Builds "The Cucumber" build. Ultimate 80-series. 1HD-FT, H152F (world's first), PTO. Titanium and carbon fiber galore. (1 Viewer)

[TurboDennis]

I got a lot of really exciting things (involving aero-space grade materials) to share about this truck in the coming weeks, so I'll try to catch up on some updates from this past season first.

This is my attempt at tackling the "entertainment" system. I wanted to upgrade the head unit, add front/rear cameras and change the front door (for now) speakers:

-Kenwood DDX9907XR head unit (among the best units on the market, as per my research)
-Kenwood 1080P dash cam. The beauty of this cam is that it's designed to work seamlessly with the Kenwood head unit. It's controlled fully from the head unit, and has built in safety features such as lane departure and collision warnings. Very nice addition to a 25 year old vehicle.
-Kenwood 720p backup cam. Highest quality, highest resolution back up cam on the market. Seamless integration into the head unit with a 720P display.

As I've been building this truck, I've developed a sort of obsessive-compulsive disorder. When i do something to it, i always ask myself: "Is it at all possible to do this better?". If the answer is "yes" or "maybe", i go back to the drawing board... This has happened a lot during this A/V upgrade. I only proceed when the answer is "definitely not".

When i do any sort of wiring, i want it to look like it was done at the factory. This, combined with my OCD, turned a rather simple head unit/cameras/speaker install into a huge ordeal... I started by removing the headliner. This gave me an opportunity to replace the roof wiring harness with one that has wires for overhead console. I installed the OEM compass sensor, and integrated the dash cam wiring into the original harness as well.

Then i proceeded to install the back up cam. I wanted to do this without making any holes in the truck. I opened up the tailgate, ran the wire through the license plate light fixture, and integrated the cam wiring into original harness (so that it runs inside the 3 factory rubber grommets into the truck's rear quarter panel. Then the wire was inserted into the floor harness.

Then i removed the dash to run both wires to the head unit in the cleanest way possible.

As for speakers.. As most of you know, it's very difficult to replace the front door speakers on the 80 without hacking things up. The problem is that the window track is directly behind the speaker, and there is very little room there to accommodate the speaker depth. OEM speakers are proprietary with impossibly shallow/low profile. Most people, when upgrading speakers, will pick a low-ish profile speaker, modify the opening in the door sheet metal to fit it, space it away from the door (so that it clears the window track), and then enlarge the opening in the door card to clear the speaker that now protrudes (and install aftermarket speaker grill on top).

I wasn't interested in doing ANY permanent modification to the truck whatsoever, so i spent many days looking for a possible solution.

The solution involved Alpine SPE-5000 speakers. They're very shallow, and 5.25" diameter. I had to trim the mounting ears and a bit of material around the speaker. Then i machined custom spacers/adapters that i epoxied to the speakers. These adapters spaced the speakers out away from the track just enough to clear (about 4mm), and allowed to speakers to mount into the factory mounting holes. The trimmed cage around the speaker allowed it to "fit" inside the factory speaker grill perfectly. While i was at it, i added sound deadening material to the inside of the doors. Lot's of work, but I'm very happy with the result. Sound is amazing, and as far as a i know, this is a first time that a true, 100% "bolts on" speaker upgrade has been done on one of these trucks.

End result:

 

[jomelo]

@TurboDennis so how do you like the head unit? I’m thinking about upgrading my current head unit. That Kenwood looks pretty nice.

 

[TurboDennis]

@TurboDennis so how do you like the head unit? I’m thinking about upgrading my current head unit. That Kenwood looks pretty nice.

Short answer: It sucks. It sucks a little bit less than other head units, but it still sucks.

Long answer: I've been buying high end head units for most of my cars for the last 20 years. And every time i buy a new one, i say to myself "OK, they must have this figured out by now." But they dont... At this point I'm convinced that there must be some secret agreement/plot among all the major head unit manufacturers to keep producing head units that lag behind the current technology by 10-15 years.

