11 Uncommon Automotive Tools Required for an EV Conversion





I have put together a short list of tools that are required for an electric vehicle conversion.  These tools are not commonly found in the garage of the average do-it-yourself mechanic.  While these automotive tools are not rare or hard to obtain, most people have either not had the need for them or know what to do with them.  I will expand on each tool to provide more information on how to use them properly.


The following tools are not limited to just electric vehicle conversions, in fact, some are highly recommended for any vehicle owner that wants to maintain their own vehicle.  I have provided a reusability rating for each tool with examples and product suggestions.



1 – Torque Wrench 1/2 Inch



To start the list is the most commonly found tool in an automotive toolbox.  The most used function of the 1/2 inch drive torque wrench is to tighten the lug nuts on a vehicle’s wheels either after a brake change or tire change.


In an electric vehicle conversion, the 1/2 inch torque wrench is used on multiple components.  These components include the electric motor mounts, transmission mount, clutch bell housing on manual transmissions or a torque converter on an automatic transmission, and driveshaft components.


Any component that will see vibration needs to have the mounting fasteners torqued to resist loosening.  Technically, every bolt is torqued during installation though consistency is only met when using a proper torque wrench.


Why a 1/2 inch drive torque wrench?


The reason for having the lower range 1/2 inch drive torque wrench is to limit the number of torque wrenches needed to cover all the torque ranges commonly used on vehicles.  This 1/2 inch drive torque wrench has a working torque range between 10 to 150 foot-pounds or 13 to 204 newton-meters.  The torque specification for wheel lug nuts ranges from 60 to 110 foot-pounds depending on the make and model.  Here is a quick reference chart for each make and model.

Always consult your owners manual for the recommended wheel nut torque specifications as the rotor thickness and material used will also determine the torque value.

How does this translate into bolt sizes when tightening bolts?  This means that bolts between 3/8″ and 5/8″ can be torqued with a range of 10 to 150 foot-pounds depending on whether they are grade 5 or 8 bolts as well as if there is any lubricant used like an anti-seize or Loctite thread sealant products.

The bolt material zinc plated or stainless steel is also a factor in determining the torque value.  Stainless steel, although highly corrosive resistant, is not as strong as steel which means the amount of torque applied to the bolt needs to be drastically reduced, typically by 75 percent.

There is a higher range 1/2 inch drive torque wrench from 25 to 250 foot-pounds that is also available and it also has a longer handle.  One of the biggest reasons to not get a torque wrench with a 25 to 250 foot-pound range is the gap between the 1/4 inch torque wrench that will be created.  If this is the path that you want to take then to provide full torque range coverage a 3/8 inch drive torque wrench is recommended.  A 3/8 inch drive torque wrench has a range from 10 to 80 foot-pounds.

I recommend only getting two sizes of torque wrenches that will cover the majority of automotive repairs.  These two wrenches have a small window of torque value overlap and do not leave any gaps of torque value coverage.


2 – Torque Wrench 1/4 Inch

This one is a little surprising when you start to do more automotive repairs, apart from the more common brake work and wheel changes.  The 1/4 inch torque wrench is versatile not only as an automotive tool but as a general mechanics tool with the working torque range of 20 to 200 inch-pounds or 2 to 23 newton-meters.


Most people are used to torque values being in foot-pounds, just like when vehicle manufacturers publish engine work output.  The conversion between the two torque values is quite simple, 12 inches to a foot.  So to reiterate the 1/4 inch torque wrench range would be between 1.6 and 16.6 foot-pounds.


The torque range allows tightening bolts from 3/8” and smaller steel bolts.  On automotive components, you will see a lower torque value to protect the parts due to either the material or a hollowed interior for weight reduction.  One such instance is the hinge replacement on a glass liftgate which requires a small torque value of 60 inch-pounds so that the hinge is tight enough without breaking the glass.


3 – Impact Socket Set 1/2 Inch Drive SAE and Metric

Impact sockets, in general, are designed to withstand the use of a pneumatic impact gun.  As a result, they are a little thicker and heavier then regular sockets which are intended for the more common ratchet drive hand tools.  An impact socket can resist cracking from the high stresses that occur when you use pneumatic impact tools.

