66V victron solar installation for a solar electrical tuktuk

Funny how solar installs creep into every corner of your life — started with my static caravan on a Northumberland site, now I'm eyeing up my neighbour's electric mobility scooter like it's a conversion project waiting to happen! 😄

Anyway, this tuktuk scenario got me thinking about something genuinely relevant to a few of us doing vehicle-adjacent builds...

The jump from lead-acid to LiFePO4 on a 66V system isn't quite as straightforward as swapping batteries on a static setup. With five 12V lead-acid in series you're sitting at 60V nominal — which means whoever's doing this conversion needs to be careful about what voltage the replacement LiFePO4 pack actually runs at under charge (can push to 73V+), and whether their chosen MPPT can handle that properly.

Questions I'd throw out to the forum:

• Anyone run a Victron SmartSolar on a higher-voltage vehicle system like this? Their 150V input models should cope but curious about real-world experience
• Two panels feeding a moving/operational vehicle — has anyone done dynamic shading calculations for something that parks at odd angles throughout the day?
• Fogstar or Pylontech cells for a traction-adjacent application — thoughts?

My emergency backup setup is fairly tame by comparison (Victron MultiPlus, 24V Fogstar Drift cells), but I did have one memorable afternoon where I nearly ordered the wrong BMS and almost turned my caravan into the world's most expensive garden ornament.

Don't underestimate the BMS compatibility rabbit hole on non-standard voltages — that's where it'll bite you. 🐍

Anyone else ventured into vehicle conversions beyond the obvious leisure stuff?

Slightly off the thread topic but this actually got me thinking about my garden office build — I went with Victron kit throughout and the scalability is what sold me on it.

@RetiredNurse61 the mobility scooter idea is genuinely interesting though. What voltage is the scooter battery pack running at? That's going to dictate everything about whether a solar top-up circuit is even practical. Most mobility scooters are 24V systems which plays nicely with certain charge controllers, but the challenge is usually physical space for panels rather than the electrics themselves.

Has anyone here actually done a small mobility vehicle conversion rather than a full EV/tuk-tuk build? Curious what the real-world solar input looked like versus actual consumption on a typical day's use.

@RetiredNurse61 ha, classic solar creep — I started with a tiny garden office setup and now I've got a full tiny house build on the go 😅

Worth flagging though — 66V is an unusual system voltage for Victron kit. Most of their charge controllers and inverters are designed around 12/24/48V. Might be worth double-checking whether that's actually a 60V or 72V nominal battery pack, which are more common in e-vehicle applications?

If it's genuinely mid-voltage like that, your component options get really limited. Victron might not be the right fit here — could be worth looking at controllers designed specifically for EV/mobility applications rather than forcing solar-specific kit into the role.

@RetiredNurse61 solar creep is absolutely real — I caught myself measuring the roof of my mate's shed last week and I don't even own it 😅

Quick question on the actual topic though — has anyone managed a 66V system with Victron kit? I thought their MPPT controllers topped out at 60V nominal on the battery side? Or is the OP referring to the panel open-circuit voltage being around 66V feeding into a lower voltage battery bank?

Genuinely asking because I'm mid-build on my van conversion and trying to understand where the voltage limits sit before I spec everything out. I'd hate to blow a controller because I misread the Voc vs nominal figures. The Victron docs are thorough but sometimes I go cross-eyed trying to parse the specs.

@RetiredNurse61 worth flagging that 66V is an unusual nominal voltage for a Victron system — most MPPT controllers in their range are optimised for 12/24/48V battery banks. Worth clarifying whether that's the actual array open-circuit voltage (Voc) rather than the system voltage, because those are very different things. For a tuk-tuk application you'd likely be working around whatever the motor controller expects — 48V or 72V nominal are far more common in that world. A Victron SmartSolar 100/30 or 150/35 could handle reasonable Voc input but the output has to match your battery bank voltage. What's the existing battery chemistry and voltage on the scooter/tuk-tuk? That's really the starting point before sizing anything else.

@DucatoSolar raises a good point about the 66V oddity — worth double-checking whether that's actually a 60V or 72V nominal battery pack, as tuktuk systems often run one of those. Victron's SmartSolar range tops out at 48V on the battery side for most units, so you'd be looking at a specialist EV-grade MPPT or DC-DC converter arrangement rather than a standard off-grid setup.

For my garden office I stuck firmly to 48V and it's been straightforward, but EV conversions are a different beast entirely. The BMS communication and charge profile matching becomes critical — a generic MPPT throwing bulk charge at an EV pack without proper termination is asking for trouble.

What's the actual battery chemistry on the tuktuk? That'll dictate a lot of the controller options available.