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Discussion Starter #1 (Edited)
​Hi, DIY Electric Forums,


My name is Jamie, I'm a high school junior from Colorado, and I'd like to do my first electric car conversion at the end of this summer. However, it's a really huge project, and I'll likely need some advice, as well as some experienced people to check my planning, which is why I'm here. Here are the dilemmas I've run into thus far--can anybody answer any of them?


AC V. DC:
I'm leaning towards AC, because my understanding is that it performs well without losing all of its range, and can do regenerative braking.. Do I understand this correctly, or would DC provide just as much range? Does the increase in efficiency that AC provides make a cost difference in the number of batteries I'd have to purchase? Would the decrease in performance AC gives make the car feel boring?

Batteries:

I'm vastly out of my depth on this one. As I understand, LiFePO4 batteries are great, they have great energy density and a longer life, but they're very expensive. What other types are there and what are their advantages? Would the battery brand matter? Could I mix and match battery capacity or manufacturer?
I am also thinking about making the battery space expandible, leaving five or ten empty slots to fill in in the case that I run all the way out and I need someone to bring me power, or if I want to go on a road trip and drive a bit longer without charging each day, or just if I have money to burn and want to expand my range later. Would the wiring, construction or controller programming be too complex for this to be practical?
I live in northern Colorado, and while I intend to go to college somewhere warm when I graduate, I will probably be spending a year driving my new EV in the Colorado winter. Thus, I may need to insulate or heat my battery box.
Would this be an issue at all? Will heating it affect my batteries? Will insulation risk overheating them in the summer?
Finally, I've seen a few builds with onboard gas generators that let them charge the batteries while driving, or while parked somewhere without a charging station.
Where could I find instructions for how to do this, and would any challenges arise, beyond pumping carbon monoxide into the cabin if a pipe was dislodged?

Motor Setup:
I've seen some systems, like the EVWest Factory Five 818 conversion, which say they use a dual motor setup. I want to make a reasonably high-performance car, so my ears perked up at this...imagine what twice as much motor could do to a light little car! Would the costs and engineering challenges inherent in this make it unreasonable for a first conversion on a high-school budget?


Donor Car Choice:
I know I want something reasonably compact, classic, and sporty, and ideally a convertible. It also must have a transmission adaptor (or better yet, a full kit) available for sale. (That's not the kind of thing I can or should engineer myself.) With all of these things in mind, I have picked the Volkswagen Karmann-Ghia.
By my estimation it is:

A serious head-turner
Built on the Beetle chassis, so it's easy to repair, and parts are everywhere
Light, fun like a Beetle
Widened floorpan compared to a Bug, so more room for batteries and cargo space
EVWest sells a kit (minus batteries) for $7,000
Moderately used coupes routinely sell for around $3000-$4000, and convertibles can go for $5500 on a good day.


However, it's not perfect. The Beetle chassis is not known for its reliability (although some of that is engine trouble, a moot point in an EV conversion) and it has nothing resembling safety equipment.
Can anyone suggest any other issues with the Ghia that I'm not seeing?

Assembly:
I don't know whether instructions exist for how to connect the motor to the drivetrain, how to wire up the batteries, and how to connect the electrical components. I am reasonably mechanically and electrically inclined, though I can't weld and don't have any auto maintenance equipment) and I know my way around a car. However, I don't really want to go into this blind. Do most kits come with installation instructions, or is there someone on YouTube who does tutorials, or some book?


Funding:
I'm a high-schooler, and so I'm operating on a high-schooler's budget. I can make a maximum of about $7,500 in a summer, and while I'd prefer not to work during the school year, I could if that's what I'd need to do. My current car (1997 Saturn SL, afflicted with a terrible case of too-boring-to-bother-converting) is worth another $800ish, and I have about $900 in other liquid assets, bringing me to a grand total of a little over $10,000, varying based on my exact profit from this summer's work.
This is obviously not enough for a $16000-20000 conversion, however there is a solution.

Though federal tax credits for EV conversions expired in 2012, the state of Colorado will refund citizens for 75% of the cost to convert a light duty vehicle to alternative power sources until 2018. Fantastic, I know. This could bring the cost of a high performance conversion, with lots of lithium cells and maybe even dual motors, down to 4-6 thousand dollars, leaving plenty for a decent Ghia. This seems almost too good to be true, so I'd like to verify it before going ahead. Here's my source:
http://www.afdc.energy.gov/laws/5246 (specifically, Category 1A)
Any troubles you can foresee?


