# Future of my Zenn



## brian_ (Feb 7, 2017)

Personally, I don't see the point in a conversion to an engine, since the only special thing about this vehicle is that it is an EV. If you want a tiny car with an engine, it would make more sense to sell the Zenn and just buy something like an old Japanese kei car.

There might be some performance improvement possible by a battery upgrade without a motor or controller change, if performance is currently limited by the battery (due to current-delivering capability, voltage sag under load, or just an operating voltage lower than the controller's limit).

I am curious, though... I thought these were all low-speed vehicles (LSV, or Neighbourhood Electric Vehicles), and generally not road legal in Canada. Are you somewhere that a LSV is road-legal?


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## Emyr (Oct 27, 2016)

Taking this 100ah agm traction battery as an example, your current battery weighs 6 x 30.4kg = 182.4kg = 402lb. As for volume, the example battery is 306x168x211mm so 6 of them occupy about 65 litres of space, which is 2.3 cubic feet. 26 kg/kwh. 9.3L/kwh.

For comparison, 1st gen Nissan Leaf modules are about 500Wh per module, 68.5Ah at 7.3v nominal (2 x 3.65v), weighing 3.8kg and occupying 3.7L of space. 7.8kg/kwh, 7.4L/kwh.

By volume, you could theoretically fit at most about 8.8kwh for 25% more capacity whilst weighing only 68.64kg, saving 113kg. Wikipedia lists your kerb weight at 1200lb, 544kg, so your acceleration and range could increase by even more, compared with the ZENN's original performance.

The limiting factor will probably be the controller's max rated voltage and whether it can be programmed for a lithium-appropriate low-voltage cutoff (lead batteries peak ~14v, cut at 12v = 85% of peak; Lithium cell peak 4.1v, cut at 3v = 73% of peak). The perfect lithium pack would be 20S for ~84v peak (to match the original), 74v nominal, so 118Ah would give 8732kwh. I'm not familiar enough with OEM EV modules to pick out the ideal option.


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## brian_ (Feb 7, 2017)

The Zenn's nominal battery voltage is 72 V, but what are the controller and motor? 

According to Wikipedia:


> The vehicle originally was built with a DC motor and GE controller, and in 2008 was modified with an AC motor and Curtis controller.


I don't know if this is correct, but what's in this Zenn?

An earlier thread
zenn curtis controller
... said that the Curtis controller was a 1236.


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## shui5612 (Dec 4, 2018)

It is very hard to get a kei car here, let alone have it be road legal... Of course I could get an old 90s kei car from someone else but that defeats the purpose to an extent.. 


if I simply upgrade the batteries to li-ion then the benefits will be range, due to the reduction of weight by give or take 1/2. BUT doing that will mean I will need a new charger , running some new wires for ballast.. etc.. the limiting factor right now is the controller which limits me to 6000rpm, and I do not have the password to unlock it to 8000rpm which half of the US market got, thus upgrading the speed to 35mph or 55kmh.. currently being limited to 40kmh due to a law in the province stating any car that goes above 40-45 needs to have suspension and airbags.


My car previously belonged to the city and was the first road legal LSV in montreal, while generally speaking yes LSVs are very limited in Canada, in fact in Quebec you can no longer even register a new LSV, only use it "offroad" or in big environmental/wildlife conservational trails. HOWEVER, all previous owners and cars that were registered prior to a certain date have the right to use their LSV on public roads. Which like I stated earlier, means about 10 of us in the entire province. 


To convert this car to use 18650 cells would mean about getting 800-1000 of them, a charger and cases etc... which just in batteries alone is about 3 grand so far.. 


So on one hand I am conflicted as to keeping this car alive and its "heritage" , on the other I would like to get something that can be used on a "daily" basis, meaning more range and speed and on the other... something that will be pretty cool and use-able...


hopefully this turns into a nice build 


EDIT:
yes ive been looking into getting a wrecked cars battery pack i.e. a leaf or a ford escape hybrid which is an option on getting some more range and reduce weight/size... 
only real issue is having to repackage them to get the voltage I need and a charger/way to ballast the cells... 


