2nd Drive Unit Failure

On a pleasant sunny day just driving up my street my Tesla began to give me a scary warning.  I don’t remember the exact words but the warning was to the effect that the car won’t likely restart.  A bit alarming but I was glad I was very close to home and parked the car in the garage.  The warning only flashed once and went away.  I plugged the car in as normal and went into the house. In hindsight I should have driven the car straight to the service center or left the car parked on the street in a flat location.

The Next Morning

I was concerned about the car, so the next morning I went to check the dash.  The car still had power but would not start and flashed a few more warnings.  I decided to call Tesla Roadside assistance as the car was not drivable.  Upon returning to the car, the car no longer had any power and the dash was not lighting up at all!  Tesla Roadside suggested calling AAA first to get the car towed as the car is out of warranty.


The first call to AAA resulted in a flat bed arriving from the East Bay a full three hours later.  None of their local outfits were available on the holiday weekend.  The tow truck driver however was not very familiar with Teslas and said I needed to get a more standard tow truck that had a dolly.

Towing without a flat bed

From all my experiences having had the car towed, every driver used a flatbed.  I didn’t realize that you could tow a Model S with a dolly.  But alas, the kind Tesla Roadside service person clarified this and showed the following picture from the Model S manual.  The back wheels are on a dolly, so the car will not accidentally overheat if the rear wheels are spinning.

Image from the Model S manual on towing

Another call into AAA to find the above kind of tow truck resulted in another two hour wait and being told no driver was available.  I decided to try again the next day.

The Third Day

Back on the phone again with AAA very early in the morning and no driver was available again.  I was informed that AAA will reimburse you if you find your own tow truck driver, and the  records show that AAA could not help you.  So I called Tesla Roadside service, they found someone who would arrive within the hour and also showed me how to jump the car.

The goal of jumping the car was simply to put the car into neutral, so it could be pushed and dragged onto a flat bed.  To put the car in neutral both the dash and the touchscreen need power.

Jumping the Model S

Jumping the Model S is quite easy.  You pop the nose cone out with a small object on the upper right.  I used a screwdriver.  The red terminal is covered with a small plastic cap, and ground is an exposed screw.  

Power terminal covered with a plastic cap
Jumping with an external battery

Three Jumping Styles

  1. The first attempt was to jump the car with just a battery conditioner which is quite weak but using that method restored some power to the car, and could have worked if given a lot more time.
  2. When the tow truck driver arrived, he tried to jump the car with an external battery but that battery did not have enough power to keep the dash on long enough.
  3. The final successful jump start was through the main cables using the truck’s power.


What I found very confusing was that the tow truck driver who arrived works for a company who also serves AAA.  The truck actually has the AAA label.  I don’t know why they did not respond to the request from AAA but did respond to Tesla. 

The driver was very knowledgeable but did forget to bill me.  The company called back the next day to get a payment.  I have submitted my receipt to AAA but have not yet received the reimbursement.  

I have been a lifetime member of AAA and until very recently had their auto insurance also.  Prior to the internet, their paper maps were essential travel items but I have not picked one up in many years.  Given this experience, I am debating keeping my membership as now it is just a tow insurance policy.  I recently used their service outside of the area with another car, but their response in the San Francisco Bay Area seems almost useless.

The handful of times in my life that I could have perhaps used them for DMV services, I forget that this service exists.

Loading The Car

Luckily after the final jump, the car dashboard would come on long enough to get the car into tow mode.  Getting the car from the somewhat tight driveway onto the tow truck was not particularly easy as the driveway has just enough slope to cause a problem if it rolled away, but after about ten minutes the car was successfully loaded and on its way to the dealer. 

Model X Loaner

The service center gave me a Model X loaner, which was kinder than I expected.  I can’t say I am a big Model X fan.   An unnecessary (for me) bigger car that did not drive nearly as smooth as my now nine year old Model S.  I surprisingly did not like the windshield either.  I found the sun distracting during the middle of the day requiring me to use the windshield visor at very unusual times.

Drive Unit Failure

I was a bit worried that my battery was giving out, but the end culprit was the drive unit.  Tesla service charges $4800 for a remanufactured one or $6000 for a brand new unit.  I hemmed and hawed and conducted a twitter poll.  The poll showed a clear preference for a new unit.  I decided to agree with the respondents and get a new unit. 

