# How do I build my own charge controller?



## VOLKSWAGNER420 (Apr 21, 2012)

I am not sure what component info I need to provide for you to be able to tell me how to go about building my own charge controller for an EV Beetle. I am in school for Electrical Engineering so I think I can do this with the right advice from the right people on where to source the right parts and the right way to configure them. Also what about building my own charger? Thanks in advance for ANY help!


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## DIYguy (Sep 18, 2008)

VOLKSWAGNER420 said:


> I am not sure what component info I need to provide for you to be able to tell me how to go about building my own charge controller for an EV Beetle. I am in school for Electrical Engineering so I think I can do this with the right advice from the right people on where to source the right parts and the right way to configure them. Also what about building my own charger? Thanks in advance for ANY help!


read this. . .http://www.diyelectriccar.com/forums/showthread.php/10kw-60a-diy-charger-open-source-59210.html

and do some searching. 

By "charge controller" do you mean motor controller?.


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## VOLKSWAGNER420 (Apr 21, 2012)

Yeah, motor controller, sorry. All the Solar stuff I do is with charge controllers. Bout to read the link that you provided. Thanks!

Just read it and let me just say thank you SOOOO much! Why doesn't EVERYONE build there own chargers instead of spending all that money on it!? (other than the fear of shocking the piss out of themselves!) Can you build your own controllers too!? Anyone building there own giant Lithium battery? Is it possible? If so how? Thanks again!


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## bjfreeman (Dec 7, 2011)

simple answer there is no standard for charging, like the 12volt one for cars.
you have voltages ranging from 24V to 765 Volts.

From a manufacturing, marketing point of view, it is hard to get a ROI for the seller.

Even Solar is limited by the amount of panels one can put on a vehicle. 
I have a 210Volt 70amp buck charger that is powered by a fuelcell that is about $12K per 5KW cell. as you can see to get a 300 amp charger at say 144volts or 765volts, would required not only a huge supply but some very sturdy electronic parts, not to mention the size and wieght.


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## VOLKSWAGNER420 (Apr 21, 2012)

BJ, I do Solar on houses not cars. it will never be feasible to put it on cars, even when they perfect Photo-voltaic paints! And I thought that most of the real deal COMMUTER EV's (not the glorified golf carts OR novelty dragsters) ran either 144V or 192V is this not the case? Also since I am looking for a kit the seller of said kit could maintain their ROI by simply stocking their "standard components" and having the parts that vary with the voltage ship separately but simultaneously to you from their supplier? In fact this might actually reduce the cost of stocking parts and therefore improve their ROI. I know how to build a good buisness model. lol I do not know how to build my EV components so you have me there! I have found a good charger kit from Emotorworksonline and Paul and Sabrina offer this controller kit for CHEAP but it only goes to 144V and 500A. I am seeing if I could customize it fairly easily or if it would be a major re-design. any thoughts/ advice? Other Sources? Thanks again!


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## Ziggythewiz (May 16, 2010)

VOLKSWAGNER420 said:


> Why doesn't EVERYONE build there own chargers instead of spending all that money on it!? (other than the fear of shocking the piss out of themselves!) Can you build your own controllers too!? Anyone building there own giant Lithium battery?


Most people don't want to build their own electronics, because they aren't EEs, they may be afraid of magic smoke, and a few may fear for their lives. Others don't realize the resources that are out there to help out (I had already bought my main components before I ever heard of open source chargers and controllers).

You can do a DIY motor controller, search for Open Revolt

There's no such thing as a DIY lithium battery. People can take things like A123 pouch cells, or small cylindrical cells and make their own battery modules/packs, but most just go with the larger prismatic cells to minimize the amount of work required.


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## VOLKSWAGNER420 (Apr 21, 2012)

Ziggy, thanks for the info! Now I can check building a Lithium battery off the list of things to learn about! (I am SUPPOSED to be hanging sheet rock in my daughters room right now) And I know what you mean about people being afraid of the "Magic white smoke" after days or weeks of huffing solder fumes. One of my professors Dr. Bashtovvy ALWAYS warns us about the very real danger of what he calls "self tazering" when working with certain electronics. I think he knows more about it then he wants to admit! lol I am very careful not to kill myself ALL the way off (broke 14 bones and dislocated a knee so far, I don't recomend the knee thing!) as I have a wife and 3 kids that I am fond of seeing every day! The last solar panels I built put out enough Amps (each) to stop three hearts! I installed them at night!  lol! How does the voltage sag at full throttle work? If I run 192 V will it be ok on a 144V motor? How about with a controller (the DIY one) that is rated 144V and 500A would it work with 192V? Don't get me wrong, on long runs I will be on the gas like a grandma on empty...but...when I am around town I want to smoke every ass possible to change a few minds about EV's! I have been building bad a$$ planet killing bored and stroked V8's for many years now and while I am ready to make amends with the Ozone layer, I am NOT ready to go slow! Thanks again for all this great info,  this site is really shortening the learning curve for me! Can't wait to start my build! I will post a few pic of the donor Beetle as soon as I am done mining for rust.


