Cost per watt-hour ($/Wh) is how you compare battery deals on equal energy—not amp-hours alone. This guide shows how to calculate battery cost per watt-hour from listings, then use Ah, voltage, and $/Wh in the estimator for total pack price.
Benefits
- Formula: $/Wh = pack price ÷ rated Wh (Ah × V).
- Forward check: total cost = Wh × $/Wh in the interactive tool.
- Benchmark LiFePO4, AGM, and NMC quotes on one unit-price line.
How it works
- Compute rated Wh = amp-hours × nominal voltage from the spec label.
- Divide sticker or quote price by Wh to get cost per watt-hour.
- Enter that $/Wh with Ah and V in the calculator to verify total pack cost.
FAQ
How do I calculate battery cost per watt-hour?
$/Wh = pack price ÷ rated Wh. Rated Wh = Ah × V. Example: $420 for 100 Ah × 12 V → 1,200 Wh → $420 ÷ 1,200 = $0.35/Wh. Use that $/Wh to compare other packs or multiply by any target Wh for budget estimates.
What is a typical $/Wh for home storage batteries?
Complete LiFePO4 packs often run $0.10–$0.25/Wh retail; AGM may look similar upfront but higher cycle cost. Premium branded rack batteries can exceed $0.30/Wh. Always divide quoted price by nameplate Wh—marketing Ah at one voltage can hide expensive $/Wh.
Should I use nominal or usable Wh for $/Wh?
Use nameplate rated Wh for comparing vendor quotes apples-to-apples. For bank sizing, apply depth-of-discharge—usable Wh may be 80–90% of rated for LiFePO4. Cost per usable Wh = price ÷ (rated Wh × DoD) when modeling runtime budgets.
Technical specifications
- Rated Wh = Ah × V.
- $/Wh = pack_price ÷ rated_Wh.
- Pack cost $ = rated_Wh × $/Wh.
- Related: battery-pack-cost-calculator, ah-to-wh, wh-to-ah.