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Discussed here many times in previous threads - Nearly impossible to do because the car was basically designed around it's 88 cell battery pack. The charger, inverter and other systems (Air conditioning, heating etc) were designed for the voltage the pack came with. If you need a 100+ mile range EV, I would look elsewhere

Don
 
An auxiliary pack would be possible and has been done before, but modifying the OEM battery pack so far does not look like it would provide additional range. A second, li-NMC battery pack could be constructed and wired into parallel with the existing pack to provide an immediate range increase. The pack would have to be 325.6 volts nominal, 88 cells or cell blocks wired in series, with automatic contactor connect/disconnect based on car's main positive contactor drive.

Even if larger capacity cells would fit and the car could be made operational, the BMU performs coulomb counting and would only use so much of the available capacity. The unknown factor would be if the i-MiEV would eventually perform a calibration and open up the unused capacity of the larger cells. You would not gain any range with this method until the point if/when the car performs a recalibration.

The bulk of this information and conversation can be found here:
http://myimiev.com/forum/viewtopic.php?f=14&t=1255
 
I never ran it for a long time but adding an additional pack will work. The range meter starts out with a normal range (like 70 miles) regardless of how many packs are connected. The segments on the meter start to drop at a slower rate with two packs and the available range drops very slowly. Although the car reads current through the original pack, it doesn't read the current of the additional pack. Therefore, the car thinks it is using less energy (like driving down a mountain) because only 1/2 of the energy to run the car comes through the original pack and it's hall effect transducer. I didn't drive it to low battery cutoff or anything near to it because there was no monitoring on the external pack. However, the range looked like it would be nearly doubled. The additional pack (which was a standard I-MiEV pack with the steel bottom mounts removed) actually fit in the back of the car with the seats folded down. The rear weight bias and the higher CG with the pack in the back made the handling a little dicey. Plus it looked a little silly with a couple of large orange power cables going out the passenger side rear window and going into what looked like the gas tank door to other drivers.
 
siai47 said:
Plus it looked a little silly with a couple of large orange power cables going out the passenger side rear window and going into what looked like the gas tank door to other drivers.

Just a quick question(s). You tied it in through the DCQC cable and manually Switched the DCQC contactors inside the battery pack under the car? The system did not lock out the drive with those contactors closed? How did you get the main contactors in the range extender battery pack to close? I'm truly sorry about your prospects for a Volt.

Currently working towards a Serial hybrid set up for the "i", so these questions help move that forward. I'm about half way there at this point. Having a serial hybrid option for the EV's would allow our household to not own an ICE automobile just EV's. So instead of a 30% -35% or so of the family driving done presently on gasoline it could approach zero at < 2% without having to worry about charging infrastructure issues and availability causing delays on longer trips.

Lousy of Chevy to pull the nationwide rollout of the 2016. They broke the golden rule of consumer based business (always promise less than you can deliver).
"stupid is as stupid does" Forest Gump

Aerowhatt
 
When I did this I was messing around with my first attempts at getting into the HV battery. The car was non QC and had a non QC pack in it, the second pack was from a QC car. I attached cables to a Anderson connector and routed them to where the QC port would have been located on the outside of the car. The other end of the cables were terminated at the inverter where the main power leads came in from the car's battery pack. This was a temporary setup to make use of a Manzanita Micro PFC-50B charger for quick charging. I wouldn't recommend this as a permanent solution as HV is available at the connector any time the car is in the ready position. The QC charge cables on the second pack were terminated with a mating Anderson connector. The HV contactors in the I-MiEV are all controlled by external 12v power fed through multipin connectors on the outside of the packs. Two wires were tapped into the wires that closed the main contactor in the original pack to provide power to close the QC charge contactor in the external pack. This way there was a way to allow the pre-charge contactor to sequence in the original pack before the main contactor closed and supplied power from both packs to the inverter. This also allowed for the car to be turned on and off in a normal manner without additional switching. The HV tie point of the second pack had to be outside of the original pack. This eliminates any power from the additional pack being read by the original packs hall effect transducer which would upset the charge/discharge calculation by the "range" meter. Like I said, this was a one time test to see if it could be done. I finally put the QC pack in the car and used the QC contactor to switch the Anderson connector for a connection point for my external Manzanita charger. All that being said, the I-MiEV IMO cannot safely handle the extra weight of an addition pack in the car. If I was to do it again, the pack would need to be on a external trailer towed behind the car. Even if you could carry the additional weight by changing rear springs, there is no way to lower the CG which really makes lane changing fun (exciting) :eek: ! BTW--both packs could be charged in this configuration by the internal charger but there was no cell balancing available to the external pack so this wasn't a real solution for a long term range extender.
 
siai47, thank you very much for continuing to post on this forum and for sharing your insightful experiences. I find it gratifying that the external pack, injected into the battery power lines just before the controller, spoofs the iMiEV into thinking it's regen-originated energy and doesn't otherwise negatively affect the system. Agree with you about the weight placement and that a trailer with power pack would be a preferable solution (and one that could be quickly attached only when needed). Still need to repair my Enginer dc-dc as that will give me lots of options with all the 48v power packs I have lying around…
 
siai47 said:
When I did this I was messing around with my first attempts at getting into the HV battery. . . . BTW--both packs could be charged in this configuration by the internal charger but there was no cell balancing available to the external pack so this wasn't a real solution for a long term range extender.