The total bill was a painful $8,300 which included $1683 of labor and $553 in tax.  Yikes!

Repeat Failures

My first drive unit failed back in 2017 about four years and 71,000 miles.  This second unit lasted about six years and 46,963 miles.  Thankfully, the first drive unit failed under warranty.

Drive Unit Inspections

I did some internet sleuthing and found that a third party service place in southern California refurbishes drive units.  The drive unit can get messy with oil and other ‘gunk’, so keeping it clean might help.  I discussed this my service advisor, and he suggested I could have the unit inspected and cleaned say between 20,000 to 30,000 miles to remove any buildup.  The cost would be in the neighborhood of $300 for the labor.  I plan on having my drive units regularly checked from now on.

Backup Power

Here in wildfire and drought stricken California, we have experienced somewhat frequent power outages over the last few years. I have considered many times various solutions for backup power and settled on a $3,000 option.

The majority of outages are a result of weak trees or weak branches falling on power lines. These are local power lines, not large distribution wires and so far have not caused any wildfires. PG&E (despite all of its many flaws) in the last few years has locally done an ‘okay’ job at keeping the wires clear of trees. But even the smallest collision of tree and power line can disrupt power for a few hours to a fair number of people. Because of these more frequent disruptions, I investigated a backup power solution.

Since the solar panels are now 16 years old, I had no luck finding a contractor who would legally upgrade the panels. Technology has changed a lot and no one wanted to mix the two technologies. I did get one quote for a battery backup and it ended up running over $25,000 with installation and wiring. Because the house already has solar panels, no rebates are available for the power walls without being combined with solar. And solar rebates are not available for homeowners who already have solar panels.

Another option I decided to explore was a backup generator. I loathed to do so but I saw an add that they start at $4,000. Unfortunately, the real quote was in the same ballpark as a battery backup, and the company has stopped running this misleading ad.

Spending $25,000 for a few power outages seemed excessive. Instead the choice was to spend about $3,000 on the following items:

A Jackery 1000 Portable power station that could be used for modem/router power during outages and other small electronics. The cheaper older uninterruptible power supply (UPS) only lasts for about six hours. The Jackery also is useful for road trips and camping for recharging a laptop and boiling hot water for coffee instead of using a gas stove.

The second purchase was two battery backup garage door openers on the important doors. New homes built in California today are required to have a battery backup on the garage door opener. The law was passed after some people died in wildfires and couldn’t manually open their door. Although the manual process is not inherently difficult, the doors are gigantic and require frequent adjusting in order to be able to lift in manual mode and open the door completely. The hack when the adjustment is off is to lift the door onto a ladder that can support the weight while driving out the Tesla. Works for a car but not a larger height vehicle. The $1800 spent was worth the money in the case of a power outage or a potential wildfire evacuation.

The refrigerator and freezer will keep cold enough for food for a considerable amount of time, and the worst case is to go to an open grocery store and buy some ice for a few old fashioned coolers.

Although these solutions do not address the entire house power needs, they work fine. I know full battery backup is quite popular now, but just seemed like a lot of money for a minor problem.

LTE Upgrade

It took me a while to decide to upgrade the electronics on my car for a better cell connection. The Tesla is now 9 years old with 114,000 miles. But honestly the car is just fine and the items I am most interested in upgrading are quite small (CarPlay and a physically smaller car), or quite expensive (a giant battery giving around 300+ miles of range).

The 3G capability of the car was getting quite unreliable. About half the time it could not connect at all. At times having the traffic data on the screen is quite useful, and other times being able to find a new place on the map was helpful by name and not by address.

I was also experiencing another problem that I was informed was related to the old electronics. The car would take quite a while to wake up. Since installing the new electronics, the car wakeup time is not instantaneous but it feels faster than before. I never measured the amount of time, so this observation may be inaccurate.

AT&T has decided to completely discontinue the 3G network, and Tesla notified us that we needed to do the upgrade. I finally caved in and had the service done, which must occur at a service center. The final bill was $218.