I know this is an awful lot of questions, but I want to make sure that I know exactly what I'm doing and not end up wasting thousands of dollars.
Thank you all so much for your help, when I get the build going at the end of the summer, I'll do a build diary on the forum.


-Jamie T.
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Hi, and welcome!

Confirm that conversion grant- sounds way too good to be true! But if it is, and you get all the rules and meet them, it's a sweet deal!

For someone with modest skills and experience, the EV West kit will be a good start. Presume that would be an HPEVS AC35 or AC50 plus Curtis controller, the latter of which is what I have in my E-Fire Spitfire (you can find my build thread here by finding the car in the Garage). It would rock in a Karman Ghia, assuming it will fit and you keep the transmission.

AC is modestly more efficient than DC and also gives you regenerative braking which can be a 10-15% range boost. They're also durable- no brushes or commutators to damage or wear out. But DC is the king for raw torque and power and is (modestly) less expensive unless you go the home-built kit controller and forklift motor route. Not for the faint of heart, and although Duncan did it, I would not recommend a huge DC motor controller as a first electronics project...

As to batteries: Li-ion are your only real choice. These days, the cheapest option is a used Leaf or Volt pack out of a wrecked car- easy enough to come by in the US. Don't mix and match cells- keep it simple.

You also need a charger, and I strongly recommend a BMS as a basic safety feature. The BMS will warn you if any cell goes low during driving, and will shut off your charger when any cell goes high voltage during charging- that's a critical safety feature. Others can chime in on what BMS options there are for the used Leaf or Volt batteries. You don't need anything fancy- just high and low voltage alarms on each cell or group of cells in parallel.

Prismatic LiFePO4 cells are very DIY friendly, safe and can be reliable, but more than double the cost of a used pack from a wrecked EV.

Forget about the onboard generator or modular battery packs. Just build the range you need for 90% of your trips, put in a J1772 port so you can plug in but ALSO keep a 115 volt plug and a long 12 ga extension cord with you all the time, and get the Plugshare app on your phone. Rent a gas engine car for those few times you need to go on longer roadtrips all in one go with no charge stops along the way.

Size your battery pack based on the range you want x ~250 Wh/mile, then divide by 0.7- you don't want to take your pack below 70% depth of discharge if you want it to last.

Plan on heating your batteries- pet heating pads are often used, with a thermostat- and removable insulation.

You'll need a heater- not sure how the Ghia cabin was heated. Most people here use ceramic space heater elements running off their main battery pack, plus a fan. You need a DC rated contactor to turn the element on and off.

Note that you also need some other goodies: either a small 12V battery and an isolated DC/DC converter or a larger battery and a small dedicated charger. An amp-hour meter to use as your gas gauge is the most critical. Most of the obvious stuff (contactor, fuse, main disconnect, shunt to measure current, transmission mounting plate and motor coupler etc.) are probably already in the EV West kit, but they can add up to a fair bit of money if not.

It's a big project, but a fun one with tons of opportunity for learning- and I'd say that a smart, motivated high schooler could do it, assuming they have a) the budget b) a place to work and c) some mentors to help out and help you keep safe- especially a mechanic and someone who has a good background in electrical.

Don't forget about insurance- talk to some other Colorado converters here to find out what they did and who insures them. It can be a real bear to get insurance in some places- next to impossible where I live, but I managed. Have a quote in hand for insurance before you spend a cent on conversion parts.

Keep a sharp eye here on the Classifieds- a project someone has lost interest in can be a cheap source of parts.

In the meantime, read and learn- and keep asking informed questions!

Best of luck!
 

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Discussion Starter #3
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Hi, MoltenMetal, thank you so much for the help.
I looked into the incentives, and found that there is a cap at $6,000 per vehicle. So, I can pay for the first $8,000 at 25 cents to the dollar-this'll buy the entire kit and around 4KwH of Volt battery packs, for about $2,000. Not as good as getting the entire thing 75% off, but still not bad.

However, I'll need some extra funding, most likely, and so I'm considering grants and ways to reduce the price. There's a couple of sustainable tech companies nearby, I could ask them for grants. I could also ask the school district, and though they're strapped for cash like the rest of the educational system, they could likely lend me a bit, as well as the Auto Shop room at the school, which is unused most of the year.

I don't know much about BMSes, do you have any recommendations for where to look? Does each cell need a separate one, or one central one?

Are there any price, performance or range differences between Leaf and Volt cells?