Stress is created when a nut is tightened to a material and a sudden torque is applied to the socket through the nut.  This can have a damaging effect on standard sockets due to the wall thickness and material used.

This same logic applies to impact sockets when using a torque wrench.  With a regular socket, the actual torque value applied to the hex nut can be lower due to deterioration of the internal structure of the socket over time.   This issue can start off mild and get worse over time to the eventual failure of the regular socket.

As for using SAE, standard, or metric sockets, you should have both on hand in your toolbox.  The only OEM (original equipment manufacturers) that are using the SAE sizes are American car companies General Motors and Ford Motor Co.  Even these vehicles may have both SAE and metric sizes on them due to many components outsourced worldwide which use metric sizes.


4 – Impact Socket Adapter 1/2 Inch to 1/4 Inch

This is the smallest and possibly most overlooked tool which is actually a tool attachment.  Having this impact socket adapter allows you to have just one set of sockets, aside from SAE and metric.  The only exception would be if there are very tight areas which would require a smaller socket.


The main purpose of this adapter is to save not only your money but valuable storage space in a tool chest.


5 – Impact Extension Bar Set 1/2 Inch

Extension bars are another tool attachment that may not seem required until you are unable to use either a torque wrench or impact gun without hitting something with the wrench.  One of the biggest reasons to have a variety of length impact extension bars is to tighten the wheel lugs on tires.

Without the proper length extension bar, there is a high chance of scrapping the paint, turning a fairly quick job into a quick paint touch up or worse.


6 – Breaker Bars 1/2 Inch Drive 24 Inch and 18 Inch

A breaker bar is an extension bar to provide more torque to remove stubborn nuts.  There are many nuts that have to be removed during an electric vehicle conversion.  The vast majority of the nuts and bolts have not been touched since they were installed from the factory, and this is the main reason for using a breaker bar.


As for the length of the breaker bar to use, it is best to use the longest one that will fit within that specific area.  A longer breaker bar will provide more torque on the nut making it easier to unseat the nut from its originally clamped position.


7 – Multimeter Battery Tester

It seems like a natural fit to have a multi-meter battery tester in your toolbox but a lot of people do not have one.  Since it is a multimeter it is not limited to just a DC (direct current) circuit which would be for your electric vehicle but also an AC (alternating current) circuit in your house.


Batteries are one of the last components to be wired up on an electric vehicle conversion.  Detail and care must be taken when attaching the positive and negative leads whether it is in series, parallel, or both.  Each battery should be at the same voltage and have the same resistance before attaching them together.  This is especially true for a lithium battery pack which can vary in voltage and resistance when they were charged from the factory.  The only way to test is to use a multi-meter battery tester prior to connecting them.

One of the benefits of a clamp multimeter is that you can test without interrupting the wired circuit.  Having a 600 Volt test limit is important for checking the EV battery pack total voltage to the motor controller and motor.

It isn’t required to have an auto-ranging multimeter, though it sure helps.  If you have ever been caught assuming that the amperage was lower then it is, then you would appreciate the auto-ranging feature unless you like to replace fuses.


8 – Insulated Wrench Set

When connecting positive and negative leads to the batteries there is a chance of electricity arcing between the positive and negative posts through steel tools.  When dealing with a single battery this is not much of a concern but is still a possibility if you are not careful and deliberate with your movements.

In an electric vehicle conversion, the number of batteries that are used increases the chance of accidentally hitting the posts with an unprotected steel wrench.

The insulated wrench is covered in rubber to isolate your hand from the steel.  If you were to contact both posts the circuit would still be closed in the steel of the wrench, with the exception of your hand not in the circuit, keeping you safe from the electricity.


9 – Heavy Duty Bolt  Cutter

Heavy duty bolt cutters will be required to cut the thick supply cables from the battery pack all the way through to the motor.  Since the location of the batteries, contactor, controller, and the motor will be in different locations, the length of wire that is required will need to be custom made and routed as required for each vehicle.  This is not an issue when you have a heavy-duty bolt cutter to create custom lengths as required.


