# 48 volts, AGM or Lithium?



## JRP3 (Mar 7, 2008)

For my Attex 6x6 conversion ( http://amp-phibian.blogspot.com/) I'm going to run a 48 volt pack. At this point I'm leaning towards the Odyssey PC1700 AGM, which I can get for $180.00 each through work, costing me $720.00 for the pack.
http://www.odysseybatteries.com/battery/pc1700t.htm
Are there better choices/prices for AGM's?
What would a similar spec'd pack go for in Lithium?


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## Wirecutter (Jul 26, 2007)

Wow. That's quite a brute of a battery for that price.

When I ran the numbers for one of my gokarts, a 72 volt system priced out about like this:

AGM: $1200
NiMH: $3500-5000
LiON: $15000-25000

The price spread is due to various capacities, and no, I never seriously considered putting the price of a new car into batteries for a "research project"-slash-toy.

I've seen a pretty broad range for lithium batteries, but at least one of the vendors I checked out is "no longer accepting orders from new customers." What I hear is that good ones are tough to obtain, and some of the less expensive ones have about a 10% infant mortality rate.

I'm not current with market conditions, so could someone with recent aquisition/installation experience enlighten us? Thanks.

-Mark


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## JRP3 (Mar 7, 2008)

I don't know what amp hours you were looking at but I think there are some lithiums now that would be a lot cheaper than the $15-$20K you were looking at. That sounds like the price for a car sized pack.


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## the slashmaster (Feb 24, 2008)

Hey jrp3, that's an interesting battery you found. I didn't know they made one for both deep cycle and automotive like that. Are you going to run a second battery for the 12 volt system? I've just been playing with the idea of buying one of these for my gas car, then when I have an electric I can use it for the 12 volt system. Have you thought about nickel metal hydride for your 48 volt system? It gave my roomba a very surprising amount of run time. Maybe you could get these http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4069 I'm still trying to figure out how many of them you would need to equal 4 of what you found.


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## JRP3 (Mar 7, 2008)

I don't really need an accessory battery for this machine.
I think I'd need almost 70 of those NiMH which would get pretty expensive.


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## the slashmaster (Feb 24, 2008)

JRP3 said:


> I don't really need an accessory battery for this machine.
> I think I'd need almost 70 of those NiMH which would get pretty expensive.


No accessory battery? How are you going to run the headlights? How did you do the math that you need 70 to equal the 4 you found?


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## JRP3 (Mar 7, 2008)

I don't think I'll be running this at night very much, and if I really need the headlights I'll probably just get 24 volt versions and tap each into half the batteries.
As for my math, I figured 48/3.6 = 14 or so, which gives me 48 volts at 13 ah. Then multiply the 13 ah by 5 to get 65 ah that the Odyssey's provide, (actually 68 but close enough). I could probably round down a little but I think the math is correct.


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## the slashmaster (Feb 24, 2008)

I see. I'm no expert but it looks like that battery you found is expensive because it both deep cycles and starts cars. Seems like it's perfect for a guy who plans on buying 1, using it now for his gas car and using it later for accesories after ev conversion. But since you only plan on using them for deep cycle wouldn't you be better off buying cheaper deep cycle lead acids of some sort?


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## elevatorguy (Jul 26, 2007)

JRP3 said:


> For my Attex 6x6 conversion ( http://amp-phibian.blogspot.com/) I'm going to run a 48 volt pack. At this point I'm leaning towards the Odyssey PC1700 AGM, which I can get for $180.00 each through work, costing me $720.00 for the pack.
> http://www.odysseybatteries.com/battery/pc1700t.htm
> Are there better choices/prices for AGM's?
> What would a similar spec'd pack go for in Lithium?


Wish I would have found those for my quad, maybe next time around...

http://www.austinev.org/evalbum/preview.php?vid=1174

Jerry


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## JRP3 (Mar 7, 2008)

the slashmaster said:


> I see. I'm no expert but it looks like that battery you found is expensive because it both deep cycles and starts cars. Seems like it's perfect for a guy who plans on buying 1, using it now for his gas car and using it later for accesories after ev conversion. But since you only plan on using them for deep cycle wouldn't you be better off buying cheaper deep cycle lead acids of some sort?



Actually it's supposed to be a special type of AGM battery. It uses thin extruded pure lead plates and supposedly lasts longer than other lead batteries, even with deep discharges. 

http://www.odysseysoutheast.com/faq.php


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## elevatorguy (Jul 26, 2007)

JRP3 said:


> For my Attex 6x6 conversion ( http://amp-phibian.blogspot.com/) I'm going to run a 48 volt pack. At this point I'm leaning towards the Odyssey PC1700 AGM, which I can get for $180.00 each through work, costing me $720.00 for the pack.
> http://www.odysseybatteries.com/battery/pc1700t.htm
> Are there better choices/prices for AGM's?
> What would a similar spec'd pack go for in Lithium?


What is the motor rated? how much do you plan to draw from the batteries?
I use AGM 12v 75AH and really wanted to go with 90 or 100 AH but didn't have the room. Running hard I draw more than 400A (as high as my amprobe will read). 
I get about 1 to 2 hours depending on driving style.
If you wire the 24v headlights in series you can go across the whole pack, probably better for the batteries keeping the draw equal on the batteries.


http://www.austinev.org/evalbum/preview.php?vid=1174
jerry


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## JRP3 (Mar 7, 2008)

I don't really know what this thing will draw. I think Jim said he's run these motors up to 120 volts and suggested a 48 volt 400 amp controller for my setup. I'm gearing for low end instead of top speed so that should allow the motor to wind up and not pull too many low RPM amps. If I can get 1 hour of run time that would be great.


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## Wirecutter (Jul 26, 2007)

JRP3 said:


> I don't know what amp hours you were looking at but I think there are some lithiums now that would be a lot cheaper than the $15-$20K you were looking at. That sounds like the price for a car sized pack.



Scratch my numbers. See this thread.
http://www.diyelectriccar.com/forums/showthread.php/affordable-lithium-batteries-way-9645.html

-Mark


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