Thanks!
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

You need a BMS board or input channel for every cell or group of cells in parallel. You need a high and low voltage alarm on each. In a Tesla module there are groups of 77 cells in parallel, but you only need one BMS channel for that group of 77 small cells. Cells in parallel act as one larger cell- and all large cells are themselves already groups of smaller cells in parallel, sometimes sharing the same electrolyte.

The Leaf packs are easier to break down cell by cell- or rather two cells at a time as they are 2S modules ( each consists of two cells in series unless I've misread things here). The volt packs are arranged in groups of something like 24 or 48 volts per group, and severing to smaller groups is hazardous. You can find threads here where Volt packs have been used to find more details.

For price, you need to do some shopping.
 

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Discussion Starter #5 (Edited)
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

You need a BMS board or input channel for every cell or group of cells in parallel. You need a high and low voltage alarm on each. In a Tesla module there are groups of 77 cells in parallel, but you only need one BMS channel for that group of 77 small cells. Cells in parallel act as one larger cell- and all large cells are themselves already groups of smaller cells in parallel, sometimes sharing the same electrolyte.
Thank you for your help, let me make sure I have this right:
Your E-Fire has a "32S" battery configuration according to the Garage. This means that you have 32 cells, wired in series. Each cell, however, acts as a group of smaller cells in parallel, (like you mentioned) so you need 32 separate BMSes. Is that right?

Secondly, here are my thoughts on batteries--am I doing it right, or do I have something backwards?
The Curtis HPEVS AC50 (same as in your E-Fire) has a maximum voltage of 130V according to the store page, and, conveniently, two of the 48V packs and one of the 24V packs from the Volt add up to exactly 10 under that. However, all of that only makes 5kWh, which by your estimate would only give about 20 mi of range, or about 15 at 75% DoD. (I chose 75% because most places say 80%, so I averaged. Plus, the math is easier to do offhand.)
So, I would need four of these 120V bundles to get a max 80 mi range, or 60 at a safe DoD. But, so that the pack doesn't exceed the maximum voltage, I'd have to wire them in three packs of 5kWh--each wired in parallel, then wired together in series. Therefore, three BMSes. Do I understand that right? I might have it backwards, and the packs need to be assembled in series, then wired together in parallel, needing only one BMS.
Other option, I could just be approaching this all wrong. Like I said, I'm out of my depth on the battery systems.
My second question regards the heating and the battery heater pad. I went online and found several thermostats like this one, and pet heating pads like this one. I also found several portable space heaters which would work to heat the cabin. However, they all require standard wall outlets to power them. Do the controllers come with outlets to power these things? Do I need an adaptor to convert from the sockets that the controller does output through? Would I need to cut apart the cable and get at the contacts?

In the same vein, you mentioned a contactor to connect and disconnect the heater. Would this also plug into the controller in the same way? Would I enable and disable it with a switch on the dash? How would that be wired?

Speaking of switches on the dash, some places I read mention an electric reverse, where one leaves the engine in the same gear and reverses the direction of the motor. Is that still a thing that gets used? Would I enable that with a dashboard switch as well?

The final part I don't fully understand is the charging system. The kit comes with a dedicated charger (an Elcon PFC2500) and a DC/DC converter (400 Watt, also Elcon) but no batteries of any kind. You mentioned that I would need either a 12V battery and a DC/DC converter or a larger battery and a dedicated charger, but the kit seems to include half of both. Does this mean that I can choose one or the other method, or did I misunderstand what you said? When you mentioned I needed a 12V battery or a larger one, am I right to assume that these are separate from the main batteries in the previous paragraph? How would these systems be wired?

And again, thank you for your help. I admire your patience with my ineptitude, and when my project is done, I hope I can be as constructive as you to the rest of the forum. However, please let me know if I'm asking dumb questions. I'd really hate to waste your time.
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

I'd have to wire them in three packs of 5kWh--each wired in parallel, then wired together in series.
This is the way to go. Each three parallel cells connect together and then all the parallel group in serie.
An option to avoid the three BMS system for each 5Kw pack is to connect the volt pack in parallel with bus bar (conductor).
In my case, the solution was to weld bus bar between cells. That can seem hard to do, but it's relatively easy if you have some welding skills (or a good and powerful spot welder). http://www.diyelectriccar.com/forums/showthread.php/smart-fortwo-ev-high-power-version-51472p31.html
 

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Discussion Starter #7
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

This is the way to go. Each three parallel cells connect together and then all the parallel group in serie.
An option to avoid the three BMS system for each 5Kw pack is to connect the volt pack in parallel with bus bar (conductor).
Hi Yabert,
So, would the solution be to just wire all of them in parallel, and if so, wouldn't that produce more voltage than the controller could handle? I had thought the series wiring kept the voltage the same while increasing the kWh?

