Posted by Bob & Holly Wilson on January 3, 2009, 5:45 pm
> . . .
>
> My inverter (true sine wave) has an inrush thermistor, but I'll add your
> suggested RF toroids.
I use the toroids to block higher frequencies from feeding back into the
12 VDC bus. I didn't want inverter noise to feed back into any of the
ECUs. The inverter vendors advises against toroids but they are there to
protect the $0,000 car, not the $00 inverter. So far, I've had no
problems.
>
> When drawing more than a kW I don't see the voltage drop that you
> reported. It could be internal resistance because conversion to 18650
> Li-ion cells affects both energy-density and energy-flow. Thoughts? (my
> car is an '04)
Did you rig up a separate LiON pack as an energy storage buffer? Do you
have a skematic and/or photos somewhere?
I've racked my brains to figure out an affordable, power isolation
approach. Sure I can put in a 100A diode so current flows one-way but
there would be a 1.2 VDC forward voltage drop, 120 W.
The only way that makes sense would be a power MOSFET with a current
sense amplifier for the gate. This would provide a fractional forward
voltage drop. Properly designed, it could limit maximum current draw
from the car and thus protect the fusable link. But there lies the path
of madness.
The next thought is to build a switching power supply with
ultra-capacitors as the energy buffer. The advantage is no battery
chemistry risks. But once I start that path, when do I stop? <grins>
>
> My inverter is heat-sunk onto a thick (0.5") Al plate, battered into a
> shape such that it attaches to the car's sheet metal at several points
> and becomes a heat pipe. It stays pretty cool for short-term use, but I
> added a 12V computer fan to keep air moving over the outer finned case.
> It vents into the car with no problems, but I've been thinking of
> running the air to the outside. If I make the system more automated like
> yours, heat may become an issue. What do you think?
In my case, I lower the hinged panel to access the inverter. This puts
it in one of the prefered mounting orientations. The unit already has an
internal fan and it is thermally protected. Since I still need to run
the power into the house, I simply keep the trunk cracked open and any
heat easily escapes.
> Also, as I understand your diagram, the traction battery charges the 12V
> circuit when the 'ignition' is ON, and you've added an automatic switch
> to the 'ignition' circuit. Can you provide details of that circuit?
Not quite. I modified my inverter to provide a remote ON/OFF switch.
This allows me to use the inverter when traveling to provide 110 VAC for
laptops or other light duty devices.
It is very important that the vehicle be ON and in "READY" when using
the inverter. The 12 VDC battery does not have enough power to run long
and you need to let the Prius engine cycle as needed to maintain
traction voltage. So my remote switch is powered by the cigarette
lighter circuit. This circuit is only on when the car is in "READY."
> We just bought a 2.5kW gas generator for backup purposes, so the Prius
> solution is less important. I may restore the original battery, freeing
> up the Li-ion pack for other uses.
Only because I'm leary of LiON batteries due to their notorious
temperature sensitivity and constant current charge-discharge
characteristics. I'd probably replace them with NiMH if only because
NiMH are less finicky and don't have a reputation for self-destruct. But
it sounds like a clever approach to handling surge loads.
Bob Wilson
Posted by Michael Pardee on January 3, 2009, 6:24 pm
> I've racked my brains to figure out an affordable, power isolation
> approach. Sure I can put in a 100A diode so current flows one-way but
> there would be a 1.2 VDC forward voltage drop, 120 W.
> The only way that makes sense would be a power MOSFET with a current
> sense amplifier for the gate. This would provide a fractional forward
> voltage drop. Properly designed, it could limit maximum current draw
> from the car and thus protect the fusable link. But there lies the path
> of madness.
Well, there is the olde generator voltage regulator approach: a relay with a
current bucking coil added. You would have to wind your own bucking coil
(which is no easy thing with compact relay designs) and it is not a perfect
zero-crossover switcher, but it does offer essentially no forward voltage
drop. Maybe a more modern approach would involve a relay driven by a current
sensing driver.
Mike
Posted by Was Istoben on January 3, 2009, 11:53 pm
>> . . .
