Need help. Converting automatic Insight to EV possible?

[TheForce]

Since I don't fully understand how the automatic Insight works I'm hoping some people here can help me out.

I know the issues with converting regular automatic cars to EV but I think the Insight would be a little different and I need some help to see if it would be possible to convert an automatic Insight to EV.


I'm looking to buy an Insight that is cheap and might have problems running to do the conversion on. I don't want to gut a perfectly good working Insight. I know I could get a manual Insight converted as I could gut just about everything and get it rolling.

My theory with an automatic Insight is that there needs to be some computer left in place to control the CVT. So one of my questions is would the computer be dependent on any of the ICE components to work correctly?


I would prefer to convert a manual Insight but I found a good deal on an automatic. I can see where converting an automatic would be nice ( no need to shift ) but it would be easier to convert a manual. Maybe.

Any thoughts?

[Cobb]

I think that is a great idea as you can always multiply your torque. It doesn't have a tradition torque converter, so basically you just need to lock the clutch pack then work the ratios. I think that maybe easier said than done.


Sent from my Autoguide iPod touch app

[Hugh-Falls]

Good used Insight CV transmissions are hard to find and a GOOD used one will fetch a very good price. Used manual transmissions are available at a pretty reasonable price and with an EV conversion, the worn synchros in even a mediocre manual transmission will not be a very acute problem since shifting will probably be minimal.

If in good condition, you can sell the CVT and buy a manual transmission and clutch and you will probably come out well ahead, especially if you do the work yourself. Or, just find yourself a good deal on a manual Insight.

The CVT has an electronic transmission control module that is matched up with the particular year model of the CVT. Tackling the problem of devising a stand alone electronic control for the CVT sounds pretty formidable. Where do you begin the design process, at the transmission or at the engine control module?

[TheForce]

So the Insight CVT is not going to be like a regular automatic transmission? With a normal car you can keep the electric motor spinning all the time to get it to work correctly. So with the automatic Insight I might have to do more to get it working as an EV?

If building some kind of interface to get the CVT working is the only answer I might as well buy a manual as I dont want all the hassle of getting it rolling.

I may buy the CVT and fix it up to sell but I just dont know about that yet.

[2Slow4u]

I would recommend not using the CVT if you were to convert it to an EV. Just use a gear box to get the correct ratio.

What kind of budget were you thinking for this conversion? Thats going to limit what type of components go into it.

Brushed DC motors are the "cheapest" and maybe conversion vehicles use the, however they are less efficient and you do not get regenerative braking.

Lead Acid or AGM batteries are the "cheapest" as well to get you up and started. But you will soon realize the range limitations, weight, and lifetime of that type of battery pack and want to switch to a lithium pack.

[TheForce]

Sounds like I should just stick to my original plan. I may think about buying the automatic Insight to fix up and sell but I just dont know.

I have a plan on the components.

Netgain motor
Soliton controller
CALB, Winston, or similar LiFePo4 battery
Running at least 144v

I'm going to try to follow Jack Rickard's approach on the conversion.

[2Slow4u]

Netgain motors are good for conversion projects, it will work well for what your trying to do with it. They also make a pretty good controller. I have a warp 9 and a 1400amp netgain controller running at 156v in our test vehicle and it can roast the tires/whoop a tesla roadster 0-60.

I have not used Soliton controllers before so I can't help you on that.

I'm quite familiar with LiFePO4 batteries. I would recommend CALB or Voltronix cells. GBS cells are good, but a little pricy.

What do you mean follow Jack's approach to the conversion? I'm quite familiar with him and his EVTV show.

A little background on me. I work for a battery management system company and am a sr. applications engineer. Basically design EV and PHEV power trains and all the details that go into them everyday. We are a supplier of Voltronix and CALB cells, but only because they have past our in house testing. We've tried several of the other brands and have chosen to support only those two for now because of the price, availability, and build quality.

If your planning on going Jacks route and not using a battery management system, I'll tell you the pros and cons if you'll listen. The cliff notes is that its an insurance policy for your cells, and your cells aren't cheap.

[TheForce]

I like Jack's design approach and yes I will be going BMS free and bottom balancing. I know the pro's and con's of BMS's. Like Jack I have not seen a BMS I like. The mini BMS comes close but I'm still going BMS free.