Also, speaking of BMSes, do you have a suggestion for a BMS that will work with Volt batteries?
Thanks for your help!
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Jamie,

Welcome. The VW is a great platform for building a first time EV. The vehicles are simple and strong and with them being light weight, they are very well suited for the conversion. I have done a couple VW's and my very first EV conversion was a 64 VW Ghia. It originally started as a 72 volt setup with a Kaylor motor/adaptor and cheap Kelly controller. That soon was replaced with a much better 9" GE motor from an Electric Bradley GT2 E. Those motors are exceptional and they also come with a built in Adapter for the VW platform and yes, you get to use your clutch and gears. That is a good thing as these are considered low voltage conversions. I kept the voltage at 72 volts and swapped out to a 72 volt 550 amp GolfTech speed controller. This provided plenty of power to drive on the freeway but it took a little bit to get to speed. Plenty of amperage from this little controller. I then decided to beta test for Synkromotive and put on a new controller and bumped my power to 96 volts. What a difference that made. Lots of power and grunt. However I was using lead acid for this build and only got about 25 miles range at 55 mph. But, it was fun and had plenty of power. With lithium it would have been a much better story. But the cost with the batteries and Synkromotive controller and the cost of the car was at best about $3400 bucks for the conversion. A low cost conversion can be done. I would totally suggest a good set of Leaf or Volt packs and re-configure them for your voltage setup.

I can tell you that going AC is a good choice and a great one for the VW platform. If you do go that route get the AC-50 or 51. The AC-51 is used with the 144 volt 500 amp controller. That would be plenty for your Ghia. Going dual motor is possible but will double the cost of the motor/controller. They are not cheap.

I currently have a 62 Bug conversion that uses an 11" Kostov motor and will have a total of 192 volts for the pack with my Synkromotive controller. My next project is my 67 VW Bus and I will be using the AC-35 with the 96 volt 650amp controller. The Bus will utilize a large pack of Leaf Modules and I will be using the stock transmission with reduction boxes at first. Should be fine for a slow but strong Bus that is able to drive the freeway in the slow lane.

A good charger and DC DC converter is also needed.

You can also check out some of the other videos that are EV related.

A few others are here: https://www.youtube.com/user/gottdi/videos these are earlier videos I did.



 

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Discussion Starter #9
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

I have done a couple VW's and my very first EV conversion was a 64 VW Ghia.
Awesome, I'm glad to find someone else who's already done a Ghia--I assume you did it before becoming a member of the forums--the only Ghia I found in the Garage was Meeuh's. Is there anything I should know about the Ghia specifically?
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Depends upon what motor you plan on using. As you can see in my pictures that big motor just fits without cutting any sheet metal. The only way to do this is to actually disconnect the transmission on the big end and drop it a little then mount the motor and lift it up as one to allow you to fit it up without cutting. Its easy to do and allows you to do so without cutting. Some motors however are too long but if you do go AC the HPEVS AC-50 will fit no problem without cutting and without dropping the transmission in order to get it to fit without cutting. Other than that, keep the clutch but get a good stage 3 pressure plate so you don't burn up your clutch. You want good pressure on that. If you can, get a special built transmission with VW Type III gearing and a 3.44:1 Ring and Pinion so you can have higher top speeds and be able to utilize the gearing better. With the stock transmission you pretty much start in 2nd or 3rd gear and use 4th for hwy driving. I have a ProStreet with setup that way. I loose some bottom end grunt but it still goes well. Be sure your brakes are in top working order. I always make sure brakes are in excellent condition. Don't ever skimp on brakes. Be sure your grounding connections for your vehicles electrical system are in good condition and tight. The old VW's were notorious for crappy grounds. Clean them up and tighten them up. Should be good to go. If your Ghia happens to be an older one with 6 volt there are a few goodies you will need in order to keep your 6 volt wiring and utilize standard 12 volt system. The 6 volt wiring will handle with no problem the 12 volt stuff. Your windshield wipers need a device to bump the 12 down to 6 so they work properly. They have them. Then you need to change out your 6 volt lights to 12 volt lights throughout the vehicle.
 