2008 Zenns and up have the AC motor with the Curtis, you are correct.


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## brian_ (Feb 7, 2017)

shui5612 said:


> It is very hard to get a kei car here, let alone have it be road legal... Of course I could get an old 90s kei car from someone else but that defeats the purpose to an extent..


I was thinking of a 15-year-old or older Japanese Domestic Market import; there are companies which do nothing but bring these into Canada. Due to their age, they don't seem to be a problem to license.


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## brian_ (Feb 7, 2017)

shui5612 said:


> if I simply upgrade the batteries to li-ion then the benefits will be range, due to the reduction of weight by give or take 1/2. BUT doing that will mean I will need a new charger , running some new wires for ballast.. etc..





shui5612 said:


> To convert this car to use 18650 cells would mean about getting 800-1000 of them, a charger and cases etc... which just in batteries alone is about 3 grand so far..


Personally, I wouldn't even momentarily consider hand-building a pack from hundreds of 18650 cells.



shui5612 said:


> yes ive been looking into getting a wrecked cars battery pack i.e. a leaf or a ford escape hybrid which is an option on getting some more range and reduce weight/size...
> only real issue is having to repackage them to get the voltage I need and a charger/way to ballast the cells...


That's what I assume would be the rational approach for a lithium conversion. All production EV batteries are built of multiple modules, so the reconfiguration consists of choosing the right number of modules, likely all in series. But yes, then there is a bunch of wiring and housing work, and a suitable charger is needed.


Do you have a photo or description of the original battery compartment? We have an idea of the total volume (since it contains six typical lead-acid batteries, perhaps GC2 size), but not the shape. It would help in suggesting which production EV modules might fit.


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## brian_ (Feb 7, 2017)

shui5612 said:


> 2008 Zenns and up have the AC motor with the Curtis, you are correct.





shui5612 said:


> the limiting factor right now is the controller which limits me to 6000rpm, and I do not have the password to unlock it to 8000rpm which half of the US market got, thus upgrading the speed to 35mph or 55kmh.. currently being limited to 40kmh due to a law in the province stating any car that goes above 40-45 needs to have suspension and airbags.


Despite Zenn's claim that they were going to build a high-speed version, these were designed as low-speed vehicles. It doesn't make sense to me to change nearly every part of the car to make it into something that it was never intended to be.



shui5612 said:


> My car previously belonged to the city and was the first road legal LSV in montreal, while generally speaking yes LSVs are very limited in Canada, in fact in Quebec you can no longer even register a new LSV, only use it "offroad" or in big environmental/wildlife conservational trails. HOWEVER, all previous owners and cars that were registered prior to a certain date have the right to use their LSV on public roads. Which like I stated earlier, means about 10 of us in the entire province.





shui5612 said:


> So on one hand I am conflicted as to keeping this car alive and its "heritage" , on the other I would like to get something that can be used on a "daily" basis, meaning more range and speed and on the other... something that will be pretty cool and use-able...


If higher speed is required, my guess is that the Zenn is not the right starting point. It could be sold to someone who actually wants a low-speed vehicle (NEV). Some people use golf cars, UTVs, and even the occasional GEM in places such as RV parks... where they belong.


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## Yabert (Feb 7, 2010)

shui5612 said:


> To convert this car to use 18650 cells would mean about getting 800-1000 of them, a charger and cases etc... which just in batteries alone is about 3 grand so far..


Today, used batteries coming from crash electric cars is the way to go.
Here is an example of supplier: https://evbatterycenter.com/HAC4/in...ashop&view=category&layout=listing&Itemid=605
You can also contact me, I have some Chevy Volt battery left. A 70 lbs battery will increase your perforance and range and can cost you less than 1K$..


