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1,797 Posts
Discussion Starter · #1 ·
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Hi everyone,

It's been bothering me for a while that so much information is out of date and hasn't been collimated together in a long time on the state of doing DIY EVs in 2019. So I'd like to change that.

Lots of parts of this website are unused, inaccessible, neglected, etc. So I wanted to do it right here in this thread where there's still some activity. Maybe at some point it'll be edited into the wiki or an article to be posted front and center on the landing page.

This first post I will continuously re-edit to update according to the discussion below, so it can always be used as a frame of reference. If I end up not keeping up on it or leave the community or whatnot in future months, moderators have permission to edit this post and keep it up-to-date.


Content will appear here. Discussion as below.

· Administrator
1,797 Posts
Discussion Starter · #2 ·
I'd like to go through and get up-to-date options (and maybe some historic options) for all major components and parts of the build process. The idea is that a newbie could come here and actually have a clue what to do. Current guides are like, 12 years out of date.

I'm not knowledgeable. I'm just going to spitball here and feel free to discuss and correct and add alternatives.

Donor Car:

- Not much has changed, same old advice is true. But something light and aerodynamic since it helps with range, though range isn't the issue it was with Lead acids.


- Cheapest option is a DC forklift motor. Free-$200 anywhere in the world. This is still a viable build. There is a giant thread telling how, we should probably summarize and photo-journal those. These were popular 25 years ago to 5 years ago, and are still somewhat common today for converters.

- Impulse/Warp 9, 11, etc. DC still. Several thousand dollars. These are basically the same as forklift motors, there's little need to buy them, I don't think anyone's bought any for a new conversion in several years (?).

- AC forklift motor. I don't know anyone doing this other than me actually. Don't know how common this is.

- Hyper 9, etc. AC motor. Or other purchased AC motor like the Siemens? I don't know much about these at all or if anyone's actually using them.

- OEM EV motors. This is probably the biggest change since all the last guides were written. back then DIY EV was the only way to EV. Now it's just a way of making the vehicle you want to be electric into electric. What are the common choices?
- Nissan Leaf FWD.
- Tesla FWD (small)
- Tesla RWD (large)
- ??? ... and all these sections should have some links to some common guides and some quick notes on their suitability, power, cost-ish, complexity, etc.


- Lead Acid deep cycle batteries. Never do this anymore. They were the only option until ~2012 (?), everyone used these. Some used marine batteries, some golf cart batteries, some ordinary storage batteries. They are currently entirely outdated. There are zero reasons to use them, not performance, not cheapness, not durability, nothing. Don't even consider it.

- Large format Lithium-Iron-Phosphate (LiFePO4) batteries. These are recently, but now thoroughly outdated. They were popular from (? 2012-2016?). LiFe cells are lower voltage than other Lithium chemistries, and at the time were more durable and higher power. These were ordered typical by manufacturers like (? and ?), ranging in capacities per cell from (? to ?), and were physically large, like two hardcover books in size. You would generally have a single series string of these to add up to your total voltage. They turned out to not be as durable as expected, and are no longer cost effective in any way. Some DIY EVers will still buy them to increase voltage and storage of an earlier build, or to replace dead or dying cells, but no one converts with these in mind anymore.

- 18650-size Lithium Ion cells. This idea was popular in (year?) but almost never implemented or finished. Around this time 18650 format (thumb-sized) lithium cells became available for sale to ordinary consumers. Tesla uses this form factor for many of its vehicles because of their configurability. Small cells are more easily reoriented to match any shape. Typically dozens to hundreds of cells would be in parallel to make an equivalent large cell, and then many of those would be in series to create the pack. There is also a popular recycling movement to convert old laptop and tool pack cells into DIY Powerwall and off-grid storage, but for vehicles it's a long and difficult process. Very few people ever did this and it's no longer cost effective.

- OEM EV salvaged packs. While not available on the new market yet, salvaged packs from crashed or obsolete OEM EVs are a plentiful source of new packs, sufficient for the DIY EV community. Popular choices are:
- Chevy Volt (years?), large format cells with not great energy density, but having a reputation for high power (performance use) and durability. They're water-cooled.
- Nissan Leaf cells. First gen (years?) cells are prone to problems. Second gen (years?) cells are decent and commonplace. These are rectangular block cells the size of hardcover books, usually in cell series pairs (7.4v). They stack easily together and are clamped together with threaded rods inserted at their corners.
- Tesla packs. Tesla packs are difficult to disassemble groups of (? how many) cells in a block, with (number?) blocks in a typical car. Each block is fairly easy to separate but blocks are often ruined by attempting to access individual cells. They are typically more expensive than other OEM EV packs.
- ??? others, and, a moderate introduction should be available for each.


