14 Build Your Own Electric Car: Balance of system

Balance of System refers to the other necessary, but perhaps not exciting components outside of the main ones. This includes items such as a main fuse, contactor, pre-charge resistor, instrumentation, etc.
For some great ideas on different vehicles converted to electric, check out the listing at the EV Album! www.evalbum.com
This video is one segment of an instructional video I created in 2010 from a home-built electric car I made in 2008. Of course, battery and motor technology has advanced quickly since then, and affordable, commercially-built, Electric Vehicles are now a reality.
This video series covers ONE low-tech and simple way of converting a car to electric. Many of these same ideas and techniques still apply to go-karts, motorcycles, boats, and lots of other projects. We hope that you enjoy watching these videos and learn a little something from them.
There are still a few copies of the original DVD for sale. Besides the video, the set also has a DVD-ROM with photos, web clips, and documents from the project.
All profits support our work and go towards future DIY Clean Transportation and Renewable Energy Projects.
300mpg.org/elec...
For CURRENT electric vehicle, DIY, and renewable energy projects, please visit 300MPG.org.
Music Credit:
"B-Roll" Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
creativecommons...

[@LatinDanceVideos]

So much detail in this I need to listen to it multiple times.

[@The1Creston]

Thank you so for all the work you put into your videos. I have learned a lot!

[@DaveElectric]

You don't need a shunt. You can use a hall effect current sensor that just clips over one of the battery cables.

[@ronaldanderson9263]

Thanks for this. I have seen pre-charge resistors and that voltage drop resistor and thought but why? Ohhhhhh. :-)

[@stephenkigera731]

A circuit breaker right at the batteries would be safer, exhaust pipes(the route the sheathed power cables are running), do get damaged by manhole covers , jacking and stuff and since all the protection devises are up front , these cables are always live. Aren't they? Great project you have going here. Learned so much from your videos.

[@BenjaminNelsonX]

Ideally, a fuse and contactor can even be INSIDE a battery pack. Modern commercially-built electric cars often have a contactor not only complete the circuit, but also break the pack in half when it's off. That way, the voltage is cut in half as well, accept when actually powering the car. The Electro-Metro project is now over 10 years old! Frankly, I can't remember every last little detail I did on it, and not every darn last little thing was covered in the video series. I believe that in the final version I had two DC fuses, with one directly on the most positive connection of the battery pack. Best practice does mean having a fuse or other over-current device right at the battery.

[@Alrukitaf]

Absolute genius.

[@mrdudeccs]

My DIY EV won't turn "on" I know the batteries are charged, but the lights and guages lit up for a second the 1st time I connected the positive cable to the cable coming from the main fuse/contactor box. WHat should I be looking for? blown fuse? I need help.

[@vincenttelfer4206]

Good to learn new things daily,good hobby, I'm surprised the 'snailpace' recharging or generating technology is. I was thinking about putting together something soon in a electric awd type, if this helps, I planned to manually switch batteries on and off charge, alternating probably the inline dc smaller battery packs, but your smart enough to design a board to control the alternating electrically. Maybe something like a distributor. D size dc battery, there is another option though. There is 2 other options for the generating I recently stumbled on,lol.

[@soniadejesus9719]

I want to make my 2013 dodge caravan into a EV what would be a good electric motor

[@brunocabral1578]

Did you publish an schematic of the components and connections inside that box? Thanks for sharing your work, it is very well explained

[@vincenttelfer4206]

Maybe a possibility of alternating panels as well, allowing a cooling period.

[@simonechristopher8727]

Cool video, but I missed how you are allowing for the 72v battery pack to charge the standard 12volt battery (the original one).

[@BenjaminNelsonX]

Hi Simone! On this project, I simply had a 12V battery charger which would charge the 12V when the car was plugged in. On most Electric Vehicles, we use a DC/DC Converter. That's a device that takes a small amount of power from the high voltage battery pack and converts it to a lower voltage, typically to charge the 12V battery on a car. You can think of it taking the place of an alternator, only being smaller, quieter, more efficient, and having no moving parts.

[@mfherreradi]

Hi Benjamin, are you isolating those negative and positive high-amps connections inside the Box? That would be a nice safety measure to be implemented.

[@Tore_Lund]

Most controllers are safe in case of failing power transistor or thyristor shorting the battery wiring through the H-bridge as the controller will detect an over current condition and shut down, faster than a fuse can. An extra outside fuse is superfluous and only protects you against a short in your battery wiring, which won't ever happen if you use grommets and double insulation (garden hose). In that case it will make more sense to place the fuse at the positive battery terminal, so it also protects against wiring faults I object to fuses and power relays in the main circuit because they give you a combined voltage loss of 1.5V or more under load, which is the same as removing a cell from your battery pack reducing your range by the same amount. The ignition key input on controllers have at least two fail-safes, and do not send your car flying through the garage door at night. So in my opinion, you are adding complexity, cost and reduce efficiency by going over the top on this, but still, "better safe than sorry" is always a valid argument. I don't know if you ever said this in one of your videos, but you do not ground your traction battery to chassis ground for the reason that only one positive wire failure is needed to short the battery or send hi-voltage through your electronics. This also means that you need a floating input DC/DC converter where the input and output are isolated (no common ground, only 12v system ground connected to chassis )

[@deathincarnatesplace]

four motors like you use a the wheel with alternators powering them direct. some people have tried on really small car to make alternators into motor and then direct connecting them using a cord and then turn the alternator with a small dc motor with a gear and ration to conserve energy and it work but break easy do the pounding of the road and up and downs of the wheel.

