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Discussion Starter · #1 ·
i just got my tax return!!! i've been waiting for this!!!
okay i am having trouble picking parts. i am going with a 144v lead acid system w/ a 500a open revolt controller.

does the volts/amp have to match my 144v/500amp system? is it ever too much or to little? in example;
~contactor (144v?)
~fuse (500amp?)
~dc/dc converter (144v to 12v?)
~shunt?
~circuit breaker (500amp?)
~ect

i have the forklift motor and coupler already mounted on my transmission. I would like to spend around $1,200 max on everything else if possible (batteries and controller is already $800) but if parts are too much, i can lower to voltage to 120v or 96v ect. can someone please guide me to the right direction. thanks in advnace! I will be looking forward in your response. links on "Best Bang 4 UR Bucks" parts will be appreciated!!!! thanks and god bless.
 

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Discussion Starter · #3 ·
thanks for the resource? but can you please answer my question about the volts and amps? i would apprecitated. since i'm running 144v and 500amps does my contactor, fuse dc/dc, ect has to be the same volts/amp?? thanks in advance. i am soo happy to finally finish my conversion. its been on hold for over a year.
 

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Your contactors need to be rated to handle the DC voltage and amperage you can pull from your pack or higher than that. Remember that your fuse is supposed to be the weakest link in the HV circuit. It needs to be rated for your DC voltage or higher and it needs to be rated under the current your pack can put out so that in the event of a short the fuse will actually blow. I don't know exactly what it should be, that is why I didn't answer it before. I can say that with my Gizmo and my 500A controller it came with a 250A fuse. Fuses have a rating at which they will blow really fast and ratings where they will only blow after some time. As I understand it my 250A fuse will take something like an hour to blow at 251A down to several minutes at 300something Amps down to a minute or so at 500A but I really don't know for sure. I do know that the 425A momentary draws from my battery pack are not enough to cause it to blow. Again, if you will go to different ev suppliers' websites you can find out what they supply with a similar setup like you describe.

You should use a 500A shunt. From what I've read from the manufacturers, if you don't actively cool the shunt it should only be run at 2/3's of the rating continuously otherwise you risk damaging it or at least changing its calibration.

Your DC-DC needs to be able to handle what ever voltage range you pack will be at. This means it has to work when your batteries are at their highest voltage during charge and not drop out when you step on the throttle and the voltage sags. It does not have to be a 500A unit. It needs to be sized to handle what ever load you will put on it.

I assume you haven't looked at the resources I suggested yet. They would have answered some of your questions. Also, look at the evalbum.com and the build threads on this site. Do some homework. It is all out there but don't expect everyone to hold your hand when you won't do some homework your self. I'm not trying to be rude here just that you will get a whole lot more help if you demonstrate that you have done your homework. For example, if you had replied that you checked out such-n-such sites and still don't understand why they use a fuse rated lower than the controller max current.

HTH,
 

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Discussion Starter · #5 ·
wow thanks soo much gizmo! i have a lot more knowlege now. thanks soo much you are soo generous! i did look at the resource. its kind of like a craigslist for ev. couldnt find much info there. i will do my homework and extra credit! i'm soo happy
 

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i will do my homework and extra credit! i'm soo happy
I am a teacher but I don't give extra credit if the assigned homework isn't done.:p

Any way, you are welcome to look at my bookmarks I've been building over the years at http://www.delicious.com/GizmoEV/ev which can be narrowed down by selecting another key word in the side bar. Here are a couple you might want to look at: http://www.kta-ev.com/General Small Car Kit Package.pdf and http://www.evsource.com/tls_kits.php

Enjoy and don't forget the extra credit!:D
 

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Discussion Starter · #7 ·
Hey GIZMO! again thanks for your bookmarks ect. it helped me out a lot.

Here is my low budget (cheap "Good" parts) set up. I would like to know what your opinion on it or if i am missing anything of if they're something i don't need. My tax should been coming anytime soon! I am hoping to get at least 40-60 miles on a full charge and a top speed of at least 75mph

EV PARTS
Forklift Motor $160 (craigslist)
Motor Mounts $17 (eBay)
Adapter $45 (custom)
Coupler $free (custom)
Blower Fan $5 (eBay)
Controller $600 (96v-138v max) / 800a max,320a continuous)
Throttle Pot Box $65 (0-5k)
Main Contactor (500+amp, 12-900vdc)
Fuse $71 (800A/300V)
Battery Charger $200 (120v)
Anderson Connector $20 (eBay)
Cables (2/0) for Charger and Batteries $65 (35ft.)
Battery Lugs $2 ea. (eBay)
Battery Terminal $0.60 ea (eBay)
DC to DC converter $159 (96v-12v)
Batteries Used 16 6v $330 (96v) gel cel batteries 200ah

I know i'm missing a shunt, circuit breaker, resistors, inertia switch, ect. some says these parts are not necessary. I did my homework and a lot of extra credit but i need someone to check my work!! again Gizmo, thanks a lot i would have not done this with out your help! Your the only person here that is generous enough to help me with spectacular knowledge! I will be posting a D.I.Y. E.V. video and will give you a shout out! I will be looking forward for your response
God bless
 

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Hi, hopefully someone else will weigh in on this. Before I go on you might want to get and read a couple of books. http://store.kta-ev.com/booksanddvds.aspx has several listed. The "Convert it" book has been around for a long while and gives a great overview. The "Build Your Own EV" book is another good one. I have the first edition of the book and they are a good reference. Also, is there an EAAEV chapter in your area? Go to www.eaaev.org and go to the EAA chapters tab to look.

I don't remember you saying what donor vehicle you have. The size and weight will have a large impact on how well your chosen components will work. I think your fuse is too big. The voltage rating is fine but I don't think you will get 800A out of those Gel batteries. This means that if you have a short the fuse might not blow which could mean trouble. I have a 500A fuse and a 1000A controller. Remember that the fuse is supposed to be the weakest link in the electrical system.

2/0 cable should be fine for your application. Remember to get the really flexible stuff. It is easier to work with and it can handle the rough treatment in a vehicle better without cracking and breaking. The wires in it are just a little larger than a human hair or two. If you can get the orange insulation that is better for emergency response people but otherwise the heavy welding cable works great.

Note that Gel batteries are not particularly fond of high currents and they can't be overcharged if you want them to last. Make sure that the charger is programmed properly for them and that it has a temperature sensor in the battery box so it can adjust its charging voltage as the temperature of the batteries changes throughout the seasons. Since you are getting used batteries understand that they may all have different capacities and definitely lower than they are rated. When new you should only expect maybe 100Ah usable out of them. If you can get any spares from the same set then do so. You don't want to mix new and old batteries if you want the new ones to last any where close to their expected life. Then, start saving immediately for a new set of lead acid or preferably LiFePO4 batteries.
 
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