electric 720....

[bratsun]

long time lurker, long time datsun fan.

 

i have 2 720's right now. a beater 1983 datsun sd25 diesel, and a 1986 nissan 720 king cab.

 

i found the king cab with a blown motor, and mint (for a datsun) body. scooped it up and began electrifying on the side of the road.

 

 

got a nissan leaf motor, inverter, and charger for cheap, they stack on top of each other. sadly the charger is too big and doesn't fit under the hood.

so used a charger unit of a outlander PHEV. its a nice small little box!

 

i make parts for doing ev conversions with salvaged OEM parts.... like nissan leaf motors and tesla drive units.

 

so i already have adapter plates for matting the leaf motor to the stock manual 5speed! which is arguably the hardest part in a conversion.

 

no clucth, direct drive to the trans.

 

 

bolt the motor up. some scrap steel for moto mounts. next!

 

battery is from a chevy volt, it was 300$ pretty beat up but works for now.

 

strapped it down in the bed. 

 

wired up the HV, and using a opensoruce controller to talk to the battery and the motor over canbus.

 

used a throttle pedal position senor from some honda, which allowed me to use the 720's accelerator pedal cable.

 

we doin one wheel peals all day!

 

full write up here: https://bratindustries.net/electric-datsun-720-pickup/

 

ill start dumping photos of the build, as theres lots more todo, brake assist, heat, power steering, new batteries, wiring clean up,  suspension, etc 

 

 

[datzenmike]

Why the transmission? Electric motors make maximum torque at zero RPM. The Leaf didn't have gears did it? direct drive

[fiveoneO]

I'm also curious why there's no clutch. I've seen quite a few EV swaps and they never use a clutch, why is that?

[bratsun]

20 hours ago, datzenmike said:

Why the transmission? Electric motors make maximum torque at zero RPM. The Leaf didn't have gears did it? direct drive

heres a old graph from this gen of leaf motor/inverter set up (80kw) you can get peak 200kw out these motors maybe more with some cooling mods.

the leaf has a single ratio gearbox 8:1 from the motor to the diff. its a trans axle, and fwd. its also a stacked architecture, so the gearbox, motor, inverter, and charger make a full drive train stack in the front of a leaf.

really great for swaping fwd cars like an old vw rabbit...which i have done.

 

but awkward for a SA RWD truck.  the quickest and simplest is matting to the original 5 speed. i also get the benefit of all the gears 🙂  i dont want to hack up the truck, so doing everything in a "bolt-on" fashion.

 

2 hours ago, fiveoneO said:

I'm also curious why there's no clutch. I've seen quite a few EV swaps and they never use a clutch, why is that?

 

 

few reason why i went with no clutch: 

 

- the bearing in the leaf motor are not designed to support the axial loads from a clutch and flywheel, making a adapter plate with a bearing support and a flanged coupler is just adding complexity 

 

-the add additional weight of the flywheel/clutch will reduce power output, and add weight... the goal is to add lightness for range and speed 😉 

 

-i almost never need to shift gears. 2nd gear or 3rd gear is all i need. i also like using R with the trany insted of spin the motor the other direction.

 

The motor can rev to over 10k rpm... this may be a bearing limitation or the stator starts to become unstable. not sure

 

when hauling stuff 2nd gear pulls 800lbs like nothing. its an Absolut rocket of a truck. it needs and LSD badly.

[datzenmike]

8:1 before the differential? what's the differential ratio?

 

'85 KC 2wd would be 3.545 rear differential. This would be added to the 8:1 on the motor gearbox?

[bratsun]

2 hours ago, datzenmike said:

8:1 before the differential? what's the differential ratio?

 

'85 KC 2wd would be 3.545 rear differential. This would be added to the 8:1 on the motor gearbox?

no thats the final drive of the leaf gearbox. roughly 8:1 from the motor to the axles. heres a photo of inside the leaf gearbox. beefy and simple. nismo japan actually makes an lsd for these funny enough!

 

 

Here's what the leaf motor looks like with out the inverter on top. there are 3 different inverter available 80kw, 110kw, and 160kw. All mate to the same motor (em57), so if you want more power, you can just get a higher out put inverter.

or replace the logic board inside the 80kw inverter with a new board...and have full control over the IGBT's (fancy transistors) and push about 140kw out of the stock 80kw inverter. fun times! 

im not using the leaf gearbox, so i just mated this straight to the 5 speed. so its just the stock trucks gearing.