I've done a lot of research before buying this unit. It was marketed as one of the best units you can buy. It's pricy (compared to competition). Why does it still suck?
It's supposed to have the best display. Sure, it's better than competition. But a $100 cell phone has a display that is light years ahead of this unit (in terms of pixel density, brightness and responsiveness). A $100 cell phone will also have hardware that is WAY more powerful and faster. And the cell phone is dozens of times smaller in volume... Why can't a decent head unit manufacturer just take one of those $100 cell phones and put it in a double din frame? I just don't get it...
Other than crappy hardware, the interface is clunky. It just doesn't feel as seamless as a factory A/V/Nav unit in a modern car. There are redundant menus which add needless complication and clutter, controls are counter intuitive, etc. If they can't be bothered to develop a nice, clean UI, then just give us the option to run Android on the head unit...

Having said all this, it does have a few nice things going for it. Wireless android auto works great - extremely well integrated. When i get into the truck, i literally only need to press a single button on the head unit to launch Waze (or whatever nav app you prefer) through my phone (which i never have to take out from my pocket). Voice commands work good. Sound quality is great. The integration of the Kenwood dash cam is great, as I said the in the previous post. Never had any issues with the unit freezing or lagging. Display quality is finally on par with an entry level 10 year old smartphone (which can't be said about competing head units- those are about 20 years behind).

 

[jomelo]

Short answer: It sucks. It sucks a little bit less than other head units, but it still sucks.

Long answer: I've been buying high end head units for most of my cars for the last 20 years. And every time i buy a new one, i say to myself "OK, they must have this figured out by now." But they dont... At this point I'm convinced that there must be some secret agreement/plot among all the major head unit manufacturers to keep producing head units that lag behind the current technology by 10-15 years.

I've done a lot of research before buying this unit. It was marketed as one of the best units you can buy. It's pricy (compared to competition). Why does it still suck?
It's supposed to have the best display. Sure, it's better than competition. But a $100 cell phone has a display that is light years ahead of this unit (in terms of pixel density, brightness and responsiveness). A $100 cell phone will also have hardware that is WAY more powerful and faster. And the cell phone is dozens of times smaller in volume... Why can't a decent head unit manufacturer just take one of those $100 cell phones and put it in a double din frame? I just don't get it...
Other than crappy hardware, the interface is clunky. It just doesn't feel as seamless as a factory A/V/Nav unit in a modern car. There are redundant menus which add needless complication and clutter, controls are counter intuitive, etc. If they can't be bothered to develop a nice, clean UI, then just give us the option to run Android on the head unit...

Having said all this, it does have a few nice things going for it. Wireless android auto works great - extremely well integrated. When i get into the truck, i literally only need to press a single button on the head unit to launch Waze (or whatever nav app you prefer) through my phone (which i never have to take out from my pocket). Voice commands work good. Sound quality is great. The integration of the Kenwood dash cam is great, as I said the in the previous post. Never had any issues with the unit freezing or lagging. Display quality is finally on par with an entry level 10 year old smartphone (which can't be said about competing head units- those are about 20 years behind).

That is really good to know. Thanks!

 

[thelal]

..like it was done at the factory. ..

impressive amount of work to make it fit "factory style" with the wiring etc.

 

[man0fsteel]

impressive amount of work to make it fit "factory style" with the wiring etc.

Agreed! I put in a Pioneer head unit and replaced a bunch of the stock speakers to get my audio system sounding a bit better (with more functionality like bluetooth etc). But as I mentioned in another build thread, I miss having steering wheel mounted controls for the audio system. I found this set:



but I'm really looking for controls that have a roller ball or wheel that allows me to adjust the volume. Have you looked into adding steering wheel controls?

Cheers,

MoS

 

[TurboDennis]

impressive amount of work to make it fit "factory style" with the wiring etc.

Thank you! I don't go into too much detail about the wiring in this thread, because it would probably bore most people (and i don't want people thinking that im crazy).. But the wiring on this truck really turned into an obsession of sorts.
When i do any sort of wiring, my standard is to make it virtually impossible to distinguish from a factory job. For example:
- Any factory option that my truck wasn't originally wired for is wired EXACTLY as it would be done at the factory - correct color coded Toyota wires, routing as per original wiring diagram, correct Yazaki terminals crimped onto the added wires and inserted into original connectors (into proper slots).
- All added wires are inserted into corresponding factory looms.
- I even use correct color electrical tape for various places as it would be done at the factory.
- For any additional (non OEM) wiring, i use Toyota (Yazaki) connectors, and add the details about it into "notes" section of the wiring diagram.

