2nd Gen Prius PHEV Conversion (Enginer plug-in lithium ion battery kit)
 

Christmas came a bit early this year for me.

For those who don't know, the Enginer PHEV kit is an additional battery pack for the Prius. This Enginer pack is a plug in pack that charges from a household 110V outlet. The Enginer pack has a 3000W dc to dc converter. This converts the 48V pack power up to 240V+ to charge the OEM Prius battery pack. So, the Enginer pack never directly powers the car, it just keeps the OEM pack topped off forcing the Prius to use more electric power. Once the Enginer pack runs out, the dc to dc converter shuts off and you return to normal hybrid mode. Users of the Enginer kit usually see 30+% increase in fuel economy when in use. The main draw back is that the dc to dc converter is limited to 3000W which is only 4hp. This doens't allow you to maintain 30-35 mph for an extended period of time. So, I can't run for a reeeeal long time on EV mode.


Of course it all starts with a story, so here goes. I'd been tracking the packages since they shipped. The kit contains 4 packages total. FedEx's site claimed they delivered two of them last night. I get home from work, no packages. :mad: I was not a happy camper. I called them up and asked what the heck was going on. They confirmed that the two packages had been delivered, obviously to the wrong house and would check with the driver. Anyway, it snowed last night and I was out shoveling this morning and my neighbor yells to me that he has two packages for me in his garage. Phew, glad to have them.

Anyway, I drug them inside (one was ~70lbs) and started opening! Here are the pics. If anyone has any requests, let me know.


Boxes!
http://www.tercelreference.com/downloads/prius027.jpg



The small box had a lot of little goodies in it. The copper bars to connect the batteries together, the battery balancer harnesses, some mounting hardware and a wrench for assembly.
http://www.tercelreference.com/downloads/prius028.jpg



The larger box contained the stainless box that holds all the goodies in the car. The build quality is pretty good, however most of the bolts I had to take out didn't really come out with the greatest of ease. I had to use the wrench to get them all the way out, no spinning them just with my fingers. This was and still is a concern of mine. This entire thing is Chinese made, its only real downside IMO. However, everything does seem to line up pretty good. I know I've had some cheap computer cases that have stuff don't really line up and its a pain to assemble. This kit doesn't seem to have that problem at least from the tiny bit I've look at it so far.
http://www.tercelreference.com/downloads/prius029.jpg
http://www.tercelreference.com/downloads/prius030.jpg
http://www.tercelreference.com/downloads/prius031.jpg
http://www.tercelreference.com/downloads/prius032.jpg



Popping the box open shows that it wasn't shipped empty. All the main components are there.
http://www.tercelreference.com/downloads/prius033.jpg



The DC to DC converter.
http://www.tercelreference.com/downloads/prius034.jpg



The charger.
http://www.tercelreference.com/downloads/prius035.jpg



100A breaker.
http://www.tercelreference.com/downloads/prius036.jpg



Cell balancer.
http://www.tercelreference.com/downloads/prius037.jpg




So, it looks like the only thing I'm waiting on is the batteries to put in the box. We'll see if they get here today or not.

In the mean time I'm feeling quite tempted to crack open that 3000W DC to DC converter to see whats inside... :)

A step by step topic on a 2nd Gen Prius PHEV conversion?

Awesome!

I would be very tempted get a Prius and do this myself if it works for you.

Doax,

Many thanks for starting this thread. I've been waiting/waiting to be able to
follow a DIY PHEV conversion from the git-go. :thumbup:

IIRC, the Enginer conversion has two battery options. If so, which one did you
get?

On the bolt hole issue; are you saying the holes in the "held on" piece need to
be redrilled, or the holes in the "held-to" piece retapped, or both?

Again, thanks, especially for the pix. I'll be looking in on you frequently.

Who knows, if all goes well -- both for your install, and for me --I could be
doing the same in the not too distant future. ;)

The Enginer actually has 4 options now. A 2, 4, 6, and 8 kWh pack. I got the 4kWh pack as it is currently on sale for $1200 less than normal!