Keep in mind the supply cables should be kept to the shortest lengths to keep the current loss at a minimum.


10 – Butane Torch and Soldering Rod

There are two ways to fasten the electric cables to connectors: solder and crimp.  Technically there are three ways when you combine them both by soldering followed by crimping the connector on the wire.  Depending on the size of cable that is used the solder can be applied using either a soldering rod or a torch for larger cables, like the supply cables where a high current will be transferred to the motor.

A soldering rod is used to heat up the wire thoroughly from the underside of the wire with the solder on top.  This will allow the solder to seep down over the wire to create a solid connection.  When using a thicker cable, with a lower wire gauge number, a soldering rod does not get hot enough for the heat to get to the top of the wire to properly melt the solder.

A butane torch is used to create concentrated heat on the wire to melt only the solder.  Care must be taken to ensure not to melt through the protective wire jacket.

Additionally, a butane torch can be used to activate the heat shrink around the connectors to protect water and dirt from getting inside the connector and wires.


11 – Hydraulic Wire Crimper 4/0

As previously mentioned, the other option to fasten electric cables to connectors is crimping.  The wire crimping tool uses various dies to crimp a steel connector onto the wire.  There are manual and hydraulic assisted crimpers available.  Fully hydraulic crimpers are an industry standard due to the volume of crimps it is used for in a day.


Comparing hydraulic assisted and manual crimpers, the hydraulic assisted are less expensive and require much less effort to operate.  The manual crimping tool, on the other hand, requires more effort to operate and are more expensive.


To recap, here are my recommended 11 automotive tools to get for your electric vehicle conversion.

    1. Torque Wrench 1/2” Drive

    2. Torque Wrench 1/4” Drive

    3. Impact Socket Set 1/2” Drive (Metric and SAE)

    4. Impact Socket Adapter 1/2” Drive to 1/4” Drive

    5. Impact Extension Set 1/2” Drive

    6. Breaker Bars 1/2” Drive 24″ and 18″

    7. Multi-Meter Battery Tester

    8. Insulated Wrench Set

    9. Heavy Duty Bolt Cutter

    10. Butane Torch and Soldering Iron

    11. Hydraulic Wire Crimper 4/0




 Here are couple more resources that you might be interested in:

  • Torque Wrenches | – AF Master Sgt Miller uses a torque wrench on flight hardware. A common tool that is used by the aerospace technician is the torque wrench. The purpose of the wrench is to precisely place the required amount of torque or tightening of a nut on a bolt without under or over torquing the nut.
  • Choose the Right Fastener Material | Keeping It Together … – Choosing the best fastener material for a particular application requires analysis of several factors. Among these are the conditions under which the nuts, bolts, and screws will operate, their chemical and mechanical properties, their cost, and even their appearance. While no single material is right for every job, the characteristics of steel, stainless steel, brass, and nylon often make each the “right” choice for specific operations.
  • how to repair torque wrench | measuring tools – … – ROK Torque (tightening force) is critically important when working with any fasteners that will be subject to some kind of load. The bolt (or nut) needs to be “preloaded” with the correct amount of force, so that it will neither break nor come loose and fall off. Automakers specify torque settings for just about all their fasteners, and a torque wrench is used to achieve the requirements.

6 thoughts on “11 Uncommon Automotive Tools Required for an EV Conversion

    • Marvel,
      It’s hard to tell you the best vehicle for an electric conversion for you, it depends. You first need to determine what your requirements are that you are looking for in the end and work your way back to the beginning. For one person a Toyota Corolla would be a great car to convert, while another could be a Ford Ranger. An EV conversion can be tailored to your personal tastes, unlike buying a new electric car. What car did you have in mind for a conversion?


  • I was also thinking of using a sequential manual gearbox would it gives it more agility are other wise I would say more torque.

    • I agree that it would allow you to control the torque at the wheels which is always an issue when you are off-roading. Manual transmission would be the way to go for your Jeep, come to think about it I don’t believe I have seen an automatic Jeep.

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