>>
>> My inverter (true sine wave) has an inrush thermistor, but I'll add your
>> suggested RF toroids.
> I use the toroids to block higher frequencies from feeding back into the
> 12 VDC bus. I didn't want inverter noise to feed back into any of the
> ECUs. The inverter vendors advises against toroids but they are there to
> protect the $0,000 car, not the $00 inverter. So far, I've had no
> problems.
>>
>> When drawing more than a kW I don't see the voltage drop that you
>> reported. It could be internal resistance because conversion to 18650
>> Li-ion cells affects both energy-density and energy-flow. Thoughts? (my
>> car is an '04)
> Did you rig up a separate LiON pack as an energy storage buffer? Do you
> have a skematic and/or photos somewhere?
> I've racked my brains to figure out an affordable, power isolation
> approach. Sure I can put in a 100A diode so current flows one-way but
> there would be a 1.2 VDC forward voltage drop, 120 W.
> The only way that makes sense would be a power MOSFET with a current
> sense amplifier for the gate. This would provide a fractional forward
> voltage drop. Properly designed, it could limit maximum current draw
> from the car and thus protect the fusable link. But there lies the path
> of madness.
> The next thought is to build a switching power supply with
> ultra-capacitors as the energy buffer. The advantage is no battery
> chemistry risks. But once I start that path, when do I stop? <grins>
>>
>> My inverter is heat-sunk onto a thick (0.5") Al plate, battered into a
>> shape such that it attaches to the car's sheet metal at several points
>> and becomes a heat pipe. It stays pretty cool for short-term use, but I
>> added a 12V computer fan to keep air moving over the outer finned case.
>> It vents into the car with no problems, but I've been thinking of
>> running the air to the outside. If I make the system more automated like
>> yours, heat may become an issue. What do you think?
> In my case, I lower the hinged panel to access the inverter. This puts
> it in one of the prefered mounting orientations. The unit already has an
> internal fan and it is thermally protected. Since I still need to run
> the power into the house, I simply keep the trunk cracked open and any
> heat easily escapes.
>> Also, as I understand your diagram, the traction battery charges the 12V
>> circuit when the 'ignition' is ON, and you've added an automatic switch
>> to the 'ignition' circuit. Can you provide details of that circuit?
> Not quite. I modified my inverter to provide a remote ON/OFF switch.
> This allows me to use the inverter when traveling to provide 110 VAC for
> laptops or other light duty devices.
> It is very important that the vehicle be ON and in "READY" when using
> the inverter. The 12 VDC battery does not have enough power to run long
> and you need to let the Prius engine cycle as needed to maintain
> traction voltage. So my remote switch is powered by the cigarette
> lighter circuit. This circuit is only on when the car is in "READY."
>> We just bought a 2.5kW gas generator for backup purposes, so the Prius
>> solution is less important. I may restore the original battery, freeing
>> up the Li-ion pack for other uses.
> Only because I'm leary of LiON batteries due to their notorious
> temperature sensitivity and constant current charge-discharge
> characteristics. I'd probably replace them with NiMH if only because
> NiMH are less finicky and don't have a reputation for self-destruct. But
> it sounds like a clever approach to handling surge loads.
> Bob Wilson
About a year ago I bought a new, 7KW, 110V/220V, made-in-China, Honda
knock-off (parts interchangeable they told me), for $00.00 complete with
electric start. When I wired my home I equipped it with a generator panel
so it was a simple matter of making the power cord. Works great and leaves
my Prius free to run for gas. I see from this ad I was very lucky to find
it on sale:
http://www.sjdiscounttools.com/newgen7013.html
Posted by News on January 4, 2009, 12:01 am
Was Istoben wrote:
>
>>
>>> . . .
>>>
>>> My inverter (true sine wave) has an inrush thermistor, but I'll add your
>>> suggested RF toroids.
>>
>> I use the toroids to block higher frequencies from feeding back into the
>> 12 VDC bus. I didn't want inverter noise to feed back into any of the
>> ECUs. The inverter vendors advises against toroids but they are there to
>> protect the $0,000 car, not the $00 inverter. So far, I've had no
>> problems.
