Frequently Asked
Questions

Lithium-ion (Li-ion) covers a family of chemistries - cobalt oxide, nickel manganese cobalt, and others. High energy density, which is why your phone battery is small. The trade-off is thermal volatility: this is what's behind the fires you've read about in phones, laptops, and e-bikes.

Lithium Iron Phosphate (LiFePO4 or LFP) uses a different cathode - iron phosphate - which is inherently more stable. Slightly lower energy density, but dramatically safer, and rated for 2,000-4,000+ charge cycles versus 500-1,000 for standard Li-ion. It's widely considered the safest lithium chemistry available, significantly less prone to thermal runaway than other variants.

It depends on what you're running and for how long. The simple approach: add up your daily appliance consumption in watt-hours (Wh), divide by your system voltage to get amp-hours (Ah), then add a margin for bad weather days.

The important distinction: with LiFePO4 you can safely use 80-90% of rated capacity. Lead-acid should only go to 50%. So a 100Ah lithium battery genuinely delivers more usable power than a 100Ah AGM - it's not marketing.

Yes - every time, no exceptions. A BMS protects your lithium battery from over-charge, over-discharge, short circuits, and thermal extremes. Without one, you risk permanently damaging a very expensive battery, and potentially causing a fire.

The brands we supply and recommend - Eco Tree Lithium, Fogstar, Roamer, and FoxyGen - all include a BMS as standard. If you're buying bare cells from elsewhere, an external BMS is non-negotiable. We won't install a lithium system without one.

Sometimes - but often not cleanly. It hinges on your existing charger and solar controller.

Charger: Many older converters are set up for AGM or gel charge profiles. LiFePO4 needs a specific profile (typically 14.2-14.6V absorption, no conventional float). If your charger has a gel setting, that's the closest you'll get - but many don't even have that. Either way, you want at least one source of charge running a proper lithium profile to get the most out of your battery.

Solar controller: PWM (Pulse Width Modulation) controllers need replacing. We always swap them out - a PWM controller cannot deliver a proper lithium charge profile regardless of its settings. If you have an MPPT (Maximum Power Point Tracking) unit, usually you just need to update the battery type setting.

Quality LiFePO4 is typically rated 2,000-4,000 cycles to 80% of original capacity. At one cycle a day, that's 5-10+ years. Many will outlast the vehicle itself.

Compare that to AGM at 300-500 cycles when regularly discharged to 50% - and the higher upfront cost of lithium starts making sense pretty quickly. Treat it well (avoid sitting at 0% or 100% for extended periods, keep it out of extreme cold) and it'll serve you for a very long time indeed.

Yes - significantly so in the UK. Panels produce maximum output when sunlight hits them at 90 degrees. In summer the sun is high, so flat roof panels work well. In winter the sun barely clears the horizon, and flat panels barely catch it directly.

Tilting to match the winter sun angle can increase output by 40-60% in UK conditions. It won't turn December into July, but it's the single most effective thing you can do with existing panels before spending money on more.

It's a second solar input point - typically a weatherproof connector mounted somewhere accessible on the vehicle - that lets you plug a portable solar panel directly into your main leisure battery system.

Those fold-out panels sold with EcoFlow, Jackery, and Bluetti power stations are ideal for this. Prop them up facing the sun wherever you're parked and you get proper winter solar gain without touching your roof-mounted setup or running cables through windows.

We fit these as a standalone job. Usually all that's needed is a second MPPT controller sized for your panel's output. Clean, tidy, doesn't disturb your existing system.

It depends on your battery size, daily energy use, and whether you want full self-sufficiency or just a useful top-up. A rough UK benchmark: 100W of solar generates roughly 30-50Wh per day in winter and 400-500Wh on a good summer day. That variability is dramatic.

As a general rule of thumb, we like to see your solar wattage match or exceed your battery capacity in amp-hours. So a 300Ah battery ideally wants 300W+ of solar, and if you've gone all-in on a 628Ah bank, you're looking at 600W+ to keep it properly topped up.