 

i have a hunch that the trans was swapped out to something else, as i got this truck some a drift kid. The truck had a blown motor, balled rear tires and the speedo was not connected.  but if it is the stock fs5w71 the following ratios would be: 3.321, 1.902, 1.308, 1:1, .833 ?

 

with the 3.545 rear end  2nd gear would result in 6.743, and 3rd would be 4.637. dose this sound right to you?

 

 

 

 

[RyanC]

Love this!!  Brother inlaw has put a tesla unit in the back of his 260z, wiring up batteries etc in the front etc and then onto the controller and charging, slowly but surely coming together.   I wondered about the gearing just select a gear and use it, nice.

[EDM620]

Personally not an EV guy but sure as hell am interested in this build. 

[datzenmike]

Transmission is consistent to what an '85 would have.

 

What does the Leaf weigh??? what tires are on the Leaf as a taller truck tire will lower the overall ratio the Leaf motor is used to. Normally 8 to 1 in the leaf you would want a similar ratio probably even lower in a heavier truck.

 

First and differential would be 11.77 but that would be hell on first gear or any gear other than 4th. All power and torque goes through the countershaft and it's bearings except 4th which is straight through. Using first at all times? First at 50 MPH ? Engine RPMs would be over 7,600. At 70 MPH over 10,600 RPMs. Bearings are splash lubricated, will it even get oil spinning that fast? 

[Dguy210]

15 minutes ago, datzenmike said:

Transmission is consistent to what an '85 would have.

 

What does the Leaf weigh??? what tires are on the Leaf as a taller truck tire will lower the overall ratio the Leaf motor is used to. Normally 8 to 1 in the leaf you would want a similar ratio probably even lower in a heavier truck.

 

First and differential would be 11.77 but that would be hell on first gear or any gear other than 4th. All power and torque goes through the countershaft and it's bearings except 4th which is straight through. Using first at all times? First at 50 MPH ? Engine RPMs would be over 7,600. At 70 MPH over 10,600 RPMs. Bearings are splash lubricated, will it even get oil spinning that fast? 

 

On 1/11/2025 at 10:58 AM, bratsun said:

long time lurker, long time datsun fan.

 

i have 2 720's right now. a beater 1983 datsun sd25 diesel, and a 1986 nissan 720 king cab.

 

i found the king cab with a blown motor, and mint (for a datsun) body. scooped it up and began electrifying on the side of the road.

 

 

got a nissan leaf motor, inverter, and charger for cheap, they stack on top of each other. sadly the charger is too big and doesn't fit under the hood.

so used a charger unit of a outlander PHEV. its a nice small little box!

 

i make parts for doing ev conversions with salvaged OEM parts.... like nissan leaf motors and tesla drive units.

 

so i already have adapter plates for matting the leaf motor to the stock manual 5speed! which is arguably the hardest part in a conversion.

 

no clucth, direct drive to the trans.

 

 

bolt the motor up. some scrap steel for moto mounts. next!

 

battery is from a chevy volt, it was 300$ pretty beat up but works for now.

 

strapped it down in the bed. 

 

wired up the HV, and using a opensoruce controller to talk to the battery and the motor over canbus.

 

used a throttle pedal position senor from some honda, which allowed me to use the 720's accelerator pedal cable.

 

we doin one wheel peals all day!

 

full write up here: https://bratindustries.net/electric-datsun-720-pickup/

 

ill start dumping photos of the build, as theres lots more todo, brake assist, heat, power steering, new batteries, wiring clean up,  suspension, etc 

 

 

Very interesting... gives me ideas. 

 

Leaf is about 3300 lbs. Heavy car, but the weight is all down low so handles very well, motor is ~105 hp and actually quite peppy. Tire size is 205/55R16 or 215/50R17 low rolling resistance depending on trim level. 

 

We actually have a Leaf and the ~24kw battery is a bit under-ranged and as it ages (we have 115K on it) the range is going down.

 

So the idea of some point in the future when the range drops to mostly unusable and it is disposable putting in a cheap AND larger battery pack and getting more power out of the motor is very interesting. I have also had some ideas of putting a propane generator on a cargo rack (or say in the bed of a pickup) on the back to charge it while it runs, which it seems like might be way more doable with an aftermarket opensource controller (or just switching between packs).

 

 

 

Edited Monday at 02:49 AM by Dguy210

[datzenmike]

OK 720 is lighter than that. that's 24.88" and 25.46" the truck are about 26" so a slight gearing loss but not much.

 

Second gear at 6.73 overall gearing may be alright as the 720 is lighter assuming the electric motor is comparable to a Z24? 300 pounds???