Anyway that's a start. If anyone wants to include missing options, fill in missing details, make corrections, etc. That'd be appreciated. I'll lump it together and start to edit the first post to fill that content in.

· Administrator
1,797 Posts
Discussion Starter · #3 ·
Oops, forgot controllers.

DC controllers:

- Forklift controllers. Cheap and readily available, but low voltage.

- 2 or 3 purpose build controllers generally from forklift or golf cart manufacturers.

- DIY community options
- Paul & Sabrina's (status?)
- Someone here was building a controller very simply a while ago, and then changed later to AC, I forget the name and this is all off the cuff or I'd be swamped in research.
- Who else?

AC Inverters:

- JHeuber's

- Someone else built that DC controller that became AC?

- Someone today posted their open-source 4-man team that just finished an inverter?

- OEM EV as designed. Bring the whole EV brain and ECU and re-use the existing inverter.
- Leaf
- Tesla, various options that work or don't work, I don't know much about them.

- OEM EV hijacked. Damien is working on one of these for a Prius and Lexus inverter. In development. Open source.

... brain is mush. I'd like this to be a community effort, I'm just collecting the info and trying to make it beginner-friendly. I'm not actually much of an expert of what's done or why or what the options are.

· Administrator
1,797 Posts
Discussion Starter · #5 ·
I take issue with much of the second post. Please delete it. This is diy. It is not do it Matt's way.
Hey, I'm sorry you hate me so much, but, you can either contribute in a useful way, or leave the discussion to people who want to have it rather than trying to dictate that other people aren't allowed to have it.

No, I'm not going to delete an entire post that is a loose, roughly-assembled beginner draft specifically for people to critique, because you "take issue with it" and somehow thing it's me trying to tell people to build things "my way", which... I don't even know wtf you're talking about, as I described 20 different options.

If you can't be bothered to at least be detailed about your criticism, and contribute useful corrections, then all you've done is show up and introduce negativity and a smug authoritarian denigration of someone else's efforts. It's not helpful, it's not useful.

Frankly, I think you hate me so much, and you're so biased, that it doesn't matter what I say, you'll find a way to say it's worthless.

It's fine if I'm wrong, it's fine if anyone's wrong. It's a discussion. I'm sure things will be corrected 100 times here, but no, I'm not going to be bluntly censored by a curmudgeon with nothing more than an opinion and a declaration.

Be a civil human being. You could use practice.

· Administrator
1,797 Posts
Discussion Starter · #7 ·
Cool idea. I will put together a post tonight expanding on battery options, I have been doing a ton of research in that area.
Much appreciated.

I'm probably going to work it like a poor-man's wiki, checking back and updating the top post with details. I just left it blank for now because I expect it to change a lot at first.

· Administrator
1,797 Posts
Discussion Starter · #9 ·
instead of pushing your opinions in the reader's face? Present options for equipment, not dictate what to use or "Don't even consider it."
Part of good advice is to give some context for beginners rather than just saying "Here are 50 options, do your research". It's nice to say "Here are 3 options, but you probably want #1. Here's a few details".

Especially when people hear old advice, it helps to identify it as such and explain why times have changed. Outside of this community, I've had people argue with me that lithium can't be trusted, and I'll have to use 1000 lbs of lead-acids in my conversion and it's a stupid idea. People hear these things, and it's neat (to me) to identify some history of why that was once true and is no longer.


But go on then, since you strongly disagree, make a case for why people should be using deep cycle lead acid batteries in their EVs today. Point to some examples of people currently doing this. I'm happy to incorporate it if it's at all convincing.

· Administrator
1,797 Posts
Discussion Starter · #12 ·
Been researching this recently, my contribution,
Great stuff. I'll probably include it verbatim. Thanks for putting in effort!

The thing is, almost everyone here is doing this kind of research, and there's a lot of reinventing the wheel. And newcomers are asking the same questions over and over, so, it's good to have more visibility and a place to send them.

· Administrator
1,797 Posts
Discussion Starter · #15 ·
There is a wiki within this forum

If someone wanted to, they could try to fix the wiki articles (clean them up, then update them), rather than creating reference-style forum entries scattered through other categories.
I've organized "what's the best way to get the best information to people the easiest way" in other communities a few times. How to transition out of where a place is and into what it could be.

Wikis are great, if there is a large enough group of people updating them with new information regularly.

The problem with this community is that we don't have that active team archiving things. And we probably won't. When there is new discussion or new things we learn (which is sometimes hard to identify, as it occurs gradually enough that the point where it is now "a thing" is never clear), no one adds them to the knowledgebase.

