How-to · same-brand only
How to add an expansion battery
Extra energy is the highest-value add-on on this site. It is also the easiest place to buy the wrong brick. Match the family, then plug in the cable the maker ships.
- Confirm the host first An extra pack is not a second power station. Anker’s BP3800 FAQ is explicit. EcoFlow extras sit behind a DELTA or Ultra inverter. Bluetti B500 sits under EP900.
- Stay inside the series, not just the logo DELTA 3 extras are not Ultra X batteries. AC200L uses B300K / B500K. EP900 uses B500. C2000 Gen 2 uses BP2000 Gen 2, not BP3800. F3800 / F3800 Plus use BP3800.
- Read the cable note on the product page EcoFlow DELTA 3 Plus extras often need the Alternator Charger XT150 output cable. Bluetti B210 on AC200L needs a separate cable. If the listing says “sold separately,” add it to the cart now.
- Update firmware before you stack Both EcoFlow and Anker push app updates that change solar and expansion behavior. Do this on grid power, not at 9% during a storm.
- Recalculate runtime, then stop shopping brands Doubling watt-hours roughly doubles hours at the same load. Use the calculator. A second logo will not handshake and will not double anything.
| Host | Extra | Energy added | Snapshot |
|---|---|---|---|
| DELTA 3 / Plus | DELTA 3 Series extra | ~1 kWh toward 5 kWh | $389 / $499 |
| DELTA 3 Max / Ultra Plus | Max Plus extra | 2,048 Wh | $899 / $1,329 |
| DELTA Pro 3 | DP3 extra | ~4 kWh class | $1,899 |
| Ultra X | Ultra extra | ~6 kWh | $2,299 |
| F3800 / Plus | BP3800 | 3,840 Wh | $1,699.99 |
| EP900 | B500 | 4,960 Wh nom. / 4,464 usable | Confirm live |
ECOFLOW
DELTA 3 extra · $389 / $499
Cheapest extra on this site. Buy with the host if nights matter.
DELTA 3 extra
ANKER
BP3800 · $1,699.99
Pairs with F3800 and F3800 Plus. Host required.
Check BP3800
DELTA PRO 3
DP3 extra · $1,899
Same family as the 4 kW portable. Ultra extras are a different SKU.
DP3 extra
How-to guides