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Discussion Starter #1
Taking a whole Nissan Leaf - not even crashed/written-off - looks like a cost-effective way of buying all the necessary components for an EV conversion.

Can the BMS, DC/DC converter and onboard charger all be reused - or are they all governed by circuit boards making them impenetrable to most DIY converters?

Surprisingly, I have hunted high a low for an answer to this without success - so any input would be gratefully received!

Thanks.
 

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I been asking the same questions for a couple of days and so far no good. But Arlin Samsone. A Canadian guy made a board and posted everything on endless-sphere. He also has some great videos on youtube. Accordingly to one of his last videos. He's been busy with a charger he was making for a company.
If he can't help. And the videos, and he's post on the endless-sphere forum. You are probably better of to wait for Paul Holmes to figure it out.

Danny posted me and said he was close. I haven't had the time to read he's project yet. So I don't know how close. But check it out My project is not quite running as of yet, but I am nearly done - just some troubleshooting that I do not have the time for remains. Here is the link, though we won't count this as a helpful source yet:


https://www.diyelectriccar.com/forum...ni-184017.html
 

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Thanks very much. So it looks like the short answer is - no - at least not yet.

In my naivete, I wonder if these systems can be made to work by taking away some of the circuitry rather than by adding to it? Surely the fundamental parts are simple, and Nissan have complicated them to try to make them tamper-proof given the dangers of DIY servicing of an EV...?
 

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Yes, for example batteries are batteries once you bypass / remove their protective systems.

But you need to know their specs, voltages and amps min / max, and then DYI your own if the tinkerer-experts haven't published / productise d the results of their reverse engineering.

And if there was a sophisticated engineered thermal management system keeping things from burning / exploding, you better be very conservative for your relatively crude simulacrum to reliably prevent disaster.

Personally spending a few grand more and buying a set of big new well-matched LFP prismatics and a solid BMS is a simpler, easier and safer approach.

The motors + controllers drivetrain pieces, seems lots more complex to me, but at least there it's unlikely your life's so much at risk while you're figuring things out, long as the brakes and steering work.
 

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Only your
a few grand more and buying a set of big new well-matched LFP prismatics and a solid BMS
Is a LOT more than second hand OEM batteries and the quality is a LOT worse

Everybody with "new well-matched LFP prismatics" has had at least a 2% failure rate

As far as I can see using OEM batteries WITHOUT a BMS is better than "new" batteries WITH a BMS because the cells are so much closer matched at the factory
 

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In my naivete, I wonder if these systems can be made to work by taking away some of the circuitry rather than by adding to it? Surely the fundamental parts are simple, and Nissan have complicated them to try to make them tamper-proof given the dangers of DIY servicing of an EV...?
The complexity is not just to tamper-proof them - that's probably not even a factor in their design. The BMS isn't there to keep you from using the battery; it's there to protect the battery. The motor controller isn't there to keep you from using the motor; it's there to control the inverter and thus the motor. And so on...

Completely open designs for these components would be just as complex.
 

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Discussion Starter #7
The complexity is not just to tamper-proof them - that's probably not even a factor in their design. The BMS isn't there to keep you from using the battery; it's there to protect the battery. The motor controller isn't there to keep you from using the motor; it's there to control the inverter and thus the motor. And so on...

Completely open designs for these components would be just as complex.
Thanks - yes, I know what the BMS is there to do. But it seems, from what I've read on this fantastic forum and elsewhere, that the BMS, DC/DC converter and onboard charger just don't work unless the whole system is taken out of the Leaf such the system still thinks it's in the Leaf.

I'm looking to repower a Land Rover from the 1950s - with no need for an electric parking brake, heater, collision detection system or proximity warning system. When it was new, doors were an optional extra, and there aren't even any seatbelts (I'm going to retro-fit these at least!).

So I just wish there was a way to link up all the bits which provide motive force and keep the 12v battery topped-up - but nothing else. A PowerWatcher can provide battery and power information such that the original dash doesn't need to be mucked-about with.