Further, many people with the most knowledge, by virtue of having the most knowledge, aren't *using* the wiki or archive or whatnot, because they don't need to. So they don't notice on a regular basis that it's out of date.

With wikis, it's very much that it *must* be active and up to date, because the answer to any question has to be "Check the wiki, it's always up to date". As soon as the answer becomes "You could check the wiki but it's old info so search for..." then there's no point. You might as well just let people keep asking the same questions over and over.

Another pet peeve is "Oh it's on my github". That's great for people who are capable of replicating your work by themselves (other EEs/programmers), and are only taking advantage of the fact that you've already done the work. It's utterly worthless for someone who's two tiers of knowledge below your and just wants to learn how to do something.

Another awful one is "Just go read this thread". Where the info gradually changes and you have to keep track of a conversation. That's garbage. A concise summary is what's useful, not "go replay an entire conversation".

Almost none of the info in many places is written the way that is useful to person it's supposed to help, typically because the people who can help aren't good at putting themselves in the shoes of the people who need help.

Anyway, a thread like this is a terrible way of archiving information, but it's the best way I could think of, for collecting that information. Maybe it'll end up in an article or pushed to the wiki or something like that in the future. But in terms of community participation, I think a discussion thread is going to work best so that's what I'm trying.

Most importantly, actually doing something rather than complaining about it is what gets things done, so, it's great to see people stepping up and chipping in where they can.

· Administrator
1,797 Posts
Discussion Starter · #18 ·
Actually, there *are* good reasons to use them. Example. I live in a cold climate.
I understand your argument, I just don't think it has much merit. If other people agree strongly with you, I'm open to reconsider, but this is exactly the kind of thing I think should be nipped in the bud for beginners. That thinking that Lead-acid batteries in 2019 for an EV is a viable, useful option worth considering. I think it would make sense to include an aside or a link about why Lead-Acids used to be popular, and why no one in the community choose to use them anymore.

But, that's the takeaway. No one chooses to use them anymore.

I mean, there's technically viable reasons to include a horse and buggy as your method of transportation, but that's so unlikely to be useful information to anyone that "What vehicle should I drive" summaries don't include it. I suppose equestrian fanatics may be upset, but that does't make their advice useful.

Finland (?) is leading the world in EV sales. Finland is cold.

What do literally 100% of OEM EVs use for batteries? Lithium.

The case for Lead-acid in EVs is dead when the combined knowledge and engineering forces of the entire planet has concluded there is no reason to use them in EVs. To say otherwise is to think you've come up with something that the rest of the planet could not. There are some circumstances where the DIY solution differs from the new market, but I don't think that's the case you're making here.

Another way of thinking about it... Lead-acids are so non-durable that gasoline is more cost effective, even if electrical energy is free. Just in replacement cost over their expected lifecycle.

Another way of thinking about it... when's the last time someone build a DIY EV using lead-acid? And, if they did, was it foolish of them to do so? Of the people who may read this, what percentage of them is it better advice to get them to consider lead-acid, than it is to tell them it's almost certainly not worth considering and give them a footnote if they're really curious to read more?

Another example - the guy who got a free DC forklift motor, total noob. You threw him out with the bathwater by eroding his confidence through "obsolete" namecalling.

What guy?

Did you read what I wrote about DC forklift motors? Scroll up and re-read it, because you're arguing against something I didn't say. Here's what I actually wrote for my notes on the topic, in a draft. "Cheapest option is a DC forklift motor. Free-$200 anywhere in the world. This is still a viable build. There is a giant thread telling how, we should probably summarize and photo-journal those. These were popular 25 years ago to 5 years ago, and are still somewhat common today for converters."

Who's confidence did I erode? Where did I use the word "obsolete"? If I had (I didn't), how is calling a technology "obsolete" namecalling?

I don't understand your criticism.

I am generally writing observationally, based on what I see people building in the end, after they slog their way through all the options, and trying to make that path shorter for them.

You can't win on this thread. Evar. All you're doing is declaring yourself to be a winner, bolstered by calling any critic or counter-arguer a loser.
Huh? Where are you reading that? This seems like you're arguing with a completely different person.

I'm not trying to win. I'm trying to kickstart writing a summary. I invited and welcome criticism. I never called anyone a loser for being critical. What I actually said was to be "usefully critical", rather than just demanding someone delete content with no explanation given.

If there was one panacea, *everybody* would be doing it. Somebody would offer a complete kit (because, according to you, each block only has one optimal choice, cost be damned).
That is not how DIY works on large or expensive projects, so I disagree with your assertion.