The problem with the bolts is the tapped holes need to be chased just to open them up a little bit. Nothing that is horrible, just annoying.

Anyway, I forgot to mention this in the first post. One thing I'm not happy with is I was expecting to get 4 cell balancers with the 4kWh kit. A few days after ordering, I got an email from Jack saying I needed to wire the balancers in parallel as shown below. IMO this is NOT what you want. One cell could go bad or even just age faster than the other that it is in parallel with and the balancer would be useless in detecting this problem until both cells go bad.

I am in contact with Enginer trying to see if they'll provide me with the two more balancers that I had assumed I would get.

http://www.tercelreference.com/downloads/prius038.jpg

Awesome! My Mom has a 2005 Prius, and eventually she will need to replace the batteries. I can hardly wait until you get this baby installed and find out how far a good ecodriver can go on a 4kW battery...

Tim, I will be back in town on SUNDAY!

Looking good so far :thumbup:

Tim: NICE Christmas present! Looks like UPS just brought you a bunch of fun.

I agree this is not desirable.

The battery pack is the costliest part of this kit. You do not want to skimp on monitoring/protecting it at the individual cell level. It becomes even more important as the cells age and start to drift apart from one another in capacity/performance.

Even with the cheap, used lead acid batteries in the ForkenSwift, I would not be satisfied with a monitoring system that only showed me the performance of each pair of batteries. I want to know what each battery is doing to protect them from damage.

Sounds like they're just trying to cut costs.

But unless someone gives you a convincing technical reason the new setup (one monitor/balancer per pair of cells) is equal to the original (one per cell), I wouldn't be satisfied.

Haha, I will be impatiently awaiting your return. Me and Ben will be doing the install this Sunday. :) However, it seems I won't have all my batteries by then. Of the 2 packages left to come, one isn't going to be here until the 30th. I am assuming that each package is 2kWh worth of batteries.

In the mean time I am going to dig through the stuff I do have, get it setup and ready for install.

So the question is: are you going to wait patiently for all 4 kWh, or set it up as a 2 kWh kit and try it out before the 2nd batch of cells comes? :)

I'm going to try it out! :D

It will NOT be very wise of you to open the DC/DC converter to browse inside and make it public!!!
They didn't supply you with the small fire extinguisher in the small box?

The fire extinguisher was in the large box.

Subscribed!

After a little back and forth with FedEx, the driver had to return today and I got half of the batteries. Even though lithium is considered light, its still a bit on the heavy side, another 70 lb package.

http://www.tercelreference.com/downloads/prius039.jpg



A little pry bar action and we find these beauties inside.
http://www.tercelreference.com/downloads/prius040.jpg



Lifting is made easy by some cords on the batteries. On two of the battery groups, the zip tie broke. Easy enough fix though.
http://www.tercelreference.com/downloads/prius041.jpg

Well, I'm glad the FedEx site lied to me. I just got the last package, all batteries are now here and accounted for! :)

I also fixed the zip ties holding the cells together.

http://www.tercelreference.com/downloads/prius042.jpg

So that photo shows 4 kWh of lithium? 140 lbs total?

That photo shows 4kWh of lithium. The package weight was around 70 lbs each. I just weighed them though. Total pack weight is 108 lbs lol (thats really light for people who don't know).

That is indeed light. My FEH NiMH pack is 2kwh and weighs 50kg

A note of CAUTION, you should charge and balance these batteries properly before use.
I will recommend you to discharge these to a safe limit through a proper dump load and recharge them again at least a couple of times before using these in the car.
Do the proper research in the extended information to be found in Prius Chat.
Also, you should band these battery packs with metal or plastic strapping, to keep these 4 very thought, being that the metallic ends with the SS straps are not supplied with this kit.
The metal end plates are being used as a safety precaution to help compress and avoid bulging of the batt. plastic cases wile charging.

I had planned on charging them and balancing them overnight tonight before installing them in the car since I'll be doing the install on Sunday.

Why the recommendation to cycle the battery before its in the car? Got any links to info on this?

