Electric Truck Conversion

Dear Anonymous,

I always appreciate a link or two on related topics, thanks. Here is another couple of research and information links on building EV's and the rapidly developing micro-EV game that is coming onto the scene:
1. An ICEV retrofit to hybrid commercial site: http://www.poulsenhybrid.com/poulsen.html
2. An EV links informational site: http://www.green-metroplex.com/EVs/Index.html

Thanks for your topic thread!

There is no gizmo required to get 120 volts from (10) 12V batteries. Connecting them in series will give you the correct voltage. After you have connected one string of batteries in this fashion, then you could parallel this string with another identical string to get double the AH capacity, increasing the range (although the weight of the batteries puts more load on the motor, so doubling the batteries does not double the range).

There is a device called a boost converter that will increase DC voltages, but it would never be used to, for instance, bring a 120V battery pack up to 240 V, partly because a boost converter that would handle vehicle loads would be very expensive, and partly because you would gain nothing (you'd get twice the voltage but half the amperage), and would loose something to converter inefficiency.

On the other hand, reducing battery pack voltage to 12 volts for lighting and accessories is commonly done, using a buck (i.e., step down) converter. In this case, the loads are relatively small, so the converter is not expensive.

Here's a good site to poke around in to get ideas and see what other people are doing.

I am beyond curious, where we would use 12v x 10 to gain 120v vs. use 120v battery? As 120v would be beneficial as opposed to 12v...

Where can you buy 120 V batteries with 75 Amp/Hour ability?

Anonymous Hero,

Where can you buy 120 V batteries with 75 Amp/Hour ability?

You can look here: www.powbat.com/pages/default.aspx?pageid=71

Hmm, looks like a string of either 12 or 6 volt batteries put together in a common container. Am I wrong?

I am not sure what the advantage of that would be. Having individual 12 Volt batteries wired in series would give you more flexibility in where to mount them and if one goes bad you don't need to buy a whole new set.

Additionally, you can individually charge discrete batteries for a much faster rapid charge.

Yes I suppose you may run a string however you see fit and yes individual cells may need be swapped out independently within a matrix as I understand it and I may be wrong.

Moving a truck requires prodigious battery capacity (consider that the Tesla, a comparatively tiny car, has a 56 kWh battery pack). Suppose we decide we want a 12 kWh pack (which would give our truck 24 mile range, assuming .4kWh/mile consumption -- a figure that would require careful driving to achieve -- and .8 depth of discharge). For $228 per battery, you can get an unknown brand 12 V AGM 100 AH batteries, which if very carefully charged, could perform quite well. (If you wanted to be sure of performance, you might buy a name brand with good technical support, and you might pay $350 per battery.) Each battery will weigh 70-80 lbs -- awkward to lift but manageable. They could be arranged in any of several ways to best use space, and to distribute weight in a way that will provide safe handling and adequate truck payload.

Alternatively you could have a monolithic 120V 100 AH battery custom made for you. My guess would be that you could have this done for perhaps $30,000, or perhaps a bit more. (You might have a very hard time finding a company to do this, I'd think, if you want a real monolith of 60 individual cells -- most custom builders will just put 12V or 6V batteries in series, like everyone else does. There are, of course, specialty suppliers of 2 volt cells, but I doubt that you could combine 60 of these as economically as you can combine mass market 6V and 12V batteries.) The battery would weigh 700 - 800 lbs, would be very hard to move around, and would not enable flexibility in positioning. What benefit would you gain for the 10 fold increase in cost?

For reasons like this, 6 and 12 volt batteries are the modules from which most battery packs are constructed for both mobile and stationary uses. (Less frequently, you see 2V and 8V.) In lithium (ion, iron, etc) and in NiMH there are no fully standardized large format sizes: these newer batteries are all over the place in format, with the Tesla battery pack (of 6000 laptop batteries) being a demonstration of just how bizarre things can get. Given the age of the original poster's truck, my guess is that he is not planning on using these newer battery types, which can be about 10 times as expensive as lead acid.

So the answer to your question, "where would we use 12V x 10 to gain 120 v?": almost everywhere in the existing electric vehicle world where 6V x 20 is not used. And of course, as you probably remember from chemistry class or elsewhere, any lead acid battery of any voltage, is ultimately made up of 2V cells connected in series -- in a monolithic battery we simply don't see the interconnections, because they are often hidden under plastic.

Nice site link Ken ... Just wish I had a decent workshop ... unless I make a wooden electric car/bike/whatever...(oooh no I already made a whatever) ????

Del

Forget the electric non-sense, buy a surplus jet turbine meant for a chopper and use that...

Something which worries me is

Picking out a motor 120 or 240 volt ...

Why have you picked these voltages?? They are common ALTERNATING CURRENT voltages, and there are many AC motors using these voltages, but you CANNOT RUN THESE MOTORS FROM BATTERIES!! Make sure you are looking at DC motors before connecting the batteries.

Am I right guys??

Bill

there are many AC motors using these voltages, but you CANNOT RUN THESE MOTORS FROM BATTERIES!!

Battery current fed through a converter then out put A/C to motor.

see example at:

www.novaelectric.com/dc_ac_inverters/nova_invert120jupiter.php

Looking at their web page, it looks like they can put out as much as 200 amps. They don't say at what efficiency, but I assume it would take more than 200 amps in... The weight penalty would be restrictive too. 950 pounds for the 200 amp version. Is this feasible for an electric vehicle?

Bill

My friend has 30 to 32 Optima 12 volt batteries wired in series. My guess is those batteries are about 40 lbs each, so he has 1200 lbs of batteries in his car!

They may not actually be that heavy, I will have to check.

40lbs is the dry weight probably

I checked with my friend. His 30 batteries have a combined weight of 321 lbs and each battery is a 12 Volt, 17 A/H battery.

That means each battery is slightly less than 11 lbs. They are made by Odyssey Batteries.

post #12 was a reply to #10 have you read #10?

The trend is toward running AC motors in more sophisticated electric cars. (The Tesla's motor is AC.) Even brushless DC motors require what is essentially an AC input (from a variable frequency inverter that is the major part of the motor controller). There are loads of brushed DC motors in use, but nowadays, many people would like to get away from brushes, for wear, electrical noise, and other reasons.

The people at - ausev@austinev.org - are amateur converters and they may be able to help. There are also several sources on the web for EV parts, batteries, controllers, etc.

If you use lead-acid batteries you will lose a lot of your truck bed to them. Be prepared for short trips at slow speeds and getting caught a block from home with dead batteries. You could also use one of the more expensive batteries, which is much more compact, to get the same results. If you don't want to have unexpectedly dead batteries you could use a small engine and generator that could keep the batteries charged even on long trips. A little 20 hp diesel will do it. But if you don't like the pollution of the IC engine my choice would be a 20 hp steam engine to run the generator. Then you can even run your electric AC or electric heater without worrying about getting stuck with dead batteries,

More on this by e-mail at - beesidemeusa@yahoo.co.uk - ask about steam-electric hybrids.