General Disclaimer: (HV) (DC) injury or death hazard, use at your own risk, may void warranty. |
Difference between revisions of "PriusPlus-Theory"
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==The PHEV Battery Pack== | ==The PHEV Battery Pack== | ||
− | The PHEV pack consists of twenty 12 volt 20 amp hour sealed lead acid batteries connected in series. The nominal voltage of | + | The PHEV pack consists of twenty 12 volt 20 amp hour sealed lead acid batteries connected in series. The batteries themselves sit in an aluminum box and are mounted above the spare tire well, but below the false floor in the trunk. The pack has a nominal voltage of 240 volts and has a total energy storage of about 4.8 kWh (not all usable.) In this design, the PHEV battery pack has a higher nominal voltage than the stock NiMH battery and is used to charge the stock NiMH battery. Contactors (large relays) are used to connect and disconnect the PHEV battery pack from the stock battery when charging is needed. The higher voltage pack cannot always be connected to the stock pack, because that would overcharge the batteries. NiMH battery packs also cannot easily be charged in parallel, so simply adding a second NiMH battery pack is not simple. The current from the battery pack is less than 60 amps, and therefore the pack is fused with 60 amp 300VDC (or higher) fuses. The batteries must be connected using 8 AWG wire or larger (smaller AWG number) to handle the amount of current. |
+ | |||
+ | ===Current PbA limitations=== | ||
+ | *The conversion adds 300+ lbs to the vehicle’s weight to provide 10 miles of electric range per charge (16.7 usable Wh/kg) | ||
+ | **Though Ron has safely driven 17,000 miles in his converted Prius, the added weight could possibly cause vehicle instability during driving, and the battery may modify the effectiveness of the vehicle’s rear crush zone. | ||
+ | **Existing conversions sit 1-2 inches low in the rear. Air shocks or heaver-duty rear springs would be nice, but have not yet been developed. | ||
+ | **Though there are indications that improved hybrid efficiency due to a lower combined internal resistance of the two-battery combination at least partially compensates for the added weight, city gasoline mileage is otherwise reduced by up to 10%. | ||
+ | *Operating costs are high due to an expected cycle life of only 300-400 deep cycles, providing only one to two years of daily driving (at 400 cycles, 10 electric miles per 2.1 kWh cycle, and $800/pack, battery cost is $0.95/kWh throughput or $0.20/electric-mile (in addition to the cost of electricity, usually 2-4 cents/mile depending on utility rates). | ||
+ | *For decent battery life, the battery must always be charged within a day of discharge, making charging a required rather than optional operation (if planning to drive to somewhere without access to electricity, temporarily turn off PHEV operation). | ||
+ | *PbA batteries perform very poorly in cold weather. Though our design includes a thermally insulated battery pack, heated during charging, this feature has been insufficiently tested due to moderate California temperatures during development. | ||
+ | |||
+ | ===Possible Future Battery Options=== | ||
+ | More advanced batteries may be retrofittable to the conversion. This will probably require upgrading to CalCars’ not-yet-designed next version of logic board, and will also probably require additional battery management electronics. Any new battery’s enclosure, mounting, and thermal management system will no doubt also be very different. | ||
+ | |||
+ | Possible future batteries and their likely characteristics (incl. low-volume pricing): | ||
+ | |||
+ | Example pack | ||
+ | {| border=1 cellpadding=2 | | ||
+ | | Chemistry || || Usable<br>Wh/kg || Cycle<br>life || Yr daily<br>driving || $/usable<br>kWh || $/kWh<br>thruput || Cents/<br>EV-mi || kWh || $ || EV mi || Wt,<br>lb | ||
+ | |- | ||
+ | | PbA<br>(current) || || 16 || 400 || 1.1 || $380 || $0.95 || 20.0 || 2.1 || $ 798 || 10 || 289 | ||
+ | |- | ||
+ | | NiMH || worst || 36 || 2000 || 5.5 || $1,200 || $0.60 || 12.6 || 4.2 || $5,040 || 20 || 257 | ||
+ | |- | ||
