Third Conversion, ultra efficient (1993 Geo Metro EV)

[unheardofinstruments]

I am currently building my battery boxes so I loved seeing what you have done, very inspirational. In Australia the rules (ncop 14) in the national code of practice prohibit some things such as tampering with chassis rails and the forces the mention for battery restraint when calculated in real terms mean dropping the car from 6 meters on it's roof and not having the batteries come out. I thought of aluminium but the shear strength and cracking fatigue made me go for light guage steel I scavenged from the back of a motorcycle shop, it was used for the packing crates the bikes come in and is smaller angle than I can buy here. I had underestimated how much effort it would take to design and make the boxes, and the time spent just lying under the car figuring. I can understand what went into this and people this guy is a legend! I can't wait to start doing some of the tests you did, great posts thanks! If we just grass roots convert the old bangers we have a revolution, let alone if we charge with a rankine cycle solar generator or syngas, or...big ups from down under, and a pat on the back hearty handshake and a (virtual) hug

[Astro]

Originally Posted by unheardofinstruments

I am currently building my battery boxes so I loved seeing what you have done, very inspirational. In Australia the rules (ncop 14) in the national code of practice prohibit some things such as tampering with chassis rails and the forces the mention for battery restraint when calculated in real terms mean dropping the car from 6 meters on it's roof and not having the batteries come out....

NCOP14 is a party pooper. I read so many success stories on this forum and then have to accept that NCOP14 would stop me replicating many of them myself.
So now i am doing my entire conversion without cutting or welding any part of the original vehicle. Everything will be bolted to existing mounting points. And the weight of each item i attach won't exceed the weight of the original factory item that was removed from that mount point. Makes everything much trickier.

EVmetro's build is amazing, definitely qualifies as conversion porn.

[EVmetro]

That is a bummer that you guys have to deal with that ncop14 stuff. As a professional collision tech, I had to be ICAR certified to repair wrecked cars, and there was a standard that I had to comply with when repairing structural damage or when replacing frame rails and other structural components. The standard makes sense in the repair industry, but not in the custom car industry. I was able to build this Metro with ICAR standards in mind as an experienced unibody tech, but I doubt that my modifications would be what ICAR had in mind. Our government here is growing at an an alarming rate, so I will not be surprised when the time comes where the government here will not allow me to do what I do anymore.

[pearl62]

Congratulations on a very nice conversion... you did great work!

I converted my Civic last summer and used the same charger and similar gauge cluster setup as you have. I have over 8000 miles on already and not a single problem!

You check it out here: 1996-civic-ev.blogspot.com

[Keito]

Originally Posted by EVmetro

That is a bummer that you guys have to deal with that ncop14 stuff. As a professional collision tech, I had to be ICAR certified to repair wrecked cars, and there was a standard that I had to comply with when repairing structural damage or when replacing frame rails and other structural components. The standard makes sense in the repair industry, but not in the custom car industry. I was able to build this Metro with ICAR standards in mind as an experienced unibody tech, but I doubt that my modifications would be what ICAR had in mind. Our government here is growing at an an alarming rate, so I will not be surprised when the time comes where the government here will not allow me to do what I do anymore.

You're a lot more than just a professional collision tech bro.
My pants got tight reading this thread.

[NeilBlanchard]

Did you bottom balance the pack, or are you using BMS?

[EVmetro]

Originally Posted by Keito

You're a lot more than just a professional collision tech bro.
My pants got tight reading this thread.

Thanks. It gets a little boring doing the same old production repairs in a body shop, and a lot of us dream of doing custom stuff, hot rods, harleys, etc. Doing these EV conversions is a great way to get outside the box...

Originally Posted by NeilBlanchard

Did you bottom balance the pack, or are you using BMS?

The pack was top balanced in parallel with a bench type DC power supply before being installed, and now the top balance is maintained with an Orion BMS.

When I first started converting vehicles to EVs, I bought an Orion to simply top balance my pack, but did not understand the difference between an Orion and other BMS units. The term BMS to me referred to a generic device that top balances a pack, but I have since come to understand that the Orion is far beyond that. It is basically my ECM, and it does everything from top balancing my pack to providing all the data for my instrumentation, to communicating with my motor controller for regulating current output in such a way that my pack can never be abused in any way. The Orion has proven to be the gateway to a very advanced EV that I never would have achieved if I had originally purchased a different BMS. I was naive when I bought the first Orion, but stumbled on something huge. I have done several conversions using the Orion, and each one is more advanced as I learn how to use all the features of the Orion.

[NeilBlanchard]

Thanks for that info - I am a newbie to all the technical stuff on EV's. Does the Orion actively balance the pack while it is in use? One of the things I have been told consumes some energy is when BMS does this. And also, some BMS units shunt the excess energy to ground when a particular cell is fully charged, and a few divert it to other cells that are still charging.

As I understand it, both of these are advantages of bottom balancing the pack.

I totally agree with you on regen, and the way you have implemented it is exactly how I like it. Only the e-Golf and the Fit EV in Eco mode, have coasting. Does your car require you to hold the "shifter" to control the regen, and if you let go of the lever, does it return to coasting?

[EVmetro]

Originally Posted by NeilBlanchard

Thanks for that info - I am a newbie to all the technical stuff on EV's. Does the Orion actively balance the pack while it is in use? One of the things I have been told consumes some energy is when BMS does this. And also, some BMS units shunt the excess energy to ground when a particular cell is fully charged, and a few divert it to other cells that are still charging.

As I understand it, both of these are advantages of bottom balancing the pack.

I totally agree with you on regen, and the way you have implemented it is exactly how I like it. Only the e-Golf and the Fit EV in Eco mode, have coasting. Does your car require you to hold the "shifter" to control the regen, and if you let go of the lever, does it return to coasting?

The Orion does not balance cells while the car is driving. When the charger is running and cell voltages are rising, the Orion will put a tiny bit of resistance on the cells that are filling up the fastest. The point where the Orion begins to add resistance is user programmed, so you can tell it when, if at all, to do it. The Orion will shut the charger off when the first cell reaches whatever value you program in, and then will continue putting resistance on the high cells as the pack settles, until a second user programmed point is reached, at which point it no longer puts resistance on those cells. I set this rig up so that as my pack is charging, it puts resistance on each cell as it passes 3.42 volts, and then the Orion shuts the charger down when the first cell reaches 3.55 volts. I set the Orion up to continue to put resistance on the high cells as the pack settles to resting voltage, and I programmed 3.40 volts as the stopping point. Once the last cell settles below 3.4 volts, the Orion is no longer doing anything. The amount of energy lost to balancing is very trivial, and would be expressed in milliamps.

As for the bottom balancing thing, there is a never ending debate about bottom vs top balancing. With all due respect to the knowledgeable folks who support bottom balancing, I do not believe that they understand the implications of an Orion, and still look at it as just a "BMS". Although I am not fond of the Prius, I do respect Toyota's educated decision to use a 16 cell version of this on the Prius. They have invested a lot more money than I have to go with this top balancing technology, and they are more up to date than the bottom balancing crowd. To me, the Orion makes bottom balancing look like obsolete practice.

As for holding the shifter button to maintain regen, that is exactly how it works. I can push the button as much or little as I want during a non regen coast, regulating the regen level, and when I release the button completely, it is back to no regen coasting that feels like a car that is in neutral.

[puddleglum]

I have a few questions about your battery choice. Have you used any of your conversions long enough to have any idea of how reliable these cells are? Have you had any faulty ones? Also, how do they compare in price to CALB or Winston for example. Do you order them straight from China and, if so, have they been good to deal with?