There is absolutely no need for this sort of detail, but doing it gives me some strange form of satisfaction....

Agreed! I put in a Pioneer head unit and replaced a bunch of the stock speakers to get my audio system sounding a bit better (with more functionality like bluetooth etc). But as I mentioned in another build thread, I miss having steering wheel mounted controls for the audio system. I found this set:



but I'm really looking for controls that have a roller ball or wheel that allows me to adjust the volume. Have you looked into adding steering wheel controls?

Cheers,

MoS

Steering wheel controls is definitely on my list of things to do in the near future. I try to avoid posting things here until they're finished, but since you brought it up, I'll share some details.

As with everything else on this truck, i wanted steering wheel controls to look as OEM as possible. So various "add on" controls such as the ones you posted are out of question. There are tons of "period appropriate" Toyota steering wheels (from 2000's) that have controls on them, such as this:

But almost all of them have the same problem - they use a dual stage airbag, which would not work with the 80-series single stage system. I didn't want to loose the airbag, so i started doing research. Turned out, there was, in fact, a Toyota with controls on the wheel AND a single stage airbag that would be compatible with our system. After actively searching for over a year, i finally found this elusive airbag this past fall:

It's a direct swap into any Toyota wheel of the same style as the previous pic. To make it work, i would just need a new clock spring that has the extra wires in it for all the controls (volume, radio, Bluetooth, and possibly other functions). From the research that I've done, modifying another Toyota clock spring to fit shouldn't be too difficult. I was originally planning to do this this winter, but i have too many other things I'm working on right now, so it'll probably have to wait until later in the year.

 

[TurboDennis]

Here are a few more teasers of some cool/unique things I'm currently working on, hoping to finish in time for the big "overlanding" trip to South Western US that i got planned for this May.

Custom CATL LiFePO4 prismatic battery pack. 302AH capacity (yes, you read that right). This will go into the original passenger side battery box. It's nearly a perfect fit.

Grade 5 Titanium seamless tubing. This stuff is INCREDIBLY difficult to find in tube form (in Grade 5). This will be used for rock sliders, and drawer/sleeping platform frame.

Garrett FMIC core, and grade 9 Titanium seamless tube for IC piping. Since no grade 9 Ti mandrel bends exist (to the best of my knowledge), this will be a pie-cut extravaganza.
Garrett cores are supposed to be light years ahead in performance compared to cheap Chinese cores that are used on most (All?) intercoolers commercially available for LC.

70 meter long (1M wide) roll of Mitsubishi carbon fiber fabric. Not pictured is aluminum honeycomb (to make CF/Al honeycomb sandwich panels). This, along with the Gr 5 titanium frame, will be used to make the most advanced drawer/sleeping platform that has ever existed.

 

[FMC80]

Thank you! I don't go into too much detail about the wiring in this thread, because it would probably bore most people (and i don't want people thinking that im crazy).. But the wiring on this truck really turned into an obsession of sorts.
When i do any sort of wiring, my standard is to make it virtually impossible to distinguish from a factory job. For example:
- Any factory option that my truck wasn't originally wired for is wired EXACTLY as it would be done at the factory - correct color coded Toyota wires, routing as per original wiring diagram, correct Yazaki terminals crimped onto the added wires and inserted into original connectors (into proper slots).
- All added wires are inserted into corresponding factory looms.
- I even use correct color electrical tape for various places as it would be done at the factory.
- For any additional (non OEM) wiring, i use Toyota (Yazaki) connectors, and add the details about it into "notes" section of the wiring diagram.

There is absolutely no need for this sort of detail, but doing it gives me some strange form of satisfaction....




Steering wheel controls is definitely on my list of things to do in the near future. I try to avoid posting things here until they're finished, but since you brought it up, I'll share some details.

