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Plug-In Supply Inc. Introduces Lead-Acid PHEV Prius Conversion System for $4,995

Plug-In Supply, Inc unveiled its PbA10 Conversion System last week at the Plug-in 2008 conference in San Jose. The PbA10 Conversion System, based on the CalCars Open Source design, turns a standard 2004-2008 model year Prius into a Plug-in Hybrid Electric Vehicle (PHEV) with an all-electric range of 10-15 miles and improved average mileage of up to 100 miles per gallon (plus 1 cent/mile of electricity).

The conversion system uses a 5 kWh pack comprising new extended life lead-acid batteries (more than 800 cycles) for better battery longevity than was previously available.  The system is designed to permit an upgrade to lithium iron phosphate batteries with an all electric range of 15-20 miles as costs for these longer range batteries decline.

The PbA PHEV Assembly is a complete, tested, and ready to install pack. It provides access to the spare tire and contains 20 PbA20-12 lead-acid batteries, plus all high voltage components and control electronics in a strong welded steel enclosure. Expected battery life for the PbA system is about 2 years. The weight of the PbA system is 360 lb (163 kg), compared to 150 lb (68 kg) for the lithium-ion system.

Maximum speed in all-electric mode is 52 mph.

Plug-in Supply is currently working on a PSI Lithium Ion Phosphate Prius+ conversion, featuring the latest batteries from Phoenix Silicon International (PSI). The chassis will provide access to the spare tire and is expected to provide 16 miles of EV mode operation and last the life of the car.

Converting the Prius to a plug-in has been a popular topic since Ron Gremban, CalCars Technical Lead, was the first to convert his Prius in 2004.  Since then, about two hundred cars have been converted in what was formerly a slow and complicated process.

By refining the design for manufacturing, Plug-In Supply’s Conversion System reduced the conversion time from several weeks to just one day in 2007.  Further improvements in design have reduced the cost and complexity while improving reliability and battery longevity.

Plug-In Supply Inc. is a Petaluma, California-based supplier of Conversion Systems and components serving the Hybrid Electric Vehicle (HEV) and Plug-in Hybrid Electric Vehicle (PHEV) aftermarket. Plug-In Supply Inc. is operated by Robb Protheroe, an engineer and long time proponent of electrically powered vehicles.



The Prius is a full hybrid with power-split. So, I don't get why it's supposed to be ICE assisted.


Yes, the Prius is parallel/series HEV. If you drive at lower speeds, or you're not accelerating too much, then you only use the electric motor, series mode. (Assuming you have enough battery charge left to do this.) If you need to go freeway speeds or accelerate harder then the Internal Combustion Engine (gas or diesel ICE) kicks in to help push ("assist") the moving car, parallel mode. The Prius HEV concept is over 10 years old. They had to split the power drive because electric motors were heavier and batteries did not have enough power output ("power density" not to be confused with "energy density"). Battery tech has improved and electric motors have gotten more power for the same weight. As a result, you can now have a full-function freeway capability in a series-mode HEV if you want. You don't need a parallel mode and can get rid of the complexity, cost, and weight of the parallel drive mechanics for the ICE. Since batteries do not have the high energy density of gasoline and diesel you still might want to have a smaller ICE to use as a generator when you need to go beyond your all-electric range. The ICE generator would used in ON/OFF mode at optimum rpm, so your vehicle will be more efficient than parallel/series HEV. If you now make your battery large enough for a 20 or 40 mile all-electric range and provide a plug-in charger, then you have a Series-PHEV, or E-REV. This is as good as it gets short of a full Battery Electric Vehicle (BEV). Much better than Prius PHEV conversion because you use no fuel at all within that 20 or 40 mile range.

The flex-fuel generator for the E-REV version of the Aptera will be roughly the size as one of those rectangular over-head stowable carry-on bags. Smaller, cheaper, lighter, and more efficient than anything in a pure ICE car.
Series-PHEV approach also makes it possible to use higher efficiency turbine generators, fuelcells, or even air batteries for the Extended-Range power source.
Does that explain?


Well, maybe PBP's and Th!nk's plans of leasing
the battery to the car buyer makes sense, after all.
I think they have to come down a bit on the
monthly fee a bit, though. $200 a month is
rather steep. I can get gasoline for that. In
fact, gasoline would be cheaper for me, even at
$4 a pop.


