Range extender !

jray3 said:

I'm a fan of solar, but view it as only a hood ornament on daily drivers. The yield compared to cost, along with the added weight and aero challenges make it difficult to justify for any reason other than "I Wanted It!".

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How about if the panel is free? I landed an LG 250 watt panel that has been shattered (kicked, I would say, by someone that hates solar. Arrived on the pallet with a hole through 2 cells and the backing). We tested the panel, and it was making 33 volts at .5 amps (2 of the 3 bus bars between the two damaged cells are severed, and the third bus bar is severed at the bottom of the second cell, so current has to travel sideways in the cells to make a connection). I was thinking to remove the cells from the frame, remove the two damaged cells (hopefully replace them), glue them down to a big sign magnet, and stick the magnet to the roof of the car. This way, the panel is low profile, easily applied and removed from the car without drilling any holes, and will be semi-flexible (able to follow the form of the roof).

I've been thinking of how to protect the cells from moisture. I could use a thin piece of plexiglass, or maybe just vacuum-sealed saran wrap for ultimate low-profile. The panel is too big to fit inside the car, but would fit nicely on the roof.

Does anyone know where to find a decent DC-DC converter to output 360 volts?

PV1 said:

I've been thinking of how to protect the cells from moisture. I could use a thin piece of plexiglass, or maybe just vacuum-sealed saran wrap for ultimate low-profile. The panel is too big to fit inside the car, but would fit nicely on the roof.

Does anyone know where to find a decent DC-DC converter to output 360 volts?

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Much easier to use the solar to provide 12V and take load off your OEM dc-dc. The flat discharge curve and lighter weight of a lithium house battery coupled with the daily recharge by solar could take a lot of the 'house load' off of the traction pack. But if adding a lithium house battery, I'd simply try to switch off the dc-dc converter while driving and switch it back on during charging. Most of the benefit for a tiny fraction of the work for solar.

A donor car roof (or brave owner) could be used to mold a plexi bubble that perfectly follows the roofline. Then bond individual solar cells to the underside, add a neoprene foam backing sheet to take up irregularities (and add insulation), and seal up the edges to bond it to the roof. These folks used a similar approach for the Prius, but the product did not take off and when I contacted them a year or so ago, they had no interest in doing it for EVs yet...
http://www.solarelectricalvehicles.com/

Any idea on how to cut off the DC-DC built into the car?

Why would you want to cut off the DC-DC converter? It is only active when the vehicle is in the "ready" position or charging. A solar panel, blocking diode and regulator could be added and put in parallel with the 12 volt battery without bothering the converter. You need it to provide stability to the 12 volt buss. You would be suprised at some of the current drain on that battery during various operations including startup and brake vacuum pump operation.

I think that's exactly why they want to shut it off

Install a higher capacity Li-Ion 12 volt battery and let it run EVERYTHING powered by 12 volts while you're driving the car, so that the missing DC to DC converter load on the traction battery equates to extra range . . . . but with your recent experience of what doesn't work when the computer senses something so trivial as a change in the current drawn by the high mount stop light, I think I'd be very hesitant to make major changes. It seems the computer controls virtually EVERYTHING in this car and I'd hate to think what would happen when it sensed the output of the converter was no longer 14.4 volts - The 12 volt system voltage would vary greatly depending on load when the converter wasn't running

Don

Don said:

I think that's exactly why they want to shut it off
............... - The 12 volt system voltage would vary greatly depending on load when the converter wasn't running
Don

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Once Again, Don hits the nail on the head. Fortunately, I've already got an EV project car and have promised the wife to limit my iMiEV hacks until something's actually broken, or the modification has been proven to be foolproof!

Don's also right about 12V system swings. My EV conversion has a 300W dc-dc converter and only about 200W average house loads plus a 20 Ah battery for buffer, but it still sees 12V readings between 12.8 and 14.4 (the setting of my converter) as I turn headlights, etc. on and off. That makes the headlights just as dim as an old VW with a tired battery at idle. Attempted fixes have been the single most frustrating part of the project. I now have a capacitor bank and 100 Ah 12V lithium pack for the next attempts.

Metron Institute has developed and offered for sale range extender for I-MiEV and the EU clones. It consists of a charger, BMS and 10kWh battery pack. It weighs 70 kg and is installed in the trunk. The vehicle remains intact. No drilling or any other invasive modifications. Final testing did not reveal any problems.

pros:
- Range is extended to 230 km
- Both batteries can be charged simultaneously from two outlets
- It's easily removable, when not needed (few minutes)

cons:
- Price: € 6,300 + VAT in EU
- Increased weight of the car
- Reduced boot space

Zelenec said:

Metron Institute has developed and offered for sale range extender for I-MiEV and the EU clones. It consists of a charger, BMS and 10kWh battery pack.

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Something like that makes lots of sense - The car remains light and efficient with adequate cargo space for everyday use and you only add the extra weight and bulk for those times when you actually need the extra range

Not sure how many customers they'll find though - Adding about 1/3rd the price of the car just to get you an extra 60 to 75 Km of range to use once in a while doesn't make good financial sense, at least not to me. I think prices would need to come down about half for them to be able to sell very many

Don

If nothing else, you've got a good power supply for tailgating or work, without reducing range or using a generator. Still, 140 mile range would allow me to use the highway to go to the dealer, or travel to our farthest jobsite on main roads.

