Range Extending the IMIEV yet again

[rmay635703]

Odd to ask such questions on a car I have never owned but other cars like the Think City and even the Leaf have places one can inject power directly, the car meters and operates correctly but is able to go further because of "free" power coming from some other source.

On the Think you can inject current through the heater circuit, the Volt you can inject a small amount of current 300-1500 watts) through the 12v (which isn't metered, I have done that mod myself)
and the Leaf is somewhere by the drive controller.

So has anyone examined the MIEV service manual for potential places that connect right up to the HV?
The heater is usually a good bet.
(any links to one anywhere would be appreciated also)

One would also think that the car would meter and understand that free power was coming in and simply monitor it like the leaf.

Any ideas?

Thanx
Ryan

 

[PV1]

Already covered in numerous places, most notably the thread titled "Range Extender!".

One member replaced the CHAdeMO port with an Anderson connector and jumpered power to the quick charge contactors and fed power in that way.

That same member and others have removed a small access plate on the Motor Control Unit (MCU or drive inverter) and tapped into the HV lines coming from the battery pack.

These methods have been successfully used to add parallel packs and/or charge from external chargers. All power feed-in requires the i-MiEV to be READY (on with the READY indicator lit).

 

[jray3]

On ... the Volt you can inject a small amount of current 300-1500 watts) through the 12v (which isn't metered, I have done that mod myself)
Ryan

Thanks Ryan, I was unaware of that method. Are you saying that the Volt dc-dc converter will reverse the current flow and start recharging the traction pack if the dc-dc sees higher than normal voltage on the 12V side, say 15-16V? Or is it just that by connecting a battery V higher than the 13.8 float voltage you unload the dc-dc and run all 'house loads' off of the supplemental battery?
Injecting 1 kW continuous could be just enough extra power on the West coast electric highway to skip a CHAdeMO stop here n there.

If just unloading the dc-dc converter is the goal, replacing the house lead battery with four LiFePO4 cells would help if those are grid-charged to 15.2V (3.8 Vpc) and floated by the dc-dc way down at 12.8V (3.2 VPC, which would use about 80% of the capacity of those cells). Just floating it at 13.8V, which I think is the i-MiEV setting, would not actually cycle the battery, so you'd need to disconnect the dc-dc during driving and reconnect during recharge. I don't know what sort of side effects there could be to disconnecting the dc-dc, and for that matter, don't know of a way to reprogram the voltage setpoints in our dc-dc. In the homebuilt EV world, this technique is relatively easy.

 

[rmay635703]

On ... the Volt you can inject a small amount of current 300-1500 watts) through the 12v (which isn't metered, I have done that mod myself)
Ryan

Thanks Ryan, I was unaware of that method. Are you saying that the Volt dc-dc converter will reverse the current flow and start recharging the traction pack if the dc-dc sees higher than normal voltage on the 12V side, say 15-16V? Or is it just that by connecting a battery V higher than the 13.8 float voltage you unload the dc-dc and run all 'house loads' off of the supplemental battery

The volt easily uses 300-500 watts idling, using a higher voltage nimh battery in the volt puts the energy meter to zero and extends low speed range significantly

 

[veimi]

Does this mean by adding a 40Ah standard lead acid car battery in parallel with the stock 12V i-miEV battery that range will be extended by 1/2 kWh (12V X 40 Ah = 0.5 kWh) or 0.5/16 or 3%=1.8 miles?

 

[PV1]

If you can successfully disconnect or disable the DC-DC converter while driving, and both batteries can cover all 12 volt loads on their own, yes. But if the DC-DC converter is still feeding the batteries, then all you've done is increase 12 volt storage for when the car is off.

 

[rmay635703]

Does this mean by adding a 40Ah standard lead acid car battery in parallel with the stock 12V i-miEV battery that range will be extended by 1/2 kWh (12V X 40 Ah = 0.5 kWh) or 0.5/16 or 3%=1.8 miles?

No, there are multiple problems with that...
There is something called a 14v 7 cell lead acid battery (yes it does exist) the trouble is finding either cells or an appropriate sized 14v battery (most 14v batteries come in a belt for camera operators and 40ahr is way way way too small to supply a full hour of 12v power to your car, remembering you can only use maybe 50% of the capacity and the fact that near the end of the discharge curve your DC-DC will start supplying some power, meaning a smaller battery may have too low a voltage too soon to stop the DC-DC from providing power)

Next your power draw off 12v is not always .5kw, on my volt 12v power used is actually significantly higher than that during acceleration or normal driving, it only settles around .5kw at idle with everything off.

http://deepcyclebattery.en.made-in-china.com/product/SBJxlMjVrbke/China-Deep-Cycle-2V-200ah-Sealed-Lead-Acid-Gel-Battery.html

Other option would be to install an 8v and 6v battery into your car in series but you would have "balance" issues

Why a single 2v 200ahr lead acid battery costs more than a standard 12v 200ahr battery is beyond me but if you can find smaller "Cells" cheap and mock up a way to charge it without setting off alarms in your car you should be able to cover all your trips

Good Luck
Ryan

 

[rmay635703]

0.5/16 or 3%=1.8 miles?

Next... On my volt it was more like 5 miles, at low speeds (25mph),
so I suppose it depends on the DOD your 16kw pack actually allows and the efficiency your DC DC provides.

 

[veimi]

Thanks for the responses.

An amazing amount of knowledge and experience on this forum!