Steve on the Motorhome Matt Podcast: Lithium Myths, 48V & Why Your Microwave Needs Maths 🎙️

Our founder Steve sat down with Motorhome Matt and Keith Gooden on the Motorhome Matt Podcast to talk all things lithium. If you haven't got time for the full episode, here are the highlights. There are cold weather myths, what really goes into a quality battery, and a very good reason not to trust the number on the front of your microwave.

How long do lithium batteries actually last? 🔋

Long. Really long. Steve explained that when we capacity test batteries we sold five or six years ago, they've barely lost anything. Most van owners simply don't work their batteries very hard. If you're cycling a battery once or twice a day in an off-grid house, it'll age faster. But in a van? It's built to go the distance, that's why Roamer have their industry leading 12 year warranty.

So what does wear a battery out early? Steve named two things:

⚖️ Poor cell balancing. Cells drifting out of balance cost you capacity over time. That's why SMART5 uses continuous active balancing to combat this issue.
🌡️ Environmental abuse. Think very high temperatures in a badly insulated van. Steve saw 40+ degrees inside a customers van this summer. That's why Roamer have battery protection mode. 

The cold weather myth ❄️

Steve and Kate head to the Alps every winter with their 48V setup, and Alex from our team takes his van to Norway in February. He's seen minus 37 with his battery! So yes, we know a thing or two about cold.

It's true that lithium shouldn't be charged below freezing, and our BMS stops charging at zero to keep things simple. But Steve says the real issue is where the battery is installed. His tip? Treat your battery like your water tank. If it's regularly dropping below zero, it's in the wrong place. You wouldn't sleep in a van that's below freezing, and neither should your battery.

If it does get chilly, just plug in or run your heater, warm the van up, and charging carries on as normal.

Heading somewhere seriously cold? That's exactly why we built XTREME. It can charge and discharge down to minus 30 without a heater.

"They're all the same anyway, aren't they?" 🙄

This is the myth Steve hears every single day, and he knows it's wrong. He specifies every part that goes into a Roamer battery. That's hundreds of decisions, each one a choice between what's best and what's cheapest. Here's what that looks like:

✅ Every battery is tested individually before it leaves the factory, and any faulty cells are thrown away
🔧 Fully serviceable. Take the lid off and see for yourself
🏗️ Cells held securely in a steel frame, with every cable and bus bar individually machined
💎 Cells that cost two to three times more than cheaper alternatives we could buy

Steve's advice when comparing batteries: ignore the headline figures. Anyone can claim 300A on a label. What matters is whether the cells, busbars and build can actually deliver it. And if a company won't show you what's inside its battery? That should raise questions.

Why Swift chose Roamer 🚐

Matt asked about certification, one of the big reasons Swift picked us to fit batteries at the factory. Our batteries are certified to ECE R10, the standard needed to be type-approved and fitted in vehicles from new, along with every certification below it.

Reliability played a big part too. Our warranty return rate is now below 0.1%. That matters, because once a battery is built into a van, nobody wants to be taking it back out.

Officially Motorhome Matt Approved 👍

This one made us smile. After a year of watching what we do and plenty of research, Matt gave Roamer his seal of approval live on the show. We're now Motorhome Matt Approved. Thanks, Matt! 🧡

Should you make the switch?

Steve's honest answer is that everyone's different, so give us a call and talk it through. If lithium isn't right for you, we'll tell you. We won't sell you something you don't need, or something bigger than you need.

He summed it up with one of our favourite lines:

"Nobody buys a drill because they want a drill. They want a hole."

Nobody buys a battery just for the battery either. Maybe you want to stay off-grid longer. Maybe you want to boil a kettle or run an air fryer. Maybe you just want a proper coffee in the morning. ☕ Whatever your reason, Steve's rule is simple: don't take out a lead-acid battery just to put another lead-acid back in.

Wait, 48 volts? ⚡

After Steve left, Matt and Keith picked up on his 48V system. It's not new technology, but it's still new in motorhomes. The first question most people ask is whether it'll trip a campsite hook-up. The answer is no. The inverter and charging electronics handle the voltage conversion, so plugging in works exactly as normal. Solar and your engine's alternator will top you up too.

The big win is current. At 48V, you need a quarter of the current for the same power, which means thinner cables and less energy lost as heat. Matt reckons higher-voltage systems will become more and more popular, and we'd have to agree. 😉

Listener Q: What size inverter do I need for a microwave? 🍿

In the Q&A, a listener asked what size inverter he'd need to run a microwave. Matt's answer is well worth knowing.

Step 1: Check the input wattage, not the output. A microwave sold as 700–800W might actually draw 1,100–1,400W. The number on the front is the cooking power. What you need is on the rating label, usually on the back or underneath in tiny print.

Step 2: Multiply by 1.5. That covers the surge when it starts up. A 1,250W microwave × 1.5 = 1,875W, so you'd go for a 2,000W inverter.

Step 3: Work out the amps. This is the part people forget. On a 12V system, divide the watts by the voltage, then divide by about 90% to allow for inverter losses. A 1,300W draw works out at roughly 120 amps from your battery. A 2,000W load could pull around 180 amps. 😳

That's a huge current, so you need to check three things:

🔋 Your battery can actually deliver that current
🔌 Your cables are properly sized, because undersized cables can overheat
🛑 Everything is properly fused, with an isolator switch to kill it all instantly

Lithium is much better suited to this than lead-acid, which will go flat fast under that kind of load. But even lithium needs the right spec. Matt learned this first-hand: his Nespresso machine drew around 120 amps on start-up, and his old 100Ah lithium battery's BMS shut everything down. That's exactly why he upgraded.

Not sure about the maths? That's what we're here for. Every Roamer battery includes Roamercare, with a free setup consultation and unlimited support from our UK team.

Watch Matt's install 🎥

Matt's van has just been fitted with Roamer lithium battery by Luke at BlueFix. A full video of the install, and of Matt putting it to use, is heading to the Motorhome Matt YouTube channel, so hit subscribe so you don't miss it.

Huge thanks to Matt and Keith for having Steve on the show. You can catch the full episode wherever you get your podcasts. 🎧

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