+ | | NiMH || best || 36 || 4000 || 11.0 || $800 || $0.20 || 4.2 || 4.2 || $3,360 || 20 || 257 | ||
+ | |- | ||
+ | | Li-ion || worst || 56 || 1000 || 2.7 || $1,200 || $1.20 || 25.2 || 4.2 || $5,040 || 20 || 165 | ||
+ | |- | ||
+ | | Li-ion || best || 100 || 4000 || 11.0 || $800 || $0.20 || 4.2 || 6.3 || $5,040 || 30 || 139 | ||
+ | |- | ||
+ | | NiZn || worst || 36 || 500 || 1.4 || $500 || $1.00 || 21.0 || 4.2 || $2,100 || 20 || 257 | ||
+ | |- | ||
+ | | NiZn || best || 36 || 2000 || 5.5 || $350 || $0.18 || 3.7 || 4.2 || $1,470 || 20 || 257 | ||
+ | |- | ||
+ | | Firefly PbA || worst || 36 || 1000 || 2.7 || $350 || $0.35 || 7.4 || 4.2 || $1,470 || 20 || 257 | ||
+ | |- | ||
+ | | Firefly PbA || best || 45 || 4000 || 11.0 || $250 || $0.06 || 1.3 || 5.25 || $1,313 || 25 || 257 | ||
+ | |} | ||
+ | |||
+ | Note that figures are for usable, not total, capacity in kWh (usually 80%, but much less for the current PbA pack (4.8 kWh total capacity), due to Peukert’s Law). | ||
==The Charger== | ==The Charger== |
Revision as of 20:14, 1 January 2007
Click show for a short list of the current PHEV conversion and kit options for the Toyota Prius. |
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For Prius conversion details see the Prius PHEV article and comparisons table.
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--={ Project Overview
}={ 2007 Maker Faire
}={ Theory
}={ Instructions
}={ Parts List
}={ RawData
}={ Latest News
}=--
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--={ Historic }={ Battery }={ Schematics }={ PseudoCode }={ Photos }=-- |
This is the home of the PRIUS+ PHEV DIY (Do-it-Yourself) documentation. These pages are currently anonymously editable, which may change in the future. Please feel free to use the Discussion page for general discussion and commentary on the main article. If you would like to add to an existing section use the "edit" link near that topic's heading. Don't forget to use the Summary field to describe your changes. While editing use the "Show Preview" button to make sure your changes look like you expect them to, before you click "Save Page". |
Intro Paragraph here maybe with a link to the main PriusPlus article, links to external sites can appear as formatted CalCars, just plain URLs like http://www.calcars.com, or fancy references such as that in the next paragraph.
Another Paragraph and such, you can get help at our Help:Contents#How do I use the Wiki Website page <ref>http://en.wikipedia.org/wiki/Help:Contents more help using the wiki.</ref> Feel free to simply remove or if you like move all of this example text to the pages discussion article.
Please feel free to hack this up or delete it, as I could have this all wrong. I just wanted to get this started. Jim P.
- Prius plus:
The Prius Plus is a contactor based conversion for an '04 or newer Prius. A sealed lead-acid battery pack is added along with a standard 120 volt charger and supporting electronics. The converted Prius Plus has an electric only range of about 10-12 miles.
The main components are:
- The PHEV battery pack
- The Charger
- The CAN-View
- Control board
The PHEV Battery Pack
The PHEV pack consists of twenty 12 volt 20 amp hour sealed lead acid batteries connected in series. The batteries themselves sit in an aluminum box and are mounted above the spare tire well, but below the false floor in the trunk. The pack has a nominal voltage of 240 volts and has a total energy storage of about 4.8 kWh (not all usable.) In this design, the PHEV battery pack has a higher nominal voltage than the stock NiMH battery and is used to charge the stock NiMH battery. Contactors (large relays) are used to connect and disconnect the PHEV battery pack from the stock battery when charging is needed. The higher voltage pack cannot always be connected to the stock pack, because that would overcharge the batteries. NiMH battery packs also cannot easily be charged in parallel, so simply adding a second NiMH battery pack is not simple. The current from the battery pack is less than 60 amps, and therefore the pack is fused with 60 amp 300VDC (or higher) fuses. The batteries must be connected using 8 AWG wire or larger (smaller AWG number) to handle the amount of current.