Thanks so much for the valuable details. I'm looking at using the bolted main cable connections just inside the battery pack to piggy back another set of power cables. They would have their own contactor actuated by whether the genset was running, or not. That way the whole thing is disconnected from the main pack inside or directly outside the main pack if the genset is off. As with stock, all of high voltage would be terminated inside the pack by the main contactor when the vehicle is parked .

The current sensors inside the pack that talk to the system are battery bank side of the high voltage cable connections (at the battery pack) to the inverter aren't they? It looked that way from Martins pack cell replacement video. Is that correct from your experience?

I can use smaller cables since they will only carry genset amperage so waterproofing should be attainable. The car should see the whole thing much like it did your extra paralleled battery pack experiment. As reduced demand by the motor system and regen when genset output exceeds motor and systems power usage.

Of course the same type of connection could be done for a trailered XR battery (or smaller onboard one) with the XR battery contactors (one at each end) run by the presents or absence of system power from the cars existing system.

I've collected quite a bit of freeway cruising Canion data suggesting that as a serial hybrid the "i" should get between 50 and 58 MPG. Again, for EV purists the unit would likely be used two or three times per year burning less than 25 gallons of gas per year and replace the current need for a gasoline car in the household, burning hundreds of gallons per year. The rest of the time would be pure EV driving charged with in house solar. Sometimes the genset would be taken along for piece of mind but not needed and hence not used.

Aerowhatt
 
I can't remember which side it is on but the hall effect (current sensor) is around the buss bar right at the end of the (I think) negative side of the HV pack right where the external cable connections are located. When you are dealing with internal pack wiring, the connection points on either side of the current sensor are switched via the main contactors. The contactors are really tough to get to which creates a connection problem if you want to provide an external source of energy to the pack as the connection will only be "hot" when the car in in the "ready" mode or connected to the EVSE. If you have a Chademo car (and don't wish to use the Chademo ever again) then the connection point is easy. When I installed the QC pack in my car I cut off the Chademo connector and soldered on a Anderson connector at that point. I put a switch on the dash to energize the HV contactor via a relay located under the back seat. For charging purposes (and I suppose it could be used for an external pack) the car had to be in the ready mode before I closed the switch to the external PFC-50 charger. Once the switch was closed, the charger could be energized and up to 10 KW could be sent to the pack. If the car was in park, nothing showed up on the energy use gauge. However, if the shifter was moved to drive, you could see the gauge move into the regen mode. If you looked at CANION data while charging in this manner, the data reported by the CANION (and the dash gauge) became increasingly inaccurate as the power input exceeded 4 KW and was about 40% low at 10KW. This inaccuracy doesn't really affect anything except the range calculation. BTW-for external charging purposes this is the only way it will work. You would think you could shut down the car and plug in the EVSE to start the charging process and close all the required contactors. I tried this and when the total power input to the pack exceeds about 4KW, the car shuts down the internal charger and opens the contactors---something the PFC-50 didn't like. I wired the switch for the QC contactor to 12v power that is only available with the car in the ready mode. This way the dash gauges work, CANION data is available, the DC-DC convertor is running and the BMS is functional. For driving with a range extender, this would not be a problem because the car is in the "ready" mode anyway. In summary, there are several ways to add external power to the car either though the existing pack or paralleling it. Each has it's own set of problems but it can be made to work.
 
Aerowhatt, I've done the same, and found that I average 23-25 amps for 60 MPH driving. What stopped me from doing a generator was the fact that I couldn't find an affordable generator capable of producing 350 volts, and a converter such as Enginer isn't powerful enough to maintain speed until a tank of fuel was used up. I started doing some research on an electric pusher trailer made up of 3 LEAF batteries (or a crap-load of laptop cells), but couldn't figure out a way to get a powered trailer with that much battery light enough. If it could've been pulled off, then I could do the route from Pittsburgh, PA to Normal, IL without any gasoline or diesel with 3 or 4 stops at quick chargers.

