recharge cost

[Grieselbrand]

Hi, I have no engineering background whatsoever.
I'm trying to estimate the recharge cost of a battery, say lead acid.

So if the battery characteristic is as follows:
capacity is 15000 Wh.
Charge efficiency is 80%
Charge current is 15% of capacity, ie. 2,250 Wh
Electricity cost is 1 USD/kWh (on grid)

If the battery is discharged for 5000 W for 1 hour,
then I need 6000 W to fully recharge?
And it would cost me USD 6 to recharge? Is that right?
What is the charge current for in this case then?

Thx

 

[IRstuff]

IS this for school? Student posting is not allowed.

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[Grieselbrand]

Not for school, I'm making biz case on battery replacement.
The current solution uses VRLA, trying to compare the cost if replace it with Zinc air.
Like I said, I have zero knowledge on electricity/battery.
I just want to make a cost projection.

 

[ScottyUK]

Do zinc-air cells exist in that size range?

 

[IRstuff]

If that's the plan, then I would question the approach as suspect. If the consumption is unchanged, and charging efficiency is unchanged, why would the battery chemistry matter? Battery chemistry relates to:
> number of cycles of recharging
> robustness to charging conditions
> robustness to discharging conditions
> life cycle cost

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[itsmoked]

Grieselbrand; Your assumption above is essentially correct. Off by a couple of hundred watts. Also 80% charging efficiency is probably too high.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[TomDOT]

Who the heck pays $1 USD per kWh for grid electricity? I'm paying $0.10

One nit: Why do you bother using Wh as a unit for most of your stuff, and kWh for the cost? Why not just use kWh throughout?

If you discharge @ 5kW for 1 hour, you need 6.25kWh to recharge at stated efficiency. Around here, that would cost you 63 cents.