[@wowongtube]

thanks for such great videos. your project is inspiring but I wonder what about the Air con and power steering systems in the converted ev car

[@BenjaminNelsonX]

One of the reasons why I chose the Geo Metro was that it was a fairly basic car. It did NOT have power steering or air-conditioning. Because of that, I didn't have to do anything for that at all. It DID have power brakes. Power brakes use vacuum created by the engine. So, without the engine, the brakes are VERY hard to operate. I added a 12V vacuum pump, small vacuum container, and a vacuum switch to automatically turn the pump on as needed. There are now electric versions of air-conditioning and power steering available, which can simply be bought and installed. Alternatively, if your vehicle has belts powering those accessory items, you could use an electric motor with a "tail-shaft". Attach a pulley to the tail-shaft and have that power the accessories in the same way the gas engine did.

[@otherrestrained4405]

Woot Double content day

[@plamenpetkov6958]

The pre charge resistors is in fact inrush current limiting resistor

[@yatravis]

Where did you buy your main contactor? Or did you build it?

[@BenjaminNelsonX]

That was just salvaged from a forklift at a junk yard. Contactors are available for sale through EV components sellers. 300mpg.org/projects/electro-metro/ev-parts-suppliers-links/

[@ankithmistry]

I am curious how you get your brake booster Power steering, and headlights and other electricals working ?

[@BenjaminNelsonX]

The brakes use a small 12V vacuum pump. The car did not have power steering, it's manual steering. In this car, I simply connected a battery charger to charge up the 12V any time the car was plugged-in, but most projects use a DC/DC converter which is an electronic device that essentially takes the place of an alternator. 300mpg.org/projects/evcycle/balance-of-system/ 300mpg.org/projects/electro-metro/why-dont-electric-cars-have-alternators/

[@ankithmistry]

Thanks a lot @@BenjaminNelsonX , BTW brilliant Built, thanks for encouraging us :)

[@aaba112]

Hi and thanks for the video. When Googling regarding Open Revolt it seems to be a more or less dead project. All the schematics and info is from like 2011-2012. Am I looking at the wrong place, or is this the solution you are referring to? Thanks

[@BenjaminNelsonX]

No, that's right, this project is from a few years back. There's all sorts of motor controllers available nowadays, including more people making some DIY ones. A person needs to know a fair amount of electronics to build their own controller though.

[@BenjaminNelsonX]

I just remembered that we DID get the Open ReVolt listed as one of the parts you could search by on the EV Album. There's about 40 vehicles listed there running the Open Source motor controller. www.evalbum.com/cntrl/OPRV/16

[@BenjaminNelsonX]

The original project thread for that controller was at the Ecomodder forum. ecomodder.com/forum/showthread.php/paul-sabrinas-cheap-diy-144v-motor-controller-6404.html

[@aaba112]

Hi and thanks for you replies. Yes I'm an electronics and software developer so it was interesting to learn about these open source projects. However when I summarize the cost to build one myself it will still be quite some money and in the range of a used commercial controller. However Revolt may bea better choice offering interesting features a very usable communication link. I’m trying to make a cost and effort calculation to convert a VW Beetle. Best regards from Sweden…

[@RyanBissell]

Audio sync problem during last few minutes.

[@geixiong5749]

I really like what you do. I'm in the process of building my own projects. Can I count on some of your experiences and perhaps get you to be a part of my venture. By the way, do to all the buraucrats and control regulations that the energy Cartels has in place. It's going to be hard to start anything and turning it to a commercial venture. Everything is so much easier and faster in over seas so I will be looking that direction. Right now, you can start anything in China in the industrialize zone with just a permit. Also, right there is where everything you need for supports and supplies. GM and Ford biggest moneys making is in China...Four time the American markets. All the smart American companies are not in Asia. You start in Asia then the next move is Africa. The future is Asia and Africa ( the moneys ).

[@themackshow8726]

Can I charge it with the cigarette lighter

[@Anthony-vm1jc]

Gasketed that a word

[@countryfresh2036]

You should attach a alternator to the output shaft and have that wired to a one direction flow to the battery's to keep charging as you drive it'll help distance maybe but at least lest time for normal charging

[@BenjaminNelsonX]

An alternator is a very POOR choice for an electric car. Here's more. 300mpg.org/projects/electro-metro/why-dont-electric-cars-have-alternators/

[@carlosarevalo3786]

Something like that yeah let me know

[@lifebythesea2948]

When can we see it drive. Lol

[@BenjaminNelsonX]

Sunday.

[@cleardanny]

just get a new electric car

[@stevencorrea7982]

Daniël De Roo lot simpler and easier. But I seen a Irish man. Build one for 1000 Euros. I think that's 1,200 American dollars. Using lithium ion recycled. I don't know enough about lithium not to explode. I guess you will have to have a battery management system. I think there was from a used Opel ampera. Chevrolet volt in America. One of the cheapest Mass produce electric cars I've seen would be the Nissan Leaf for $7,000. Some go for high is $12,000. New Chevrolet bolt $30,000. A new Nissan Leaf $35,000. New model X $100,000 new model S hundred thousand dollars I'm not great at math. But I know which one causes more. I wish I was great at math.