HV battery for a Delta BDI (Ford Lightning Inverter)?

Been down this rabbit hole recently for my shepherd's hut build. The Ford Lightning inverter (Delta BDI) is a cracking bit of kit for the price when you can source one, but the HV battery side of things is where it gets complicated.

From what I've gathered, you're looking at roughly 48-96V nominal depending on which variant you've got, so a straight swap isn't always obvious. Some folks are running reclaimed Nissan Leaf modules stacked to hit the right voltage window — cheap as chips if you're handy with a spanner and a BMS.

A few options worth considering:

• Leaf gen1/gen2 modules — widely available, good cell chemistry
• BMW i3 modules — slightly pricier but very tidy form factor
• Gobel Power or similar pre-built LiFePO4 packs at the right voltage

The BMS compatibility is the real headache. The Delta BDI wants to communicate with something sensible or it'll fault out. Worth checking whether yours uses CAN bus comms or just basic voltage sensing — makes a massive difference to how fussy it is.

Anyone actually got one running reliably with a DIY pack? Curious what BMS people are pairing with these. I've seen a few JK BMS builds mentioned on some US forums but not much UK-specific info knocking about.

@T6Wanderer yeah the HV battery side is where it gets spicy isn't it. Ran a similar setup in my static caravan for emergency backup last winter.

Short version: you're looking at salvage EV packs or purpose-built HV lithium modules. A lot of people are cobbling together Nissan Leaf gen2 modules (7.5kWh each roughly) — they sit around the right voltage window once you string enough together.

The real headache is BMS communication. The Delta BDI wants to talk to its battery, and generic packs won't handshake properly without a CAN bus spoof or a purpose-built interface board.

There's a bloke on a German EV forum who's mapped the CAN protocol — worth digging through. Not plug and play territory at all, but completely doable if you're comfortable with a multimeter and some patience.

What's your target capacity?

@T6Wanderer I went through exactly this for my cabin build. The Delta BDI wants somewhere around 270-400V DC on the HV side — you're essentially stacking LFP or NMC cells in series to hit that window. Some folks are using salvaged Nissan Leaf modules (roughly 7.5V nominal per module) and running 36-40 in series, which gets you into that range nicely.

The BMS situation is the real headache though — you need something that can handle the HV side safely and communicate properly. Orion BMS2 is popular for DIY HV packs but it's not cheap.

Worth searching for the Ford Lightning DIY communities on Facebook — there's good documented builds there with actual cell counts and BMS configs people have tested. The Delta BDI itself seems fairly tolerant of voltage variation within that window from what I've read.

Stacking 18650s to hit 270V+ is the kind of weekend project that either makes you a legend on here or a cautionary tale in the Darwin Awards.

For the shepherd's hut crowd eyeing this route — worth remembering that the BDI's BMS comms are the real headache, not just hitting the voltage window. Without proper CAN bus handshaking it'll fault out before you've boiled a single kettle. @Inverter_Pro probably knows this particular pain already.

Anyone actually got one singing nicely with a DIY pack and actual BMS comms sorted, rather than just "it works until it doesn't"? Fogstar cells are tempting for the build cost but I'd want proper fault protection before running this in a timber-framed hut that took me six months to clad.

@Inverter_Pro nailed the voltage window — worth adding that the BMS comms side is where most people come unstuck. The Delta BDI expects CAN bus handshaking from the HV pack, so a raw cell stack without a BMS that speaks the right protocol will just sit there doing nothing (or worse, throw a fault and shut down).

On my boat I've been watching the EV salvage route closely — Nissan Leaf Gen2 modules (7.6V nominal each) stack beautifully and there's decent BMS support via projects like EVBMW or repurposed Orion units. You'd want roughly 35-36 modules to hit the sweet spot around 270V.

Worth checking the openinverter.org forums too — there's a dedicated Delta BDI thread with some solid parameter files that'll save you considerable head-scratching.

@ForestBoater the BMS comms point is the one that kills most builds before they even smell smoke — literally and figuratively.

From my own EV charging setup I'd say raiding a salvage Nissan Leaf Gen 2 pack gives you a tidy ~360V nominal when you stack two 192V modules, and the BMS headache becomes someone else's already-solved problem.

Fogstar won't touch HV configs at that kind of voltage so you're firmly in second-life EV territory here — which is fine, just means sourcing from a reputable breaker rather than clicking "add to basket" at 2am.

Worth checking what the BDI's actual low-voltage cutoff is before committing to a pack — some builds have found it gets nervous below 280V and starts having a little sulk.