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## Ziggythewiz (May 16, 2010)

Well, the magic smoke I was referring to is what makes an electronic component work. If you plug it in wrong it lets out the magic smoke and no longer works  Although I connected a DC-DC wrong yesterday and got a good stream of smoke out the side of the brick but it still works seemingly fine.

DC is usually much safer than AC. It's more of an explosive force than a muscle spasming taser so you tend to just jerk away or drop whatever is causing it. So how'd you electrocute 14 bones, or did you just fall off a building?

Voltage will sag proportionally to the current pulled and the IR of the batteries. For my lead a 15% drop is typical, for lithium it should be less, but not 0. If your controller can handle higher voltage, it can limit the amount that gets sent to the motor, so you can run the controller at 192V and deliver a max of 144V to the motor with just a setting.

A 144V controller can not be safely run much over that. Why the desired 192?

If you just want more total power capacity, you can just use 144V with higher AH cells; if you need 192V you'll need to build a controller to handle it. A light bug at 144 should move plenty quick.


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## VOLKSWAGNER420 (Apr 21, 2012)

I was going with 192V cause best I can tell I can fit about 20 regular sided 12v car battery's and I don't like quiet music (especially in a convertable) any more than I like slow cars so I was going to dedicate four battery's in series to the lights, heat, and jams. Hell I am not ever sure that the accessories even run on 12V in a 71 Beetle! I need to go get a repair Manuel for it. Do you know? From what I have gathered so far the Volts are how quick you can accelerate and your Amp Hours are your range so I figured that since I can't afford BETTER battery's then more battery's means more of both! Like I said when I am around town (Close to my plug) I want my Beetle to haul ass! Oh,and I broke 9 bones riding my dirt bike of a cliff in N.M., the old "mid-air" brakes didn't work for me any better than it used to for Wile E Coyote! The other four and my knee were from jumping over the hand rail of my front porch like I have many times, guess I was older and fatter that time?  Now I use the stairs like a chump.


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## MPaulHolmes (Feb 23, 2008)

One guy did a 192v with the 200v components on his, and it actually worked for 300 miles. haha. Now he's running it at 168v for the last 2000 miles. I think it's not very safe at all though. It's easy enough to change the mosfets yourself. I would try these:

They have basically the same gate charge as the IRFP4668PbF that I use, but higher resistance from drain to source while on and are more expensive.

http://search.digikey.com/us/en/products/IXFX140N25T/IXFX140N25T-ND/2126321

Or these:
http://search.digikey.com/us/en/products/IXFX120N30T/IXFX120N30T-ND/2126323

Here are some 400v diodes that would make a decent replacement to the stth6002c's that I use. Larger voltage drop, so they would make more heat, but they are rated for 400v instead of 200v.
http://search.digikey.com/us/en/products/APT30D40BCTG/APT30D40BCTG-ND/1494477

For the capacitors... Having looked inside a 144v 650amp Kelly, I see that their capacitance is TEENSY WEENSIE! So, I bet you could just change from the usual 16 of 200v 820uF (or 1000uF) to 16 of these and it would work fine:
http://search.digikey.com/us/en/products/EET-ED2E681CA/P11641-ND/483239


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## VOLKSWAGNER420 (Apr 21, 2012)

Paul, thanks! I think for my first go round I will stick with one of your kits as is and tailor the volts to it. I am not stuck on 192V I just want to pack as many Volts and Amps in my beetle as possible without having to cough up the cash for Lithium....maybe when the "breathable" ones from IBM come out! I also want (EVEN MORE) too have long life and reliability from all my components. If I wanted to sit on the side of the road I would be making a FORD EV! So first let me ask you this, is it possible to have TOO MUCH controller or just to little? Probably gona go with the big one if I can swing it. How many volts would YOU go with for the 1,000-ish Amp controller? I know I need Amps too, but they throw those in for free with the purchase of Volts don't they!? thanks again for ANY and ALL help! Steve


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## MPaulHolmes (Feb 23, 2008)

I would do 156 or 168. It uses 250 mosfets and 400v caps, but still 200v nominal, 250v surge caps, and larger isolation gaps on the power board and driver board.


