First Enginer PHEV Installation in Portland Or Area

Hello Everyone,
Back to the 2010 Prius with 6kwhr Enginer system.

I got a low range the other day. Cell5 went low before I expected it.

In the past I had been doing about 7 charge pulses during an hour. I did this after the full charge was complete. This combined with the MottCell overcharge protection accomplished a top balance. My timer locked up so I stopped doing this for a couple of weeks.

I started again balancing at the top and even had a little magic happen with the timer now working again. Cell 5 is behaving better again.

So my conclusion is that cell 5 has, for some reason, tended to drop a little charge relative to the other cells over time. It does seem to need a balancing every few days to keep the system optimized.

This is on a 2 year old system. Do any others have history on LiFePO4 cells for 2 years. Is it normal for self discharge to vary after this amount of time?

I am still getting around 100mpg for 25-30 miles.

Thanks,
Dan Lander

 

Hi Dutch,
The issue is not voltage but current.

To top balance, the full cell needs to bypass current while the low cell is using the current for charging.

So over time, the average current being bypassed needs to be as big as the average current from the charger.

As an example the Pacific EV system turns on a resistor anytime the cell gets above a preset voltage. That bypass current can go up as high as 1/3a. At the end of charge, the charger pumps a current of 2a or so into all the cells, but 1/3a bypasses the high cells. Then the CellLogs hit an upper alarm limit and turn off the charger. The resisters that bypassed current then drain 1/3a from the high cells until the voltage drops. Then the CellLog alarm goes away and the charger comes on again.

So the charger is on and off and on and off. So the charger puts in 2a when on and 0a when off. The resistor is a constant 1/3a all the time for the high cells. These as long as the time off is long enough there is not any damage.

Thanks,
Dan

 

Hi moving,
The system is finicky. It can be the cells, but more likely the BMS.

2000-3000? Nobody knows. The LiFePO4 cells have not been in public use for long enough to have real data. Personally I take supplier data with a grain of salt.

So part of the purpose of this thread is to give others a data point on how my system is doing. I think I have one of the longest continuously running Enginer systems.

Thanks,
Dan

 

Hi Moving,
How would you measure SOC?? When its full its 100% when its empty....

I do notice that I seem to get less distance before the red light. But there are so many variables that it is hard to tell.

Thanks,
Dan Lander

 

Hello Everyone,
Yesterday I used the full capacity of the system. I got 56.7miles at 91.9mpg. This is for a 6kwhr battery pack. I calculate that I am getting 3.8 electric miles per kwhr.

The best that I ever did consistently with the new batteries was about 4.3, so that is a drop in capacity of 13% over 3 years of usage.

Note that I think I am still putting the same power into the batteries, so that would mean the 13% is going to heat during charge and discharge.

Thanks,
Dan

 

Hi Moving,
If you want Pure EV, then go buy a Leaf. Pure EV is not good for a Prius PHEV conversion. The motor may not run or it may run cold and the gear box may not get the same level of oil pumped through it.

The thing you really want to do is to get the ICE water temp up to about 180degF on every trip. That will make the ICE and gearbox OK.

Thanks,
Dan

 

Be sure to get a good installer who knows what he is doing. The real problem is not the life of the batteries. The real issue is the need to test everything and understand all the bugs and anomalies that will happen.

I tell all users that they will have 3 warranty failures in the first year.

Thanks,
Dan Lander

 

Hello Everyone,
Today was a perfect day with a perfect trip.
I went 20.2 miles and got 158mpg.The trip had stops at about 5 miles so that the Enginer system could fully recharge the Prius.but the stops were short enough so that the Prius did not cool down too much. It was about 85% EV.

Thanks,
Dan

 

Hi Again,
Today was a normal day so I wanted to report it so that no one would get false expectations based on yesterday's good results.

I did 27.8 miles at 100 mpg. This is normal for me. I am good at it. My wife gets 75-80 mpg when she "just drives" the car with the Enginer system on.

Thanks,
Dan

 

Hello everyone,
I fully used the 6kwhr pack today. I got 99.9mpg for 44 miles. I figure this is about 3.3miles per kilowatt.

This is lower than what I have seen in the past. But more noticable is that I got a premature red light. That is because to as the cells age they are not as tolerant of high current draw. The cells had been puting out about 3/4C for quite some time when one of the cells dropped low causing the red light. After it rested for a while then it gave me what I estimate as another 10ah before it and the rest of the pack went low together.

This is the way that I see LiFePo4 cells aging. When the cells are getting to the top of each charge they do some surface plating of Li onto the plates. This is a resistive coating. This causes that cell to loose some of its ability to be used at high rates of charge and discarge. If the cell is charged and discharged slowly it still has good capacity. But I clearly see limitations in older cells when doing fast rates of charge or discharge.

Have others seen this effect in older packs?

Thanks,
Dan

 

Hi Everyone,
A little over 3 months later and still running well. I got 109 mpg for 28 miles today and still had capacity left.

Thanks,
Dan

 

Hello Everyone,
A couple of weeks ago I had a cell in my 2kwhr pack go bad. It appears that the balancing wires between packs has too much resistance and the one pack with cell 16 going high and low needed too much current going down that wire to protect it.

So I replaced 2 realforce pouches and rebalanced. I was very careful to get a good rebalance because I can not rely on my BMS to keep it in balance. I am checking the data on this every day.

In the process I turned down the converter and I now need to adjust it back up. So it will be a while before I am back running at 99.9mpg.

Anyway, I think that the typical usefull life of these systems is only about 2 years and I got 3. I guess I expected that may be the case when I started. This is still a long ways from being a economicly viable system.

Thanks,
Dan Lander