Mazda MX-5e Tesla Powered
Discussion
In the MX-5e we can get away with a much smaller 12V battery as we have a lot more control over the 12V system loads and there is no ICE to crank over. So we are using this motorcycle battery, which weighs less than the redundant wiring and brackets we have removed from the engine bay. This much smaller battery is easier to locate in the engine bay, so we can use much short lengths of high current wiring to various components, saving more weight.
We can also use clever bits of hardware like this 3-way ANL fuse block to simplify the wiring and save even more weight. This replaces the quite large fuse box that is found in the MX-5/Eunos engine bay.
robcollingridge said:
In the MX-5e we can get away with a much smaller 12V battery as we have a lot more control over the 12V system loads and there is no ICE to crank over. So we are using this motorcycle battery, which weighs less than the redundant wiring and brackets we have removed from the engine bay. This much smaller battery is easier to locate in the engine bay, so we can use much short lengths of high current wiring to various components, saving more weight.
Nothing constructive to add, just wanted to make sure you know I’m following your progress and I’m looking forward to how it turns out!The new radiator arrived today and it fits nicely. Like the rest of the cooling system, it uses 19mm inlets/outlets. This radiator weighs just 2200g. It will be fitted with an 8" fan and a custom aluminium shroud to mount it and duct the air nicely. It also has a 16mm threaded insert for the fan temperature switch/sensor.
Along with the fan, came this aluminium 1.2 litre header/expansion tank, which will be mounted on the bulkhead. It weighs just 425g.
Along with the fan, came this aluminium 1.2 litre header/expansion tank, which will be mounted on the bulkhead. It weighs just 425g.
Making huge progress porting the Driver Control Unit (DCU) to a single ESP32 processor. This is great because it can 'deep sleep' when the ignition is off and is using less than 2mA in this standby mode.
When the ignition is on it is doing driver detection using BLE and then personalising the EV interior with addressable RGB LEDs to do the ambient lighting. It communicates via Wi-Fi, has GPS, a 3-axis accelerometer, data logging, monitors all the temperature sensors, 12V battery level, etc.
The DCU uses another cool bit of electronics we have developed to intelligently control the speed of the Tesla pump in the cooling system. We have developed a custom speed controller for this.
Edited by robcollingridge on Tuesday 23 January 17:28
To get the great driver user experience we want in our MX-5e and the OSSEV, I have developed my own Driver Control Unit (DCU) which will be open-sourced. This now features two ESP32 processors to meet my ultra-low power requirements and also support all of the required features. This will be turned into a custom PCB design and also open-sourced. It's described in a lot of detail on the OSSEV website for those that are interested.
robcollingridge said:
To get the great driver user experience we want in our MX-5e and the OSSEV, I have developed my own Driver Control Unit (DCU) which will be open-sourced. This now features two ESP32 processors to meet my ultra-low power requirements and also support all of the required features. This will be turned into a custom PCB design and also open-sourced. It's described in a lot of detail on the OSSEV website for those that are interested.
EmBe said:
You might have covered it here or on your website but - will the OSSEV platform be transeferrable to other cars? I like a project, and I can see this being a nice way to turn something like an older, lightweight, sporty hatchback into a local runabout.
Yes, we plan to publish as much of the designs and software as possible, so people can reuse parts in their own EV conversions. The final OSSEV will be a set of components that build a complete sports EV.Rob
DHL delivered this today
It’s the fixed gear 1.8:1 reduction box that bolts to the Nissan Leaf motor and reduces the speed down to something that works better with the MX-5 differential, giving a top speed of about 109mph and better acceleration than any MX-5 I’ve ever been in It is an expensive part of the MX-5e project but, it’s beautifully made and is an essential part of the design. It is from a company in the USA called Inductive Autoworks.
Edited by robcollingridge on Wednesday 31st January 09:34
Designed the speed sensor ring and I'm currently getting this laser cut from 5mm steel plate. The speedometer sensor uses the teeth to drive thge speedo. and mileometer.
Completed my design for a two channel Tesla water pump speed controller using two ATtiny85 processors and have programmed these. Just getting the PCB manufactured now.
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