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## VOLKSWAGNER420 (Apr 21, 2012)

Paul, 168V it is! So the trick is to put together a battery pack that is 168V with as many Ah as I can afford right? That's cool with me 'cause now I can have six battery's in series for lights, heat, and jams, I see a sub-woofer in my Beetles future!


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## MPaulHolmes (Feb 23, 2008)

It has programmable max current. My beta tester is going to start it at 400 motor amps, and then gradually increase until it explodes or temps get too hot too fast or 1000amp. The backs of the mosfets are soldered directly to a 1" x 0.25" x 13.5" bus bar, so it will be interesting to see how the bar temperature changes w.r.t. current and time. Liquid cooling is also easy this time. Just use a bigger aluminum plate, and I can mill some nice channels right below the bus bars, which are clamped against the plate. There's only a thin layer of re-enforced isolation pad between the 2, so the heat transfer should be decent.


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## VOLKSWAGNER420 (Apr 21, 2012)

Sounds good, I can just run a small trans cooler and a low volt water pump to keep it cool in the N.C. summers. If I am gona do all that I will mount ALL my electronics to one big aluminium heat sink and plumb the whole damn thing just to be sure. I am a BIG believer in some OVERKILL! P.S. how much is the kit for the bigger controller?


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## Ziggythewiz (May 16, 2010)

VOLKSWAGNER420 said:


> That's cool with me 'cause now I can have six battery's in series for lights, heat, and jams, I see a sub-woofer in my Beetles future!


You're a EE, right? You'll want your ACC batteries in parallel, not series. You may need them separated as well, as you usually try to keep the amp battery separate from the important stuff.

Do you realize how heavy these batteries will be? It would be fun to throw my amp and 12's in my bug, but I really don't want that weight in there till after I swap all the lead for lithium.


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## MPaulHolmes (Feb 23, 2008)

Ya, I had six 75 pound batteries where the back seat was, and that made it ride pretty low in my super beetle. You might need to upgrade the shocks, and maybe the drum brakes.


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## VOLKSWAGNER420 (Apr 21, 2012)

Ziggy, DUH! MY BAD! Parallel to keep the same Volts, series to add....shameful! Today is my day off and, well, lets just say that there is a GOOD reason for the last three charicters of my screen name I am only half way to being an EE, just about dangerous!  As soon as I graduate I plan to start on my Bachelors degree too. I think that is a great point about keeping the jams separate from the headlights! Doesn't the DC to DC charger keep all that stuff up? I was also gona add fog lights and some LED's here and there for effect but for far trips I am turning off ALL the heat and BS and run the jams on low, but around town, it's on! About the weight, I had already planned on upgrading to all wheel disk, adding a heavy duty sway bar, and putting all new tie rod ends and ball joints. I was gona go with adjustable coil overs in the front and the same in the rear or air bags, what do you think? Am I forgetting anything? I was thinking about extending my range by throwing a 3,000 Honda generator. Around town it might keep up, and self charge while parked where AC is not available, but would that have much effect on the highway or even be worth doing? Thanks for the tip Paul, what kind of Battery's were they?


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## MPaulHolmes (Feb 23, 2008)

420. rofl.


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## VOLKSWAGNER420 (Apr 21, 2012)

Before --->       <---After! All the Bug lovers and planet savers on here...I can't be the ONLY one!


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## Ziggythewiz (May 16, 2010)

VOLKSWAGNER420 said:


> Doesn't the DC to DC charger keep all that stuff up?
> 
> I was thinking about extending my range by throwing a 3,000 Honda generator. Around town it might keep up, and self charge while parked where AC is not available, but would that have much effect on the highway or even be worth doing?


If you're doing a dc-dc, you'd only need 1 ACC batt. Just be sure to size it for what you think your typical max power needs would be.

A generator isn't going to do squat. For highway it won't put a dent in your energy needs, and for around town, why bother? Plan to have enough juice to get around town and be able to recharge.


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## VOLKSWAGNER420 (Apr 21, 2012)

Yeah I am starting to come around to the fact that I could do away with the generator idea and go with coil overs in the rear instead of air, and take that money and the money I will save if I can pull off making my own charger and motor controller and just cough up the cash for lithium. It lasts what 2,3,times as long as lead? Would I be better off with a few big or several small battery's?


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