The rebuild of my 2009 FEH HVTB using new MaxPower battery sticks has been completed and I've been driving the car for 2 weeks now.

At the outset, this is not a job for the beginner or faint of heart. While the procedure is not particularly complicated, it is quite involved. There are a LOT of fasteners to deal with of different sizes and types. If you did not encounter the problems we did, it is an 8-10 hour job. Unfortunately, we did run into two problems. I watched every FEH video I could find on YouTube regarding the disassembly of the HVTB and did not see anyone else encountering what we did, so I must assume my battery pack was the exception. My very good friend who helped me is an ASE Master Tech and he has worked on my car several times, including installing the charging cable in the original location, the main relay.

You can't purchase the batteries directly online. You contact them through the website asking for pricing. A woman named Lucy responded to every one of my inquiries the same or next business day. Payment was a bit on an issue. I was told to pay by bank transfer or PayPal. I opted for PayPal due to its buyer protection, but my payment was almost immediately refunded. I was told they couldn't accept PayPal for an amount that large and they wanted a bank transfer. When I declined to do that, they relented and accepted PayPal in two payments. Total price, including four day shipping from China by UPS, was $2450. The two boxes combined weighed approximately 45 lbs.

After I paid, Lucy advised my batteries were scheduled for production and would be shipped within 2 weeks. Within that time frame I was provided with tracking.

They arrived in 4 days and were very well packaged. Each shipping box was lined with sheets of Styrofoam and each stick was individually boxed with foam protecting the connectors at each end. Nothing was damaged during shipping.

Disassembly of the HVTB was a daunting task, Ford used a LOT of fasteners of various sizes and types...Torx security, Torx, Phillips head and regular bolts. I had 8 plastic bowls for fasteners and we could have used more. Document everything very carefully. The best YT video I found was "Dissecting a Ford Escape hybrid battery" by Monty's.

We left the HVTB in place. On the passenger side, we removed the main components... the main relay, the BCM and the service disconnect assembly. On the end closest to the rear, we removed two plastic trim pieces which hold the fan outlets to the HVTB case, but not the fans themselves, and disconnected the wires to the HVTB. On the driver's side, the gray foam covered bundle is held to the HVTB by zip ties looped over posts. We also removed the gray foam itself as ultimately we moved the charging cable to the vestigial black and gray connectors.

Next we removed all the fasteners holding the top battery tray in, disconnected any connectors and lifted the top battery tray out. We then removed more fasteners and the tray opens up, exposing the battery sticks.

This is where it got nightmarish. Down the center of the battery tray is a black cover. This is where the positive and negative ends of the battery sticks are bolted together. Bolts are embedded in the plastic below and then the batteries connectors go over the bolts and are secured by nuts. Several of the nuts were frozen on the bolts and and the bolts broke out of the plastic tray as we were trying to remove them. The electrical connectors broke off with the bolts. Not good. There was no evidence of rust or corrosion, but the nuts were permanently attached to the bolts. We pounded the heads of new bolts into the black plastic and epoxied them in. We then soldered in wires to replace the broken electrical connectors. This part sucked.

As indicated above, I watched every YouTube video I could find on FEH HVTB disassembly and no one else seemed to have encountered that issue. The inside of my HVTB was absolutely spotless with zero evidence of water intrusion, so I'm not sure why we were the lucky ones.

Once you get past that, installing the battery sticks was actually kind of fun, they only fit one way. The MaxPower connectors are identical in configuration to the OEM connectors.. Still document their position by photographs prior to taking the old ones out.

We could have left the bottom tray in the car and replaced the sticks there, but a few more of those same bolts broke.

We encountered one other issue. On the passenger side of the HVTB there are two orange assemblies where the top half and the bottom half together "join" the top and bottom halves of the pack electrically...one near the service plug and one by the relay. They have ceramic insulators and several of those broke, We used 16mm (or possibly 20 mm...I had ordered both) ceramic insulator buttons from Amazon to replace the top ones. I was not there when by friend did this as this rebuild spread out to over several days between the issues and waiting for parts, but i understand he modified plastic washers to replace the bottom ones.

