Paul & Sabrina's cheap DIY 144v motor controller

[rgathright]

Why not stick with 500 amp peak per board and then stack another board for double the capacity?

Spreading the load is sometimes the best solution when you reach the brick wall of available circuitry / limitations.

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I have been watching this discussion of heatsinks with great interest because I work with the hardware in servers on a daily basis. A good 80Mx40M 12VDC cooling can can dispel over 450 watts of thermal energy on an Intel Server. Why not do the same with your controller?

In fact, here is a cooling fan with a built in temperature probe. You can put the probe in the metal fins and move the fan to the end of the board. As the temperature increases the air flow will also increase over all the heatsinks.

Antec 92mm Smartcool Case Fan-Best Computer Online Store Houston Buy Discount Prices Texas-Directron.com

MPaulHolmes, PM if you want some.

[MPaulHolmes]

That is awesome! I never knew such fans/temp monitors existed! I hope they aren't expensive. 12v would be perfect. It could be powered by the 12v car battery.

[Oval_Overload]

Is there some painfully obvious reason as to why we can't submerge the entire mosfet board in non conductive mineral oil? If it can be done, you could use a power steering or A/C cooler as a radiator, in addition to the stock heater core.

[rgathright]

Originally Posted by Oval_Overload

Is there some painfully obvious reason as to why we can't submerge the entire mosfet board in non conductive mineral oil? If it can be done, you could use a power steering or A/C cooler as a radiator, in addition to the stock heater core.

Your idea does work in PC applications, however when mounted in a car the vessel that holds the mineral oil must be built to handle the stresses of frequent bumps and tips.

Also, finding the right vessel to contain the fluid would be tricky because it could not be a conductive material either.

[MazdaMatt]

mosfets should be close together so they receieve the same current to the gate from the driver. Would it be reasonable to use multiple boards, each with a driver where all the drivers are driven in parallel. Presumably they have a high impedence input and there would not be a timing issue between them. Stacking for power would be HUGELY markettable and allowyou to expand/upgrade/downgrade or take one out that is damaged and drive home.

[Oval_Overload]

Originally Posted by rgathright

Your idea does work in PC applications, however when mounted in a car the vessel that holds the mineral oil must be built to handle the stresses of frequent bumps and tips.

Also, finding the right vessel to contain the fluid would be tricky because it could not be a conductive material either.

What about a watertight electrical enclosure? They can usually be found in plastic.

[rgathright]

Originally Posted by MazdaMatt

mosfets should be close together so they receieve the same current to the gate from the driver. Would it be reasonable to use multiple boards, each with a driver where all the drivers are driven in parallel. Presumably they have a high impedence input and there would not be a timing issue between them. Stacking for power would be HUGELY markettable and allowyou to expand/upgrade/downgrade or take one out that is damaged and drive home.

The only problem that could occur would be the lone board operating in limp home mode burning up as well from to much current. YET, there is a solution! Restrict the size of both input lines from the battery array to the maximum current for the board. Have a feed block that distributes the current to controllers installed. Car audio systems use this. Doing this would save time trying to current limit the boards and give you assurance that the limp home mode would not destroy the remaining board.

Here is a sample image... obviously you would need two blocks in our scenario one for each pole (+/-).

[bennelson]

I don't think we need to get too crazy with liquid cooling and everything.

Remember, we want something relatively simple and inexpensive that many people would be able to build themselves.

All this other stuff is a lot of fun to think about though.

I do like the "modular-power" concept though. Since the controller is already seperate "smart" and "powerful" components, it seems well suited to some sort of modular power system.

It would be pretty slick to build one of the power units to run your can on, and then add another one as time and money allow for increased power.

[Oval_Overload]

I like the liquid cooling method because the coolant could be used to provide some heat without tearing up the dashboard. Just my 2 cents.

[esoneson]

Ahhhhh, the utter beauty of open source engineering demonstrated before our very eyes!

Each one of these forward thinking, bright contributors has the ability to take the open source design......modify and improve.....and give back to the open source community. And along the way, have a chance at developing and marketing commercially viable products.

Music to my ears.

Eric