It seems the best place to tie into the HV bus is inside the motor controller, with the auxiliary battery contactors driven by the main pack's positive main contactor (there is sequencing involved with the positive, negative, and pre-charge contactors that make the positive contactor the most suitable for aux. power interface). It's the last to engage at startup and the first to disengage at shutdown. If you tie onto the main negative contactor, then the condenser discharge circuit may try to discharge the aux. battery if it is voltage-based and not time-based. Plus, at startup, the aux. pack would engage before the pre-charge is complete (negative and pre-charge contactors engage first, then the positive engages as the pre-charge disengages).

The i-MiEV will shut down if it sees too much power going into the battery during a normal charge. This threshold is pretty close to the max output of the charger (4 kW threshold on a 3.3 kW charger), I guess to protect the charger from overload. My friend with a Ford Focus Electric has successfully added a secondary charger and CHAdeMO capabilities to his Focus. The Focus doesn't have as many safeties and protections and will allow him to inject an additional 3 kW during a level 2 charge for a total of 10 kW charging. Also, he can leave his car in READY and is able to use a CHAdeMO quick charger at full power. With a much more active thermal management system on the battery, it will cool or heat as necessary when charging and driving. But, that's a separate topic.

That is odd how the needle won't move into the Charge zone while in Park. If I hold the high beams on, the needle will move up a bit showing the extra load on the 12 volt system while in Park.
 
siai47 said:
In summary, there are several ways to add external power to the car either though the existing pack or paralleling it. Each has it's own set of problems but it can be made to work.

For my purposes some of the problems that you encountered will be to my advantage. I can use the main contactor function to lock out the generator functions (no power to the main cables from the pack and the generator can't start, etc). I want the system live and workable only when the car is in ready mode anyway.

I'm sure the 4kw or so shutdown when the onboard charger is running is a safety. If the charger goes wonkie and puts out more power than it is supposed to, the car disconnects the pack from it and disconnects the AC via the EVSE. Not an issue for my intensions since the car will read all the genset charging voltage as lowered demand or regen.

How the range calculation reads this setup and how long it takes to normalize after a long trip might be an issue. Likely a manageable one though.

Your data, experience, attention to detail are invaluable. I wish I lived next door to you. We would have a great time putting this thing together and It would be done 6 months earlier!

Aerowhatt
 
PV1 said:
Aerowhatt, I've done the same, and found that I average 23-25 amps for 60 MPH driving. What stopped me from doing a generator was the fact that I couldn't find an affordable generator capable of producing 350 volts, and a converter such as Enginer isn't powerful enough to maintain speed until a tank of fuel was used up. I started doing some research on an electric pusher trailer made up of 3 LEAF batteries (or a crap-load of laptop cells), but couldn't figure out a way to get a powered trailer with that much battery light enough. If it could've been pulled off, then I could do the route from Pittsburgh, PA to Normal, IL without any gasoline or diesel with 3 or 4 stops at quick chargers.

That's what I found too. The genset is going to have to be stock 240VAC 28 amps (advantage here is it could be used for EVSE charging in a pinch too, or other uses in an emergency). The conversion to 360 VDC is going to have to be custom. Not happy about that but, it is what it is.

I'm averse to burning any fuel too. But our whole society is built around burning lots of it. Added batteries just doesn't work at some point. Too much space used and weight added. Diminishing returns as you add more. Until battery density gets a lot better, burning some fuel occasionally is just a reality of life. Besides, most fast charging on the road is going to be powered by what source . . . fossil fuel. With a genset you aren't really changing that metric much, just adding convenience by not needing to stop to charge along the way.

If it gets an (extra) gas car off my insurance bill or eliminates the gasoline expense of having one of each instead of two EV's (or both) then it will pay for itself in a couple of years, even if it never gets used!

Aerowhatt
 
You could put a relay on the J1772 input that will break the circuit from the main contactor drive link. A normally closed relay with a 120-240 VAC universal driver will prevent the auxiliary contactor on your generator from engaging when charging from AC, but will allow the generator to function when in READY. Basically, this relay senses voltage on the J1772 input and will break the circuit driving the auxiliary contactor when the car is charging (the main contactor engages, but with this relay breaking the circuit, the aux. contactor won't engage). When the car is put into READY or is quick charging, however, the aux. contactor will close and allow the generator/battery to feed into the system.

The RR is calculated based on the previous 15 miles of driving among other things, so it will take 15 miles for the range to fully update. It will probably stay where it is or slowly increase as you drive. My personal record without any aux. power input was a drop in RR of 2 miles over 10.5 miles of driving.

You could use a Manzanita, Elcon, or Brusa charger to go from 240 VAC to 360 VDC. While most public charging is fossil-powered, it is cleaner than an ICE, but I agree, one less gas car is still a plus. A few gallons here or there in a PHEV setup beats a full-time ICE.
 
I'm pretty sure you can parallel just about any auxillary battery pack to any main battery pack. The only thing that matters is you have to use the same pack voltage. It doesn't even have to be the same size (ie. battery amphours) or even battery chemsitry (at least within the lithium family).

