Illustrative equipment photography, not this model.
SimpliPhi battery
Built for reliability in hard environments and priced for it. There is no communication port, which is a design position rather than an oversight: every limit is set in the charge controller.
Published figures
Usable capacity
3.8 kWh
Capacity
75 Ah
Voltage window
44.0 to 57.6 V
Max charge current
75 A
Max discharge current
75 A
Comms
none published
Form factor
Wall mount
Units in parallel
12
Source status: Provisional figure Typical street price $2,500 to $3,500. Charge and discharge limits are per unit. Wiring packs in parallel raises both.
How many you need, by inverter
One pack accepts 75 amps. An inverter that can deliver more than that needs more than one, or the charge rate capped in settings. Both are valid, and the second one costs you charging speed on the short days when you need it most.
No document tracked here names a specific inverter for closed-loop operation with this pack. That does not mean it will not work. It means nobody has published the test.
Where the figures come from
SimpliPhi has no public document library this site has been able to verify. Every figure on this page therefore needs checking against the paperwork that shipped with your unit.
Where to buy the SimpliPhi PHI 3.8
Listings for the SimpliPhi PHI 3.8 plus the rack hardware and cabling a clean install needs.
Affiliate links. As an Amazon Associate this site earns from qualifying purchases, at no extra cost to you. Prices and stock change often, and a listing appearing here is not a statement that the pairing above is approved.
Questions people actually ask
How many SimpliPhi PHI 3.8 packs do I need?
One pack accepts 75 amps and holds 3.8 kWh. Match the pack count to your inverter’s charge current first, then check the energy. A Sol-Ark 15K at 275 amps would take 4 of them to charge at full rate.
Does the SimpliPhi PHI 3.8 do closed loop communication?
No, there is no communication port at all. Every pairing with this pack is open loop, and the inverter estimates state of charge from terminal voltage, which is unreliable through the middle of a LiFePO4 curve.
How many can I wire in parallel?
The published limit is 12 units.
Which inverters pair cleanly with the SimpliPhi PHI 3.8?
None of the inverters tracked here clear all four checks with this pack. Most land on unverified because nobody has published the comms or surge figure, which is a gap rather than a fault.