Reassembly is the reverse.

The car started immediately and the batteries were still fully charged. Soon though, a wrench light and MIL came on and threw code P0A17 OBD-II: Motor Torque Sensor Circuit. I reset the PCM and the BCM and cleared codes, hoping for the best. No luck, wrench and MIL back on, but with new codes...P0A9B and P0A9B-60, both related to battery temperature sensors. The ICE started and ran fine, the hybrid display indicated idle charging of the HVTB and regenerative braking appeared to be working. The fans turned on immediately and stayed on even though we were outside with the temperature at 61 degrees. The ICE would not shut off and the car would not go into EV mode. That turned out to be our fault, after much checking we figured out we had not reconnected the two battery temperature sensor cables properly.

None of the problems we encountered were the fault of the MaxPower battery sticks. Between the frozen bolts and broken ceramic insulators, a difficult job turned into a very difficult and frustrating one.

I drove home and reset the PCM and BCM again using FORScan Lite. I noted the Delta_ Mod_ V was flashing between 0.06 and 0.00. I initiated a rebalance which took about 18 minutes to complete. Delta_ Mod_V was a steady 0.00 at that point.

After resolving that final wiring issue, the car has been running great. Gas mileage has increased dramatically...from 28 in the city to 34, but that also coincides with much cooler weather and not running the AC nearly as much. I did a 300 mile round trip yesterday. 90% of it was interstate driving at 70+ MPH and I averaged 33.1 MPG. It drops into EV mode easily and the transition seems smoother. Regenerative braking is working as expected. In short, the vehicle is running better than at any point since I have owned it.

I will pull FORScan data next week and post it here. If there is anything in particular you want to see, let me know.

 

do you have some photos to share ?

 

Gator,

Thanks for the great info on your rebuild. I wanted to respond to that and some other posts you have made. As you know from my PM, I'm considering doing a rebuild myself. But then I came across the posts about intermittent self-discharge and I'm wondering if that's what I have going on. I see Steve advised to do some tests to see if it was the battery or a parasitic load from the vehicle. I'd be curious to hear about your experience trying to chase that down. Hopefully it's not the battery on my car.

But if it is, I also saw somewhere that Steve recommended Bumblebee for off the shelf replacement batteries. I found out that they are only about 120 miles from me and I could by them there without the onerous sales tax we have in Washington. They have their premium battery with new cells for $3K. I see they were recently purchased by LKQ, so I hope they are still a good source.

Greg

 

I did not go through the suggested diagnostics.

Part of my issue is related to the layout of my subdivision. It is very large (12 square miles) and consists of 45 sub subdivisions or villages. From the entrance to the subdivision to my home is 2 miles, the speed limit is 20-35mph for the first 1.7 miles and 20 mph for the last 0.3 miles. . My car spends a good deal of that trip in EV mode, essentially all of the last 0.3. I was frequently parking my car with a largely depleted HVTB unless I put it in low and tried to keep the ICE running and charging. After 3-4 days of sitting, it wouldn't start, but I only needed to attach the charger for 30-60 minutes to bring up the charge high enough to start.

By the way, you might want to double check the cells in those Bumblebee HVTBs. That $2999 HVTB is listed as having reconditioned OEM batteries. The price differentials appears to warranty length related.

BumbleBee FEH

 

I intended to and did take photos of the new battery sticks, but we ran into that broken fasteners issue it was practicable to do so..

 

That's very interesting about your situation. I'm learning alot more about this in a hurry from guys like you.

I haven't figured out what I'm going to do. I've heard good things about Bumblebee, but haven't decided. I may do what you did or just do the on repair mine with OEM cells.

I do seem to see a pattern where some days it will discharge overnight and others where it seems to take more time. It would be a shame to replace the battery and then find that is still happening because of some other cause.

Again thanks for your input. Hopefully I'll have something to add later.