Hybrid Electric Water Heater

I recently installed a hybrid heat pump water heater to replace a gas water heater.  As one of the early adopters of an electric hybrid heat pump water heater, I learned a lot during the process about the technology.  Hybrid electric water heaters are great in the mild California climate for a larger house. In about seven years, the cost of the installation (with some local generous rebates) will be paid back in about seven years. In much colder locations or much smaller homes, alternative technologies may be better choices.

Hopefully this article will help you understand the technology, the installation process, and the benefits.

Rheem brand Hybrid Electric Water Heater

Hot Water Household Needs

Before installing any a hot water heater, the most important question to ask yourself is “How does your household use hot water?”

  1. Showers and baths -YES. A minimum of 120°F is generally recommended to avoid legionnaires disease.
  2. Washing clothes – Generally NO. Most clothes wash fine in tepid water and last longer.  In special circumstances you may wish to wash with hot water — cleaning reusable diapers or if someone in the household is sick.
  3. Dishwasher – Generally NO.  Most modern dishwashers have water heating elements in them.
  4. Hand washing – Generally No.  From the CDC:  “Use your preferred water temperature – cold or warm – to wash your hands. Warm and cold water remove the same number of germs from your hands. The water helps create soap lather that removes germs from your skin when you wash your hands. Water itself does not usually kill germs; to kill germs, water would need to be hot enough to scald your hands.”
  5. Scrubbing pots and pans – Sometimes YES.  Like hands pots and pans do not require hot water but hot water can loosen up grease or tough areas that requiring scrubbing. 
  6. Other hobbies and interests – Maybe. Perhaps for some special hobby that requires hot water?

In looking at this list, a typical household only needs hot water during a short period of the 24 hour day.  The primary need is while taking showers with perhaps small usage during meal preparation.

But most households have a large giant pot of boiling water ready to be used 24/7 at their convenience.  Have you ever used a gallon of hot water at 3am? How much energy our world is using for this perhaps excessive convenience?

Methods to Heat Water 

Gas Water Heaters

Almost all homes in California have a water heater powered by gas located in a garage, a mechanical room, or a utility closet.  These water heaters are heated using natural gas and are kept running 24/7 at a constant desired heat.  The vast majority of gas hot water heaters have a mechanical dial allowing you to turn down the hot water when gone for extended periods of time. But because of the remote location, a household cannot realistically adjust the knob multiple times a day.  A small nascent market exists so that you could control the timing of the water heater by installing a wifi dial on the control knob, but I do not personally know anyone who has installed such a device.

Electric Water Heaters

Electric water heaters come in a few different kinds of configurations.  The type I chose to install is a hybrid hot water heater that contains both a heat pump and an electrical resistant unit.  

Heat Pump

A heat pump water heater is in a sense a refrigerator in reverse.  A refrigerator pulls heat from a box and pumps it out into the room it sits in.  A heat pump pulls heat out from the surrounding air to heat the interior of the box (or water in this case).  Both appliances have small fans and should have similar noise levels.  Because both devices move heat around instead of generating cold or heat, they are very efficient.

Heat pumps although very efficient do not heat up hot water very quickly and typically can take 2-3 hours if completely cold around 60°F to achieve a 120°F.

Heat pump water heaters work great in warmer climates (or rooms) that remain in the 40°-90°F range year around and have a decent amount of air space around them. Each water heater has an air space requirement. The model shown for example cannot be put in a small closet but can work fine in a large mechanical room or garage.

Electrical Resistance Water Heater

Electrical Resistance Water heaters have a tank of water with a simple heating element submerged inside.  Electricity is used to heat up the element and subsequently heat up the water.  Because electricity is used to generate heat, electric resistance heating is significantly less efficient than a heat pump.

Hybrid Water Heater

For a central hot water heater, a hybrid electric option is also available that contains both a heat pump and an electric resistance element.

Tankless Water Heater

A tankless electric water heater operates in a similar manner to an electric resistance water heater but without a tank.  Water is heated exactly when used without any tank at all.  A tankless system can operate faster than a heat pump and can be used as an on-demand hot water heater in a bathroom. 

A central tankless water heater would not work well for a large house with a lot of water pipes.  Each time you want to run the hot water you will need to drain out a lot of water (or heat up all your recirculating water) before reaching the hot water itself.  So in general not a practical solution for a large house.