>>
>>>
>>> When drawing more than a kW I don't see the voltage drop that you
>>> reported. It could be internal resistance because conversion to 18650
>>> Li-ion cells affects both energy-density and energy-flow. Thoughts? (my
>>> car is an '04)
>>
>> Did you rig up a separate LiON pack as an energy storage buffer? Do you
>> have a skematic and/or photos somewhere?
>>
>> I've racked my brains to figure out an affordable, power isolation
>> approach. Sure I can put in a 100A diode so current flows one-way but
>> there would be a 1.2 VDC forward voltage drop, 120 W.
>>
>> The only way that makes sense would be a power MOSFET with a current
>> sense amplifier for the gate. This would provide a fractional forward
>> voltage drop. Properly designed, it could limit maximum current draw
>> from the car and thus protect the fusable link. But there lies the path
>> of madness.
>>
>> The next thought is to build a switching power supply with
>> ultra-capacitors as the energy buffer. The advantage is no battery
>> chemistry risks. But once I start that path, when do I stop? <grins>
>>
>>>
>>> My inverter is heat-sunk onto a thick (0.5") Al plate, battered into a
>>> shape such that it attaches to the car's sheet metal at several points
>>> and becomes a heat pipe. It stays pretty cool for short-term use, but I
>>> added a 12V computer fan to keep air moving over the outer finned case.
>>> It vents into the car with no problems, but I've been thinking of
>>> running the air to the outside. If I make the system more automated like
>>> yours, heat may become an issue. What do you think?
>>
>> In my case, I lower the hinged panel to access the inverter. This puts
>> it in one of the prefered mounting orientations. The unit already has an
>> internal fan and it is thermally protected. Since I still need to run
>> the power into the house, I simply keep the trunk cracked open and any
>> heat easily escapes.
>>
>>> Also, as I understand your diagram, the traction battery charges the 12V
>>> circuit when the 'ignition' is ON, and you've added an automatic switch
>>> to the 'ignition' circuit. Can you provide details of that circuit?
>>
>> Not quite. I modified my inverter to provide a remote ON/OFF switch.
>> This allows me to use the inverter when traveling to provide 110 VAC for
>> laptops or other light duty devices.
>>
>> It is very important that the vehicle be ON and in "READY" when using
>> the inverter. The 12 VDC battery does not have enough power to run long
>> and you need to let the Prius engine cycle as needed to maintain
>> traction voltage. So my remote switch is powered by the cigarette
>> lighter circuit. This circuit is only on when the car is in "READY."
>>
>>> We just bought a 2.5kW gas generator for backup purposes, so the Prius
>>> solution is less important. I may restore the original battery, freeing
>>> up the Li-ion pack for other uses.
>>
>> Only because I'm leary of LiON batteries due to their notorious
>> temperature sensitivity and constant current charge-discharge
>> characteristics. I'd probably replace them with NiMH if only because
>> NiMH are less finicky and don't have a reputation for self-destruct. But
>> it sounds like a clever approach to handling surge loads.
>>
>> Bob Wilson
>
> About a year ago I bought a new, 7KW, 110V/220V, made-in-China, Honda
> knock-off (parts interchangeable they told me), for $00.00 complete
> with electric start. When I wired my home I equipped it with a
> generator panel so it was a simple matter of making the power cord.
> Works great and leaves my Prius free to run for gas. I see from this ad
> I was very lucky to find it on sale:
>
> http://www.sjdiscounttools.com/newgen7013.html
>
>
Here you go:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item (0298932926
Posted by Was Istoben on January 4, 2009, 1:14 am
> Was Istoben wrote:
>>
>>>
>>>> . . .
>>>>
>>>> My inverter (true sine wave) has an inrush thermistor, but I'll add
>>>> your
>>>> suggested RF toroids.
>>>
>>> I use the toroids to block higher frequencies from feeding back into the
>>> 12 VDC bus. I didn't want inverter noise to feed back into any of the
>>> ECUs. The inverter vendors advises against toroids but they are there to
>>> protect the $0,000 car, not the $00 inverter. So far, I've had no
>>> problems.