Is this not doable...? :confused:
 

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Anything is "doable" given enough time knowledge & skillz.

The bare motor is likely dumb, batteries are covered. So that leaves whatever acts as motor controller, or you find a better known & documented unit instead.
 

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I think you are looking at this in a mechanical way rather than electronic. The whole car works as a computer code, removing a bit is not designed to be tamperproof. It’s like the computing equivalent of taking out a con-rod. It needs the whole program to run. Can you emulate parts of the program to say, switch on the DC converter, yes. You have to understand the command to do that, by simply removing other parts of the communication network in the original car you effectively disable other systems, what they may be who knows, depends on what system you want to keep and what you want to throw away. The Volt is a prime example, the CAN messaging system has been mapped, you want the charger, simple, wire it up and send the command to charge. Problem is you send that command when you are driving you have a potentially lethal situation. You have to know what commands and when to send them. It’s not designed to be tamperproof, it’s just designed to work.
The DIY EV car builder has to add basic programming to his box of tools, not all problems can be solved by a wrench anymore. A 50’s Land Rover solves a lot of issues because you can pick the parts you need. Add a CAN transmitter and have it feed the signals to the component you want to work at the time you want it to work. Transplanting the whole system means you can bypass some of this but I can guarantee there will be some of the messaging system that needs more input. It’s just a new skill set you have to learn, like leading torque setting, only it’s not something you can just feel. Unfortunately.
 

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It’s not designed to be tamperproof, it’s just designed to work.
Exactly! :)

Thanks - yes, I know what the BMS is there to do. But it seems, from what I've read on this fantastic forum and elsewhere, that the BMS, DC/DC converter and onboard charger just don't work unless the whole system is taken out of the Leaf such the system still thinks it's in the Leaf.
I'll try this again...
The components only work properly in a Leaf because they are designed to work in a Leaf. It's not some conspiracy to keep DIY builders from using the components, and they are no more complex than necessary for a modern vehicle.

The same situation exists with engines, for the same reason. If you take the engine out of car and try to use it in an unrelated car, you probably need to use an aftermarket engine computer to make it work, or the computer and wiring harness sold by the engine manufacturer for installations in racing and modified vehicles. You can have a GM V8 engine installed in a Mazda MX-5 by just ordering a stock item from a Miata specialist company... but it costs $50,000 due to all of the special and modified components and work required. GM isn't trying to make their engines difficult to use, just as Nissan isn't trying to make it difficult to use Leaf components; all manufacturers just design the systems to work in their vehicles.

I'm looking to repower a Land Rover from the 1950s - with no need for an electric parking brake, heater, collision detection system or proximity warning system. When it was new, doors were an optional extra, and there aren't even any seatbelts (I'm going to retro-fit these at least!).

So I just wish there was a way to link up all the bits which provide motive force and keep the 12v battery topped-up - but nothing else. A PowerWatcher can provide battery and power information such that the original dash doesn't need to be mucked-about with.

Is this not doable...? :confused:
It's doable. Just use the Leaf motor, the Leaf battery modules, and perhaps the inverter power stage... and nothing else. You supply a simplistic control system for them, to match your vehicle, instead of expecting Nissan's components - which are designed for a modern vehicle with much more complex requirements - to work in a very different context.

Here's the gasoline engine equivalent: if you want the engine and transmission from a modern pickup truck in your Land Rover, you can try to take everything out of the truck, but none of the electronic control systems will be happy in the Land Rover. Instead, you buy the bare engine (salvaged or as a crate engine) and transmission, and control them with an aftermarket engine computer and aftermarket transmission computer. If you pick a popular enough engine and transmission then you can buy those aftermarket computers because many thousands of other people have wanted to do the same thing; if you can't buy the equivalent for a Leaf, it's not surprising because there are only a handful of people on the planet who really want to do this.
 
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