BlueSolar Duo 12/24v 20a SCC010020000 manual and lithium

Running into a similar situation with my cabin setup and thought this was worth raising here.

I've got an older Victron BlueSolar controller and I'm looking at swapping out my AGM bank for lithium — most likely Fogstar Drift cells. The documentation situation with some of these older Victron units is genuinely frustrating. The newer MPPTs have brilliant support through VictronConnect and loads of community resources, but some of the earlier models with those small onboard displays seem to have fallen through the cracks documentation-wise.

My main concern is whether the charge profiles are actually configurable on these older units, or whether you're stuck with fixed presets. With lithium you really need to be able to set:

• Absorption voltage (typically 14.2–14.6v for 12v LiFePO4)
• Float voltage (ideally 13.5v or lower)
• No equalisation

Has anyone successfully run one of these older BlueSolar controllers with a lithium bank? I'm wondering whether the safer option is just to replace the controller entirely with a newer MPPT 75/15 or similar — at least then you've got proper lithium presets and full VictronConnect support.

Also curious whether anyone has tracked down a proper manual for the SCC010020000 variant specifically — I've found similar docs but nothing that matches the display layout on mine exactly. Victron's own archive seems patchy for this generation.

Would be good to hear from anyone who's navigated this rather than just assuming compatibility and frying a battery bank.

@PartnerProject the SCC010020000 is one of the older non-programmable units — that's the real issue here. No user-adjustable charge profile means you're stuck with the factory presets, which aren't lithium-friendly at all.

Victron themselves are pretty clear that this model isn't suitable for lithium without a BMS that can do the heavy lifting on charge termination. If your BMS has a charge disconnect relay, it can work in a basic sense, but you're essentially letting the BMS protect the cells rather than the controller doing it properly.

Honestly, for a cabin setup I'd just budget for a SmartSolar MPPT — even a 75/15 or 100/20 depending on your array. The Bluetooth and proper lithium preset alone makes it worth it. Fogstar drift cells deserve better than a controller that's fighting them.

@NeilJackson is right, it's a dead end with that unit. The SCC010020000 has hardwired charge profiles — you're not tweaking anything.

Bluntly: don't hang lithium off it. The absorption voltage ceiling on that controller sits around 14.4V which sounds okay but the float behaviour is the killer — it'll sit there trickling into a lithium bank that doesn't want it, and depending on your BMS you'll either get nuisance disconnects or silent cell stress.

Picked up a SmartSolar MPPT 75/15 for my static van when I faced the same situation — Bluetooth programmability changes everything. Set absorption, float, tail current, the lot.

The SCC010020000 had its day with sealed lead acid. It's done. Retire it or keep it on a dedicated AGM auxiliary. Don't bodge it.

@PartnerProject went through almost exactly this situation on my narrowboat a couple of years back. Had an older BlueSolar that I was convinced could be coaxed into working with a Fogstar lithium bank — spoiler: it couldn't, not safely anyway.

The hardwired profiles @NeilJackson and @WhatsAFuse65 mention aren't just a minor inconvenience — without being able to set absorption voltage and disable the float properly, you're genuinely at risk of stressing the cells long-term, or worse triggering your BMS to disconnect at an awkward moment.

The upgrade that actually sorted everything for me was stepping up to a SmartSolar with Bluetooth — the MPPT 75/15 or 100/20 depending on your array. VictronConnect makes profiling for lithium genuinely straightforward. The cost difference was less painful than I expected, and you get proper integration if you ever add a Cerbo down the line.

@CallumHobbs curious what you ended up doing — did you swap the controller entirely or find a workaround?

I'm in a similar boat (literally, narrowboat here too 😄) and was eyeing the SmartSolar 100/20 as a drop-in replacement. The Bluetooth alone would be worth it for monitoring, never mind the proper lithium profiles.

@PartnerProject one thing worth checking — what lithium cells are you actually going with? Some of the Fogstar Drift packs have their own BMS that can tolerate slightly higher charge voltages, which might give you a bit more wiggle room with a non-programmable controller. Not ideal long-term though.

Is anyone running the SmartSolar 100/20 with a Fogstar or similar budget LiFePO4 setup? Wondering how well VictronConnect handles the profile setup for those.