I was reading about the Chevy Volt and saw that they had very explicit instructions about disarming the car in emergencies. Similar instructions appropriate for an EV could make things safer for occupants, first responders and could save equipment from unnecessary damage.
I intend to have a manual disconnect to separate the pack from the vehicle
and an intermediate manual disconnect (Anderson connector?) to split the pack into two segments
Instructions to Emergency Services
(1) - Pull big red lever - in front of handbrake
(2) - under the bonnet - pull Red Handle - marked Emergency disconnect
Some one told me once that EMS responders in the US are being trained to look for large orange cables leading to the controller and/or batteries and to cut them with insulated cutters.
I think i spotted on a forum last year that certain parts of canada had banned ev conversions then changed their minds but specified a large warning sticker had to fixed to the car. I wonder if we could get those?
if you have a picture, lots of the vinyl sticker shops can copy and make'em, for ya. However, I think a scarey looking sticker might scare off a Responder when you most need it!
The key I think is for YOU to build a vehicle with multiple safeties like:
- mid-pack fuse - quick acting
- main circuit breaker - slow acting
- manual pull disconnect - reachable from driver's window and seat
- inertia switch on main contactor/controller
...probably some legislated standard like the the manual pull disconnect MUST be near the driver's left knee and have some standard color/graphic so it can be accessed from driver's window by Responders....
and some mechanical safety standards, as much as I hate regulation, for our own good like:
- some standard sticker/emblem on exterior of driver's door indicating vehicle has high voltage
- main battery cabling from pack to motor must be routed under the center of the car to
avoid 'jaws of life' that typically cut doorsills and pillars
- batteries terminals and bus bars must be covered to prevent accidental shorts
The driver's air bag firing should trigger a circuit breaker. Saying this, I have no knowledge of air bags or the way they work other than a novel I read claimed the explosive material was very poisonous.
the whole idea of an inertia switch in the main contacter loop is exactly this. in an impact strong enough to deploy an airbag, the main would open... just like the original design cuts power to the fuel pump. no need to tie it to the airbag system. easy to add, even in pre-airbag cars.
ok, so.. just to summarize the related info. For Emergency Responder safety and comfort in rescue should you ever need it, I would recommend:
- designs to include routing HV under middle of car to avoid possible cuts w/ jaws of life, main pack fuse, circuit breaker, key-switch contactor, and:
- inertia switch in the key-switch 12v+ to your main contactor which will cut power in case of crash
- some obvious badge or sticker on driver's side at very least identifying vehicle as electric (presuming they understand that means having high-voltage)
- manual pull 'kill' switch/lever/pull reachable from outside driver's window that a Responder might be able to see and pull to feel 'safe' before going in w/ jaws of life....
I have my own vinyl cutter and made some 3" high voltage (triangle with lightning bolt inside) and put one on the back and high on both front fenders. My car also has "electric" stickers on it. I plan on integrating an inertia switch soon too.
My ultimate plan would be to get the DMV license plate division to issue a new plate for electric vehicles. That way we could use our local parking charging stations (gas cars get ticketed if they park there) and let people know the vehicle is electric.
Here is a link for the U.S. NATIONAL ELECTRIC VEHICLE SAFETY STANDARDS SUMMIT report. Don't know if anyone has looked through it but it has quite a lot of information for the safety standards for mew EV's. http://www.nfpa.org/assets/files/PDF/Research/RFUSNEVSSSummit.pdf
I hastily scanned the U.S. NATIONAL ELECTRIC VEHICLE SAFETY STANDARDS SUMMIT report. It appears to be a report on the meeting. I didn't find any definite recommendations. It did mention NEC 625 which covers charging electric vehicles. It appears that charging at over 120 volts or 20 amps could have some insurance implications.
I am putting a decal on the bottom left corner of the windscreen (near the VIN#) that says "In emergency pull yellow connector by hand brake". There is the large anderson connector right obviously there. I also encased the + and - in separate 1" pvc from trunk to front batteries. One time one of the electric order pickers stuck on forward for no reason (contactors welded shut) with no stopping it. Running past customers until the driver had the savy to run it into the wall, VERY scary as you think about it.
not exactly a safety issue, but caught my eye. you may be better off to run the + and - together inside a larger pipe. The closer together they are, the more they cancel each others EMF, and would have more air space around them for cooling for continuous high current draw.... but that is a minor concern.
You also should try to run down the center of the car, perhaps in the old exhaust tunnel, and avoid runs along the edges so as not to be subject to damage in accident or cut with 'jaws of life' if they need to pry open doors.