The Civic hybrid is "flawed" because it cannot run with the ICE stopped. But it provides equivalent mpg as the Prius using a more elegant (simpler) concept. The Prius is "flawed" by it's inability to drive the weels directly without running power into one Motor-Generator and sending the electric power to the other M-G.
It's so-called CVT is roughly the same concept as a GM-EMD locomotive using the M-G to M-G link to vary the OA ratio. The GM 2-mode transmission is the most sophisticated of all. It can drive all electric like the Prius and all mechanical like the Honda. But it's not too elegant in it's simplicity. My choice? Save your money. We all know worthwile hybrids are just around the corner.
But don't forget, every day is a winding road.


But you won't go anywhere without the ICE (unlike the converted Prius you mentioned). Well, at least neither far nor fast. Hence it's not ICE assisted.

Granted the mechanics might seem more complex for a parallel or power-split hybrid than a serial hyrbid, but that's no problem. There are a lot of things you need to consider when building a serial hybrid and creating the operation strategy for the ICE, making the serial hybrid more complex.
Think of how you want to operate the ICE: stationary, intermittend or phlegmatic? All the things you need to factor in: power requirement (current or average over time?), speed, state of charge, temperatur of the catalytic converter, etc.
Furthermore you need to convert energy twice which lowers the efficiency. Admittedly, with better batteries and bigger electric range (like you mentioned: range extender), who cares about the ICE to wheel efficiency?

The ICE of the Prius is able to drive the wheels directly (one gear ratio).
Two-Mode even allows for 4 (fixed) gears.


JRod, the battery depreciation formula is straightforward (using 4 mi/kWh for typical sedan):

($/kWh)/(4 mi/kWh * cycle life * DoD window) = $/mile

Lead acid
($160/kWh)/(4 mi/kWh * 400 * 50%) = $0.20/mi

NIMH (e.g. RAV4-EV)
($600/kWh)/(4 mi/kWh * 2400 * 80%) = $0.08/mi

LiCoO2 (e.g. Tesla)
($400/kWh)/(4 mi/kWh * 500 * 80%) = $0.25/mi

LiFePO4 (e.g. A123)
($600/kWh)/(4 mi/kWh * 4000 * 80%) = $0.05/mi

($200/kWh)/(4 mi/kWh * 2000 * 80%) = $0.03/mi

LiTi5O12 (e.g. Altair)
($640/kWh ??)/(4 mi/kWh * 16000 * 100%) = $0.01/mi

24 mpg sedan with gasoline @ $4/gal = $0.16/mi

Cycle life is the key parameter. Lead acid and consumer grade li-ion are too short-lived, but other chemsistries last long enough to beat gasoline.



With numbers like that why are they using lead acid? Thanks for the info though. I am going to check out some of the others. Maybe I won't have to give up on my electric scooter just yet. I have learned whenever someone is trying to sell you something that is battery powered the first thing you check is the life cycle. Especially when they report every other stat...



Quoth mds:

Do you have a $500 deposit on an Aptera or are you just another whiner who won't put his money where his mouth is?
I've seriously considered it, even though I'm a long way from California (I have a friend who'd supply the delivery address).  And if I hadn't just committed a pile of money to another project, I'd be in the delivery queue already.


Previous comments re the economics of the conversion pack.and hybrids generally make sense and suggest strongly that this is not yet the time for them.

Yes liquid fuels are great , so do not overlook coal to liquids technology, specifically RENTECH , RTK who have developed coal to liquids with carbon capture, as the way to maintain the rolling stock of the nation and still keep our $s here at home.

Ronald Schaefer

I wish people would get off this alternate fuel for now and concentrate on Hybirds and making better batteries and more powerful electric motors and improving gas mileage.

There isn't a distribution system in place for alternate fuels. Hydrogen is a good example you can't produce Hydrogen cars until you have a distribution system in every gas station, and no one is going to invest in a distribution system if you don;t have cars. Its a catch 22.

Go Hybrids for now to give us short term relief for foreign oil dependency while working on better solutions.