As with everything else on this truck, i wanted steering wheel controls to look as OEM as possible. So various "add on" controls such as the ones you posted are out of question. There are tons of "period appropriate" Toyota steering wheels (from 2000's) that have controls on them, such as this:
View attachment 2947763
But almost all of them have the same problem - they use a dual stage airbag, which would not work with the 80-series single stage system. I didn't want to loose the airbag, so i started doing research. Turned out, there was, in fact, a Toyota with controls on the wheel AND a single stage airbag that would be compatible with our system. After actively searching for over a year, i finally found this elusive airbag this past fall:

View attachment 2947766

It's a direct swap into any Toyota wheel of the same style as the previous pic. To make it work, i would just need a new clock spring that has the extra wires in it for all the controls (volume, radio, Bluetooth, and possibly other functions). From the research that I've done, modifying another Toyota clock spring to fit shouldn't be too difficult. I was originally planning to do this this winter, but i have too many other things I'm working on right now, so it'll probably have to wait until later in the year.

Here are a few more teasers of some cool/unique things I'm currently working on, hoping to finish in time for the big "overlanding" trip to South Western US that i got planned for this May.

Custom CATL LiFePO4 prismatic battery pack. 302AH capacity (yes, you read that right). This will go into the original passenger side battery box. It's nearly a perfect fit.
View attachment 2947776
Grade 5 Titanium seamless tubing. This stuff is INCREDIBLY difficult to find in tube form (in Grade 5). This will be used for rock sliders, and drawer/sleeping platform frame.
View attachment 2947777
Garrett FMIC core, and grade 9 Titanium seamless tube for IC piping. Since no grade 9 Ti mandrel bends exist (to the best of my knowledge), this will be a pie-cut extravaganza.
Garrett cores are supposed to be light years ahead in performance compared to cheap Chinese cores that are used on most (All?) intercoolers commercially available for LC.
View attachment 2947778
70 meter long (1M wide) roll of Mitsubishi carbon fiber fabric. Not pictured is aluminum honeycomb (to make CF/Al honeycomb sandwich panels). This, along with the Gr 5 titanium frame, will be used to make the most advanced drawer/sleeping platform that has ever existed.

View attachment 2947779

I literally have no words for you. This is incredible (understatement). Looking forward to your progress!

 

[man0fsteel]

Steering wheel controls is definitely on my list of things to do in the near future. I try to avoid posting things here until they're finished, but since you brought it up, I'll share some details.

As with everything else on this truck, i wanted steering wheel controls to look as OEM as possible. So various "add on" controls such as the ones you posted are out of question. There are tons of "period appropriate" Toyota steering wheels (from 2000's) that have controls on them, such as this:
View attachment 2947763
But almost all of them have the same problem - they use a dual stage airbag, which would not work with the 80-series single stage system. I didn't want to loose the airbag, so i started doing research. Turned out, there was, in fact, a Toyota with controls on the wheel AND a single stage airbag that would be compatible with our system. After actively searching for over a year, i finally found this elusive airbag this past fall:

View attachment 2947766

It's a direct swap into any Toyota wheel of the same style as the previous pic. To make it work, i would just need a new clock spring that has the extra wires in it for all the controls (volume, radio, Bluetooth, and possibly other functions). From the research that I've done, modifying another Toyota clock spring to fit shouldn't be too difficult. I was originally planning to do this this winter, but i have too many other things I'm working on right now, so it'll probably have to wait until later in the year.
[/QUOTE]

Dang! I didn't even think about this kind of solution!! I'm not sure I'd have the gumption to find these parts, but could you shed some light on the part numbers for the wheel and the single stage airbag? Not to jump further down the rabbit hole, but what are the chances one could convert our airbag into a dual stage airbag?

Never mind...forget I even asked the question LOL!

That bed system...I can't even imagine dreaming up such a thing. Titanium...just wow. I am in awe sir.

 

[thelal]

Custom CATL LiFePO4 prismatic battery pack. 302AH capacity --- wow ; for the capacity and fits in 2nd battery tray. Very interested as well as the Steering controls and the .. and the ...

 

[FJRanger]

Here are a few more teasers of some cool/unique things I'm currently working on, hoping to finish in time for the big "overlanding" trip to South Western US that i got planned for this May.