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## shui5612 (Dec 4, 2018)

So as far as being cars go.. yes there are brands that bring them over here but it wouldn't be able to be registered in Quebec to be road legal..

As far as the speed concern goes... I'm not "too" concerned due to these same chassis and components drive around at 110kmh in Europe on gas-diesel engines.. 

For the compartment size in the back it's basically 30inches wide by 14 inches long by 11 inches deep. 
I won't mind if I have a pack that sticks out higher than that. It is exposed to the elements so I could close off the bottom and invade into the cabin Abit. 

Up front you have two batteries and in front of them is the deltaQ charger, the Curtis controller and the DC to AC converter.. 

Behind and lower the batteries is the motor from which the halfshafts connect to both sides of the motor...

I'd be very interested in doing a swap to maybe a pack off a Leaf or Prius maybe? 

Just wondering if I have a pack that is say 288-300v at x amps, is there something you guys use to reduce the voltage (like a regulator) to say 72v etc? Would make finding a pack easier with nothing to fiddle with besides connections and the charger...


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## brian_ (Feb 7, 2017)

shui5612 said:


> So as far as being cars go.. yes there are brands that bring them over here but it wouldn't be able to be registered in Quebec to be road legal..


They're legal federally. I didn't realize that Quebec has some rule which bans them; they're legal in other provinces.



shui5612 said:


> As far as the speed concern goes... I'm not "too" concerned due to these same chassis and components drive around at 110kmh in Europe on gas-diesel engines..


So they're only low-speed here. Not safe at high speed from a collision protection viewpoint, but roadworthy.


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## brian_ (Feb 7, 2017)

shui5612 said:


> For the compartment size in the back it's basically 30inches wide by 14 inches long by 11 inches deep.
> I won't mind if I have a pack that sticks out higher than that. It is exposed to the elements so I could close off the bottom and invade into the cabin Abit.
> 
> Up front you have two batteries and in front of them is the deltaQ charger, the Curtis controller and the DC to AC converter..


I'm not sure that it is worthwhile to use the front battery space, and deal with the wiring and packaging complications, since a reasonable set of production EV modules which fit in the main battery space will have significantly more capacity than the entire original lead-acid battery set.



shui5612 said:


> Behind and lower the batteries is the motor from which the halfshafts connect to both sides of the motor...


Presumably this is actually from both sides of a _differential_, which is driven by the motor through a set of reduction gears... likely in the same Comex transaxle as used in the Microcar MC1/MC2, but without the CVT.



shui5612 said:


> I'd be very interested in doing a swap to maybe a pack off a Leaf or Prius maybe?
> 
> Just wondering if I have a pack that is say 288-300v at x amps, is there something you guys use to reduce the voltage (like a regulator) to say 72v etc? Would make finding a pack easier with nothing to fiddle with besides connections and the charger...


It's expensive to convert the voltage down from the battery pack to the controller input; instead, the normal solution is to use a lower-voltage pack by configuring an appropriate combination of the modules of a production pack.

Current production EVs typically run around 360 V (nominal), and so you could use only less than one quarter of the pack. These packs are much bigger and heavier than the Zenn could accommodate, so you couldn't use the whole pack, anyway; you would use only a few modules. The Nissan Leaf and Tesla Model S/X are the popular choices (mostly because they are the most common EVs), but there are others.

a stack of three Tesla Model S/X modules (with a supporting rack, and protective housing) should fit in the main battery space, and if connected in series would have a combined capacity of about 16 kWh at about 70 volts
a stack of 20 Nissan Leaf modules (pre-2018), connected in parallel pairs then those pairs in series, would fit in the main battery space and have a combined capacity of 10 to 12 kWh (depending on generation) at about 75 volts