Current PbA limitations
- The conversion adds 300+ lbs to the vehicle’s weight to provide 10 miles of electric range per charge (16.7 usable Wh/kg)
- Though Ron has safely driven 17,000 miles in his converted Prius, the added weight could possibly cause vehicle instability during driving, and the battery may modify the effectiveness of the vehicle’s rear crush zone.
- Existing conversions sit 1-2 inches low in the rear. Air shocks or heaver-duty rear springs would be nice, but have not yet been developed.
- Though there are indications that improved hybrid efficiency due to a lower combined internal resistance of the two-battery combination at least partially compensates for the added weight, city gasoline mileage is otherwise reduced by up to 10%.
- Operating costs are high due to an expected cycle life of only 300-400 deep cycles, providing only one to two years of daily driving (at 400 cycles, 10 electric miles per 2.1 kWh cycle, and $800/pack, battery cost is $0.95/kWh throughput or $0.20/electric-mile (in addition to the cost of electricity, usually 2-4 cents/mile depending on utility rates).
- For decent battery life, the battery must always be charged within a day of discharge, making charging a required rather than optional operation (if planning to drive to somewhere without access to electricity, temporarily turn off PHEV operation).
- PbA batteries perform very poorly in cold weather. Though our design includes a thermally insulated battery pack, heated during charging, this feature has been insufficiently tested due to moderate California temperatures during development.
Possible Future Battery Options
More advanced batteries may be retrofittable to the conversion. This will probably require upgrading to CalCars’ not-yet-designed next version of logic board, and will also probably require additional battery management electronics. Any new battery’s enclosure, mounting, and thermal management system will no doubt also be very different.
Possible future batteries and their likely characteristics (incl. low-volume pricing):
Example pack
Chemistry | Usable Wh/kg |
Cycle life |
Yr daily driving |
$/usable kWh |
$/kWh thruput |
Cents/ EV-mi |
kWh | $ | EV mi | Wt, lb | |
PbA (current) |
16 | 400 | 1.1 | $380 | $0.95 | 20.0 | 2.1 | $ 798 | 10 | 289 | |
NiMH | worst | 36 | 2000 | 5.5 | $1,200 | $0.60 | 12.6 | 4.2 | $5,040 | 20 | 257 |
NiMH | best | 36 | 4000 | 11.0 | $800 | $0.20 | 4.2 | 4.2 | $3,360 | 20 | 257 |
Li-ion | worst | 56 | 1000 | 2.7 | $1,200 | $1.20 | 25.2 | 4.2 | $5,040 | 20 | 165 |
Li-ion | best | 100 | 4000 | 11.0 | $800 | $0.20 | 4.2 | 6.3 | $5,040 | 30 | 139 |
NiZn | worst | 36 | 500 | 1.4 | $500 | $1.00 | 21.0 | 4.2 | $2,100 | 20 | 257 |
NiZn | best | 36 | 2000 | 5.5 | $350 | $0.18 | 3.7 | 4.2 | $1,470 | 20 | 257 |
Firefly PbA | worst | 36 | 1000 | 2.7 | $350 | $0.35 | 7.4 | 4.2 | $1,470 | 20 | 257 |
Firefly PbA | best | 45 | 4000 | 11.0 | $250 | $0.06 | 1.3 | 5.25 | $1,313 | 25 | 257 |
Note that figures are for usable, not total, capacity in kWh (usually 80%, but much less for the current PbA pack (4.8 kWh total capacity), due to Peukert’s Law).