 

Tommy what does your '85 2wd weigh????

[Dguy210]

2 hours ago, datzenmike said:

OK 720 is lighter than that. that's 24.88" and 25.46" the truck are about 26" so a slight gearing loss but not much.

 

Second gear at 6.73 overall gearing may be alright as the 720 is lighter assuming the electric motor is comparable to a Z24? 300 pounds???

 

Tommy what does your '85 2wd weigh????

 

Motor alone weighs way less, 123 lbs without transaxle or brackets. On paper horsepower (107hp) is about the same as a Z24 but seat of the pants it has a lot more get up and go. 

Edited Monday at 06:10 AM by Dguy210

[datzenmike]

So 720 would be at least 300 pounds lighter. I've asked Tommy to chime in with 720 weight. So then second gear may be alright with 6.23 overall ratio down from the 8.1 Leaf ratio.

[bratsun]

15 hours ago, datzenmike said:

Transmission is consistent to what an '85 would have.

 

What does the Leaf weigh??? what tires are on the Leaf as a taller truck tire will lower the overall ratio the Leaf motor is used to. Normally 8 to 1 in the leaf you would want a similar ratio probably even lower in a heavier truck.

 

First and differential would be 11.77 but that would be hell on first gear or any gear other than 4th. All power and torque goes through the countershaft and it's bearings except 4th which is straight through. Using first at all times? First at 50 MPH ? Engine RPMs would be over 7,600. At 70 MPH over 10,600 RPMs. Bearings are splash lubricated, will it even get oil spinning that fast? 

note i only have the leaf motor and inverter. nothing else from the leaf.

 

i never use 1st. its way to much to handle. too much instant torque. 

 

if im nipping around town ill use 2nd, its rocket in 2nd. if not wanting to beat everyone on the road, 3rd gear/ or if im hwy driving. 

 

it will move in from a stand still in 4th or 5th.

 

i suspect it has a different transmission in it. im updating some of the coolant ports, so ill have the inverter off this week and will have a better view of the gearbox.

 

[bratsun]

being i just got the drive train and charging running for a bare bones system and it worked great all summer, theres 3 additional areas im now starting to work on:

-brake assist

-heat

-power steering

 

 

for brake assist i went with an electric brake booster (ibooster) out of a tesla model y. i got it for cheap....100$ cad.  full write up here

id rather not have a vacuum pump running and making noise, and just upgrade to something stronger. 

 

trucks stock MC was 14/15" bore, the ibooster from the tesla has a 1" bore. perfect. and loads more brake assist. just needed to add a 10lbs residual valve for the rear drums. 

 

M12x1.5 bubble x M10x1.5 inverter flare adapters for the original hardlines, new firewall bracket, M8 x M10 female to male coupling for the push rod and thats it! 

much better braking. smooth and consistent. I also get the brake pedal pressure data over the canbus from the ibooster, so ill use that data to increases regen in the motor.

 

 

next is power steering. 

 

i picked up a mazda epas pump for 80$ off marketplace, delivered! 

using the original power steering lines and 3 fittings later...

 

 

the original banjo off the 720 pump is a bigger JIC fitting and the mazda pump banjo is a M14 JIS. 

 

so JICxJIS + jis union + M14 banjo. beats having to get a custom line made.

 

there are easier epas pumps out there, such as the volvo ones, to get running. this one needs engine rpm over the canbus, and steering wheel angle via a analog input. but found some code on github to run it and had a few Arduinos laying around so this is the cheapest to just getting it all working.

 

honestly dont really like this approach as the pump is 20 some odd pounds, takes up space in the engine bay, and is noisy. + needs hydraulic fluid. 

 

may do a electric column swap from a prius. looks like there are enough splined rag joints and ujoints available to coble something together without having to weld the steering column shafts to make it work. 

 

my sd25 has a manual steering box so i might swap that in and do the prius column, and put this in the diesel. diesel gets PS and no extra power loss!

 

[datzenmike]

It's a Z series transmission. They only came in mid ratio, 3.321 first or wide ratio 3.592 first. Fourth is always 1 to 1.

[bratsun]

20 hours ago, datzenmike said:

It's a Z series transmission. They only came in mid ratio, 3.321 first or wide ratio 3.592 first. Fourth is always 1 to 1.

whats 2n and 3rd? 

[Icehouse]

Rad build!   I helped my brother build this car before there was any electric option available.  He sold it years ago but is about to get a 3 wheel city vehicle from 2008 that needs a rebuild.  We upgraded it to a Volt battery eventually.  Before that it had some of those Chinese square lithium batteries.    