There are hundreds of car options available. There is no sense in a generic "kit". The mechanical constraints of each donor car is fairly unique in terms of a solution.

Further, economic constraints matter too. What someone can find in their area and for what price is widely variable.

Just because there is not a kit, does not mean that a summary of the state of affairs of the meta of the current DIY EV community has no value. Quite the opposite. It means that there are some choices to make, that most people are leaning in a certain direction, and here's how to think about the choices available to you based on your preferences for performance, budget, suitability, etc.

While you might think you're god's gift to a universal EV build, it's weapons-grade bullshit to even think there is one.
Honestly you keep putting words in my mouth and insulting me over things I didn't say, don't think, haven't implied, etc. I invite criticism and instead you're openly hostile.

What I did was kickstart a community project to address what I think is the biggest hole in our knowledgebase, and be the easiest way to fill that gap for people who join the community.

· Administrator
1,797 Posts
Discussion Starter · #19 ·
You REALLY want to help newbies at this? Post up a correlation between electric motors and ICE setups.
That's something I'm happy to collimate but I'm too far out of the loop.

DIY EVs are at 2 extremes, generally:

1 - The frugal.
2 - The performance-minded.

I see a lot more of the frugal here, partially I think because performance-minded people are more secretive due to their competitiveness and due to the money involved. Damien ran into that a few months ago, two different groups of professional racers had the same problem with something he built, that he helped tweak to fix, but I think some of them took most of his solution and then finally figured out a result, and, despite being open-source, didn't want to share it. They wanted their competitive advantage.

I see a lot of value in someone contributing things from a performance perspective, that's important. But to be extra-specific goes a bit against the point of this guide. I think a solid overview of the basics is important to know what kinds of ballparks to expect (though apples-to-oranges is going to be a bit of an issue).

I could write up a very loose overview but I wouldn't trust my finger being on the pulse of that part of the community much. Happy to collect and incorporate whatever anyone else contributes though.

· Administrator
1,797 Posts
Discussion Starter · #22 ·
You're again being busy defending *your* choices to *your* problem set, and seem to be completely missing my point.
I don't have a choice to be "defending" when you decided to make bizarre attacks.

You set that narrative when you made an attack. At that point I can either accept and agree with your nutty assertion, or refute it. I refute it, then you set the narrative again by saying I'm "being defensive".

"Who's done lead acid lately?" is crowdthink nonsense. It all depends on the problem being solved. [...] Yes, there are still people doing lead-acid, including OEMs.
I think, if you showed up in a beginner's thread, asking about batteries, and started recommending Lead Acids, you'd get laughed at by everyone else in that thread.

Honestly, I can't think of the last time ANYONE suggested it. No one gives that as advice. It's not useful advice for anyone. This really seems to be a sticking point for you.

I guess I'm wrong about 100% of OEMs being lithium. Can you point out some sources on which OEMs are using lead-acids? That's interesting enough to note.

The latter you can't do for anyone, though I perceive that's exactly what you're trying to do, because your assumptions will be incorrect due to every problem set being different.
Fer Christsakes, tone down the rhetoric.

Jesus, all I'm trying to do is create a helpful beginner document, and you're making it seem like there's no place in the world for that. Everyone better get a PhD and to read 1000 forum threads before they dare start making any decisions about EVs.

I'm skeptical this will go anywhere without being optimized for one specific problem set -- yours.
There are multiple options, I don't know what you're saying otherwise. Actually read what I wrote in my loose notes of what sections should mention.

There are many options for motors both in type and size.
There are many options for controllers.
There are many options for battery sources.
There are many options for donor vehicles.

You can keep trying to declare my efforts to force everyone to build one thing one way. That's not what I wrote, that's not what I intend to write.

But now thanks to a few people jumping in immediately to pick fights, pretty much ruined the positive outlook of this thread and anyone wanting to contribute. Mission accomplished contrarian jerks.

· Administrator
1,797 Posts
Discussion Starter · #31 ·
Just wanted to post and say I've been neglecting this thread but haven't abandoned it.

I'm in the process of getting my EV donor vehicle here, this week hopefully.

Please continue to post things you would like answered, or answers to things questioned, or criticism of points made or engage in civil discussion. Every little bit that people can chip in helps.

Ideally I will not be the source of most of this info, I'm just going to be piecing it together in a coherent way.

Things like... "What are people using for a BMS these days?" I don't actually know. If someone asked that question I wouldn't know what to tell them, or what the current meta is for BMS selection.

And so on, all the stuff that was fairly well documented 10 years ago, a modern update.
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