The banding idea is interesting and probably a great idea, thanks!

To balance out of the car because these are out of the car and at the same time you can use the vehicle for any need that may arise with out having to drive away with a looong extension cord around town.
In the way these batt are supplied to the end user are basically how they arrived from China from a long sea journey and, unfortunately, we found that the Manufacturer's QC is not the best.
So, you may have in your hands some unmatched cells; better to take care of all issues in a control environment.
Patience is a virtue.
PS.
I saw that you opened a new thread in Prius Chat about the same topic than this.
A good topic on Enginer batteries can be found here

It sounds to me like a lot of people are having balancing issues. It sounds as though cell quality is really an issue. This even more so reinforces the need for individual balancer monitoring for each cell, not two cells in parallel.

What are your thoughts on this mrbigh?

SVO gave me heads up on this...very cool Tim! Can't wait to see what you get out of this kit! I knew once you had the Prius in your hands it wouldn't be long before you started working on it...this is great...congrats!

As you found, balancing on this type of LiFePO4 batteries is a PITA.
Again, I will recommend you to safely discharge these to a safe level of about 2.55 VDC to a dump load, single cells or by pairs, after completion of this process put them in the charger and let the balancers do their thing until all of them are equally charged, re-start the discharge cycle again on the dump load by pairs or single cells.
Low voltage discharge is the most important factor for a healthy battery pack and will prevent further major problems down the road.

NOTE
The Prius NiMH additional batteries I installed (168 in total) went through the same process 5 consecutive times before I configured the battery assemblies (6), and all of them went through a battery analyzer paired to a computer for graphing representation.
- - - - - - - - - - -
The dump load I use since the las 4 years is an electrical water heater, 220v element rod, installed in the cover of a 5 gallons plastic container filled with water that can be recycled.
It is a safe and inexpensive way to do things like this while the voltages that you will handle do not exceed 40 VDC.

We should also talk to EL-Camino Tom about what he is using on his Lithium pack.

The last time I talked to him about his Lithiums, he said he had
"..... a BMS which only
monitors all cells, does not balance them. Many feel that the balancers
are wasteful and can even unbalance the packs more. If you are willing
to treat them well, LiFePO4 batteries will return the favor. Keep ALL
cells over 2.7V at ALL times, and you will get along if you have a proper
charger."

We can check what he is using for BMS. As a custom electronics engineer, he knows a few things about it.

Good stuff Ben, I didn't think about him.

As of right now, two of the four packs are on the balancers. When they are both done, I will charge them up and monitor voltages as they charge. We'll see if any of the cells charge faster than the others and if I get any alarms.

Last night I had reconfigured one pack to run in the 'buddy pair' setup. I think I'm just going to setup to run with the two balancers and just run half the pack so I don't have any cells in parallel. This will allow me to monitor every single battery and show if there is any problems.

http://www.tercelreference.com/downloads/prius043.jpg

El Camino-Tom must be using a "Battery Monitor System "and not the common acronym of BMS for Battery Management System, these are two different devices, the later being a more complex piece of equipment.
A "balancer" is neither.

The balancers that come with the Enginer kit kind of monitor the batteries. They have a high and low voltage warning beep that goes off when one of the cells goes too high or low.

Enginer said they'd send me to two extra balancers, but they won't cover anything that goes wrong if I use them. This is BS. The whole point of this is to avoid bad cells. If I can't detect them, they ruin more cells, but if I monitor them all and find bad ones, then I have to pay for their bad product. :mad: The thing that urks me even more is their site says its supposed to use 4 balancers, so I had no way of knowing of this until I bought the kit.

That sounds pretty crappy on their part. I would force their hand!

Hmmm - we could get the extra balancers sent to me, and then I could bring them over :rolleyes:

If the kit was spec'd with 4 balancers originally, then what's their problem?

They're being silly. Doesn't reflect well on the company.

If the kit was spec'd with 4 balancers originally, then what's their problem?

They're being silly. Doesn't reflect well on the company.

