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Discussion Starter · #1 · (Edited)
Took delivery of volt #772 last night, and I'm dreaming of ideas. This one is crazy but still interesting so bear with me.

I'd need to do the math but it would be interesting if we could extend the range of the Volt in EV mode by allowing it to charge off a bank of 10x12 volt batteries wired in series.

The idea is to use a battery bank in the trunk to recharge the car while it's parked at a train station for 10 hours a day, with no access to a plug. I'd expect to maybe get an additional 3-5 mile range this way depending on how many amps the sealed Pb batteries have. The battery bank would require a Pure Sine Wave Power Inverter to convert the 110 VDC to AC that the car would accept for a recharge. There would be alot of wasted energy with all the energy conversions taking place, but it could be a fun experiment to get the full EV commute round trip. Not sure how cost effective it would be either... but still it would carzy to have a Volt pluging into itself.

How long would it charge on a battery bank of 10 12volt 18 amp hour batteries? 30 minutes and hour..? What error would it throw?

http://www.gruberpower.com/gruberpower/advertising/Batteries/Allbatteries/
 

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How long would it charge on a battery bank of 10 12volt 18 amp hour batteries? 30 minutes and hour..? What error would it throw?
12 volts * 10 batteries * 18 AH = 2.16 kWh. With losses in the inverter and Volt charger maybe a little less than 2 kWh available. So you might get another 5 or 6 miles. Of course, you're also carrying around a lot of lead in the batteries plus the weight of the inverter. And you would need to buy the batteries and inverter, secure them against shorting out as well as against becoming projectiles in the event of a crash, and come up with a means to charge them as well as the car every night. This also would reduce your cargo space to near zero.

You might be better off working out an arrangement with the manager of the train station to use their electricity.

Keep in mind that the Volt already carries a means for creating electricity when the battery is depleted. Just add gasoline.
 

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I would not want the batteries in the cabin compartment with me for safety reasons.

The charger for the Pb batts are pretty costly.

If you are determined to try this I would definitely talk to Bob Batson at Electric Vehicles of America about how to accompolish it. He will help you figure out the safest, most cost effective way to accompolish it. He will recommend Trojan batts. The Trojans are more expensive than your garden variety Pb batt, but in the BEV they have proven very durable. It was 10 years before I had to replace one, which is pretty incredible considering the demands placed on the batts in a BEV.
 

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Discussion Starter · #4 ·
Valid but obvious points.* The inverter would act as its own charger for the battery bank.* The batteries are $25 each so 250 bucks.* The pack would weigh under 150lbs, call it 200 lbs.
A square 8 inches tall 36x36 raising trunk floor 8 inches.* All for 5 miles additional range... Demonstrates the energy density of lipo's.* But if the objective is to conduct a commute gas free, then there you go.....* yes I said it crazy..
Sent via DROID on Verizon Wireless
 

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Discussion Starter · #5 · (Edited)
The inverters can be had for under $200 bucks. And let's face it none of us are driving volts right now because the main objective is to save money... Its a thought experiment to help demonstrate the engineering behind this car.
 

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Well normal car 12 batts are not going to cut it, they just don't handle being deep drained and charged up frequently. You are going to need a "golf cart" type battery, which are heavier and more expensive.

Hmm I understand that you are going to use the inverter to convert the 120V dc to 120 V ac to charge the Volt traction pack. How are you going to use this same inverter to charge the 120v Pb batt pack?
 

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Discussion Starter · #7 ·
That's what the inverters do.. they work as battery bank chargers in reverse, for wind, and solar applications and others. It may not be all that crazy but to recapture the investment may takes a while. Check out the sealed pb batteries in the link I provided as the inverter type mentioned. The seal pb batteries I.I.described are used in applications from children ride on toys, Scooter, Wheel chairs, some smaller golf carts, as well as UPS back up power supplies.
 

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Chargers do much more than just invert the power. For starters there are safety features, that monitor the charging process, and shut it down if problems are detected. I think it would be extremely risky to use a straight up inverter to charge a battery pack.
 

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Well, that would certainly be feasible. I'g go with a few large batteries though. We power some communications equipment with 110Ah Sealed Lead Acid batteries. They are about the size of a typical 12V automotive battery, and are safe for air shipping, so there is no danger having them in the cabin. Four of those in parallel can easily be charged overnight with a 40A automotive charger. That would give you about 5kW of power, rechargeable overnight, and safe to carry in the car. I thing the cargo compartment could probably hold up to 10 of these for the hardcore system :)

The downside: the batteries weigh 80 lbs each and cost about 250$ each, so it's not a cheap proposition.
 

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Discussion Starter · #10 ·
They sure do, I've hand plenty of experience with digital charges, and early lithium cells.from A123 and other vendor before they had balancing taps and low voltage warnings and.shut offs. Pb's are about as forgiving as they come. Not sure what we are debating here. Pure Sine Wave inverters and deep cycle battery banks are well proven.. from light houses, solar and wind farms to the early Gm EV1.
 

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while the deep cycle type SLA batteries wold work better than regular car batteies they still have a cycle life limit of 200 to 250 cycles, many actualy achieve a lot less, especialy if you dont recharge them right away.
 

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The problem would be maintaining a stable 120VAC for a sufficient period to do any good. The Volt onboard charging module isnt very tolerant of "dirty" AC or lower than anticipated AC amplitudes. (the primary reason why using a "generator" is not recommended for charging) So it might work initially (depending on how "pretty" the AC sine waveform your inverter produces) but once the Pb state-of-charge began to nose-dive and terminal voltages decreased much below 11VDC the Volt would likely just bail and set a bunch of charging DTCs.
WOT
 

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Discussion Starter · #14 ·
Can give me your source for tolerance of the volts charging system you mentioned... My information is a little different, yet not offical. Id like to understand more about this topic since others have wondered about solar charging station that are not grid tied.
 

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The total cargo capacity is 750 lbs including passengers and driver. So 4 average people and 200 lbs of batteries exceeds maximum load.
It's be interersting to see how extra weight affects range. Maybe putting in 3 miles of extra batteries would reduce the range by 3 miles.
 

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Another thing to consider is C rating. In your original design you had 2.16 kwh of batteries. The Volt charger is 3.3 kw so you are asking the Pb batteries to put out 1.5 C. ---not sure they would like this.

Maybe you could switch to some cheap Chinese Lipos. Thundersky comes to mind. Not sure but maybe you could get the lipos at around (200$/kwh???-probably not) but you would end up w/ a nicer package.
 

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To me the biggest problem is weight. I used to have a phev conversion in a 2010 Prius. I didn't get the shocks altered and the thing dragged butt everywhere. I simply wouldn't do it with this car. Way too many sacrifices. However, theoretically it would provide a marginal improvement.
 
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