Custom CATL LiFePO4 prismatic battery pack. 302AH capacity (yes, you read that right). This will go into the original passenger side battery box. It's nearly a perfect fit.
View attachment 2947776

Really interested in the LifoPO4 cells in the engine compartment. What do you have planned for dealing with the temperature extremes under the hood? Or am I overthinking it? Have thought about the doing something similar, but keep getting held up on the temp. That said, I but don't have any data supporting either side.

 

[WiscoPat]

As a recent owner of my first 80 series, a 95 HDJ81 with a 1HD-FT, this is inspirational as hell. Appreciate the write-up, and hope you enjoy this work soon enough!

 

[TurboDennis]

Dang! I didn't even think about this kind of solution!! I'm not sure I'd have the gumption to find these parts, but could you shed some light on the part numbers for the wheel and the single stage airbag? Not to jump further down the rabbit hole, but what are the chances one could convert our airbag into a dual stage airbag?
Never mind...forget I even asked the question LOL!

That bed system...I can't even imagine dreaming up such a thing. Titanium...just wow. I am in awe sir.

The airbag has to be from a 2003-2004 Tundra or Sequoia. These models had the single stage airbag up until 2004, and had the optional (but VERY RARE) steering wheel controls starting in 2003. As for steering wheels, most of Toyota's from 2000's used this style of steering wheel, so it should be very easy to find one at any scrap yard.

There is absolutely no feasible way to convert our system to dual stage. However, it may be possible to convert a dual stage airbag into single stage. The explosive charge in the airbag is removable, and i just happened to notice that the bolt pattern on the charge is the same for both single and dual stage Toyota airbags, and it looks like they could be swapped. The airbag may or may not work properly after this, so I'm in no way endorsing this.

Really interested in the LifoPO4 cells in the engine compartment. What do you have planned for dealing with the temperature extremes under the hood? Or am I overthinking it? Have thought about the doing something similar, but keep getting held up on the temp. That said, I but don't have any data supporting either side.

Temperature is a non-issue in 80-series. The factory battery boxes are completely isolated from the rest of the engine bay via a set of rubber seals and foam insulators (which are probably missing on most trucks at this point, but can easily be replaced). Both battery boxes are also vented with fresh outside air through the radiator mount. If you touch the battery after a long drive, you'll notice that it's fairly cool (unlike the rest of the things under the hood). Im willing to bet that the battery box never gets as hot as the inside of the truck when you leave it out in the sun on a hot summer day.

 

[jellis]

Why are you bothering with AL honeycomb? That's only necessary for high-temp applications. These are cheaper/easier panels to work with (fiberglass skins over plastic honeycomb and it looks like they can fill with insulation now would would really help with road noise), I built a camper out of the non-filled version:

Composite Laminated Panels - Carbon-Core Corporation

Carbon-Core lightweight panels are wet laminated, molded products and suitable for structural use in marine construction, trailer and camper sidewalls, moisture and chemical resistant areas.

www.carbon-core.com

 

[TurboDennis]

Why are you bothering with AL honeycomb? That's only necessary for high-temp applications. These are cheaper/easier panels to work with (fiberglass skins over plastic honeycomb and it looks like they can fill with insulation now would would really help with road noise), I built a camper out of the non-filled version:

Composite Laminated Panels - Carbon-Core Corporation

Carbon-Core lightweight panels are wet laminated, molded products and suitable for structural use in marine construction, trailer and camper sidewalls, moisture and chemical resistant areas.

www.carbon-core.com

View attachment 2969684

CF is stronger and stiffer than fiberglass, and AL honeycomb core is also stronger than plastic (or even Aramid) cores. So CF/AL sandwich panels offer the highest possible specific strength and specific stiffness. Lightest possible weight is my main design criteria.

 

[jellis]

Lightest possible weight would be plastic not AL. Finished 1" thick plastic FRP's come in at ~0.8lbs/ft2. Plastic also reduces road noise a lot better than AL. More importantly for most people, it's also ~10% the cost!

How do you plan on the DIY lamination of CF to the panels? That's a non-trivial undertaking.

 

[TurboDennis]

Lightest possible weight would be plastic not AL. Finished 1" thick plastic FRP's come in at ~0.8lbs/ft2. Plastic also reduces road noise a lot better than AL. More importantly for most people, it's also ~10% the cost!