(Makes a good way to tie the solar in, either on the roof or a trailer with about 1,000 watts.)

Zelenec said:

Metron Institute has developed and offered for sale range extender for I-MiEV...

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Looks as though they use a dc-dc converter to feed the iMiEV battery, starting with a nominal 52v pack, similar to the system Enginer used (until they went out of business).

I have two different high-capacity Lithium battery packs that fall into this input voltage ballpark:
Six Enerdel 2P12S (31Ah each) with usable (20%-80% SOC) voltage range of 39v-47v
Two Headway packs in series yielding 4P16S (48Ah) with a usable voltage range of 49v-55v.

Either of these should work, and I have separate BMS' for each.

I would be interested in finding a dc-dc converter with a carefully regulated output voltage of around 350vdc (IIRC for the iMiEV this is around 65%SOC), or maybe a bit higher, which can handle an input voltage range of 39v-55v and which will not be damaged by directly connecting it to our battery pack. I would expect 10A to be sufficient as this is simply a gradual range extender, although a higher current would perhaps be preferable. Would need to rig some sort of a low voltage cutout. Anyone have any source for such a dc-dc?

I've resisted simply taking a common inverter output and rectifying it as that is a pretty dirty unregulated source.

For the rare really long trip with the iMiEV, I envision simply loading these batteries + converter into the back and plugging in to an Anderson connector tapped into the HV wires going to the motor, thus leaving the existing iMiEV battery/BMS intact (siai47 comment?). Alternatively, maybe even build a small Lithium range-extender trailer - heck, it could have fossil-fuel genset on it for further backup - jray3 has such a setup but I don't think he's hooked it up to the iMiEV (yet?), or even some solar panels on the trailer to keep PV1 happy.

Too many projects, too little time...

JoeS said:

or even some solar panels on the trailer to keep PV1 happy.

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You know 1,000 watts will fit on a trailer fairly easy.

Has anyone checked out Solar Journey USA's setup? Their original concept was to build a trailer housing two big rolls of solar panel to tow behind a Tesla Roadster. Charge by day, drive at night. Now, they have "leaves" of solar panels that all stack on a rack for transport and spread out on the ground when needing more than one layer's worth of power. Here are some pictures:

http://www.solarjourneyusa.com/news.php#nov16

Not saying an i-MiEV will need to tote around this kind of power, but this trailer makes enough solar power to simultaneously charge two i-MiEVs with minimal drain on the trailer's batteries.

PV1 said:

Not saying an i-MiEV will need to tote around this kind of power, but this trailer makes enough solar power to simultaneously charge two i-MiEVs with minimal drain on the trailer's batteries.

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Good thing! That 20 foot tandem axle car hauler trailer they're using to tow around their PV system weighs about 2,000 pounds alone - Probably well over 3,000 the way they have it equipped. They did add a trailer brake controller to the car

You could *maybe* tow a lightweight 4 X 6 trailer with a few panels behind an iMiEV. If you had 1,000 watts of panels, it wouldn't recharge the iMiEV in a full day of sunlight . . . . and the iMiEV sure wouldn't be able to drive all night even on a full recharge

Don

I wonder if this could be adapted to provide a little extra range
http://www.pistonheads.com/news/default.asp?storyId=28683

i found an interesting article on a battery range extender http://eauto.si/en/new-projects/

We had some words about it here.

The first prototype was bought by DEM, a HPP-group on the Drava river. When I get my ordered OBD reader, I plan to test the car with a built-in RE.

The price is high, so maybe the best option is a group of I-miev drivers buy it together and use when really needed. RE can be removed and installed to other car in 15-20 minutes after initial installation.

How it works:

Propulsion motor is co-powered by RE with constant power of max 4kW.

With moderate or slow driving PM uses the stored energy equally from both batteries. The initial RR after full recharge does not represent the sum of both batteries, but only the original 16kWh battery, however RR is decreased slower as usual, because of the help of the RE. After RE is discharged, the RR represents the value we are used to.

If driving fast with AC and (or) heating ON, it's possible to happen the main battery is discharged before RE. In that case RE becomes useless. RE can not move the car solo or charge the main battery, it only helps the main battery to discharge slower.

More about it after testing the RE.

Thanks to the number of LEAFs out there, those replacement batteries are becoming more available- both salvage and new.
11 kWh at 182V for $2500 would make an attractive basis for a range trailer or EV conversion pack. The LEAF modules can be easily configured for a pack with any multiple of 7.6V, 60 Ah modules at $109 apiece. That is cheaper than CALB pricing, of approx $1.30 per Ah, or $156 for comparable capacity. Of course, the BMS remains a question for these modules, but any DIY'er should be able to provide better thermal management than Nissan did!

http://hybridautocenter.com/HAC4/index.php?option=com_hikashop&ctrl=product&task=show&cid=4&name=new-11kw-h-battery-block-182v-60ah&Itemid=605

Anybody seen a salvaged i-MiEV pack hit the market yet?

Moderator, maybe this thread should be transferred to this topic because of the same issue and almost the same title.

Zelenec said:

Moderator, maybe this thread should be transferred to this topic because of the same issue and almost the same title.

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Done