SMART BatteryProtect 220A, cannot handle an 2000W Anchor winch (broken after first use)

Fitted a Victron SmartBatteryProtect 65A on my shepherds hut build and nearly made the same mistake — these things absolutely hate inductive loads, and a winch is basically just a motor wrapped in disappointment waiting to happen.

The clue's buried in the datasheet: the SBP uses a MOSFET switch rather than a relay, so inrush current from motors can fry it faster than you can say "warranty void." Victron's own docs say do not use with electric motors — it's a protection device, not a load switch. 🤦

Few things worth considering if you're trying to protect a winch circuit properly:

• Use the SBP to trigger a relay or contactor instead, keeping the high-current motor path completely separate
• A proper BEP or Littelfuse VSR might suit better for that kind of switched load
• Your BMS1000 should theoretically handle the overcurrent trip anyway, so ask yourself whether the SBP is even doing what you think it's doing in that chain

My Fogstar batteries came with similar warnings about downstream device compatibility — it's not just a Victron quirk, it's physics being awkward as usual.

What gauge cable are you running to the winch? Sometimes the voltage sag on a long run makes the SBP think there's a fault and it shuts down anyway, which might actually be what happened before the magic smoke escaped.

Anyone else here successfully integrated a winch into a protected 24V system without sacrificing expensive bits of kit to the off-grid gods?

@CharlieCampbell66 good catch. Worth clarifying why though — the SmartBatteryProtect has no back-EMF protection, so inductive loads (motors, winches, compressors) cause voltage spikes that fry the MOSFET instantly. Victron are explicit about this in the manual but it's buried.

For motor loads you've got a few options:

• Use the SBP to trigger a relay/contactor instead of running the load through it directly
• Switch to a Victron BatteryProtect with a relay output wired to a suitably rated contactor
• On my narrowboat I ran a 200A Albright contactor controlled by a low-current relay — handles the inrush without complaint

What's the actual load you're protecting? That'll determine whether you need a proper pre-charge circuit as well, particularly if there's any capacitance downstream.

@ExFirefighter makes a crucial point about back-EMF. What I found on my shepherds hut build was that the SmartBatteryProtect is genuinely brilliant within its design parameters — low voltage disconnect, battery protection, that sort of thing. But it's simply not engineered to sit between a battery and anything that kicks back hard on switch-off.

For anything motor-driven — winches, compressors, even some inverter surge loads — you really want a proper relay or contactor on that circuit instead. The Victron docs do actually spell this out if you dig into them, though it's easy to miss.

Lesson I keep coming back to: match the component to the load type, not just the amperage rating. A 220A rating means nothing if the device fundamentally can't handle the load characteristic.

Exactly why Victron explicitly state in the manual that the SmartBatteryProtect is not suitable for motor loads — it's a load disconnect, not a motor controller, and the lack of bidirectional MOSFETs means that back-EMF spike has nowhere to go except straight back through the device.

For winch duty you want either a proper contactor (Gigavac, Albright) rated for inductive loads, or just a heavy-duty relay with a snubber diode across the coil — been running an Albright SW180 on my motorhome winch setup for two years without a hiccup.

@ExFirefighter is on the right track — the 220A rating is almost irrelevant here, it's the topology that kills it, not the current capacity.

@FormerCop yeah the manual wording is pretty unambiguous on that — people just don't read them 😅

Had a similar near-miss on my van conversion. Ended up routing anything motor-based (compressor fridge, a small winch, bilge pump) through a proper contactor instead. Bit more faff to wire but the SmartBatteryProtect then just handles the low-draw stuff it's actually designed for.

For the OP's situation — a Victron BatteryProtect + separate motor-rated relay/contactor combo is probably the cleanest fix. Or depending on the setup, a decent DC circuit breaker on the winch line rated for inductive loads handles it too.

The 220A rating on these things fools people into thinking they can handle anything beefy. Amps aren't the whole story with motor loads.