How do you plan on the DIY lamination of CF to the panels? That's a non-trivial undertaking.

Sandwich panels made with AL cores will have a higher strength to weight ratio than plastic cores. Plastic core may be a little lighter, but AL is significantly stronger, so the finished panel can be thinner and lighter at the same strength.

These panels will be used in interior only, so road noise is not a factor.

As far as cost, you're right - using CF/AL honeycomb panels for an application like this is pretty ridiculous, and may be hard to justify for most people. However, im not too concerned with the price because it's a pretty small, one off project. Final build cost for me is going to be similar (likely lower) to what people pay for premium "off the shelf" drawer systems that are made from PLYWOOD.

I've done a lot of research on this topic. There is still more to do. Working with advanced composites is an extra skill that i want to add to my "toolbox". So i look at this particular project as an opportunity to learn/practice this craft. This is my main reasoning for choosing these materials.

From the research that i did so far, laminating CF to AL is easily done using resins that are specifically designed for this exact combination. Lay a CF panel on the bench, brush resin on it, position AL core on it, place another CF panel on top (dry), vacuum bag it and pull vacuum to press it down. Wait for it to cure. Then turn over and bond the second CF panel to the other side using the same technique.

 

[TurboDennis]

Really behind on updating this thread... Will try to fix that in the coming weeks.

Unfortunately i was not able to finish the titanium and carbon fiber goodies in time for the Utah trip we did in May, so those projects got pushed to winter.

But i did do some other interesting things in time.. Like the auxiliary battery system for example which im excited to share bellow.

I've been planning this mod for quite some time. Im running the 12V (1HD-FTE) starter on my truck, so the second battery tray was not being utilized. I definitely wanted to go lithium for extra capacity, and i assumed that buying one was my only option and i was close to pulling the trigger. But then i saw a video of a guy on YouTube opening up one of these premium Li batteries. Less than half of the case's volume was actually used by cells. The case was half empty, and the cells they used were cylindrical (so lots of wasted space in between). I immediately realized that there must be a better way... After doing a whole bunch of research, i determined that 4 prismatic (naturally square) 3.4V sells of the common size will JUST fit inside the factory battery box. Just barely..

I bought 4 of these CATL cells, 302AH capacity (same company that makes them for Tesla nowadays). Then the work on case design/build began. These lithium cells require a battery management system (BMS). I wanted the case to be self contained (to include BMS), AND i wanted to use the factory battery tie-downs to secure it. Another challenge was that case had to prevent the cells from expanding during use (which they are known to do). This mean that the case's internal dimensions had to be VERY precise. I've decided that building it from Aluminum would be the best plan.

Each of the 4 sides, and the bottom were individually machined to precise tolerances (under 0.25mm).

Then the case was TIG-welded together. The inside was lined with UHMWPE (courtesy of McMaster Carr.. great source for this sort of stuff) to prevent a possible short. Tabs on the sides were added for factory battery tie-downs.

The BMS that i selected for this sits on top of the battery pack, between the terminals. So it adds zero volume to the battery pack. It's riveted to the lid.

Final touch was the RedArc BCDC1250D charger. Originally the plan was to install it in front of the main battery (there is lots of room there). But then i noticed a small "pocket" in the inner fender inside the aux battery tray. By pure luck, the charger happened to fit that pocket almost perfectly. You want the charger to be as close as possible to lithium batteries, so this worked out great.

Overall, I'm really happy with how this project turned out. It's absolutely crazy how well it fits - as if the factory battery box was built by Toyota for this exact battery pack. There is 1-2mm clearance on all sides of the pack. Including between the lid and the hood. The BMS has full Bluetooth controls and monitoring via phone app. BMS also has an external temperature sensor. The temperature inside the battery pack NEVER went up more than 1-2 degrees above ambient air temperature during driving in Utah/Arizona in late May, so mounting the lithium battery inside the engine bay is a non-issue (due to superb, fully isolated, vented design of the OEM battery box.)

