Lithium power systems
In the world of unplugged power, lithium is leading the charge. Here’s the low down on lithium power systems for caravans.
We’re alone in a national park, a day’s drive from a 240V supply, yet the coffee machine is hissing, the toaster is glowing and once the hair dryer has blown its wave, we’ll sit down to eggs benedict cooked in the electric frypan.
Then, after running the iron over a couple of shirts, we’ll put the washing machine on to do its thing while we walk to that idyllic lagoon.
Not remote area caravanning as you know it? Well, it’s a brave new world out there that a number of travellers are already enjoying, many others envy and a lot more will regard as normal practice in the near future.
It’s created by lithium power; it’s not for everyone, but it’s available now and it’s going to change the way we travel and the vans we buy in the future.
We’ve got a definitive guide to this new-age power source and what it can do for your lifestyle.
A conventional wet cell lead-acid AGM battery, typically fitted to most caravans, consists of heavy lead plates and acid electrolyte. In a lithium ion battery (sometimes referred to as Li-Ion) the lithium ions move from the negative electrode to the positive electrode during discharge and back when charging, eliminating the weighty plates.
Because they are much lighter, quicker to charge and more efficient, lithium batteries are the most popular type of rechargeable batteries for portable electronic devices, from mobile phones and cordless drills to golf carts. They offer the same voltage as lead-acid batteries for about one-third the size and weight, and can be used in conjunction with large capacity inverters in caravans to power a wide range of domestic appliances. This is not practical with conventional lead-acid batteries, as a similar-sized inverter would require multiple batteries to draw on.
Not all lithium-ion batteries are the same and their chemistry, performance, cost and safety characteristics vary. Those developed for caravan use are Lithium-Ion Phosphate (LiFePO4) batteries, as they deliver the optimum combination of performance, reliability and safety best suited to mobile applications.
Compared to a typical AGM (lead-acid) battery, a typical lithium caravan battery of similar output is much smaller and around 65-75 per cent lighter. For example, a 200Ah Enerdrive lithium battery puts out the equivalent power of three 115Ah AGM batteries, yet occupies around one-third of the space and weighs just 35kg (not 100kg-plus).
This is important in caravans at a time when industry focus is on reducing Tare weights to cope with the increasing number of standard comfort options, while welcoming smaller and more economical tow vehicles.
The other big advantage of lithium batteries is they can be charged to 100 per cent capacity and will give nearly their maximum voltage even when drawn down to 20 per cent, whereas most AGM batteries run at about 85 per cent and lose voltage below that in a linear fashion. Lithium batteries also recharge quicker.
Lithium batteries have been fitted to caravans for a few years now with varied results. If you’ve heard horror stories about them failing, overheating, or even catching fire, these have invariably been those purchased on the internet and fitted piecemeal – often by amateurs – without correctly matching components or their wiring.
So if a battery failed, there was little recourse from its (Chinese) manufacturer and the supplier usually blamed the BMS (battery management system) or the installer, and so the customer lost out.
While virtually all caravan lithium batteries are manufactured in China, the biggest handbrake on their industry adoption until recently has been the lack of support and accountability for a complete lithium power system in Australia.
The breakthrough came last year when Brisbane-based specialists Enerdrive offered caravan manufacturers a fully supported and warranted lithium power system – opening the benefits of lithium up to the broader RV market.
Only selling to the industry and not selling components individually, Enerdrive has taken the mantle of responsibility off the shoulders of the caravan manufacturers who are now happy to purchase and fit the systems. So if the battery or BMS fails, Enerdrive takes responsibility for its replacement.
LITHIUM IN VANS
Two of the biggest names in top-end Australian offroad caravans – Queensland’s Kedron and Bushtracker – are currently fitting lithium power systems supplied by Enerdrive to the majority of their new vans.
Three-quarters of the Kedrons on display at the 2015 Queensland Caravan Show in June were fitted with Kedron-branded Enerdrive lithium systems, while Bushtracker says it’s seen a similar demand and take-up for lithium from its customers.
Other highly respected manufacturers known to be optioning lithium power systems include Australian Off Road, Halen Vans, Trakmaster, Roadstar, ZoneRV, Paradise and Free Spirit.