EDIT: are you sure they're saying they won't cover ANY parts (cells), or just the extra 2 balancers?

They didn't specify exactly. These are their exact words:

So, in order to keep my warranty, I guess I'm going with the buddy cell setup. However, I just started reconfiguring the packs tonight and guess what? I don't have enough connectors to put all the cells together... This is getting old very fast.

Customer feedback survey:

1. "How would you rate our advertising? Did the product match what we described in our marketing?"

2. "How would you rate our quality control in packing your order? Did you receive all the parts you ordered?"

3. "If you experienced any problems, how satisfied were you with our response/support decision(s)?"

4. "Based on your experience, would you recommend our company/products to others?"

You don't have to answer these if you want to be diplomatic. I think we can guess pretty closely what your answers would be.

balancing
 

Let me shed some light on this issue since my company was the first to install the Enginer 4kw kit it a Gen 2 back in May 09.
The issues with the parallel pairs was needed to help balance the high and low cells. What I would recommend is to separate all cells before any charging and record the static charge on them. Add all voltages together and divide by the total number of cells you have. This will give you a cell average that you are looking for. I would then start matching highs and lows within the cells to match the average as close as possible. This will give you the best pairings for each parallel pair.
The reason we have to do this is because you are charging the whole pack to around 58 volts and the biggest danger to these cells is overcharging. You could have a low cell starting the charge cycle at 2.7v and a high cell at 4.1v.
If they are wired in series they will both continue to receive charge until the total system voltage is achieved. This would in our experience drive the high cell to over 5 volts and damage it before the low cell would be high enough.
Connecting these in parallel, creates a balancer for that high and low cell by using one to balance the other.
We have been fighting this battle since may and my company has been through about 3 complete sets of the batteries, while trying to get all the bugs worked out.
The ideal setup would be to have individual chargers for each cell and have a low cell monitor to shut down the dc/dc when the low cell monitor detects any cell below the preset low limit.
These features would add additional cost to the system and would end up making it unaffordable to the average enthusiast.
My company is working on some upgrades for the system to allow those with the desire to improve the basic system to do so.
We will make these available on our website soon at Remanufactured Hybrid Vehicle Battery Packs
I will try to follow this thread and answer any other questions anyone has or please feel free to contact me directly.

Nice. That's almost twice the power density of an Insight's NiMH cells. What's the total net weight of all the components going in the Prius?

How does the Enginer pack know whether it's over-charging the Prius pack? Can you trick it into charging both packs when you plug the car in? That would give you ~5KWh.

They claim the entire package is 165 lbs.

The Enginer kit's dc to dc converter simply puts out a voltage. This voltage is at 70% of the OEM pack's full charge. So, it will only charge the OEM pack to 70%.

First I want to thank you for this work. It is grassroots efforts like yours, AutoBeYours and other independent shops that we develop a sensible, sane, USA capacity to keep these vehicles running.

A little off topic but I wanted to ask if you think the older, NHW11 modules are worth refurbishing?

Near as I can tell the "O" ring around the B+ terminal deteriorates, probably from heat, and this allows out-gassing and loss of water from the electrolyte. Although distilled water can be added to these modules and their original capacity returned, I've not found a practical way to reseal the B+ terminal. The Toyota 'sealing' gunk does not impress me. Do you see a practical way to seal the B+ terminals of the older NHW11 modules?

What sort of Ahr capacity are you finding in the NHW20 modules when they come in?

Does discharge-charge cycling restore capacity in the NHW20 modules?

The reason I ask is I do not see a restoration of capacity to the NHW11 modules without adding water. But once the electrolyte is rehydrated, cycling the older modules brings their capacity back (actually a little more than 6.5 Ahr.)

If you have some low capacity, NHW20 modules that defy restoration of capacity, not dead cell but lost capacity, I would be interested in getting some for refurbishment experimentation.

One pattern I'd noticed at "Prius Technical Stuff" is a tendency for traction battery failures to occur in hilly and hot areas. Have you noticed any service area patterns from customers with failed traction batteries?

Thanks,
Bob Wilson