An alternative would be battery modules from a plug-in hybrid. These packs run similar voltages to battery-only EVs, but they're smaller (typically about 15 kWh, rather than 30 kWh to 100 kWh). The Chevrolet Volt is probably the most popular in this category by far; there are now some others, but they are recent and so salvage battery packs will be less common.

the space is awkward for Volt modules because two won't fit side-by-side running across the car, but a single row across the 30-inch width of the main box plus another row in the front box might work (if the front box is wide enough); about half a pack would be needed for enough capacity but would need to be in two smaller sets in parallel to hit a suitable overall voltage

Non-plug-in hybrids tend to run somewhat lower voltage (200 to 300 volts), but have very little capacity; you would need multiple complete packs, and would still need to disassemble and reconfigure packs for lower operating voltage.


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## shui5612 (Dec 4, 2018)

brian_ said:


> They're legal federally. I didn't realize that Quebec has some rule which bans them; they're legal in other provinces.
> So they're only low-speed here. Not safe at high speed from a collision protection viewpoint, but roadworthy.


Most provinces require an inspection if a vehicle comes from outside of the province or has not been plated for over 12 months, which would mean the kei car would have to be inspected, which it most likely wouldn't pass because then there would be a LOT more on the roads here then there are today.. im sure there is a work around but quebec is so strict we cant even register right hand drive vehicles anymore unless they were imported and registered before a certain date...


As far as roadworthiness goes.. they drive them around in Europe but here... would be kinda sketchy with all of the f150s and other massive cars roaring down the highway ay 120kmh+.. not to mention having no airbags which motorocycles don't have either.. 


id have no problem taking the car on a 70kmh or 90kmh road but going down a freeway is a slightly different story... maybe in a rural area... 


Thanks for all the help, im actively looking for some Nissan leaf modules which seem to be the easiest route to go or look up some teslas but its hard to find anything here yet... 


As far as cooling goes, will I need to think up of some way to circulate water in the tesla packs? is this something to even consider or will I not even be close to heating those up?


Lastly, for the charger, any clue as to where to start looking to get something reasonable? 


thanks again.


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## brian_ (Feb 7, 2017)

shui5612 said:


> ... im actively looking for some Nissan leaf modules which seem to be the easiest route to go or look up some teslas but its hard to find anything here yet...
> 
> 
> As far as cooling goes, will I need to think up of some way to circulate water in the tesla packs? is this something to even consider or will I not even be close to heating those up?


Yes, I think that the Tesla modules should have coolant circulation, as much to even out temperatures among the cells as for overall cooling or heating of the modules. The Leaf modules do not have active thermal management (although you can add a heater - the Leaf has one optionally), so in that way they are easier to work with.


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## shui5612 (Dec 4, 2018)

I have my fingers crossed for my search.. looking for a bargain on either tesla modules, leaf cells, or even chevy volt modules.. so far those three are the ones that would require the least amount of work and fit in the space pretty well.. also giving me more kwh while reducing my weight over stock...


add a solar panel at the top and I can drive forever! lol just kidding. but a panel would probably give me 100-200w/h in sunlight.. so.. 1 mile an hour or so.. 


having looked it up I also think I have a Curtis 1236 controller (password locked)
something along the lines of a an AC12 550A(??) motor..
which makes some sense due to it being 72v, the main fuse is rated for 600A.. which means about 37hp max, and 86lb-ft (im sure its toned down in the controller settings). with something like a KY06 gearbox.. 


don't know what I have as the dc to ac converter...
and a Delta-Q quick charger which I fixed..


So.. looking to start this project next spring and see where it goes...


hopefully I don't get a bug and end up wanting a 100mph EV speed-kart


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## brian_ (Feb 7, 2017)

shui5612 said:


> having looked it up I also think I have a Curtis 1236 controller (password locked)
> something along the lines of a an AC12 550A(??) motor..


There have been lots of variations of the Curtis 1236, with different voltage limits and current capacities. Is there a more specific model number marked on the controller? It would be helpful to know what voltage options you have for the battery.



shui5612 said:


> don't know what I have as the dc to ac converter...