Recirculation Pumps

For any hot water heater located in a central location, a small recirculation pump is installed nearby in order to provide hot water directly to the faucets when needed.  These recirculation pumps are needed for gas water heaters and electric water heaters (resistance, heat pump, or hybrid) but not for tankless water heaters located in individual rooms.

Recirculation Pump


Peninsula Clean Energy (PCE) is the non-profit energy provider in San Mateo County.  PG&E still provides the infrastructure to deliver the energy, but residents can choose PCE as their electricity provider. PCE’s energy is 100% renewable and slightly lower in cost than PG&E.  Even with solar panels, a homeowner still has a contract with an energy provider unless they are completely off grid.

The San Francisco Bay Area has a lot of separate municipalities.  Most people are probably familiar with the 3 largest cities:  San Francisco, San Jose, and Oakland.  The Bay Area actually has 101 different towns and cities.  These municipalities work together in the Association of Bay Area Governments (ABAG).

During 2021, PCE was offering a rebate of $1500 for the installation of an electric water heater to replace any gas water heater.  On top of this generous rebate, ABAG (through its affiliation with BayREN) offers an additional $1150 — for a combined rebate of $2650.

Installation Process

Encouraged by this generous rebate, I contacted a local contractor to inquire about this process.  Because of the incentive program, the steps are well organized with a list of recommended contractors who are familiar with the process.

Replacing a gas heater with an electric one requires both an electrician and a plumber.  The electrician needs to connect it to an outlet with sufficient electricity.  Luckily the mechanical room had a breaker panel with extra plugs available making this part of the process almost trivial.

The plumber took considerably more time and actually had a three person crew.  The process included draining the old water heater, removing the water heater, capping off the old gas line and chimney pipe, installing the new water heater, installing a new recirculation pump, and adding earthquake straps.

The exact water heater is a 50-gallon Ruud Heat Pump Water Heater, Model #  PROUH50 T2 RU375-30.  My first impressions was that this thing was great.  Fit in fine and it was quiet.  Unfortunately, the unit became quite noisy when configured correctly.


When the heat pump was in operation, the unit was extremely noisy.  The noise traveled through the mechanical room into the house and could be heard about 20 feet away inside the house.  The noise is a bit hard to describe and kind of more like a squeal than anything else.  

When a water heater is first installed there can be some air in the pipes that can cause this squealing but after turning on all the faucets in the entire house, air in the pipes was ruled out as a cause of this noise.

After a lot of time spent with the sales person from Rheem, the plumbers returned and replaced the fan.  Rheem admitted to trying to save money by using an inexpensive fan in a number of their units and unfortunately made the unit very noisy.  At the same time, the plumbers also installed a vibration reduction plate in the unit.  These changes vastly improved the level of noise.  

Cheap fan that was causing all the extra noise

The new recirculation pump also had some noise issues and they replaced the recirculation pump with another model.  

During this time the contractor and Rheem were quite responsive and the unit was functional.  After about a month and at no additional cost, the unit was working fine with a completely acceptable noise level.

Water Heater Application

The first noticeable change with the water heater was the ability to control it completely through an app.  I was very excited about this feature and played with it before the electricians left to make sure it worked.  The first step is to configure it to connect to wifi. The application is reasonably straightforward but there is not any real documentation on how it works.   A few of the features are a bit strange but it is a powerful tool and allows you to relatively easily monitor your usage by the day, month or year.

Heat Modes

The unit has four heat modes and the names are non-intuitive.  

Off — completely off

Energy Saver — an algorithmically tuned approach using both the Heat Pump and electric resistance to use the least amount of energy possible

Heat Pump — only using the heat pump but this mode will use more energy than ‘Energy Saver’

High Demand — a mode that warms up water as fast as possible.  The energy use is quite high per minute but it is a valuable mode to get hot water produced fast.

Electric — uses only the electric resistance feature.  This mode is very silent but uses a lot more energy than any other mode

Vacation — a mode that is good for colder climates where pipes can freeze if the unit is left off.