>>>
>>>>
>>>> When drawing more than a kW I don't see the voltage drop that you
>>>> reported. It could be internal resistance because conversion to 18650
>>>> Li-ion cells affects both energy-density and energy-flow. Thoughts? (my
>>>> car is an '04)
>>>
>>> Did you rig up a separate LiON pack as an energy storage buffer? Do you
>>> have a skematic and/or photos somewhere?
>>>
>>> I've racked my brains to figure out an affordable, power isolation
>>> approach. Sure I can put in a 100A diode so current flows one-way but
>>> there would be a 1.2 VDC forward voltage drop, 120 W.
>>>
>>> The only way that makes sense would be a power MOSFET with a current
>>> sense amplifier for the gate. This would provide a fractional forward
>>> voltage drop. Properly designed, it could limit maximum current draw
>>> from the car and thus protect the fusable link. But there lies the path
>>> of madness.
>>>
>>> The next thought is to build a switching power supply with
>>> ultra-capacitors as the energy buffer. The advantage is no battery
>>> chemistry risks. But once I start that path, when do I stop? <grins>
>>>
>>>>
>>>> My inverter is heat-sunk onto a thick (0.5") Al plate, battered into a
>>>> shape such that it attaches to the car's sheet metal at several points
>>>> and becomes a heat pipe. It stays pretty cool for short-term use, but I
>>>> added a 12V computer fan to keep air moving over the outer finned case.
>>>> It vents into the car with no problems, but I've been thinking of
>>>> running the air to the outside. If I make the system more automated
>>>> like
>>>> yours, heat may become an issue. What do you think?
>>>
>>> In my case, I lower the hinged panel to access the inverter. This puts
>>> it in one of the prefered mounting orientations. The unit already has an
>>> internal fan and it is thermally protected. Since I still need to run
>>> the power into the house, I simply keep the trunk cracked open and any
>>> heat easily escapes.
>>>
>>>> Also, as I understand your diagram, the traction battery charges the
>>>> 12V
>>>> circuit when the 'ignition' is ON, and you've added an automatic switch
>>>> to the 'ignition' circuit. Can you provide details of that circuit?
>>>
>>> Not quite. I modified my inverter to provide a remote ON/OFF switch.
>>> This allows me to use the inverter when traveling to provide 110 VAC for
>>> laptops or other light duty devices.
>>>
>>> It is very important that the vehicle be ON and in "READY" when using
>>> the inverter. The 12 VDC battery does not have enough power to run long
>>> and you need to let the Prius engine cycle as needed to maintain
>>> traction voltage. So my remote switch is powered by the cigarette
>>> lighter circuit. This circuit is only on when the car is in "READY."
>>>
>>>> We just bought a 2.5kW gas generator for backup purposes, so the Prius
>>>> solution is less important. I may restore the original battery, freeing
>>>> up the Li-ion pack for other uses.
>>>
>>> Only because I'm leary of LiON batteries due to their notorious
>>> temperature sensitivity and constant current charge-discharge
>>> characteristics. I'd probably replace them with NiMH if only because
>>> NiMH are less finicky and don't have a reputation for self-destruct. But
>>> it sounds like a clever approach to handling surge loads.
>>>
>>> Bob Wilson
>>
>> About a year ago I bought a new, 7KW, 110V/220V, made-in-China, Honda
>> knock-off (parts interchangeable they told me), for $00.00 complete with
>> electric start. When I wired my home I equipped it with a generator
>> panel so it was a simple matter of making the power cord. Works great
>> and leaves my Prius free to run for gas. I see from this ad I was very
>> lucky to find it on sale:
>>
>> http://www.sjdiscounttools.com/newgen7013.html
>>
>>
> Here you go:
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item (0298932926
Yep, add electric start to that, drop the shipping, and it's just like mine.
>
> My inverter (true sine wave) has an inrush thermistor, but I'll add your
> suggested RF toroids.