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Discussion Starter #11
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

An option to avoid the three BMS system for each 5Kw pack is to connect the volt pack in parallel with bus bar (conductor).
In my case, the solution was to weld bus bar between cells.
Sorry, I misunderstood what you said, let me rephrase my question. You said that wiring the 5kWh packs in series was the way to go, but then you said to put them in parallel using a bus bar--How should it go?
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Well, if you have three 5 kWh battery in front of you (30S 1P, 112,5v and 45Ah each), you will need to connect each 3 parallel cells from the three groups to obtain a 112,5v and 135Ah battery.
 

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Discussion Starter #13 (Edited)
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Well, if you have three 5 kWh battery in front of you (30S 1P, 112,5v and 45Ah each), you will need to connect each 3 parallel cells from the three groups to obtain a 112,5v and 135Ah battery.
Ok, sorry if I've not been understanding very well thus far.
If I can make sure I understand, here's some diagrams of what I'm envisioning, I don't know which one you mean (I'm pretty sure it's #1.)

http://www.digikey.com/schemeit/#2v05
(the diodes are the outputs, to the controller.)

I'm sorry if I'm still getting this wrong.

Another question: charging. I know I'll need a charger and a DC converter, and I'm fairly sure I'll need a 12V battery. (Am I right about this?) Do they just connect to the controller?

Please let me know if I'm asking dumb questions; I'm glad more people than MoltenMetal have come--I'm just afraid of wasting three people's time instead of one.
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Congrats on an excellent choice, young Endorphin!
I'd suggest a full read of my blog at www.karmanneclectric.blogspot.com
Others here can go far deeper on the merits of different electric components, but if you wanna talk about which year of Ghia to pick, the merits of a pan (chassis) modification, and other unique aspects of a Ghia conversion, I'm happy to help. I'll PM direct contact info.
But for basics- AC is awesome and regen adds a whole 'nuther layer of fun, especially in hilly country. But, the Curtis AC drives are still more endorphin than adrenaline; you won't have the vision-blurring acceleration potential of a DC drive (or the attendant cost of broken VW transaxles and burnt clutches).
Build the battery you need now, with an eye for future expansion/serviceability. That's why I favor cutting the pan and making battery boxes as large as will fit. It's far easier to add foam block fillers than expand the battery box later on.
If you get a Ghia with a good engine, build a pusher trailer. They're stupid simple and work great for road trips, especially with a regen-enabled EV.
http://insideevs.com/explained-mitsubishi-miev-range-extender-story/
-Jay
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Ok, sorry if I've not been understanding very well thus far.
I'm talking about cells connection (red, blue), not battery connection (yellow).
Of course the yellow connections are really easier to do and can work in you case of building a 30S 3P battery (112,5v and 135Ah), but you will need to manually verified the balancing between cells or install 3x 30S bms.
It why I prefer to connect each parallel cells together. Only 1 bms. The second picture is one on my 90v and 90Ah battery
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

I'm talking about cells connection (red, blue), not battery connection (yellow).
Of course the yellow connections are really easier to do and can work in you case of building a 30S 3P battery (112,5v and 135Ah), but you will need to manually verified the balancing between cells or install 3x 30S bms.
It why I prefer to connect each parallel cells together. Only 1 bms. The second picture is one on my 90v and 90Ah battery
OOOOOOOOOOOOOOHHHHHHHHH.
Oops...:eek:
I think I get it now, thank you for your patience. I'm not much of a welder, and I'd like to keep the wiring simple, so I think three BMSes will probably be an easier choice. Thank you again.
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Hey EndorphinEV- I missed your previous messages, and Yabert knows more about the Volt packs than I do anyway.

Remember that the cell voltages differ- my LFP cells are 3.5 V nominal, 3.8 V HVC max, but the Volt cells are 4.2 V nominal.

130 V nominal is all the 96V Curtis 1238 can handle. It gives 650 A which gives more low end torque than the 144 V 1239 which puts out only 500 A.

If you don't buss bar the individual Volt cells in parallel to one another like Yabert did, you could wire the three 30S packs in parallel at the pack level, but you would need a separate BMS board or input channel for every cell. You could do that with a whack of cheap celllog8s - cheap but sketchy- but any other way is going to be expensive. Or you could take the risk of running without cell level BMS- not worth the risk in my view.

I have 32 cells in series, each cell being 180 Ah, and I have a miniBMS celltop board on every one. Cheap insurance for a very expensive pack- my pack cost the earth compared to a used wrecker Volt pack. The BMS protects against both overcharge and over discharge. Regrettably I don't think the miniBMS is offered for any voltages other than LFP so it's not an option. The Orion BMS is very spendy but very powerful and adjustable. Others may have other options for you.

