Orion-Tr Smart 30A vs 18A — worth the extra for a 200Ah lithium bank?

Right, so I've been running a Fogstar Drift 200Ah LiFePO4 under the bed for about eight months now, charged primarily through a Victron SmartSolar 100/30 on the roof. Works a treat when the sun's out, but the alternator side of things has been my weak link — currently just limping along with a basic B2B I picked up off eBay that rattles like a tin of bolts.

Time to sort it properly. I'm between the Victron Orion-Tr Smart 18A (around £140) and the 30A (around £200). The van's a 2018 Transit with a 180A alternator, so headroom isn't really the issue. My concern is more about whether 30A actually reaches the battery meaningfully faster on a typical 45-minute motorway run, or whether the BMS just throttles it back anyway once the cells hit 80%.

I've read the Victron docs and yes, the 30A can push roughly 360W versus 216W at 12V nominal — on paper that's a decent gap. But real-world absorption behaviour on LiFePO4 seems to swallow a lot of that difference.

Anyone actually run both and got a feel for it? Or swapped up from 18A and thought "yes, that's made a proper difference"?

Hamish1980 | 847 posts

@VanJim good timing on this question — I went through exactly this decision last year with a similar setup.

Short answer: the 30A is worth it if your alternator can handle it. The 18A will give you roughly 250W input, whereas the 30A pushes closer to 430W — on a longer motorway run that difference adds up considerably when you're trying to top off a 200Ah bank.

One thing people overlook though — check your van's alternator rating first. Older Transits and Sprinters with 90A alternators can get a bit unhappy with the 30A unit running flat out alongside engine loads. The Orion Smart has an input current limit setting which helps, but it's worth factoring in.

Also, are you running the alternator sensing wire or relying on voltage detection? Makes a real difference to charging behaviour.

WattHamish | 312 posts

@VanJim went through this exact decision for my garden office setup (different use case but same chargers). Ended up going 30A and honestly glad I did — the extra headroom when alternator input is the only charge source on a cloudy stretch makes a real difference.

That said, 200Ah LiFePO4 isn't a massive bank. If your solar is doing decent work most days the 18A is probably fine.

Key question — what's your typical daily draw? If you're hammering 100Ah+ regularly and relying on driving to top up, go 30A. More modest usage, save the £50 odd and stick with 18A.

Both units are solid, the Bluetooth monitoring on either is genuinely useful for keeping tabs on what the alternator's contributing vs the SmartSolar.

Jason1992 | 1,203 posts

@VanJim one thing worth mentioning that I haven't seen flagged yet — check your alternator. Older vehicles (pre-2015ish especially) with a basic non-smart alternator will be absolutely fine with the 30A, but if you've got an ECU-managed "smart" alternator the 30A can occasionally confuse it under certain conditions. The 18A tends to play nicer in those situations.

That said, for a 200Ah Fogstar Drift I'd still lean toward the 30A personally — you're looking at roughly 2.5 hours to put 75A back in from flat versus nearly 4 hours with the 18A. When you're wild camping and engine time is limited, that difference genuinely matters.

Budget allowing, grab the 30A and just make sure your cable run and fusing is up to scratch. Many people undersize the wiring and then wonder why it's underperforming.

JennyPalmer | 524 posts

@VanJim something nobody's touched on yet — the 30A genuinely earns its keep if you're doing short drives. With a 200Ah bank you want to shift meaningful charge in a 45-minute supermarket run, and the 30A pushing roughly 360Wh versus the 18A's ~216Wh makes a noticeable real-world difference.

Also worth knowing: both models have the same input voltage range and Bluetooth functionality, so you're not losing anything by going smaller — it's purely about throughput.

@Jason1992 makes a fair point about alternators though. If you've got a newer Euro 6 van with a smart alternator, make sure you've checked compatibility before buying either — the Orion-Tr Smart handles it well, but it's worth confirming your specific vehicle. Plenty of threads here covering that if you search.

IanHenderson79 | 87 posts

Running a similar setup in my static caravan — Fogstar 200Ah with an Orion-Tr Smart 30A from the tow vehicle. Went 30A and haven't regretted it.

One thing worth adding: with a 200Ah LiFePO4 you've got plenty of headroom to accept charge fast, so throttling yourself to 18A feels daft. The 30A will typically get you from 20% to 80% noticeably quicker on shorter drives.

@Jason1992 makes a fair point on the alternator — mine's a bog-standard 90A unit and the Orion handles it fine with the smart alternator detection doing its job properly.

Cost difference between the two units is maybe £40-50 depending where you shop. Spread over years of use it's nothing.

Go 30A.

ExTrucker63 | 2,847 posts

Worth jumping in here from a practical angle — I spent years driving artics and the alternator health point @Jason1992 raised is spot on, but there's another side to it. With the 30A unit you're pulling a consistent load off the alternator for longer motorway runs, which actually suits it better than short stop-start driving where neither charger size makes much odds anyway.

For a 200Ah Fogstar specifically, the 30A gets you back to meaningful SoC within a realistic journey time. The 18A honestly struggles to make a dent if you've had a heavy overnight draw.

SmartSolar_Master | 2,847 posts

@VanJim welcome to the forum — great first post, and solid setup already with that SmartSolar 100/30! 🙌

To actually answer your question directly: yes, get the 30A. On my narrowboat I ran an 18A for a year before upgrading and the difference in recovery time whilst cruising was immediately noticeable. With a 200Ah Fogstar you've got the capacity to absorb that extra current properly — no point bottlenecking yourself at the alternator stage.

One thing nobody's mentioned yet — make sure you've got the Victron Connect app configured correctly for LiFePO4 absorption/float voltages on both your MPPT and the Orion. The Fogstar Drift is quite tolerant but getting those charge profiles matched across devices makes a real difference long-term.

MI_OffGrid | 341 posts

@VanJim one thing nobody's mentioned yet — check your van's alternator output before committing. Older vans (Transit pre-2019, Sprinter, Ducato) often have smaller alternators that struggle when you stack loads. The 30A draws more obviously, and if you're running lights, heating blower, wipers in winter, you might actually be pulling more than the alternator comfortably provides long-term.

That said, for a 200Ah bank the 30A makes mathematical sense — you're looking at roughly 6-7 hours from flat versus nearly 11 with the 18A, assuming decent engine runtime. Worth the premium if you're doing longer trips between solar top-ups.