# Lead Acid vs Lithium Ion batteries



## Kamleshgk (May 24, 2012)

Hey guys,

I live in India and i have never bought a car all my life bcos of guilt of using OIL and now Reva is launching 2 new electric cars in India, later this year!

And i feel its the right time to support these companies and get one!

The REVA NXR will be available with either lead-acid or lithium-ion batteries.

Now my question to experts here is, 

Which is better?
Lead Acid or Lithium Ion?

Im Aware that Tesla Motos in USA, uses Lithium Ion and Lead Acid is old technology, but is more mature technology.

In terms of performance and in terms of battery life, which is the best battery solution?

Any answers would be appreciated.

Gracias,
Kamlesh


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## jeremyjs (Sep 22, 2010)

Lithium Ion. It will last four times longer before needing replacement, have at least four times the range for a similar weight, be more expensive upfront, but it should make up for the added expense with how long it should last.


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## dougingraham (Jul 26, 2011)

I agree, Lithium is the only way to go.


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## tomofreno (Mar 3, 2009)

What warranties do they offer on the two types of packs? Should give a clue of how long they expect them to last. Knowing the manufacturer of each would also help. Is the lead pack made of flooded lead acid batteries, or sealed? I've been using CALB LiFePO4 for about 2 1/2 years now with no problems. Supposed to last 3000 cycles at 70% Depth of Discharge (DoD), or about 10 years. No one knows though, as no one has had them in use that long. They are much lighter than the same kWh lead acid pack, sealed - so no corrosion to deal with and no need to water as with flooded lead acid cells. The Lithium-based cells also give more energy because of lower Peukert Effect than lead batteries. The life of the lead batteries will depend strongly on how you use them. If you are going to drive mainly in the city at lower speeds, maintain them well, and recharge at only 50% DoD they may last you 6 or 8 years. Depending on price difference, it may be cheaper to use lead in that case, and it may serve your needs well. If you plan to push the batteries hard - larger discharge currents, greater DoD, I think lithium will give you better overall value - iif the spec for cycle life holds true.


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## onegreenev (May 18, 2012)

jeremyjs said:


> Lithium Ion. It will last four times longer before needing replacement, have at least four times the range for a similar weight, be more expensive upfront, but it should make up for the added expense with how long it should last.


I'd say more like 10 times or greater life before needing replaced. Range is about 4 times and cost over the life is cheaper but expensive up front. No muss no fuss either. Lead is dead and heavy and messy. Low life. And over the life of a typical lithium cell it is expensive. Lead may be a mature business but its OLD like in OLD. Your Grandma is mature too. No longer young and vibrant. Not what you want in your EV. Fine for the mobility scooter but for your main ride? Naaa. 

Go with lithium.


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## Kamleshgk (May 24, 2012)

Thank you for all the replies.

tomofreno - i shall look up the warranties, the manufacturers of the batteries etc.
So Lithium-Ion it is. 

One more question 

So when it comes to Lithium Ion batteries, do we have to keep tabs on the Depth of Discharge? 
Or we can use 90% of the charge without worrying bout the battery life like Lead Acid?


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## Ziggythewiz (May 16, 2010)

Kamleshgk said:


> So when it comes to Lithium Ion batteries, do we have to keep tabs on the Depth of Discharge?


Of course, even more important than with lead. You'll need a good AH counter. Depends on the manufacturer, but some quote 2000 cycles at 80% DOD and 3000 cycles at 70%. I've also seen 5000 cycles quoted for 70%.


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## tomofreno (Mar 3, 2009)

Kamleshgk said:


> Thank you for all the replies.
> 
> tomofreno - i shall look up the warranties, the manufacturers of the batteries etc.
> So Lithium-Ion it is.
> ...


 I would expect if you choose the lithium option the pack comes with a battery management system (bms) and a charge (Ah) counter. Check on that, and how they warranty the pack. If not, you will need to buy both. You can get good quality lower cost versions of each (minibms, evdisplay) here: http://www.cleanpowerauto.com/. Also the owner is knowledgeable and can give you good advice. No, I don't get a kickback, but I have been using his minibms for a couple years. 

The cycle life depends on DoD and the discharge currents you draw. The spec'ed cycle life varies with manufacturer. The capacity of the battery in Ah is denoted by 'C'. Currents are many times given as fractions or multiples of this. Best to stay below 3C discharge current, 1C for longer periods. Very short bursts, few seconds, of larger than 3C, up to 10C are supposed to be ok, but like I said no one has had them long enough to know the effect on lifetime. The easier you are on them the longer they should last. My CALB cells are 180Ah and spec'ed at 3000 cycles at 30% DoD, 2000 at 20% DoD. So C is 180 Ah, and a '3C' discharge current is 540A. The charge counter is your fuel gauge. For example, 3/4 hr at 100A discharge current is 75Ah. The charge counter will read this out as Ah used. You'll need at least 100Ah cells for that (94Ah would leave you 20% charge left, but no one makes a 94Ah cell). Look around some more, read up, so you know what you are getting.


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## lowcarbon-idea (Sep 2, 2010)

lion battery will be the best choice, I think.


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