· SH Energy editorial
It changes the inverter rating, the certification scope, the shipping class and the deposit. That is why two quotes with the same headline capacity can differ by far more than 50% — and why price per kWh is a poor way to compare them.
1. Nameplate kWh is not usable kWh
A battery rated at 10 kWh does not deliver 10 kWh to your load. Depth of discharge, round-trip efficiency and the inverter's low-voltage cutoff all take a share. A 10 kWh unit may deliver roughly 8–9 kWh of usable energy; a 15 kWh unit proportionally more.
Ask for the usable figure and the conditions behind it. A supplier who quotes only nameplate capacity is either simplifying or has not checked.
2. What actually changes between 10 and 15
- Cell count and batch — more cells, often a different lot, which changes cost and sometimes the certification scope.
- Inverter rating — a larger battery is usually paired with a larger inverter. That is often the bigger cost difference, not the cells.
- Enclosure and weight — heavier units change packing, handling and container loading.
- Certification coverage — the 10 kWh and 15 kWh variants may not share the same test reports. Verify per model.
- Deposit and MOQ — a larger unit ties up more capital per unit, and the MOQ may differ by model.
3. Why price per kWh misleads
Divide price by kWh and you get a number that ignores everything else in the delivered scope: the inverter, the mounting, the document pack, the freight, the duty and the after-sales path. A cheaper $/kWh can be more expensive over two years if the inverter is undersized or the spare-parts path is absent.
Compare the delivered system instead: same model family, same inverter pairing, same Incoterm, same warranty terms, same document list.
4. Freight and duty: the Nigerian variable
Lithium batteries ship under dangerous-goods rules. Weight, packaging and state of charge affect the freight quote, and the container loading plan affects the per-unit cost. On top of that, clearance depends on the HS code, SONCAP scope and the documents the importer holds.
Ask for the freight and clearance assumptions separately from the unit price. A CIF Lagos number with undefined duty and clearing is not a landed cost.
5. The decision rule: load, hours, recharge
Do not choose 10 or 15 by habit. Use three numbers:
- Essential load — the measured continuous draw of what must stay on.
- Backup hours — how long you want to cover, and the longest plausible outage.
- Recharge window — how many hours of grid or generator you get between outages.
If the recharge window is short, a larger battery may never refill, and the extra capacity is wasted. If the load is small, 15 kWh buys runtime you will not use.
6. How to compare two Nigerian quotes
Put both offers into the same table before comparing price:
- Exact model and usable kWh
- Inverter model and continuous / surge rating
- Certification held for the exact model
- Incoterm, port and freight assumptions
- Duty and clearance responsibility
- Warranty terms and who performs the repair
- Spare-parts availability and lead time
Copy-ready comparison sheet
7. When 15 kWh is the right answer
Choose the larger unit when the measured load is genuinely higher, when outages regularly exceed the smaller unit's runtime, or when the recharge window is long enough to refill it. Choose 10 kWh when the load list is modest and the recharge window is short — a smaller battery that refills every day beats a larger one that never does.
Where this fits
Nigeria-specific import and documentation context is on the Nigeria sourcing page. Model-by-model document status is on the documents centre. For a dealer line, see the partner programme.
Is a 15 kWh battery always better than 10 kWh?
No. If the inverter cannot charge it in the available window, or the load never uses the extra capacity, you pay for energy you cannot use. Match capacity to the measured load and the recharge interval, not to the biggest number in the brochure.
Why is price per kWh a misleading comparison?
Because the battery is only one part of the delivered system. Inverter rating, certification scope, packing, freight, duty and after-sales support differ between offers. Two quotes with the same $/kWh can have very different total cost of ownership.
Does a bigger battery cost more to ship to Nigeria?
Usually yes. Lithium batteries ship under dangerous-goods rules, so weight and packaging affect freight and handling. A heavier unit can also change the container loading plan, which affects the per-unit logistics cost.
What should I ask before choosing between 10 and 15 kWh?
Ask for the measured essential load, the desired backup hours, the inverter's charge current and the time available to recharge. Those four numbers decide the capacity far more reliably than a rule of thumb.
Discuss a Nigeria sourcing enquiry
Send the load list, the backup hours and the destination city to jimmy@sunhongenergy.com, or message the desk on WhatsApp.
Scope
This guide explains cost drivers, not prices. Actual pricing, duty and freight are confirmed in writing for the exact model and destination.