[2Slow4u]

Well then I wish you the best of luck. You'll be missing out on doubling the warranty period on your cells, using the full capacity of your pack, safe fast charging and balancing every cycle, charge/discharge control to prevent over charge/discharging, extending your packs lifetime, and an actually accurate state of charge with adjustments for temperature, parasitic losses, and SOH.

LiFePO4 batteries have some great advantages over lead acid batteries, but if you use them outside their parameters they are permanently damaged and do not come back to life like lead acid batteries. Just remember, every cell has different internal resistances and become more and more out of balance every cycle because of that. So don't get too comfy with manually balancing once then walking away.

Here's my personal opinion about not using a BMS. With lead acid batteries you can only use about 50% of their capacity without damaging them. With LiFePO4 cells it is totally possible to safely use the middle capacity of the cells without monitoring them, however you can only use about 70% of their capacity that way. At which point the usable capacity equation against lead acid batteries isn't too huge of a range gain. With a good BMS you can safely use 100% of the capacity of your cells and not have to worry about it. There is a science to the business and that is what we do. To me it doesn't make sense to upgrade to lithium cells and not use their full capacity, its like driving around with an extra 10 gallons of fuel in your trunk and never using it, even when your out of gas.

[MN Driver]

I'm not buying that you could only use 70% of their capacity, extending pack lifetime, or preventing overcharge/discharge don't really need a BMS. "Just remember, every cell has different internal resistances and become more and more out of balance every cycle because of that." You've got the exact cause of what causes cells to go out of balance, but a very simple LVC system along with a good Ah counter could get you to the full capacity and allow you to monitor the parameters of the cell to not damage them as you can check them during charge occasionally to be sure nothing is getting to a point where they may overcharge and large changes won't happen overnight anyway. BMS or not you are still limited to the cell with the least capacity unless going with a capacitive balancing system or something similar to shuttle the charge but those are more expensive and typically inefficient enough to actually be worth getting to gain a few % of extra capacity.

Doubling the warranty period? I'm not even sure you need a warranty period on these because there really aren't many failures from what I'm seeing of everybody using CALB or TS/Winston cells. If there are any real failures I'd expect them to be beyond the warranty, also if anyone is looking for a real warranty, it has to be handled by whoever the US distributor is because getting a battery mailed to a port and dealing with customers would be a massive PITA. If I have a cell failure, I'll just remove the affected cell and accept a slighter lower voltage as the range and performance will be overkill on my own conversion.

To me it's a cost/benefit and a simplicity factor, its hard to overcharge to be an issue in a high voltage pack when charging to a slightly lower voltage where the capacity is pretty much all still there, for example 3.5 volts per cell and 60 cells with a 192v nominal pack would allow for 6 volts of wiggle room, that would mean that you would have to have some serious cell problems to create an issue and most people are seeing the difference between 3.45 and 3.6v termination voltages to have so little extra energy to the point where its not really an issue at all and when you check if you see a cell charging at a higher voltage then you would know to investigate the cause.

If I believed your 70% of their capacity, I'd probably consider a BMS but I don't. These cells are rated at 80% DOD anyway and going below 90% DOD and ripping heavy current through them gets them hot fast so overdischarge would become an issue if I had plans to frequently run them below 90% DOD, which I could do with confidence with an LVC that costs about $50 which is less than the cost of a single cell. This allows me to easily just buy an extra cell or a few with the extra money that a 'BMS saves me for saving my battery pack'.

Tell me where I'm wrong? I'm genuinely curious where I could come out ahead other than a little extra time that I would have my not using a DVM to manually check things a few times a year after making a deeper run into my range to be sure everything is still lined up. I understand most people aren't willing to or know what to look for to check their pack but I'm not seeing a 10% drift from IR losses in the matter of even a half a year. I'm not in the camp of just throwing cells together not balancing at all and just throwing a pack into the car and connecting leads and never looking at the pack at all like Jack was(he's since reformed himself a little), but I'm not seeing only having access to 70%. I don't drive my gasoline Insight to where I have less than 10 miles to go and I wouldn't do the same with an electric either. For me that is 10% and for max battery life you wouldn't want to be below 90% DOD anyway but you could do it without catastrophic damage without a BMS if you know what you are doing.