 

 

 

What do you use for a BMS?  Also what ECU do you use to control all the CAN messages to make everything work happily together?  A good heater was always hard to figure out.  What's your plan for that? 

[datzenmike]

2 hours ago, Icehouse said:

 

What do you use for a BMS?  Also what ECU do you use to control all the CAN messages to make everything work happily together?  A good heater was always hard to figure out.  What's your plan for that? 

 

 

 

 

 

3 hours ago, bratsun said:

whats 2n and 3rd? 

 

Mid Ratio........ Wide Ratio (Diesel and Cab/Chassis models)

1st..... 3.321...... 3.592

2nd... 1.092...... 2.057

3rd.... 1.308...... 1.361

4th.... 1.000...... 1.000

5th.... 0.833...... 0.813

 

There is a close ratio 5 speed, but only used on the '80-'83 280zx Non Turbo.

[bratsun]

8 hours ago, Icehouse said:

What do you use for a BMS?  Also what ECU do you use to control all the CAN messages to make everything work happily together?  A good heater was always hard to figure out.  What's your plan for that? 

 

well i first had the chevy volt pack in it, the build that i drove all summer was no more than 2500cad all in....but i used the stock volt bms. talked to the slave modules over can with simpbms running on a teensy 3.2 https://github.com/Tom-evnut/AmperaBattery

 

but im now assembling half a pack from a 77kwh ioniq 5. so about 38kwh battery. 96s, 400v. i will likely use the original slave modules as it is a generic LTC cell monitoring chip inside and there has been some hacking done to figure them out.  ill probly get 250km/hwy out of this pack based off what im seeing with the heavly used votl pack

i have so fun aero mods for the future 😉 

 

the VCU is the opensoruce zombieverter https://openinverter.org/wiki/ZombieVerter_VCU 

 

i have a alternative build thread on the openinverter forum...the defacto ev hacking/building forum with more technical details

 

i just got a vw ID.4 PTC heater, it runs on HV and is controlled via lin, the code for the zombieverter to run it is not official yet, still testing. but for you computer nerds here ya go: https://github.com/damienmaguire/Stm32-vcu/compare/master...Tom-evnut:Stm32-vcu:Heater-Update-12-2024

 

the unit is pretty big compared to the original heater core, and after some serious cutting... i have it fitting. just need to weld up a aluminum bracket and itll be mounted.

 

the zombiverter is pretty powerful. it just has a bunch of general purpose i/o and coms, so if you figure out the communication protocall for any device really, you can get it running with the zombie.

 

the list of devices (motors, heaters, pumps, dash's, chargers, dcdc converters, etc) is starting to get big and more and more keep getting added 

 

 

6 hours ago, datzenmike said:

 

 

Mid Ratio........ Wide Ratio (Diesel and Cab/Chassis models)

1st..... 3.321...... 3.592

2nd... 1.092...... 2.057

3rd.... 1.308...... 1.361

4th.... 1.000...... 1.000

5th.... 0.833...... 0.813

 

There is a close ratio 5 speed, but only used on the '80-'83 280zx Non Turbo.

okay so i defiantly have a wide ratio, because how it drives 2nd gear is more likely to be 7.29 final drive, and 3rd 4.82. 

 

im running 205/55/16 

[datzenmike]

Place in first, turn the input 20 times, count the output or driveshaft turns. If wide ratio that 5.5 turns, if mid ratio it's 6.0

 

Wide ratios were not used with the 2wd Z24 engine. The Diesel did but the transmission shown isn't for a diesel. The '81-'82 cab/chassis was a z series with wide ratio and the '82-'83 S110 200sx. The only other way is to put the Z series front case onto a diesel 5 speed. I doubt this was a wide ratio.

[bratsun]

35 minutes ago, datzenmike said:

Place in first, turn the input 20 times, count the output or driveshaft turns. If wide ratio that 5.5 turns, if mid ratio it's 6.0

 

Wide ratios were not used with the 2wd Z24 engine. The Diesel did but the transmission shown isn't for a diesel. The '81-'82 cab/chassis was a z series with wide ratio and the '82-'83 S110 200sx. The only other way is to put the Z series front case onto a diesel 5 speed. I doubt this was a wide ratio.

hmm well it was drift kid whom i got the truck from, he had another gearbox for it, and had definitely done some funky stuff. so i doubt its the stock trans

[datzenmike]

Only definitive way is to count input and output in first.