When to Use This Checklist

I'm a procurement manager at a 180-person renewable energy contractor. I've run our equipment purchase budget ($240,000 annually) for six years, sat across the table from 20+ suppliers, and logged every order in our cost-tracking system.

This checklist is the exact sequence we follow when evaluating BYD battery storage—whether it's for campus charging, solar backup, or both. Seven steps. Each one has a specific verification point. Skipping any of them is how budgets get blown.

One note before we start: if you're only adding a small battery to an office building, "seasonal energy storage" probably isn't your problem. It only matters when your load swings meaningfully between months. Pull your 12-month utility history and put it on the table—that takes 20 minutes and prevents buying the wrong sized system.

Step 1: Map Your Peak Load and Seasonal Curve

Before you call anyone for quotes, pull the last 12 months of utility bills. Highlight your highest daily peak and your lowest. The gap between them is what seasonal energy storage is meant to cover.

For us, that gap was 22 kW (41 kW peak in January vs. 19 kW trough in July). If your gap is under 10 kW, you probably don't need storage with seasonal switching—a system sized for daily load shifting will do. If the gap is large, keep the word "seasonal" on the table through every subsequent calculation.

Step 2: Verify Battery Capacity Specs—Don't Mix Product Lines

BYD spans both vehicles and stationary storage, and that's where spec confusion starts. Our own team tripped on this. Someone quoted BYD Atto 2 battery capacity (nominally around 45 kWh depending on market—verify against your local config as of January 2025) as a storage benchmark. That comparison is meaningless. The Atto 2's Blade battery is an automotive pack; stationary storage uses a completely different module stacking.

What to verify instead:

  • Usable kWh (not nameplate)—typically 85%–92% of rated
  • Continuous power output (kW), not peak
  • Cycle life with warranty backing behind the claim, not just the marketing headline

Everyone told me to verify usable capacity before signing. I only started doing it after a 2023 mistake where the sheet said 30 kWh and we got 22 kWh usable. That skip cost us roughly $1,800 in year-one utility costs while we ran undersized.

Step 3: Get BYD Solar Battery Price—But Calculate TCO Over 6 Years

BYD solar battery price varies widely by region, installer, and capacity. As of January 2025, our residential-scale quotes landed between $8,500–$14,000, and commercial storage quotes ran $420–$850 per kWh installed. Always verify current pricing with your installer—these numbers move fast.

But unit price alone misses the point. Our TCO spreadsheet tracks:

  • Unit price (specify per-unit vs. per-kWh)
  • Installation and retrofit costs
  • Warranty coverage and duration
  • Expected replacement cycle
  • Software/monitoring subscription—this one is often buried in an annex

One quote we saw undercut a competitor by 12% on the headline number but added 4% once a five-year monitoring fee was bundled back in. Everything counts.

Step 4: Match Charging Infrastructure to Your Use Case

If this evaluation includes EV charging for a campus or fleet, the question "how many kW is a Level 2 charger" comes up fast. Answer it early: most Level 2 chargers run 6.6 to 19.2 kW depending on voltage and amperage (240V × 30–80A). We standardized on 11.5 kW units at our site, which balances overnight top-up speed against panel capacity.

Use this to sanity-check: if a vehicle needs 45 kWh to reach target charge and you're on a 7.2 kW charger, plan for a 6+ hour window. Anything shorter and you either need a higher-amp charger or a fleet schedule adjustment. Do that math now, not after installation.

Step 5: Validate Seasonal Energy Storage Claims Against Real Data

Here's where a lot of evaluations go wrong. Sales decks show a nice chart with 12 months of beautiful performance. What's often not stated is that the figures were modeled on optimal solar exposure for a different region.

Ask for:

  • Monthly production averages for your specific geography in the worst month, not the best
  • System efficiency loss percentages under deep cycling
  • What battery reserve looks like after three consecutive cloudy days

One competitor quote we reviewed advertised "guaranteed supply" but their own published data slice showed 68% usable capacity in December under a three-day cloud scenario. Nobody tells you that at the pitch meeting. You have to open the spreadsheet and check.

Step 6: Lock Delivery and Installation Windows in Writing

Storage projects slip. Delivery certainty is worth paying for, especially when your operation depends on it. We paid $1,800 extra on a 2023 pilot to hold a delivery date; when the original supplier said "probably end of February," we switched to one that would commit in writing for a rush fee.

Confirm before signing:

  • The specific install window, with week-level precision
  • Remedies if the window is missed
  • Who handles storage costs if equipment arrives before the install crew
  • Acceptance testing responsibilities and pass criteria

Here's something sales teams don't volunteer: "standard delivery" often includes buffer time vendors use to manage their production queue. It's not necessarily how long your order takes. Get your date in writing.

After we confirmed the rush fee, I second-guessed myself for a week. What if we could've just pushed the schedule? Then the original supplier's window slipped six weeks for other customers, and we were the only site in operation on time. Worth the money.

Step 7: Compress Everything to One Page, Then Wait 48 Hours

This is the step most people skip. Force the specs, price, timeline, and warranty terms onto a single page. Then wait 48 hours. We've killed two quotes that looked fine on the first pass but had issues we only caught on the second read—one had ambiguous usable-capacity definitions, the other had a warranty that covered cells but not the full system.

Notes and Common Mistakes

A few closing cautions, each from a mistake we actually made:

  • Don't confuse vehicle battery specs with storage specs. Asking about BYD Atto 2 battery capacity is one question; storage system capacity is another. Vendors know this and mix the numbers in proposals.
  • Verify prices with timestamps. BYD solar battery price changes quarterly. "Someone told me last week" isn't data.
  • "Free installation" almost never is. Check the annex for higher equipment markups or separate wiring line items.
  • Seasonal claims need worst-month production data. Not annual averages.
  • Level 2 charger kW drives your fleet schedule. A 7.2 kW unit may be fine—or it may not be, depending on your charging window.
  • Delivery certainty is worth a premium. Only when the contract specifies remedies, otherwise you're just paying extra for a verbal promise.

Follow all seven steps and you'll spend three extra days on the evaluation. What you avoid is typically a four- to five-figure mistake. That math is easy.