The Charger
The charger runs on standard 120v (or 240v) AC power and is used to recharge the PHEV pack. Three options are planned:
- a Delta-q charger (http://www.delta-q.com) designed for the PbA battery pack, at a projected price of $800. We are in discussions with the company and will soon know if/when pre-production units will be available; UL-approved units are likely to be available in 2007.
- the Brusa NLG503 charger, available through http://www.metricmind.com/index1.htm for $2650 retail including cables (a group rate is possible). Users can reprogram this charger for other voltages and battery chemistries, so it would be a good purchase for developers anticipating an eventual high-tech replacement battery.
- (eventually) the Manzanita Micro PFC-40 charger, available through http://manzanitamicro.com for around $2000. This charger has programmable but less sophisticated charging algorithms, but can also double as a high-power DC:DC converter between the battery packs. Its output is not line isolated. Its incorporation will require modifications/enhancements of this conversion, and control circuitry and algorithms that have not yet been developed.
Useful information on charging lead-acid batteries can be found at http://batteryuniversity.com/partone-13.htm
The CAN-View
The CAN-View monitors activity on the CAN bus (the bus which the different microprocessors in the Prius communicate) and provides a user interface to the PHEV and instructs the contactors on the PHEV battery pack to open and close to charge the stock battery. CAN-View itself is simple to install and typically requires between a half hour to one and a half hours to install. There are 2 versions of CAN-View currently available. Version 3 requires an '04 or '05 Prius and makes use of the built in display (or MFD) while Version 4 works with an 04-07 Prius but requires an external touchscreen. For more information, see CAN-View.
The parameters I (Ron) am currently using for the CAN-View relays are as follows (RL2 and RL3 are NOR'd together; the result is OR'd with RL5 OR RL6; the EV-only parameter is not used):
- RL2: > 77 OFF < 75 %SOC -OR- < 55 OFF > 60 CCL for 0 seconds
- RL3: < 40 OFF > 45 mph -OR- < 5 OFF > 20 %throttle for 3 seconds
- RL5: < 200 OFF > 235V -OR- < 200 OFF > 235V for 0 seconds
- RL6: < 60 OFF >63 %SOC -OR- < 60 OFF > 63% SOC for 0 seconds
Note: The result of "RL2 NOR RL3" is the AND of the complement of all four RL2/RL3 conditions. Therefore, the above "(RL2 NOR RL3) OR RL5 OR RL6" control board logic, when simplified (ignoring the "X seconds" timing), becomes the following logic for activating HVRL1, which parallels the PHEV and OEM battery:
( < 77 OFF > 75 % SOC
-AND- > 55 OFF < 60 CCL
-AND- > 40 OFF < 45 mph
-AND- > 5 OFF < 20 %throttle)
-OR- < 200 OFF > 235V
-OR- < 60 OFF > 63 %SOC
Control Circuit Board
A circuit board is added to control the heaters, fans, contactors, etc. This board also provides an interlock for the charger so that the car cannot be driven away while plugged in to a live outlet.
Sub parts of this board are;
- Power management
- Battery Heating & Cooling
- System diagnostics
- The board itself
Power Management
You want the system to know when to send power to the original battery and when it should take power from the regenerative braking system. It should also know when to shut the pack completely down such as when it is empty or when it is charging. Also, you want to tell the Prius battery computer that it has a high State of Charge so it keeps trying to use up the power.
Battery Heating & Cooling
Lead acid batteries do not function properly when they are either hot or cold. The pack is heated and cooled as necessary by three Wal-Mart heating pads and three fans. When cooling, the warm air has to go somewhere so it now goes out the two 2” holes under where the spare use to be. The circuit board is responsible for controlling the heaters and fans.
System Diagnostics
Let’s say you blow a fuse or something is wrong somewhere how would you know? A ribbon cable is sent to the dash from the circuit board to show lights for what systems are working when.
The Circuit Board
It is a small board about 6” by 5” is my guess. I’ve held it but I did not measure it. So you now know what it controls, but it still needs power to run so that is another cable. It talks to the Canview to so yet another cable. It needs cables to the fans, the on off of the heating pads, and the charger too.
References
<references/>