I have been using this setup for 4 months now, including a 9000km trip to Utah in May and a couple of shorter camping trips. Zero issues or complaints. A typical lead-acid Gr27 battery has about 50AH of usable capacity. An off-the-shelf lithium battery of the same size has about 100AH. My pack has 302AH of actual usable capacity, which is absolutely INSANE.

During our trip to Utah, i turned the charging off completely for a week (done via phone app). After a week of running a fridge/freezer, lights and music during camping, and charging various devices every evening it was down to 83% capacity. Having this much battery capacity will allow me to run things that were never considered to be possible on a small overlanding rig - such as battery powered hotplate for cooking, water heater, and portable air conditioner. I have a lot of really cool ideas that I'm going to work on for next season...

 

[mudandrock]

Really behind on updating this thread... Will try to fix that in the coming weeks.

Unfortunately i was not able to finish the titanium and carbon fiber goodies in time for the Utah trip we did in May, so those projects got pushed to winter.

But i did do some other interesting things in time.. Like the auxiliary battery system for example which im excited to share bellow.

I've been planning this mod for quite some time. Im running the 12V (1HD-FTE) starter on my truck, so the second battery tray was not being utilized. I definitely wanted to go lithium for extra capacity, and i assumed that buying one was my only option and i was close to pulling the trigger. But then i saw a video of a guy on YouTube opening up one of these premium Li batteries. Less than half of the case's volume was actually used by cells. The case was half empty, and the cells they used were cylindrical (so lots of wasted space in between). I immediately realized that there must be a better way... After doing a whole bunch of research, i determined that 4 prismatic (naturally square) 3.4V sells of the common size will JUST fit inside the factory battery box. Just barely..

I bought 4 of these CATL cells, 302AH capacity (same company that makes them for Tesla nowadays). Then the work on case design/build began. These lithium cells require a battery management system (BMS). I wanted the case to be self contained (to include BMS), AND i wanted to use the factory battery tie-downs to secure it. Another challenge was that case had to prevent the cells from expanding during use (which they are known to do). This mean that the case's internal dimensions had to be VERY precise. I've decided that building it from Aluminum would be the best plan.

Each of the 4 sides, and the bottom were individually machined to precise tolerances (under 0.25mm).
View attachment 3104701
Then the case was TIG-welded together. The inside was lined with UHMWPE (courtesy of McMaster Carr.. great source for this sort of stuff) to prevent a possible short. Tabs on the sides were added for factory battery tie-downs.
View attachment 3104702


The BMS that i selected for this sits on top of the battery pack, between the terminals. So it adds zero volume to the battery pack. It's riveted to the lid.
View attachment 3104703


Final touch was the RedArc BCDC1250D charger. Originally the plan was to install it in front of the main battery (there is lots of room there). But then i noticed a small "pocket" in the inner fender inside the aux battery tray. By pure luck, the charger happened to fit that pocket almost perfectly. You want the charger to be as close as possible to lithium batteries, so this worked out great. (Pardon the dusty engine bay)
View attachment 3104741
Overall, I'm really happy with how this project turned out. It's absolutely crazy how well it fits - as if the factory battery box was built by Toyota for this exact battery pack. There is 1-2mm clearance on all sides of the pack. Including between the lid and the hood. The BMS has full Bluetooth controls and monitoring via phone app. BMS also has an external temperature sensor. The temperature inside the battery pack NEVER went up more than 1-2 degrees above ambient air temperature during driving in Utah/Arizona in late May, so mounting the lithium battery inside the engine bay is a non-issue (due to superb, fully isolated, vented design of the OEM battery box.)

I have been using this setup for 4 months now, including a 9000km trip to Utah in May. A typical lead-acid Gr27 battery has about 50AH of usable capacity. An off-the-shelf lithium battery of the same size has about 100AH. My pack has 302AH of actual usable capacity, which is absolutely INSANE.

During our trip to Utah, i turned the charging off completely for a week (done via phone app). After a week of running a fridge/freezer, lights and music during camping, and charging various devices every evening it was down to 83% capacity. Having this much battery capacity will allow me to run things that were never considered to be possible on an overlanding rig - such as battery powered hotplate for cooking, water heater, and portable air conditioner. I have a lot of really cool ideas that I'm going to work on for next season...

Great Scott! No flex capacitor?