For reliable year-round living, solar alone usually isn't enough. The best approach combines solar for daytime generation, a DC-DC charger for charging while driving, and shore power when it's available. That three-way combination means you're rarely caught short. And if you want to extend your time on campsites without relying on hook-up, an Auxiliary Solar Input Connection lets you plug in a portable tilting panel wherever you're parked - a great addition when you need that little bit extra.

PWM (Pulse Width Modulation) is the older, simpler technology. It connects the panel directly to the battery and pulses the connection to regulate charge. Cheap, but typically 15-20% less efficient than MPPT, and it can't handle higher-voltage panel strings at all.

MPPT (Maximum Power Point Tracking) continuously finds the panel's optimal power point and converts that to the correct voltage for your battery. Efficiency sits at 93-97%. It handles series-wired panels, works in partial shade far better, and is simply the right choice for any modern system.

For any LiFePO4 system, or panels over 100W, MPPT is the answer. The extra charge you get back more than covers the difference in cost.

No - and this catches a lot of people out. The current (amps) is the same number, but the power is completely different because it depends on voltage too.

5A at 240V is 20x more powerful than 5A at 12V. This is critical when sizing fuses and cable - what looks like a modest draw at mains voltage becomes a serious demand on a 12V system.

This one confuses a lot of people, particularly when comparing Victron against other brands.

Watts (W) is real power - the actual energy delivered to run your appliances. kVA (kilovolt-amperes) is apparent power - it includes the extra current drawn by inductive loads (motors, fridges, microwaves) where voltage and current aren't perfectly in phase.

Victron rates in kVA because it's more honest about capacity for inductive loads - it prevents the inverter being overloaded when devices have a poor power factor. When comparing against a brand quoting Watts directly, multiply the kVA by 0.8. That said, Victron appear to be moving with the times - their recently launched Multiplus 12/4k suggests a shift toward Watt-friendly naming is underway.

A DC-DC charger (also called a B2B charger) sits between your vehicle's starter battery and leisure battery. While you're driving, it takes the alternator's output, regulates it to the correct charge profile for your leisure battery, and charges it properly - regardless of what voltage the alternator is putting out.

A split-charge relay (or VSR - voltage-sensing relay) simply connects the two batteries together when voltage is high enough. Simple and cheap, but it means the leisure battery only gets whatever the alternator produces with no proper charge profile. On modern smart alternators - which drop output voltage to save fuel - the relay reads it as a full battery and stops charging altogether.

An inverter converts your 12V (or 24V/48V) DC battery power into 230V AC - the same as a UK mains socket. It's what lets you run a kettle, laptop charger, hair straighteners, or any standard 3-pin appliance from your leisure battery - as long as the combined wattage of your appliances doesn't exceed the inverter's rated output. Push it too hard and you'll either hear alarms going off or start blowing fuses.

There are two types: modified sine wave (cheaper, works for simple resistive loads) and pure sine wave (matches grid power exactly - needed for sensitive electronics, motors, and transformers). We only install pure sine wave inverters. Modified sine wave is a false economy for anything modern.

Whether you need one depends on what you want to run. If everything is 12V USB and sockets, you might not. If you want to use standard plug-in appliances, you do.

All cable has resistance, and when current flows through it, some voltage is lost as heat. In a 12V system, even a small drop matters - you're working with a narrow voltage window and your equipment needs to see the right voltage to work properly and efficiently.

Under-sized cable causes excessive drop, wastes energy, and in serious cases creates a genuine fire risk. Correct cable sizing is about matching the cross-section to the current it carries and the length of the run - not just what fits through the gland.

Extremely important. Undersized cable doesn't just lose you a few watts - push enough current through cable that's too thin and the cable itself becomes the fuse. That means heat, melted insulation, and in serious cases, fire.

