  So I popped the hood and it wasn't really that much louder but I immediately realized what I wasn't hearing.

In my previous LEAFs, I could hear a faint sound of rushing water. The water is used to cool the Inverter while it converts AC power from the wall into DC power that can be stored in the battery.  This was again very faint and easy to miss if you are not listening for it. In fact, many long time LEAF owners swore up and down that their car did no such thing....that is until they went out to check.

Now, I was concerned.  I do know that in some instances, the water pump turned on immediately and sometimes it took a while but I had been charging almost 2 hours and with my fastest charging option yet, my Clipper Creek at 24 amps! (previous options were EVSEupgrades at 12 and 20 amps)

So I put my hand on the PDM (its the valve cover looking thing) or power distribution module which houses the inverter along with several other components, and it was warm. I was immediately shocked. In all the times I have charged including during 100+º  heat, I have never felt anything resembling warmth before.  In fact, the underhood area is so cold that even Mice avoid it!

I unplugged the car right away thinking water pump failure but knowing this DOES NOT MEAN BEING STRANDED like a gasser would have been. That pretty much put a smile on my face for the rest of the day. My mood got better and better as the day went on. I think my making a point to everyone I talked to that my water pump went out and I was still driving the car and watching their reactions might have had something to do with it... :)

Anyway, as luck would have it, I was working in Bonney Lake which meant driving right past Bill Korum Nissan in Puyallup and the best LEAF tech in the region, Aaron McAfee!  This was simply too convenient!

So called up their service dept, set an appointment for 2:30 and kinda hoped that I would be close to making that time. I was on a Rep client job which means I have to work at their pace which usually means slowly and inefficiently and this was no different. And we were doing 3 locations to boot.  Luckily I was able to get out on time despite taking a 45 minute lunch 2 hours into our day. Since the first two jobs were in Puyallup, I was less than 2 miles away from the dealership and had a brief thought of running down there early to see if they could fit me in but in my previous experience with dealerships combined with the fact that I would be a first time customer there, I figured there was no way.

Anyway, after the job was completed, I went to the dealership arriving 15 mins early. I pulled up to the service area and sensors automatically opened the service bay doors. As I was exiting the vehicle, I could hear Aaron being paged.  I guess they were expecting me!

My total time at the dealership was roughly 20-25 mins. This included check in,  brief explanation of what I was seeing and what I suspected and the diagnostics which included collecting data to confirm and the MOST time consuming part of the visit. BSing with Aaron over the general state of EV affairs and the LEAF.  In reality, I could have been easily out of there in under 15 minutes if I was in a hurry. I have never seen a more efficient process along with a service department that valued my time more.  I know I am preaching to the choir here but if you want the best for your LEAF, take it Aaron at Puyallup Nissan!

Anyway, Aaron plugged the car in then started monitoring temperatures and it was confirmed that the pump was running but not moving much water. The squealing sound was likely the pump running at full speed.  The pump was also vibrating meaning one of the impellers was likely broken. He mentioned he had already seen a few of these.

This could be a concern.  There was no codes thrown and this could eventually lead to inverter failure which is a much harder part to get. (Water Pump should take a day or two to arrive)  Now, before anyone freaks out, the BMS would slow the charge rate down if the temperature got too far out of control but I wasn't really willing to take the risk and with NCTC, I was ok with shifting most of my charging (well, kinda already was... :) ) to DC only until the pump was replaced.

Either way, I think this is something LEAFers should check on just in case. Better to be in front of this then to be stranded, right!

Monday, April 3, 2017

March 2017 Drive Report; Battery Health Update

This month was unusual for several reasons. I am still trying to collect as much data on battery cooling as I can by checking the pack at random intervals between fast charges.  To reduce outside influences as much as possible, I am only collecting measurements when there was no L2 charging during the interval.

This meant a lot of charging on the road with charging before and after work common.  I soon began to realize that someone living in a situation where home charging was not practical could actually get away with all public charging with just a few well placed stations.  Yes, I did get out on the road early a few times and no there isn't as much to do in the morning to cover that time (other than Facebook, etc.) but early is something I do often so it was mostly a question of sitting at home before work or sitting at a charger before work.

The afternoons were easier because every job requires work at home and I simply did it while charging. Since this is a billable event,  I am getting paid and it does lessen the work I need to do when I get home so its a wash on time demands. All this really means that my weird work schedule simply gets weirder.

For the month, the LEAF traveled 2501.3 miles costing $32.65 or 1.3 cents per mile. My home costs dropped from 9.2 cents per kwh to 8.9 cents per kwh.  I collected 365 kwh from NCTC. I had 9 days over 100 miles driven which includes one 300 mile day and two 200 mile days.

Battery Health Update;  No changes from new 7980 miles.

My pack balance is more than twice the delta of my 2013 pack but only went to "L2 full charge" seven times during the month but only once (the 300 mile trip) during the 2nd half of the month.  With balance averaging 20-25 mV,  not extreme but a far cry from the frequent single digit readings my 2013 pack normally displayed.

All this got me thinking about just how effective pack balancing was when sitting in garage all night and I found that it... well wasn't.  No improvement overnight in the balance. In many cases it was worse in the morning than it was the previous night.  Now, I know there is a lot of noise in these readings including temperature, recent charges and discharges, etc but even when allowing car to sit for at least 4 hours before taking baseline measurements, I was still seeing no changes.

But when the car is on and running or charging (remember, I have a LOT of recent experience with the latter!) nearly all my shunts are active. Generally, I see 5-20 blues so nearly all red all the time so what are these shunts doing cause the results seem pretty slim??

So I decided to see if I could determine how many were active after the car had sat a while. Well, problem is that without the pack connected, LEAF Spy doesn't show everything but it did allow me to see that the shunts come on in waves.


So now the question becomes what are we seeing here?  There is really only two plausible explanations;

1) The load of the car turning on is enough to initiate balancing among all the red cells

2) None of the cells were actively balancing until the car was turned on and the traction pack engaged. It was only after the BMS was active that the pack started sending out balancing requests.

Now first off, yes I know that there were a few red ones right off the bat but LEAF Spy shows old data until new data is read so what you see initially is primarily previous readings from the last power down or last time LEAF Spy was logged off.  Yes, we see codes running in the background but I think those are related to the other stuff like tire pressures, charge counts, etc.

Now when the car is turned on we notice first the reset to all blue and 11 mV delta but as the red ones come on, the delta increases accordingly.  I had everything off and unfortunately, LEAF Spy does not measure loads, it only parrots back what the LEAF is telling it so all we had active was a "standard" 200 watt accessory load which is not actually measured according to Phil (Peef at Priuschat.com or Engineer (sp?) at mynissanleaf.com) the creator of EVSEupgrade.com.

Either way, there is evidence that supports both explanations above so I need your help. I know there is someone out there that has already answered this question so chime in so we can all find out (or at least allow me to be the last one to come in from the cold)

I guess my other option is to simply power up the car, turn off as much as I can and let it sit a few hours or so to see if there are any demonstrable improvements in pack balance which is what I am actually doing this very minute.  I would have done it sooner but opportunities for this have been slim lately!

So let me know!
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Oh wait!.. almost forgot. The Corolla went 62.7 miles costing a few bucks or something like that.  In reality it was my plan to have ditched that car by now but Chevy is simply not allowing that to happen so probably have to tolerate its presence in my driveway for another 7-8 months or so!