# Benefits to 120V



## Guest (Jul 8, 2011)

Really it is just a matter of what you want. Pretty much each rung of the ladder will cost more. 96 costs more than 72 and so on up the ladder. You choose. I chose 120 because 96 was not quite up to the task. 120 gives pretty good performance and I am quite sure so will 144 and 156 and so on and so on up the ladder. Then it becomes an issue of what controller will handle what you want. It really is a matter of what you WANT not what you NEED. I guarantee it. Then it becomes how much can you spend on lithium cells and how many you can stuff in into the car. Figure those things out and then build your vehicle. 

Then go have a blast. I like 120 volts but I want to go up to 156 volts.

Pete


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## lowcrawler (Jun 27, 2011)

What I want depends on what's best for me.  

For instance - 120V will get me the performance I want (based on what others have reported)

But I can easily go to 144V given the size pack I need.... and the cost delta would be essentially zero.

My personal preference would be the higher voltages (better acceleration and speed can't hurt... even if it's not needed) but if there are some intrinsict benefits to 120V (Given it's near wall-voltage) then I'd go that way. Basically, I don't care between ~120V and ~144V so I'm looking for a reason to go one way or another...

Both my tentatively planned motor (warp9) and extremely tentatively planned controller (skyromotive) can handle 144V so that's not even an issue to help me make my choice...


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## rmay635703 (Oct 23, 2008)

lowcrawler said:


> Are there benefits to going with a 120V pack -- assuming you can get the power/performance you want from one?
> 
> Or is it really irrelevant and all systems are more or less the same difficulty/cost (within reason - say 96V-160V)?


I maybe a little old school but I take things from a cost only perspective (not just the conversion cost but also operation cost)

You need to decide how fast you need to go and what speeds will you REALLY be traveling?

Basically if you don't care about performance but do care about using the least amount of juice from the wall and experiencing the least wear you want your WOT to coorespond with the speed you want to travel + about 3mph in your different gears. So if you need to go 35mph most of the time and in 1st gear to the floor that is about the speed you go that will make your travel less expensive, increase your range and reduce wear on batteries and components.

If you choose a voltage that results in you using about 50% or less throttle most of the time you will use a lot more power from the battery, wear the battery and controller more and even add unnecessary heat to the motor (which may or may not matter)

In other words the better your voltage matches the top speeds you want to travel in each of your gears the less expensive your travel will be (assuming you don't plan on travelling often with on massive amp draws in top gear due to too low of a voltage)

So you will need to factor performance versus top speeds, if you can get a good selection of gears so that you can select a higher gear to get up to speed more quickly then down shift to make benefit of low amp draws you may have a winner if it also can get you to the top speeds you need once and a while.

Good Luck
Ryan


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## Guest (Jul 8, 2011)

lowcrawler said:


> What I want depends on what's best for me.
> 
> For instance - 120V will get me the performance I want (based on what others have reported)
> 
> ...


We can't tell you what's best for you. Only you can. The higher the voltage the better. Lower amp draws means easier on the batteries and higher mph per given gear. You will also have greater acceleration available too. Don't under build your system. You can have a killer 192 volt system and 300 AH cells and a killer 9" motor you will have all the power needed when ever you do need it or want it. You could have a 120 volt system and 100 AH cells and never have enough. If you have never driven an electric vehicle you have no clue. I am not sure you would go out and buy a car from the dealer using the criteria you presented. Build what you want. 

At minimum you should have:

120 volts Controller should be one that can be upgraded to higher voltages when you decide to go higher. You will. 
100 AH cells (lithium). Consider 200 AH instead.
9" motor/adaptor/clutch. If you go with a manual go with a clutch. 
DC DC converter to match your chosen pack voltage. Get a good one. 

120 volts will give nice performance. 100 AH cells will give minimal distance.

Don't cut corners and don't skimp.

Plan and plan and plan before you ever buy anything. 

Buy good quality. 


Or just go by a Leaf and be done with it.


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## lowcrawler (Jun 27, 2011)

gottdi said:


> We can't tell you what's best for you.


Agreed. Which is why I'm looking to know if there are intrinsic benefits to 120V over say 144 or 108 simply because it's "wall voltage"? For instance, are accessories easier to find/hookup? Chargers? Can you get buy with certain things (say, heating elements) made for 120AC and use them at 120DC? Etc etc...




gottdi said:


> Or just go by a Leaf and be done with it.


Bwhahahaaa! Don't tempt me!!


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## Ziggythewiz (May 16, 2010)

I'd say go 144, for me it would have cost more, so I did 120. Just make sure your motor can handle what you want to do with it.

On 120V I can drive in just 2nd and hit over 45 mph with good acceleration. Top speed limit on my route is 55, which I figured I could do (still in 2nd) if I upgraded to 144V, HOWEVER, I ran the numbers and at 50+mph in 2nd my motor would be redlined, and if I floored it would probably EXPLODE!! So just make sure your motor can do what you want it to.


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## Guest (Jul 8, 2011)

> I'm looking to know if there are intrinsic benefits to 120V over say 144 or 108 simply because it's "wall voltage"


NO. 

My leaf uses wall voltage to charge but you must remember you also have available 220 volts too. I use both. I use 220 for my MG. I have 110 but use 220. 

