Anyone else built a decent 12v system for under £300? Here's what I cobbled together

So I've been piecing together a basic off-grid setup for my Transit camper over the past few months, trying to keep costs down without ending up with something that'll catch fire or die after a fortnight. Ended up with a 200Ah AGM leisure battery from Bimble Solar (about £120), a 175W panel off eBay (£65), and a Victron SmartSolar 75/15 MPPT controller (£75 new from Amazon). Total came to just under £270 including some 6mm² cable and a couple of ANL fuses from Merlin Solar.

It's been running solid for about three months now. Powers a 12v compressor fridge (about 45Ah a day in this weather), phone charging, LED lighting, and occasionally a 12v travel kettle if the sun's been out long enough. I'm in South Yorkshire so we're not exactly blessed with Mediterranean sunshine, but even on dull days I'm pulling 30–40Ah back in. Doesn't quite keep up in deep winter but it's manageable.

The thing I skimped on that I now slightly regret is the ANL fuse holder — bought the cheapest one I could find and the connections are already looking a bit iffy. Probably worth spending an extra fiver on something decent there.

Has anyone else put together a working system on a tight budget? Curious what corners people found were worth cutting and which ones came back to bite them.

MoorClive | 847 posts | ⭐ Trusted Member

Nice one @SteveBurns, sounds like you're going about it sensibly rather than just chucking money at it. Curious what you landed on for the battery side - are you running a leisure battery or did you manage to stretch to a LiFePO4?

I did something similar in my old Sprinter about three years back, kept it well under £300 by sourcing a decent 100Ah AGM from a local motorhome breaker rather than buying new. Saved about £60 right there.

One thing I'd flag for anyone reading - don't scrimp on the fusing, even on a tight budget. A £4 inline fuse holder has saved more than one van from becoming a very expensive bonfire. Pennies well spent.

Looking forward to seeing your full parts list!

VanBarry | 312 posts | Regular Member

Good thread this. One thing worth mentioning that catches people out on tight budgets - don't scrimp on the wire gauge and fusing even if you've saved money elsewhere. I made that mistake early on and ended up with voltage drop killing the efficiency of everything downstream. Proper crimped terminals too, not just twisted and taped.

@SteveBurns what are you using for charge control? If you're running solar into that setup a half-decent PWM controller can be had for under £25 on Amazon and it'll protect your battery properly. The really cheap unbranded ones are a false economy in my experience - had one cook itself within six months. Victrix and Renogy both do entry-level units that won't break the bank but will actually do the job reliably.

VanMark | 156 posts | Regular Member

Great thread @SteveBurns. One thing I'd add that saved me a fair bit - don't sleep on second-hand AGM batteries from UPS systems. Companies upgrade their backup power units regularly and the pulled batteries often have loads of life left. Got two 100Ah ones from a local electrical firm for £40 the pair, tested fine. Worth ringing round small IT companies or checking eBay for "UPS battery pull" listings. Obviously test them properly with a load tester before committing, but the savings can be significant. Frees up budget for decent cable and a proper fuse setup, which honestly matters more than people realise. Keen to see what @SteveBurns ends up with for the full parts list.

ShaunButler | 156 posts | Regular Member

Great thread @SteveBurns. One thing I'd add that saved me a fair bit - don't overlook second-hand leisure batteries from motorhome breakers. Picked up a decent 110Ah Banner for £45 that had barely seen any use because the previous owner had upgraded to lithium. Obviously you're taking a gamble on cycle history, but if you can get them tested before buying you can find some real bargains. Also worth checking Facebook Marketplace for solar panels - plenty of people selling off complete systems when they move house or switch setups. Got my 100W panel for £30 that way. Just inspect the junction box carefully for water ingress before committing.

George1975 | 847 posts | Senior Member

Done similar in my van conversion - honestly Fogstar are your best mate for budget lithium. Their 12v 100Ah cells punch well above their price point.

One thing nobody's mentioned yet - don't cheap out on the BMS. Learnt that the hard way 😅 Saved £40 buying a dodgy unit and spent twice that sorting the aftermath.

Also worth grabbing a proper battery monitor from the start. Even a basic Victron BMV-712 off eBay (secondhand is fine) means you actually know what's going on rather than guessing. Flying blind with cheap gear is how people end up on the hard shoulder.

@SteveBurns what solar controller are you running? That's often where folk either win or lose a budget build.

OddJobBob79 | 312 posts | Regular Member

Nice one @SteveBurns, good to see someone actually documenting this stuff properly. One thing nobody's mentioned yet - keep an eye on Marketplace and Gumtree for used leisure batteries from motorhomes. Picked up a pair of 110Ah batteries last spring for forty quid the lot from a bloke breaking a Bailey. Had them tested at a local auto sparks, both holding over 80% capacity. Obviously it's a gamble but if you can get them checked before handing over cash it can massively stretch your budget. Also worth joining a few local Facebook camper van groups - people are always offloading decent kit when they upgrade to lithium. Saved myself probably £150 doing exactly that on my Sprinter build.