Do you mean DC-to-DC converter (for 72 V battery to 12 V conversion)?


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## shui5612 (Dec 4, 2018)

Here's where I may be confused...
Being an AC motor, and my batteries supplying DC current, is there not something that switches it to alternating current? 

As far as the controller goes.. I'll try to find some info online but unfortunately it's tight up behind the bumper so I can't see what the controller model is.. I'll try to look at it tomorrow and see If I can find anything..


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## MattsAwesomeStuff (Aug 10, 2017)

shui5612 said:


> Here's where I may be confused...
> Being an AC motor, and my batteries supplying DC current, is there not something that switches it to alternating current?


While in common parlance it changes one thing into another thing, and thus, is a "converter", most people describe that component and function as an "inverter". Especially as, a DC-to-DC (which is also an inverter) is called a "converter".

I suppose "conversion" seems definite and fixed. As a DC-DC is. While an "inverter" describes the process but leaves the result open ended, as a speed controller would be.


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## Yabert (Feb 7, 2010)

shui5612 said:


> For the compartment size in the back it's basically 30inches wide by 14 inches long by 11 inches deep.


Perfect dimensions to receive a 6 kWh battery build from Chevy Volt modules. That represent around double the capacity of your current pack because a 7 kWh lead acid battery discharge in less than an hour have only around 3.5 kWh available.
Similar pack had been test at 675A of disharge in my Smart few years ago: https://www.diyelectriccar.com/forums/showthread.php/power-capability-chevy-volt-battery-109698.html

70 lbs and dimensions of 30x12x10''.
Only possible reprogramation of your controller could be challenging.


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## brian_ (Feb 7, 2017)

shui5612 said:


> Up front you have two batteries and in front of them is the deltaQ charger, the Curtis controller and the DC to AC converter..





shui5612 said:


> having looked it up I also think I have a Curtis 1236 controller (password locked)
> ...
> don't know what I have as the dc to ac converter...





brian_ said:


> Do you mean DC-to-DC converter (for 72 V battery to 12 V conversion)?





shui5612 said:


> Here's where I may be confused...
> Being an AC motor, and my batteries supplying DC current, is there not something that switches it to alternating current?


You were listing two separate devices: the Curtis 1236 controller and a "DC to AC converter". While something does make DC into AC - an inverter - that's done by the Curtis 1236.

In other words, the Curtis 1236 controller *is* the inverter - it inverts DC to AC at a controlled frequency and voltage.

If you have another box, separate from the Curtis, and connected to the battery, it is probably to convert 72 V DC power from the battery to 12 V DC for everything that runs on 12 volts (headlights, radio, whatever). Some careful checking across input and output terminals with a voltmeter (set to a range handling more than 72 volts) should confirm what the box does.


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## brian_ (Feb 7, 2017)

MattsAwesomeStuff said:


> While in common parlance it changes one thing into another thing, and thus, is a "converter", most people describe that component and function as an "inverter". Especially as, *a DC-to-DC (which is also an inverter)* is called a "converter".


I think that makes things more confusing than necessary. While there may be an inverter, transformer, and rectifier inside, overall a box with DC output is not called an inverter.

any change of voltage with DC output = converter
DC input and AC output = inverter


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## shui5612 (Dec 4, 2018)

thanks for all the replies,


so far I called up three places and most want 4000-5000$ Canadian for chevy VOLT battery packs....


looking up online the ``cheapest`` I found was 2200$ for a chevy pack and its about an 8 hour drive away... for the Leaf packs.. nothing under 3200-3500... Tesla.. a pack is 1100-1500 and I would need three.. still way out of budget...


HOWEVER, I did manage to find an entire pack off a ford escape hybrid for 500, already disassembled.. and some cheap prius-camry packs here localy (20 min drive).


im hoping to stumble upon a scrap-yard where I can come in and get the whole chassis or take the pack out myself for cheaper...


any recommendations as to where to look? im in the montreal area, quebec. 


