First Enginer PHEV install in the Portland Or area, Gen2

Hi Force,
Yes, the topoff is less than 50 watthours. The purpose was to exercise the process of data collection. It is not worth it for the 50 watthours.

Also this shows which cells are about to alarm when the charger has ramped down fully to low current levels. I do not get that data when I turn off the charger at 5 amps due to an alarm.

Thanks,
Dan

 

Hi JonnyD,
I am sorry, I do not understand. What "problem" are you thinking of in your message?

I did not think I was describing a problem. I was just intending to state the facts around the data that I was able to collect.

If you think you see a problem in this data I would like to discuss what you are seeing.

Thanks,
Dan

 

Hi JonnyD,
Yes, you are correct.

This is because the balancers use are really designed for smaller cells. The Balancer shunts 300ma from the highest Cell. This Is probably OK for the size of cell used in Ebikes and other applications. The problem is that the charger is still supplying 5 amps or so at this time and 300ma is not enough to let the cell voltage to level out.

Enginer is working on a better balancer that should solve this. In the mean time. Enginer Kit users need to manually monitor the charging and shut it down if they get an alarm. I do this regularly. It is easy to do. It is just an annoyance.

Thanks,
Dan

 

Hello Everyone,
I drove 20 miles on Saturday and 26 or so on Sunday. Both at about 65mpg. Sunday I had the CellLogs running.

You can see that I stopped 2 times. I had my low cell alarm set at 2.75v and did get an alarm in the middle. I have now set it for 2.70v because Jack said that was OK so long as the cell recovers quickly.

I could hear the CellLog alarm faintly. Today I managed to add a buzzer to my upper CellLog. It has an alarm port but it switches the lowest negative battery lead from the cells it is checking so you have to use the Enginer cells to drive the buzzer or you have to put in a relay to isolate the Enginer battery from the Prius 12v system. Also this means that you cannot use 1 buzzer on 2 CellLogs without a relay. This was not simple but it is doable and now I should be hearing all the alarms on my upper pairs of Cells. When I get a second buzzer I will get the lower cells done.

Thanks,
Dan

 

Hi Chan,
Yes, This 300ma is while pulling 55a-70a from the pack. Note that when the current is off it immediately drops to about 50mv. So that difference is resistance differences.

Do you see this type of change in delta between drawing current and not drawing current?

Thanks,
Dan

 

Hi Everyone,
I did 26 miles at 69.7mpg.

I am getting a charging alarm regularly for upper pair#6.

But it looks like upper #2 and #3 and lower #2 and #5 are the lowest at the end of the 26 miles. All 4 of these Cell pairs are right at 2.8v. My total cell voltage is going down to 47.5v.

So the data indicates that I am OK.

After looking at this data I think I would get better readings if I had lower resistance between my buddy pairs. I am more and more convinced that Buddy pairs is very important. When I get my next kit I will buddy pair with copper straps.

Thanks,
Dan

 

Hi Chan,
Thanks, I think the differance between my data and yours is the way I have the cells buddied together. The resistance in my buddy jumpers makes it so that I only read the side of the buddy jumper that the CellLog is on. Even though the buddy jumper is working to keep the buddy cells balanced, This happens a little slower than when the cells are buddied with big copper straps.

Note that our deltas are similar as soon as the current is off.

Thanks again,
Dan

 

Hi Chan,
Thanks for the advise. I am monitoring closely as you advise. It sure is nice to be able to get the data off of the CellLog. Also I have an external buzzer working on the CellLog with the worst cells. I got a second buzzer today but it is not yet wired up.

The cell log caught the history Sunday when one cell went to 2.75v. It clearly had not hit the knee of the discharge curve yet.

I had set the alarm down to 2.7 and got that today for 10 seconds. At that point, I turned the system off. I had driven 22 miles and gotten over 80mpg. So I had used the system pretty hard (for one converter). Anyway I will down load the CellLogs later and see what data I get. I expect that I am now close to the knee but still not there.

In a normal Buddy pair the resistance between cells is probably not measurable. Maybe 1-2 mOhm. In my Buddy pairs I have about 25-40 mOhm between the cells. I see up to 5 amps going through those jumpers. That is 125-200mv voltage drop across the jumper. That is the reason that I have bigger deltas than you. With your lower resistance buddy pairs both read the same voltage. With my higher jumper resistance I get a slightly different voltage at each of the 2 buddy paired cells. The Cell logs are only reading one of the cells. In some cases this is the higher voltage cell and in other cases it is the lower voltage cell. I am confident that I have an understanding of this and that it is not as risky as it looks.

I did get the Copper today to redo my Buddy pairs and I recommend everyone to do Buddy pairs with the heavy copper straps rather than the way I did it.

Thanks,
Dan Lander

 

Hi Chan,
I did get a cell that hit the knee on the bottom. The CellLog caught it safely. It was not one of the lowest cells in the 300mv imbalance but rather one that had been in the middle of the pack. It clearly went down over about the last 20 minutes of operation. I put a 2.5a charger onto the cell that hit the bottom and the cell next to it and they both gained enough so that the balancers and a regular charge cycle got everything back to the "normal" state.

I love the CellLog. It alarms loud enough to alert me. And I catches the data so that I can figure out exactly what is going on.

Thanks,
Dan

 

Hello Everyone.
I am still running this system successfully. I did 2 trips yesterday with a charge in between. It was a total of about 45-50 miles with 65-70mpg.

I am getting one buddy pair that is clearly discharging to its lowest level limiting the pack to about 25 miles.

Charging is predictable and so I am able to be sure to be at the charger to unplug it just before I get a charging alarm. As an alternative I could now do this with a timer or turn down the charger a little.

Jack has agreed to send me out replacement cells for the weak cells. I have 2 boxes in the mail so in a few days I will see if those boxes are the cells or other parts.

Thanks,
Dan