There is also a heavy duty switch we use in our drag cars to disconnect power in an accident or fire. That switch is usualy located on the outside of the car at the rear as a turn switch or a push pull on off. These switches are off heavy equipment rated at high volts and I believe 2000 amps. Most emergency responders are familiar with these switches here in the US. Only problem is there always turns out to be a funny guy who likes to pull or turn a switch located on the outside of a vehicle just for fun to see what happens, so probably not a good idea to put it outside & clearly marked but a thought.
My project is a two door hatchback. I'm thinking of putting a label on the two fixed windows behind the doors and on the hatchback glass. I'm reluctant to use the word "Danger", but I do want to put a diagram on it. That way, First Responders would feel comfortable using whatever means necessary to get anyone out. Here's the label I'm thinking of:
My goal was to show the cable routing as well as the location and count of batteries. I also wanted to highlight that they're not exotic LifePo or Flooded Lead Acid batteries.
I didn't want to get into locations of fuses, disconnects, or the impact sensor. I just wanted to provide reassurance that it's okay to chew up the doors or pillars as necessary.
My project is a two door hatchback. I'm thinking of putting a label on the two fixed windows behind the doors and on the hatchback glass. ... I just wanted to provide reassurance that it's okay to chew up the doors or pillars as necessary.
Thumper, any ideas where these decals are already available? I've got a pair of the standard "high voltage" triangles stuck on my EV, one near the windshield and one over the rear window. But I really like the one you showed with the "electric vehicle conversion" on it.
Thumper, any ideas where these decals are already available? I've got a pair of the standard "high voltage" triangles stuck on my EV, one near the windshield and one over the rear window. But I really like the one you showed with the "electric vehicle conversion" on it.
The Ontario MTO gives them to you when you register your conversion. I don't know where you can buy them.
You could right click on the image in my post and Save as a jpg to your desktop. Then print it on Avery sticker paper.
I went to a graphics shop that does car wraps and had them print me some on waterproof vinyl.
The best video I have seen related to First Responder training for electric vehicles. For DIY'ers - pay attention to the required badging, where NOT to put your high voltage cables, and how production car safety loops are designed.
I own a Model S... and this video made me sick to my stomach as I watched them take a beautiful new car and chop it apart with the jaw-of-life... (Just kidding.)
I changed some of the design of my DIY project after watching this...
Excellent information. It was impressive to see the techniques for dash removal and the cutting of other parts of the vehicle for safe extrication of occupants. I can see where DIY conversions may need special consideration and perhaps some standardization for the safety of first responders as well as the occupants in case of an incident.
Perhaps a high voltage and/or current detector could be designed which can pick up the electric or magnetic field of a significant amount of voltage or current in cables and other components.
The location of the battery pack of the Tesla under the floor pan may be overall the best, but it will make it subject to damage from rocks and other debris on roads, and especially if the vehicle should land on a guard rail or metal lamppost or road sign. I would assume it is made of strong steel to resist puncture and dents that may damage the Li-Ion cells.
The location of the battery pack of the Tesla under the floor pan may be overall the best, but it will make it subject to damage from rocks and other debris on roads, and especially if the vehicle should land on a guard rail or metal lamppost or road sign. I would assume it is made of strong steel to resist puncture and dents that may damage the Li-Ion cells.
I was happening to read through this old thread, and came upon this. Good call, I think you might be psychic As I'm sure everybody is aware, exactly this happened a couple of weeks ago.
Earlier this week, a Model S traveling at highway speed struck a large metal object, causing significant damage to the vehicle. A curved section that fell off a semi-trailer was recovered from the roadway near where the accident occurred and, according to the road crew that was on the scene, appears to be the culprit. The geometry of the object caused a powerful lever action as it went under the car, punching upward and impaling the Model S with a peak force on the order of 25 tons. Only a force of this magnitude would be strong enough to punch a 3 inch diameter hole through the quarter inch armor plate protecting the base of the vehicle.
ffffffffffffffff&@#
it punched a 3inch hole through a piece of quarter inch plate
if that happened to a normal car that would be like an armor piercing bullet, it couldv done anything
allow me to (re)summarize what I think are appropriate warning and disconnect safety design elements for a DIY ev.
1. external sticker/badge identifying vehicle as an EV for Responders. rear bumper or drivers-side fender badge area are where they look on OEM cars.
2. a big fat DC rated circuit breaker, somewhere between most pos/neg HV terminals and controller. Sized to expected max continuous DC current.