I have a 2010 Zero DS motorcycle that I took apart to add a Cycle Analyst (a display that keeps track of volts, amps, miles, etc.) While it was apart I added a couple of Anderson connectors to the main pack which was only 48 volts (fairly safe). Later I added some 5 ah Hobby King Li-poly packs from my electric bicycle just to experiment with which added 0.24kwh to the 4kwh main pack. I just wrapped the li-poly packs in a towel and stuff them in the fake gas tank. It worked great. All the computers (main bike board, bms, etc.) just ignored the extra pack and the bike just appeared to be more efficient but obviously not by much :lol: .

Those early Zero motorcycles were barely functional and I could barely make my 16 mile commute (terrible coefficient of drag :shock: ) With this extra 5 ahrs I could go about 2 miles further or 2 mph faster on the freeway but not both. :mrgreen: I thought it was a great experiment though. :lol:
 
I'm also getting some power supplies, which I'm planning to stack to get 7.5 A at 360 VDC. I'd either feed them from 230 VAC mains while parked (although the 4 kW limit is a bummer - I'd need to only do 6 A at 230 VAC at the J1772) or while driving from a 80-100 VDC boost LiFePO4 pack or with a 230 VAC inverter from a 12 VDC pack. I'll need to do some testing with the power supplies once I receive them on which strategy or strategies I can use.
 
ed5000 said:
I'm pretty sure you can parallel just about any auxillary battery pack to any main battery pack. The only thing that matters is you have to use the same pack voltage. It doesn't even have to be the same size (ie. battery amphours) or even battery chemsitry (at least within the lithium family).

I agree, I am still running some eGO cycles with LiFePO4 XR packs and AGM lead acid main battery packs. The LiFePO4 has energy density and the lead acid has power density. The LiFePO4 couldn't power the bike alone (not enough power density for 200 amp peaks) and the lead alone gave insufficient range. By using this this approach I could turn a 14-16 mile range motorcycle into a 40 mile range motorcycle with a slightly higher top speed and similar acceleration without increasing the stock battery weight by more than 50%. For most of the trips the onboard charger charged both fine with only the added step of a balancing charge with an off board LiFePO4 charger once a month or so for the LiFePO4 only. This was more than a decade or so ago when Lithiums were far more expensive than they are now and less capable of high power density. It doesn't make as much sense anymore, except to get good range at lower (up front) cost.

Aerowhatt
 
PV1 said:
You could use a Manzanita, Elcon, or Brusa charger to go from 240 VAC to 360 VDC. While most public charging is fossil-powered, it is cleaner than an ICE, but I agree, one less gas car is still a plus. A few gallons here or there in a PHEV setup beats a full-time ICE.

Elcon and Brusa are no good they don't have anything that goes near handling 28 - 30 amps. Sure the Brusa can be stacked but 2 at $2800.00 each, nah. Manzanito might work but it is far more complicated ($$$) than what is actually needed. Another possiblity is that I have a couple of perm 132 motors which make a very efficient lightweight DC generator too. Direct drive would limit output to 72 volts but a whopping 7 KW continuous output from one of them. That's a 5 times V boost circuit which may not be ideal at all. Plus it would have no ancillary uses like a 240 AC genset would. :?

For something like this you don't really need all the complicated charging circuits in a battery charger. It's more of a tightly regulated, low ripple, safe high amp 360 volt DC power supply that's needed. No bells and whistles required. It's not to charge the battery so much as it is to slow it's discharging on an extended drive.

Aerowhatt
 
Eclon 8000W TCCH-288-24 can go up to 24 amps, but it's a little pricey as well:

http://www.evassemble.com/index.php?main_page=product_info&cPath=3&products_id=27

Three of those and I could charge at 22 kW from the widely available 2x32A Type 2 around here. ;)
 
If you decide to go with a 240 VAC generator, eMotorWerks sells a charger that would work pretty well for the i-MiEV. Available in either 12 kW or 25 kW models, they are fairly compact. Plus, an optional CHAdeMO controller and connector could be purchased to allow CHAdeMO charging, if your power source can handle it.

Just posting this as another option.

http://emotorwerks.com/dc-charging-systems/75-quickcharge-25000-hv-a-25kw-pfc-charger-for-higher-voltage-batteries/category_pathway-17
 
Here in euroland where three phase is commonly available, it's probably best to have three chargers that can take at least 6.6 kW each. That way you can take the best advantage of public Type 2 charging.

Thanks to some hesitation on my part and communication issues with the Chinese supplier, I should now receive just two 350W or 48VDC 7.5A power supplies. They won't be of any use with the C-Zero, but I can test them in my DIY EV, which only has a 25s LiFePO4 pack. If it all works out as planned, I'll order five more to get a ~2700W boost on the road for the C-Zero. That should give about 20 km more range.
 
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