Few electrical systems, except the largest lithium ones, can run an air-conditioner unassisted for very long, as the current drain of even the most efficient reverse-cycle unit would outstrip the battery replenishment offered by even a roof-load of solar panels.
However, when used in conjunction with a small generator, the battery management in an Enerdrive system recognises that the generator is contributing to the load and will only draw the additional power required to run the air-conditioner from the battery, which can be offset additionally by whatever the caravan’s solar panels generate.
The cost of a full lithium battery/charger/inverter system often becomes secondary in a luxury offroader in the $90,000-$130,000 bracket when you offset its lifestyle benefits. However, there’s no hiding the fact it is more expensive upfront than a comparable AGM power solution.
A typical integrated lithium power system that would suit the average 18-20ft offroader, consisting of a 200Ah battery, a 1600W combined inverter/charger and a battery management system, is likely to cost about $5500 more than a conventional twin AGM battery system combined with a 600W inverter and matching battery charger on a new caravan.
Allowing for replacing both AGM batteries several times over the expected 10-15 year lifespan of the lithium battery, that cost shrinks considerably and, if you take the inverter out of the equation, the two systems should just about balance out.
However, many people don’t keep their caravan for 10 years, so working on a five-year cycle with one complete dual AGM battery change, the added cost of lithium will probably work out closer to $3000. But you will be enjoying considerably greater power – for longer – as an offset.
Aside from the additional cost, the other negative with lithium batteries is that while they hold a higher charge for longer, when they fail, they fail suddenly. So if you’re in mid-cycle on your top-loader out on the Tanami, it’s a problem. This is unlike a lead-acid battery that usually drops one cell at a time.
You’re not going to find a replacement lithium battery nearby, let alone someone competent to fit it, but I’ll bet you the next roadhouse will have a simple heavy-duty car battery they will be only too happy to sell you. And, with this connected, you’ll be able to run most of your essential appliances for the rest of your trip until a new lithium battery can be fitted at home.
The alternative back-up is a portable generator but national parks, not to mention most of your neighbours, don’t want to hear of them.
THE IDEAL SYSTEM
Like the question, ‘What’s the best caravan?’, the answer depends on where you want to go and for how long.
Enerdrive’s most popular EPL-200AH-12V system delivers similar power to three conventional 100Ah AGM batteries, is dimensionally much smaller at 448x336x224mm and weighs just 35kg. Ideally, it will be coupled with an Enerdrive ePRO Combi 1600-12 60A charger/1600W inverter and two or, ideally, three 150W solar panels. The final component would be a DC-DC charger to ensure the full charge from your tow car’s starter battery and solar panels gets to the van’s batteries.
Larger lithium batteries of 300Ah, 400Ah and even 500Ah are also available, but as these grow in size, so does their weight, so the largest units are only really suitable for very big offroad caravans or mobile homes in remote areas. They can be matched to larger ePRO Combi combined charger/inverters delivering up to 120A of charge and 2600-3000W of inverter capability, so with the largest of these you could power a small air-conditioner without generator assistance.
NOT FOR EVERYONE
Let’s put this upfront. Lithium isn’t for everyone. If you are travelling popular tourist routes and staying within reach of 240V power four to five nights a week, save your money. It might be bulky and heavy, but a pair of 110-115Ah AGM batteries and a single 150W solar panel combined with a portable 150W-300W inverter will probably do you.
While you can retrofit lithium systems to older vans, the expense may be prohibitive, given the cost of its conventional AGM battery system, charger and inverter has already amortised.
Lithium power is only making inroads in the caravan world because of companies such as Enerdrive attaining the industry’s confidence by supplying, assisting with fitting, and fully supporting the integrated systems.
So they are not about to risk their reputation by selling you, your electrician mate, or a caravan maker with no lithium experience, a part of their system.
As the technology is still new and evolving in the caravan industry from the top down, some van salespeople may look at you blankly if you ask about it. But if you want the advantages of lithium power for remote area comfort, then you are likely to want a caravan from a manufacturer that has already embraced this new technology and has customer experience with it.
My recommendation is to talk to one of those manufacturers first and ask them to show you a lithium power system installation in a van and to explain how it works. Then get them to refer you to customers who already have lithium-powered caravans and enjoy its advantages in the sorts of places that you want to travel to.
The full feature appeared in Caravan World #540 August 2015. Subscribe today for the latest caravan reviews and news every month!