The "egg-laying wool milk pig": PSU+charger+BMS+ESC device?

[[Team1] Gabriel]

Like some of you guys know already, we are a group of students who want
(as an economical+engineering project which might be put into reality later)
to compile and construct a small, lightweight and easy-to-use drive system.

Because of that ist should be attractive to people who hesitated or did't dare
to "jump ship" into the electronic sector before.
(here is the post with the main characteristics)


Even I higly doubt that there is such a system especially designed for lightweight e-bike applications, it can never hurt to ask. So I ask you:

Is there a small and lightweight device out there which includes:
- Power Supply Unit
- strong charger (lol)
- Battery Management System
- Electronic Speed Controller around 250-300W with 24-36V (still not sure if RC or with sensors)

Best if every system used the same heat sink, so it would also be space-saving
And it should be cheap too! (now it got impossible :lol: )

We sure could piece together these things one by one, but then it will get big and also heavy.

In Austria we say to such a jack-of-all-trades-device, an "egg-laying wool milk pig" (literally!) :lol:

I bet there is nothing like that out there, but like I said... it can never hurt to ask.

Maybe there is a small PSU+charger+BMS combo out there which we could combine with a sufficient ESC... or something like that

greetings,
Gabriel

 

[jag]

]
Is there a small and lightweight device out there which includes:
- Power Supply Unit
- strong charger (lol)
- Battery Management System
- Electronic Speed Controller around 250-300W with 24-36V (still not sure if RC or with sensors)

Best if every system used the same heat sink, so it would also be space-saving
And it should be cheap too! (now it got impossible :lol: )

You might investigate what the benefits of integrating all those components in one might be. (Other than sharing the housing).

In your previous post you proposed a ligthweight battery and charger that one could bring with inside to charge. Then why add the controller that more naturally stays on the bike? They don;t share components anyway.

 

[[Team1] Gabriel]

Then why add the controller that more naturally stays on the bike?

THAT... I realized too, just after posting this thread :lol:

But anyway, what if we change our opinion and decide to design the whole drive+batt in one piece?
(That is still not so clear! Maybe we switch to an all-in-one detachable design after all)
Then a device like this would be nice.

You might investigate what the benefits of integrating all those components in one might be.

That sounds like you know something I don't... maybe this should be a hint to use the search function a little bit more?
But sorry, I'm too busy at the moment for rummaging in many threads, otherwise I would also be more active in threads not concerning our project.

 

[Solcar]

I did something partially like the "egg-laying wool milk pig," we can say it is just an egg-laying pig. :wink: I built a motor controller/charger for my ebike. Since the motor is a brushed type, both functions can share parts, but it is trickier. The bike ran off of just 12 volts, with a single transformer being used for both the switching power supply in the charger and another switching power supply as a push-pull voltage booster for the motor.

 

[amberwolf]

Gabriel"]Is there a small and lightweight device out there which includes:
- Power Supply Unit
- strong charger (lol)
- Battery Management System
- Electronic Speed Controller around 250-300W with 24-36V (still not sure if RC or with sensors)

There's nothing I'm aware of that does all these at once, but also no reason you couldn't create such a thing in theory. Problem is, it adds size and weight to what goes on the bike, that is not often needed while riding (charger section, and the balancing parts of a BMS).

The best reason not to have a combination system is probably so that you can easily swap out one part for another for upgrades using stuff that wasnt' specifically made for the purpose. However, if you already have a modular system, you could sell upgraded parts to do this: faster charger, more powerful controller, more feature-rich BMS, etc.

Best if every system used the same heat sink, so it would also be space-saving

That could present a problem, unless you ensure that the heatsink is expanded in size to be able to dissipate the extra heat of multiple systems dumping heat into it at the same time (BMS balancer and charger and PSU will all need to run at once, for instance. Possible that the discharge pass-thru parts of the BMS will also need heatsinking at the same time as the controller.)

A heatsink is generally only going to be made large enough to just barely keep the parts it's cooling down to some "livable" temperature, in many commercial applications. So adding any other heat load to it can and probably will push the temperature of the other load already on it to go up beyond what it was supposed to tolerate.

You then have to make the heatsink bigger, and/or add active cooling to it (fans, etc.), making it either bigger and bulkier and heavier, or more expensive (or both). It might still be smaller and cheaper than multiple heatsinks were; that's something you'd have to run the numbers on with an actual design.

Another issue is that a common heatsink also pushes heat into the other devices sharing it even when they are not in operation, which can reduce their lifespan a bit (or a lot, if it's a lot of heat), when having separate heatsinks not venting heat into the same space would not do that.

 

[Hillhater]

...In Austria we say to such a jack-of-all-trades-device, an "egg-laying wool milk pig"

Hey, that sound like a girl i used to know ! 8) :lol: :wink:

 

[[Team1] Gabriel]

Another issue is that a common heatsink also pushes heat into the other devices sharing it even when they are not in operation

You got me. Didn't think about this issue.

you could sell upgraded parts to do this: faster charger, more powerful controller, more feature-rich BMS, etc.

Thats not so a bad idea, we thought about that too. But we only considered upgrading the battery Pack if one ride, for example of a commuter, would take more than 10-20km (6-12miles).

But a fully integrated system (PSU+charger+BMS, even if is just a standard PSU + a slightly modified HobbyKing charger) would be handy I think, becase you would have to take the charger and PSU with you anyway (you have only juice for one ride).
Therefore it would be better if we had the Battery + the whole charging system in one pack rather than everything extra (which would also have only 2 cables: hidden extensible 230V plug + power supply for ESC in the drive unit).
Without the system you would have to stuff the charger and the PSU in your backpack... and would have less space for other things.
But if everything is in one box on the bike, you wouldn't have to carry extra weight on your back and would simply grab the box on a handle and take it with you after dismounting.

And of course when you have an all in one box-system, you wouldn't have to connect the battery or balancer wires, just plugging the 230V plug into a wall, pressing a button and there you go. 8)

 

[magudaman]

Well there is a car application that does this to an extent, AC Propulsion. Now this is a 268hp electric car system that totally kicks ass and weights in at 168lbs but the same ideals apply. They actually utilize the coils in the motor while charging for inductors and their controller for the charger. They can charge at something like 18kw and can actually feed your house from batteries if you want to!

Check them out here: http://www.acpropulsion.com