Our rule of thumb: when in doubt, go one size up. A slightly larger cable than needed is money well spent. However, going excessively large is money wasted - 70mm² cable to power a USB socket is overkill - so there's a sensible middle ground.

The key variables are the current the circuit will carry, the length of the run (resistance increases with length), and the ambient temperature. All of these feed into the correct size. It's not guesswork - it's maths - and we always spec cables properly rather than just grabbing whatever's on the shelf.

If you're confused, stop and understand it before you continue - wrong cable sizes combined with wrong fuses is genuinely dangerous. If it's all feeling a bit overwhelming, we can take care of it for you. That's what we're here for.

But if an analogy helps, try this one. Imagine your battery bank is a reservoir. To feed a main river, you need a large opening - a wide channel to let the water flow freely. Smaller streams then branch off that main river to supply different areas, each one sized for the flow it needs to carry.

Electricity works in exactly the same way. It's not called current for nothing. Large appliances like inverters demand enormous current and need thick cable to carry it safely. Smaller appliances - a USB socket, a reading light - need far less, so smaller cable is perfectly fine. Size the cable to the current it carries, and you won't go far wrong.

We're at Unit 10, Century Street Industrial Estate, Sheffield, S9 5DX - South Yorkshire, easy access from the M1. What3Words: ///leaves.behave.kind

Open Monday to Friday, 9am-5pm. Give us a ring on 0114 470 4562 or send a WhatsApp before heading over and we'll make sure someone's ready for you.

Yes - manufactured campervans, factory-built motorhomes, self-build conversions, and everything in between.

The electrical principles are the same whether it left a factory or was built in someone's driveway. What matters is that the installation is safe, correctly specified, and does what you need it to do.

It depends on the job. A straightforward DC-DC charger install could be half a day to a full day depending on cable routing. A full lithium upgrade with solar, an inverter, and a proper rewire could take anything from 2 to 5 days depending on the system.

We'll give you a realistic time estimate in your quote. We don't rush and we don't drag things out. If you need the van back for a specific trip, tell us when you book and we'll plan around it.

Honestly, it varies too much without knowing your vehicle and what you're trying to achieve. A simple DC-DC charger install is a very different job to a full lithium system build.

We don't do quotes, we do estimates. If the job turns out to be simpler than expected, we'll reduce the hours accordingly. What we can promise: we'll only recommend what you actually need, we'll explain why, and you'll have a full itemised estimate before any work starts. No hidden extras, no surprises.

We provide a 12 month warranty on all our workmanship. On top of that, the components we supply carry their own manufacturer warranties - and some are very generous. Victron, for example, offer a 5 year warranty on most of their products, so you're well covered on parts long after we've done the work.

If something we've fitted gives you grief, call us - we'll sort it.

For motorhome owners worried about voiding the manufacturer's warranty: we're experienced at working within warranty-safe boundaries and will discuss the best approach for your specific vehicle before any work starts.

In short: we'd rather you didn't, and here's the honest reason why. We make margin on the products we supply - that's a normal part of how a business like ours works - and it's what allows us to keep our hourly labour rate competitive. When we supply and fit, you're effectively getting a better total price.

If you prefer to source your own equipment, we completely understand, but we'll add 25% to our hourly rate to offset the lost product margin. That's not a penalty - it's just the maths. If you're trying to save money by supplying parts yourself, you'll almost certainly find you end up spending more, not less.

There's also a practical side: when we supply the equipment, we know exactly what we're fitting, we know it's genuine, and we stand behind it. With customer-supplied parts, we can fit them but can't warranty the product itself.

However suits you best. We're easy to reach:

📞 0114 470 4562 - Monday to Friday, 9am-5pm.
💬 WhatsApp - often the quickest, especially if you've got a photo of your setup.
✉️ admin@powerhouseoffgrid.com
🌐 Contact page - fill in the form and we'll be straight back.

We're a small team and we genuinely like talking to customers.