If I were you I would get the kit people to credit you for the DC/DC and just use a 12V lead acid battery for your 12V auto needs (lights etc) with a separate charger. Perfect isolation between your 12V and high voltage systems and low cost. The DC/DC would give you longer run time and higher voltage with a smaller lead battery, but at more cost.

The heater will just run in parallel with your controller off your pack, with a DC contactor to turn it on and off. A dash switch on the coil of that relay (you'd operate that coil circuit with 12V DC) would operate the heater contactor.

The Curtis/AC50 Kit comes with a master contactor that will disconnect the pack from the controller and everything else. The controller turns it on and off. You'd still need a disconnect, preferably with a pull cable to operate it from the dash.
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

Remember that the cell voltages differ- my LFP cells are 3.5 V nominal, 3.8 V HVC max, but the Volt cells are 4.2 V nominal.
Hum! 4,2v max voltage and 3,75v nominal for the Volt cell and 3,2v nominal for LFP.

Regrettably I don't think the miniBMS is offered for any voltages other than LFP so it's not an option.
No, you have the choice: http://cleanpowerauto.com/store/#!/MiniBMS-Cell-Module/p/63834149/category=0
 

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Discussion Starter #19 (Edited)
Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

...I have a miniBMS celltop board on every one...

If I were you I would get the kit people to credit you for the DC/DC and just use a 12V lead acid battery for your 12V auto needs (lights etc) with a separate charger. Perfect isolation between your 12V and high voltage systems and low cost. The DC/DC would give you longer run time and higher voltage with a smaller lead battery, but at more cost.

The heater will just run in parallel with your controller off your pack, with a DC contactor to turn it on and off. A dash switch on the coil of that relay (you'd operate that coil circuit with 12V DC) would operate the heater contactor.

The Curtis/AC50 Kit comes with a master contactor that will disconnect the pack from the controller and everything else. The controller turns it on and off. You'd still need a disconnect, preferably with a pull cable to operate it from the dash.
Hi again, Moltenmetal,

1: That MiniBMS looks fantastic for my needs--under $45 for the whole BMS system. Regarding the BMSes, do they need any power of their own? If something is wrong with the battery, how will it warn me?

2: I definitely see the advantages of skipping the DC/DC converter (chief among them being the ability to save $300.) However, one thing that I don't know: OneGreenEV said older Ghias had 6 volt electrical systems. The battery and separate charger have an advantage there, because I could use the existing battery system--unless a DC/DC converter had a setting to produce 6 volts instead of 12. Is this a feature on most converters, or only some, or none?
Also, regarding cost-cutting measures: (as skipping the DC/DC converter would at least partially be) The state conversion incentive combined with the incredible prices for kits and batteries and the like on the classifieds have made cost no longer a real issue.

3: Finally, the heater, thermostat and battery heater pad. As you said, these are wired in parallel off of the pack--great, but how would I plug in these, which ordinarily use wall-outlet plugs? Would I solder wires to the plugs, or cut the cords and split them to get at the cable, or something else?

Thanks again for your help; slowly but surely I'm picking it all up.
 

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Re: Noob Intro:​ High Schooler, want advice for first conversion (VW Karmann Ghia)

OK, you're scaring me now. You need to do much more than just split cords of 120 VAC devices to use them on your car...you will need some electrical help on your project for sure, and to do a lot more reading here.

Yabert has the correct voltages for the cell types. Good that the miniBMS is available for the Volt and Leaf cells now.

The miniBMS requires one ~ $15 board per cell, plus the ~$45 head board. Each cell board is powered by the cell it is attached to- using very little current- and has a relay on it which opens when the cell is in high or low voltage alarm state. The headboard is powered by 12VDC and sounds an alarm and/or closes a relay when any one cell board is in alarm. It uses the state of the keyswitch input (12V from your car's ignition switch) to tell what it should be expecting- a high voltage alarm during charging, or a low voltage alarm during driving. The lvc relay can be used to stop your charger, and the HVC alarm warns the driver to take their foot off the accelerator.

I'm also very concerned about your understanding of the incentive program- it sounds way too good to be true. Don't spend any money until you have this very clear and in writing! But if you have the money and the system is 12 V on your car, DC/DC or not is a minor issue. Many things you may want to use will be 12v only so steer away from 6V.
 
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