Temptation


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## rwaudio (May 22, 2008)

lowcrawler said:


> Agreed. Which is why I'm looking to know if there are intrinsic benefits to 120V over say 144 or 108 simply because it's "wall voltage"? For instance, are accessories easier to find/hookup? Chargers? Can you get buy with certain things (say, heating elements) made for 120AC and use them at 120DC? Etc etc...
> 
> 
> 
> ...


Be careful in your thinking that 120v AC and 120v DC have anything in common, they do not!!
You simply can't plug in something ment for 120v AC into a 120v DC battery and expect it to work. If you are lucky it does nothing, if your not lucky it blows up in your face.

Go for the 144v or higher system...


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## lowcrawler (Jun 27, 2011)

gottdi said:


> NO.


That's what I needed to hear. Seemed logical that 120DC might have some benefits - specifically when it came to charging... bridge rectifier with some caps and you'd be gold. But after looking (and this thread) it appears that's not the case....

Another thing checked off my list.



> Temptation


If you weren't so darn helpful, I'd smack you!  





rwaudio said:


> Be careful in your thinking that 120v AC and 120v DC have anything in common, they do not!!


Good to know.   Logic doesn't always lead to the right conclusions... 



> Go for the 144v or higher system...


Sounds like I'll be doing just that. Thanks!


p.s. Another thing I noticed -- man, chargers are EXPENSIVE!


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## 1-ev.com (Nov 4, 2010)

Hey guys you can go up to 160 volts with ADC, please see some conversions at EValbum

http://www.evalbum.com --- search "160 volts"

My 2c...
-Y.


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## Coulomb (Apr 22, 2009)

rwaudio said:


> Be careful in your thinking that 120v AC and 120v DC have anything in common, they do not!!
> You simply can't plug in something meant for 120v AC into a 120v DC battery and expect it to work.


That's not quite true. You can use resistive loads, like heating elements for the car heater, or a 120 V incandescent worklight, and a very few motorised gadgets that use brushed AC motors (they will work on DC just fine). The main thing to watch is the power switch; these will almost certainly not be rated for DC. So that really reduces the convenience.

The other thing is that your 120 V nominal pack will be more like 130 V after being charged, and over 144 V while being charged. So your incandescent light may be very bright but not last long.

Anything expecting AC will be disappointed. It will expect 170 V from rectifying the sine wave of the mains, so it may or may not work. That includes compact fluorescent lights. Anything with a transformer in it will look basically like a short circuit, either blowing up, or blowing a fuse, but the fuse if there even is one may not be DC rated, so it could explode as well.

So overall, there isn't much benefit to "matching" your pack voltage with wall voltage; the heating element is about the only one.


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## rmay635703 (Oct 23, 2008)

lowcrawler said:


> That's what I needed to hear. Seemed logical that 120DC might have some benefits - specifically when it came to charging... bridge rectifier with some caps and you'd be gold. But after looking (and this thread) it appears that's not the case....
> 
> p.s. Another thing I noticed -- man, chargers are EXPENSIVE!


There are several threads here and on ecomodder telling you how to build your own charger.

A 120v charger is cheaper for YOU to build YOURSELF but its functionality is more limited if its cheap and simple without a transformer. 120v AC ->DC is the easiest to run on a Bonn type charger but it isn't the most efficient and power factor is poor. A buck charger could also handle 120v more easily (read cheaply if you build it) 

Generally the cheapest charging setups are sets of automatic 12v chargers hooked to each set of batteries, add volts add another charger.

Some don't like the approach but it is less expensive than most charging solutions unless you build your own.

Building a charger isn't hard but it is very time consuming and may not be reliable.

On another topic, if you aren't running an AC motor higher voltage is NOT more efficient!

Controller losses get rather massive if you are running 50% or less throttle on a series DC motor, so if you run 300v and can blow your motor to kingdom come in 1st going 85mph your amp draw will be much higher and wthr per mile rates will also be much higher than if the voltage allows you to just achieve your goal speed in one of your lower gears at a safe RPM. 

Your controller is only 99% efficent at WOT and goes down from there. So if you can safely achieve your goal speed in a middle gear at WOT and have a gear above and below you will be golden so long as the amp draw is not massive.

Good Luck
Ryan


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## rwaudio (May 22, 2008)

Coulomb said:


> That's not quite true. You can use resistive loads, like heating elements for the car heater, or a 120 V incandescent worklight, and a very few motorised gadgets that use brushed AC motors (they will work on DC just fine). The main thing to watch is the power switch; these will almost certainly not be rated for DC. So that really reduces the convenience.


While that is correct, it's not specific to 120v DC only. Especially with the ceramic heaters that will self regulate to an extent and actual DC voltage isn't critical (or specific to 120v DC only).

It's safer to say to a new person that you can't plug anything 120V AC into your 120V DC pack *until* they have learned more about AC/DC and how things behave with respect to voltage, current, transformers and rectifiers and they understand ohms law. Or at the very least they are copying something very specific that someone else has done (ceramic heater etc.)


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## lowcrawler (Jun 27, 2011)

rwaudio said:


> Or at the very least they are copying something very specific that someone else has done (ceramic heater etc.)


... which is definately something I will be doing. (MN, after all)

Just a rough overview (when I get to it, I'll look up specifics) what's required to make a ~144V system power the ceramic heaters?


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## rmay635703 (Oct 23, 2008)

lowcrawler;250011Just a rough overview (when I get to it said:


> A good quality 120v ceramic heater will handle 144v without issues, just make sure to include a higher volume fan and decent high temp shrouding, like a standard incandencant lightbulb its life will be cut by about 33%


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