# Why do these batteries not get used in EV's?



## camiguel (Oct 14, 2009)

These batteries seem like they could eliminate alot of weight problems for an EV and would help need less cells in parrallel and allow for more cells to be conected in series. As a bonus they are about the same as other deep cycle batteries and have a 1200 Ah rating which is alot more than Optima batteries that have about 100 Ah. And there are even 2000 Ah batteries that cost $400 but not sure if they are true?

Could these batteries be used in an EV and are they too good to be true? Are these batteries reliable and give good run time and speed is the question that I am asking.


----------



## TheSGC (Nov 15, 2007)

camiguel said:


> These batteries seem like they could eliminate alot of weight problems for an EV and would help need less cells in parrallel and allow for more cells to be conected in series. As a bonus they are about the same as other deep cycle batteries and have a 1200 Ah rating which is alot more than Optima batteries that have about 100 Ah. And there are even 2000 Ah batteries that cost $400 but not sure if they are true?
> 
> Could these batteries be used in an EV and are they too good to be true? Are these batteries reliable and give good run time and speed is the question that I am asking.


It's simple: Those are NOT deep cycle, nor are they 1200 Ah. They have 1200 CA, Cranking AMPs, completely useless rating for an EV. CA is used to turn over an engine, and CA means how many AMPs the battery can produce in 15 seconds before dropping to 7.2 volts. True Deep Cycle batteries do not have a CA, CCA or MCA rating at all.

You must understand battery terminology, check out the wiki. Amp Hours (Ah) has NOTHING to do with CA or CCA or MCA or any other Cranking rating. Also, Optima's D31T's have a Ah rating of 75 Ah, not 100. 

So, the batteries you are asking about would never work in an EV, and would be a huge waste of money and probably die after 5 or 6 cycles if you were lucky.


----------



## camiguel (Oct 14, 2009)

Thank you so much for explaining this to me so how many Optimas would I need for about 60 mile range on a honda civic?


----------



## TheSGC (Nov 15, 2007)

camiguel said:


> Thank you so much for explaining this to me so how many Optimas would I need for about 60 mile range on a honda civic?


At least 24 D31Ts, but 60 miles is a lot for lead acid EV. If you want 60 miles in an EV you will need 144 volts of 6 volt 225 Ah golf cart batteries or LiFePO4 batteries.

Here is a useful calculator: http://www.evconvert.com/tools/evcalc/
Play with the calculator and look through the EV Album for similar EVs. I have 8 Walmart MAXX29s for a 96 volt 125 Ah EV in my Civic and I get maybe 20 miles per charge, dealing with lots of hills at 35 MPH.


----------



## camiguel (Oct 14, 2009)

Tahnk You again.


----------



## camiguel (Oct 14, 2009)

Now would these batteries be capable of running a car? I would use 12 of them. How much range would this give me and about how much top speed?

I hope this doesnt bother anyone as I am a complete newby and I am learning as I ask Questions.


----------



## Bowser330 (Jun 15, 2008)

Hello camiguel, welcome to the forums.

Several aspects of your EV setup will affect range, some which are the same for any vehicle, whether EV or not...

Here is a list of things that can help your range...

(1) AH (amp-hour) rating of the battery pack.
-The more you have the better range you will have..

(2) Battery chemistry
- Lithium ion is a more efficient battery at higher amp draws than Lead-acid, however Optimas are good LA batteries to use.

(3) Overall vehicle weight 
-takes more power to move a heavier vehicle than a lighter one
-lower speeds affected more by weight than wind resistence.

(4) Aerodynamics of vehicle
-Less wind resistence the less power you will need
-higher speeds affected by wind resistence more than lower speeds
-you can modify your donor car to be more aerodynamic than stock with some simple mods.
(a) Underbody tray/cover
(b) Cover the openings in the front of the car, ex:grill, bumper opening
(c) Smaller side mirrors or internal kind
(d) lower car
(e) covers for rear tire well

(5) Rolling resistence
- skinnier tires have less drag from the wheels against the road.


----------



## Bowser330 (Jun 15, 2008)

camiguel said:


> Now would these batteries be capable of running a car? I would use 12 of them. How much range would this give me and about how much top speed?
> 
> I hope this doesnt bother anyone as I am a complete newby and I am learning as I ask Questions.


The 100AH battery you showed would work, but there is something else you must know about battery ratings...

This battery is 100AH @ 20hr rate...

Will you be discharging this battery slowly over 20 hours? likely not right 

You will probably be discharging it while driving for about 1 hour...

so you need to multiply the 100 by .57 = 57AH....

So... 100AH @ 20hr = 57 @ 1hr....

So if you had 12, so 144V and 57AH = 8.2kwh

So if your EV gets the average wh/mile rating of 300 wh/mile then you would get 27 miles per charge (that is to 100% dead which is not good for the battery life, you should only go down to 50% and then charge back up)

so 50% pf 27 miles = 13.5 miles total safe usable range  

trust me we all know what you are thinking right now....we've all been there...

about your top speed, this sort of depends on what controller, motor, and transmission (gearing) you use... but roughly speaking...the 800 cranking amps (of those batteried you linked) is enough torque to get your short term low-end acceleration to be good and 144V is enough to get you up to freeway speeds (65-75mph)...


----------



## vpoppv (Jul 27, 2009)

The company camiguel mentions in the first post:

www.powermastermotorsports.com has a very interesting LiFePO4 battery with a built-in BMS. I bet ONE of those batteries costs more than my whole conversion...


----------



## camiguel (Oct 14, 2009)

Ok, I am starting to grasp the subject of what type of battery a EV needs and this is all very helpful. On the other hand I dont have enough money for Lithium batteries so I am going to stick with lead acid. I will lower my expectations now that you guys have showed me the capability of LA batteries.

Thanks Again.


----------



## Voltswagen (Nov 13, 2008)

Camiguel
I have a 120v system using 15 - 8 volt deep cycle batteries.
My vehicle weighs about 2600 - 2700 lbs. My range to 80% DOD is about 40 miles at 35 - 40 mph - my top speed about 65 mph.
I bought my batteries at Sam's Club - EGC8's - 170ah - 20 hour rating
Cost was about $72.00 US per batt. and don't let them charge you a disposal fee - $9.00 per batt. You'll pay that when you wear them out and exchange them.
I don't know where you live but check out Sam's Club if there is one near you. They won't last as long as Trojans but reasonably priced.


----------



## camiguel (Oct 14, 2009)

I am a member of Sams so I will check it out thanks.


----------



## Wirecutter (Jul 26, 2007)

The thing that frustrates me about SLA (Sealed Lead Acid) batteries is that, the more range you want, the more (range-reducing) weight you need to carry. Sure, this is true of any battery technology, but lithiums have the dual advantage of higher power density for given volume and higher power for a given weight. And despite their fussy charging requirements, if treated right, you can get more cycles out of a lithium pack.

I guess that's why folks are willing to pay so much more for them.

-M


----------

