# Lets clarify DoD terms



## TheSGC (Nov 15, 2007)

Yes, Depth of Charge is how far you have drained the battery. So 80% DoD means that there is 20% capacity left in the battery. (Usually you don't want to discharge any further.

Now battery voltage and the DoD is not even close. A lead acid battery is fully charged with 12.6+ volts and completely discharge when it reaches 10.5 volts. The charge of a battery is more geared to how many amp hours are left in it from it's max to 0. If your battery drops to 0 volts, it has been destroyed badly.

There used to be a chart on the wiki, but I cannot find it, so I will do some explaining. Your 144 volt system will actually read 151.2+ volts when it is fully charged.(12 batteries * 12.6+ volts = 151.2 volts) When it has been depleted it will read 126 volts. Now the lowest you want to go is 80% DoD, and that happens to be 11.58 volts per battery or 138.96 volts. (12 batteries * 11.58 volts = 138.96 volts) The relationship is not linear and there really isn't a simple equation for it, so it's easiest to get a hold of a lead acid DoD chart and keep it handy.

A PakTrkr or E-Meter will be the best way to see how much juice is left in your pack.


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## ngrimm (Oct 19, 2007)

Here is a link that has a dod chart as well as a lot of other useful information regarding lead acid batteries:
http://www.marine-electronics.net/techarticle/battery_faq/b_faq.htm#12



Digital Voltmeter Open  Approx State-of-Charge Hydrometer Average  
 Circuit Voltage 
12.65 100% 1.265 
12.45 75% 1.225
12.24 50% 1.190
12.06 25% 1.155
11.89 Discharged 1.120

All readings at 80* F


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## DVR (Apr 10, 2008)

ngrimm said:


> Here is a link that has a dod chart as well as a lot of other useful information regarding lead acid batteries:
> http://www.marine-electronics.net/techarticle/battery_faq/b_faq.htm#12



Excellent link ngrimm!!


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## dimitri (May 16, 2008)

Boy, was I off the chart, its embarrassing 

Thanks for setting me straight 

I wish there was a simple table correlating DoD to voltage, because its still a little confusing how you come up with these numbers. 

I looked everywhere on US Battery Web site and couldn't find these numbers for my battery type.

Thanks


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## CPLTECH (Sep 14, 2007)

Would like to add something to the good info *SGC* just gave…

I remember reading some info that (in the case of a 120V system) one needs to read exactly 75Amps on the meter and note the voltage. If above 105V, you have not reached 80% DOD yet. This info was for those without an E-Meter and was wondering what the state-of-charge was while driving. Can’t find the article at the moment.


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## e_canuck (May 8, 2008)

Hi guys.

I ca'nt find that DOD chart in the wiki anymore.
But found this one
http://www.ccis.com/home/mnemeth/12volt/voltchart1.gif

The web site is for RVs.
http://www.ccis.com/home/mnemeth/12volt/12volt.htm

Can someone confirm those numbers?

take care,

DP


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## ngrimm (Oct 19, 2007)

e_canuck said:


> Hi guys.
> 
> I ca'nt find that DOD chart in the wiki anymore.
> But found this one
> ...


It kinda threw me when I first saw the differences between the two charts listed until I realized that one showing discharged is 10.5v is calculated when the battery is under load.
One question I have though is, why do my batteries always show 13.09 when fully charged? This is even after I have let them cool down to 80* I don't get 12.6 until I have ridden for a while.


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