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#### brian_

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Optima Yellow-Top batteries are AGM lead-acid batteries, not any kind of lithium-ion battery. Lead-acid batteries are good for starting engines, but are obsolete for electric cars.

The is no single standard size of lithium-ion battery or battery module for electric cars, so you can't assume some amount of range per battery. You need to determine how much energy would be required to drive the car the desired distance, and that is the measure of battery size. For instance, if you decide that 50 kWh is the required amount of energy, that could be held in the four very large modules of a Tesla Model 3 Standard Range battery, or the 10 smaller modules of a Chevrolet Bolt battery, or 16 of the 33 small modules in a Jaguar I-Pace battery. You really need to look at the energy capacity of the module you are considering, not just count modules.

The relevant unit of energy is a kilowatt-hour (kWh); a kilowatt (kW) is a measure of power, not energy.

#### brian_

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I want to use an optima yellow top, specifically a d51, and can't seem to find the wattage/kw. From what I've found it's maybe 9kw? that doesn't sound right though. Basically if I had 5 or 6 of the optima batteries then that's the same a the Tesla battery pack? Is that right? I'm not sure but I think im missing something.
An Optima YellowTop D51 has a charge capacity of 38 amp-hours (when discharged very slowly, much less in EV use); at 12 volts, that's 38 Ah * 12 V = 456 Wh (or 0.5 kWh). And that's kWh, not kW. You would need more than 100 of them (weighing much more than a ton and costing about \$25K) to hold 50 kWh, and perhaps 200 (over two tons, over \$50K) to deliver that much energy at the relatively high discharge power of an EV.

In case that doesn't make sense yet...
• an amp of current flowing for an hour is an amp-hour of charge
• a watt of power for one hour is a watt-hour of energy (or 3600 joules of energy)
• one amp of current at one volt is one watt of power - you really can just multiply amp-hours by volts to get energy in watt-hours
• when a battery is discharged quickly the power lost to internal resistance means that less of the energy is usefully extracted, and Peukert's Law explains that the voltage drops and so reduces available power (so the usual capacity rating for deep-cycle lead-acid batteries don't apply for EVs)

#### brian_

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I want to use an optima yellow top, specifically a d51...
I realize now that this battery choice came up last year in the same member's other thread:
Shouldve been more clear, was thinking about lithium ion, probably optima for the weight...
So, repeating this point:
Optima Yellow-Top batteries are AGM lead-acid batteries, not any kind of lithium-ion battery.
Classycrusader, you seem to have the impression that Optima batteries are lithium-ion, but they're not. They're a specific construction of lead-acid battery called "AGM", meaning "absorbed glass mat", which means that the electrolyte (acid) is soaking a mat of glass fibres between each pair of lead plates, rather than just being an open pool of liquid.

#### brian_

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all duly noted. what would be a good lithium ion battery? I'd like to use car batteries because they're more easily refurbished when they go dead.
Second, how much would, let's say, the d51 optima give?
You say "all duly noted", but did you actually read any of the responses? You're still talking about using Optima batteries, which you have repeatedly been told are not lithium-ion. You're asking again 'how much an Optima D51 would give', but I worked that out for you already.

#### brian_

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calm down im just asking for reference, ill look into the real lithium ion but as stated I'd prefer lightweight car batteries because it's easier to refurbish them and coming from the ICE world I know that optima is the best in terms of weight.
I can't seem to find the exact numbers I need for the optima d51 atm.
Try reading the post that I already wrote for you a month ago, and pointed out to you again today, in response to the first time that you asked this. But don't ask for clarification if you don't understand it, because you're certainly too much of an asshole to bother helping any more.

AGM isn't "not real" lithium-ion, it's completely different.

And like I said, I am not educated in electricity, I'm a mechanical engineer, not electrical. That's why I came to you for help. If I understand what kind of range I could expect (roughly of course because of factors) with one good car battery I can work out the rest through reverse engineering. That's why I came to you, for help, not flaming.
I suggest that you burn or return your engineering degree. A first-year engineering student in any discipline knows the difference between power and energy, and can deduce the range per D51 battery from the earlier posts.

#### brian_

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Apparently you can't so you're not much better, let alone helpful
I already did work out and explain everything that you're asking - it's all there in this thread. Good luck with having other people do your project, and repeatedly explain to you what they did for you.

#### brian_

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Maybe I missed something along the way, but why would anyone expect useful performance (in terms of either power or range) in an Infiniti G35 from one-third of the battery of a Chrysler Pacifica Hybrid, which only has a 30-mile electric range? Yes, the G35 is a bit lighter and has less aero drag... but one-third of the power and energy?

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