I get tired of wading through comments about batteries from people who haven't even read up on the subject. Why spend 10 minutes posting if you haven't taken five to go to Plug-In Supply and find out how this stuff works?

Answer: Lead-Acid (PbA) secondary deep-cycle battery packs can usually be discharged and recharged for 300-400 cycles. However, discharge rates are also subject to temperature and weather conditions throughout the life of the pack. This means potential replacement for deep-cycle battery packs is about every one to two years. LiFeBATT guarantees its cells for 2000 deep discharge/charge cycles before a 10% degradation of overall capacity may occur. Past the 2,000 cycle threshold, the cells still don't need replacement, but the user will notice a 10% reduction in battery capacity after a full charge. For an electric vehicle, a driver might see a 10% reduction in distance traveled as the battery pack ages beyond 2,000 cycles.

The definition of 2,000 deep discharge cycles for LiFePO4 chemistry is 72% - 98% depletion before recharge. Shallow discharge/recharge cycles will prolong battery pack life, extending it beyond 5,000 cycles with little loss in overall capacity, up to 10,000 cycles before degradation of overall battery capacity starts exceeding 10%. Shallow cycles are defined as less than 72% discharge and can be maintained by always allowing more than 28% of the battery pack capacity to remain undischarged when reconnecting the battery pack charger.

At 2,000 deep discharge/charge cycles, averaging 1 cycle per day would allow for 5.5 years of use before a noticeable loss of capacity. 10,000 shallow discharge/charge cycles would last around 13+ years.

The Prius has a power spliting "differntial" right at the ICE output that sends power to both the generator and wheels. It can only drive the wheels "directly" by also running power into the generator and sending the electric power to the motor. The drag of the generator is necessary.
Cut the wires to the generator and you cannot get any ICE torque to the wheels.

Douglas Hvistendahl

I suggest doing a search on ("zero pollution motors" AND "minicat OR citicat") Look Ma, no batteries! But a PHAV at half the cost of a PHEV is worth looking over. For most of us, however, the lowest cost solution is going to be a conversion, such as the Electrocharger, when they get into production. There are a number of partial answers out there - expect rapid change. At present, I'm saving about 9% with a lubrication enhancer, and about 6% with a fuel enhancer. Return on Investment runs about 300% annual, and will help pay for later developments. Another few percent comes from using a few hypermiler tricks, like coasting engine off when a known stop is coming up and there is no traffic. With a manual transmission, it is easy to start again just by lifting the clutch.

Henry Gibson

Most cars and houses are not bought with energy efficiency and low cost or payback periods in mind. The buyers spend as much as they think they can afford for beauty alone, almost. Beauty is in the eye of the beholder; a Hummer for one a VW for another. The TH!NK car with the ZEBRA battery is the most beautiful electric car on the market, but it should be a series hybrid as well. The most beatiful electric locomotive in operation is a diesel electric fitted with ZEBRA batteries as a hybrid. The most beautiful locomotive was a diesel steam hybrid the Kitson-Still.

The TZERO and its prototypes showed that the lead batteries were more than adequate ten years ago, but beautiful batteries now must be LiIon. Large number mass production and competition are needed to get battery costs low enough to compete with engines.

The cheapest automobile transportation is an operational old used car and gasoline at the current pump prices. Semi-trailer trucks could use high efficiency; most of the US ones should convert to dual fuel with natural gas. ..HG..


Economics is not there for the battery now - because we don't charge correctly for the fossil fuels. Once the carbon tax is added - battery will become economical.

Obviously it is more economically to be polluting than not ... just look at China's industries.


I guess I confused the THS with a pretty similar power-split gear, which is capable of driving the wheels directly. Thought I read it was possible, that's a shame since that would be the most efficient.

The "differential" is a planetary gear. The ICE is connected to the planet carrier, the generator to the sun gear and the ring gear to the output (chain drive) and electro motor.
When you fix the sun gear, all power goes to the ring gear and therefore to the output. But I'm not sure if that's actually right... planetary gears are so confusing and it just gets worse with the added motors.


Inexpensive ($600/kwh) Lithium-ion batteries are available on ebay.

You should be able to get 2KWH Lithium-ion conversion kit at the same $4995 price range.

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