Custom Scheduling

The app is quite powerful and you can customize your schedule any way you want.  Here is a sample Sunday schedule where the heater is completely off except for the two hours between 11am to 1pm on a Sunday.  At any time you can interrupt the schedule and change the operation.  For example if you need to take a shower unexpectedly in the evening, you might want to change the mode to High Demand to be able to take a shower say in 30 minutes instead of waiting a couple of hours.

I attempted to calculate the net energy used to create water hot enough for a shower, showering, and then turning off the unit completely. In the Energy Saver mode during the warmer summer months, the heater takes about 1 1/2 – 2 hours, and maybe about 30 minutes in High Demand mode. To accurately test the energy usage in these scenarios is quite difficult, but with a small amount of testing I didn’t find High Demand mode used in this fashion to be wasteful. But one would need to be careful to turn the unit Off immediately after showering. In a sense, High Demand mode can be thought of as ‘on demand’ heat in an unusual situation; this ‘on demand’ heat however does require a wait time of about 30 minutes.


You can see how much energy is used daily, weekly, monthly and yearly in the app.  One very odd usage is that every four hours the unit uses a mysterious amount of energy that adds up to 0.85kWh/day.  I asked Rheem about this mysterious waste of energy and have of yet not heard back from Rheem.

For the first three full months of usage, the total average monthly usage was 62kWh/month. As a Tesla owner that is about one tankful of electricity or about 200 miles worth of energy.  Another strange way to interpret the data is that each day the hot water heater uses about 6 miles of energy.

I expected the electric bill to go up after installing the hybrid water heater but in fact it has not.  The heater is programmed to warm up water only a few hours a day with the most efficient setting and then turned off. The energy consumption has been surprisingly low in fact so far basically unnoticeable and some months the household unexpectedly used less electricity than last year.

Energy Used by Old Gas Water Heater

The house is warmed through a radiant floor using a natural gas boiler for several months a year. Natural gas is also used for the gas stove and an outside gas barbeque.  The best estimate of average yearly usage of the gas water heater was about 67 therms /year for an annual bill of close to $500.


Because both plumbing and electricity are involved, your municipality will likely require a permit and an inspection.  The building inspector literally spent about 5 minutes on site having only done a handful of these inspections before.  He glanced at the electrical panel and saw that the gas connection was removed and was on his way.  The permit cost $78.


The total bill was $5950 + $78 permit fees.  Which was a total of $6028

Three rebates included $1000 (PCE), $500 (PCE) and $1150 ABAG

Net cost $3378

Since the incremental electric cost is so minimal, the cost should recouped in 7 years with 3 years left on the warranty.

Replacing Other Appliances?

Although the process was slightly painful because of the noise, the electric water heater is a clear win in both costs in the long run and for the environment. The house also uses gas for two additional purposes:  cooking and heating the house via the radiant floor.  Cooking both inside and outside on the barbeque uses minimal gas.  Heating the house even with the efficient radiant heating method uses significantly more gas than heating water.

The same contractor I used for the heat pump also gave me a vague estimate of $20,000 – $30,000 to replace the boiler with a heat pump.  This heat pump requires a 3’x3’ space and cannot be in the mechanical room due to lack of air space for the heat pump itself.  Because of that restriction the large estimate is primarily the need to move the equipment outside or potentially in the garage.

But with the negative experiences of a noisy heat pump and the high cost, I have chosen to wait for someone else to successfully replace their boiler with a heat pump.  I would want to do a site visit and listen to the heat pump.  Unlike a hot water heater, the heat pump for the house would be running during a reasonable amount of time during any given day. Also as the climate has been significantly warmer in the last few years during the winter months, the heating requirements have gone down significantly this year.

New 12 V Battery

After 4 1/2 years, I got another warning light that my 12 Volt battery needed replacing.

I have to admit, I love Tesla Roadside service. I scheduled an appointment for a week out. Every few hours I checked the app for an earlier appointment and I eventually got a next day appointment. I think a fair number of customers reschedule appointments, so its pretty easy to get an earlier time slot.

The service person was kind and efficient as always and wore a mask in the open garage. He even checked the wear on my tires. They are holding up after 6,000 miles very nicely at 8.5/32 on all four tires. I am planning to go in for my free rotation at the tire shop regardless.

Although the service was excellent, he couldn’t tell me where the 2nd key fob is. I figure someday it will show up in a pocket somewhere.