And you guys are right the third box is most likely the dc to dc converter that makes for 12v dc out..


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## rmay635703 (Oct 23, 2008)

shui5612 said:


> thanks for all the replies,
> 
> 
> 
> ...


Hybrid batteries will only drive you maybe five miles

A Prius pack has about as much capacity as a single common 6v golf cart battery


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## brian_ (Feb 7, 2017)

shui5612 said:


> HOWEVER, I did manage to find an entire pack off a ford escape hybrid for 500, already disassembled.. and some cheap prius-camry packs here localy (20 min drive).


Here's the Wikipedia note about the original Escape Hybrid battery:


> Sanyo Electric Co. built the 50 kg (110 lb), 330 volt 5.5 Ah (would make it 1.8kWh storage), 250-cell nickel metal hydride (NiMH) battery pack for the 2005 Escape Hybrid.


You would need a few of these, and would need to break the internal connections to split it into smaller blocks then wire them in parallel to get a suitable operating voltage. Toyota hybrid (other than the plug-in Prius Prime) battery packs are similar, although most are smaller than this Escape pack.

NiMH works well for the relatively high power and low energy storage requirements of a non-plug-in hybrid.

There were some prototypes of plug-in hybrid Escapes, but I don't think that ever went into production. Production Ford plug-in hybrids have been the Fusion and C-Max "Energi" variants, not Escapes.


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## Boulder Hybrids (Jan 30, 2013)

The build quality and safeness of a Zenn is just slightly better than a golf cart. 

I suggest selling the Zenn for whatever you can get, buy a used Leaf, even an early Leaf with tired battery is 10 times the car of a Zenn. 

While a used Leaf will cost $6-$10k, you'll have a useful car that could save your life if an SUV hits you.... and you won't have to mess around building a battery pack/BMS/charger etc.

If you have tons of time and like to "roll the dice" I guess you save some money by trying to upgrade the Zenn, but it's throwing good money after bad IMHO.


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## shui5612 (Dec 4, 2018)

im not looking for a daily but I like the zenn due to its uniqueness...


its the same as saying ``throw out the ford model T, it will never be a camaro``. While if you throw enough money into it, it might get somewhere close, a model T with Camaro performance sure is better than an old-beat to hell Camaro...


A couple of Zenns have been in collisions with big SUVS, infact one was T-boned by a sequoia and simply bounced off it and flew 20-30 feet 


I got my zenn for 4k CAD in 2013, it cost me 0$ in electricity since my condo supports charging it for free, about 250$ in repairs (assorted plastics that were missing when I purchased it), and today the odometer shows 1200 miles on it. (I purchased it with under 600). 


A build is a build, it may not be fast, or the safest but nothing beats the looks of people wondering what a golf cart is doing on the streets, which there wont be many more left in the coming years anywho. (Since were already only 10, spread out all over the province).


The build is to recycle-re-use some old EV batteries instead of purchasing new Lead-acids , which may also help the car become more ``useful`` due to the increased range.


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## dain254 (Oct 8, 2015)

If you run a 2kwh Volt module in series with a 1kwh module you will have 3kwh and 75.6V peak. The lead acid 72V charger is likely quite a bit higher than this... so you will need to check output and may still need to change your charger to utilize the Volt cells. Paralleling between two of these 3kwh groups would give you 6kwh for more range - buy a new charger that is set for 73 or 74V and balance charge with a cheap 18S BMS. Monitor voltage and stop driving when pack hits 55V. The modules, BMS, and charger can be bought on eBay. I always thought the Zenn's were cool looking little vehicles. Good luck!

https://community.electricforum.com/t/chevy-volt-specific-bms-harness/13198

Link for paralleling and a BMS that I currently use on my CozE electric vehicle.


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