3. manual pull disconnect to main HV traction pack.... something like a choke cable run to your main traction pack Circuit Breaker (probably a big DC rated Heinman or similar). This would be the primary access for Emergency responders IF the open driver door, or break window to reach thru to access hood latch. Having the battery disco right by hood latch makes it pretty obvious.
4. under-hood... clearly labelled HV touchpoints or exposed buss bars, and main Circuit breaker, or orange HV 'cut here' cable loop like the OEM mfg are doing
5. low-voltage KSI interrupt to open KSI circuit on impact.... easy to use a ICE vehicle fuel pump switch. Just make sure the 'reset' button is labelled, accessible, and that it is mounted in the same orientation it was designed for. Usually red-top 'up'.
6. 'clutched' coupling between motor and transmission. in case all else fails in case of controller stuck in full-on accelleration, and manual disconnect failure. push in clutch, over-rev motor, but stop the car.
3. manual pull disconnect to main HV traction pack.... something like a choke cable run to your main traction pack Circuit Breaker (probably a big DC rated Heinman or similar). This would be the primary access for Emergency responders IF the open driver door, or break window to reach thru to access hood latch. Having the battery disco right by hood latch makes it pretty obvious.
4. under-hood... clearly labelled HV touchpoints or exposed buss bars, and main Circuit breaker, or orange HV 'cut here' cable loop like the OEM mfg are doing
5. low-voltage KSI interrupt to open KSI circuit on impact.... easy to use a ICE vehicle fuel pump switch. Just make sure the 'reset' button is labelled, accessible, and that it is mounted in the same orientation it was designed for. Usually red-top 'up'.
6. 'clutched' coupling between motor and transmission. in case all else fails in case of controller stuck in full-on accelleration, and manual disconnect failure. push in clutch, over-rev motor, but stop the car.
Since production EVs (and production engine-driven vehicles) do not have any kind of system to mechanically disconnect the drive system, I don't see why such a system would be needed when an electric motor is adapted to a conventional transmission. If you interrupt the high voltage connection by dropping the power to the contactors, the motor won't run. Yes, both a collision-triggered switch and some sort of readily accessible (and labelled) manual switch would be good to drop that connection, and this all assumes that you are using contactors (relays), not just a manual high voltage master switch.
Since production EVs (and production engine-driven vehicles) do not have any kind of system to mechanically disconnect the drive system, I don't see why such a system would be needed when an electric motor is adapted to a conventional transmission. If you interrupt the high voltage connection by dropping the power to the contactors, the motor won't run. Yes, both a collision-triggered switch and some sort of readily accessible (and labelled) manual switch would be good to drop that connection.
this concern, and suggestion for a clutched coupling, is really only a concern when using a (non) production controller, and probably only a concern with DC controllers at 120-160v pulling enough current to weld contactors or controller internals if you attempt to 'break' the circuit while under heavy loads.
The clutch is the LAST line of defense, if the KSI interupt doesn't work, contactor is welded closed, etc. This did happen occasionally in the 'old days' with some home-cooked controllers, and does happen occasionally if you attempt to key-off a contactor under heavy load, get a big arc, and the contactor welds itself closed.
Lets say you are accelerating, and you hit a tree. fuel pump KSI interupt cuts power to the main contactor relay but you are still pulling big amps, tries to open contactor but arcs, welds contactor and you can't turn it off, and your right foot is still trapped on the accellerator somehow. key-off won't help, manual pull MIGHT, but if that welds the main circuit breaker due to a second arc, then your last try is to push clutch, allow motor to over-rev and hope you have over-rev limiter shut down controller before weights fly off the Stator and you ruin the motor
worst case doesnt happen often, but you need to consider it when you are responsible for the design rather than a big OEM. a clutch w a transmission is one additional level of disconnect as opposed to a sold clutchless design.... which you might as well do if you are using a transmission, but obviously not if you are using a pre-packaged motor/drive sub-assy from a production EV
All of this logic to handle the case of contactor failure by welding contacts makes sense... except that it would make much more sense to use contactors with adequate current-interrupting capacity.
opening contactors under high DC current loads and reasonably high (120vDC-160vDC) creates LONG arcs. If there aren't strong fast springs, big enough gaps, magnetic 'blowouts', or under specced contactor to save a little money.... bad shit happens (occasionally)
Tesla fit those as standard instead of the main fuse - they have the advantage that they will disconnect FAST as soon as they reach the set current - unlike a fusible link
i think you can trim the test down I wouldn't want someone reading a novel as I bleed out in the car treat and if you need to know about more question you can search it on google for better result
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