Tested: Enerdrive lithium powerpack

It’s hot, and you’re going tent, trailer or caravan camping ‘off the grid’ but your 4WD or tow vehicle has only a single ‘cranking’ battery.

You know from past frustration that your portable fridge will keep stuff frozen when plugged in as you drive, but only around two days at best when parked. So what to do?

A plug-in portable solar panel via a regulator is the simplest solution, but what if the place where you’re camping is shaded?

Leaving it connected to your cranking battery via your vehicle’s ignition accessory switch, or hard-wiring it directly, isn’t a good idea, unless you want to flatten it overnight. Nor is running the engine for hours in a pristine area.

A generator? Not allowed in most National Parks, nor in most other placed at night. Bagged ice? The nearest is 100km away.

Simple solution

We faced this sort of dilemma in a recent 5500km return trip from
south-east Queensland to the tip of South Australia’s Eyre Peninsula when we hooked our Trakmaster caravan up to a borrowed Isuzu D-MAX ute.

The destination was four nights at remote Memory Cove at the very tip of the Lincoln National Park, where we planned to feast on King George Whiting, local oysters and prawns purchased from a trusted Port Lincoln fish wholesaler on the way.

The problem was that we were travelling there through very hot, remote areas, and we needed the combined capacity of our caravan's 140-litre Dometic compressor fridge and our elderly 45-litre portable Engel to keep quick meals of Bolognese meat sauce for pasta or tacos, beef curry for rice, pork meat balls, plus our precious seafood, frozen or very cold in ambient temperatures up to an egg-frying 46 degrees.

The most reliable answer for this long-term refrigeration need was an auxiliary battery, but our borrowed D-Max had only its cranking battery.

Many people with a smaller SUV who change vehicles regularly and little spare space under the bonnet, would have a similar problem. True, there are battery packs that will allow you to keep your drinks cool in a portable fridge over a long boating, camping or fishing weekend, but none that will stay frozen longer.

Oddly, there are no fully-packaged portable auxiliary batteries of this type on the market – or none that I could find – although various battery retailers, including Battery World franchises, will make up something to suit your needs.

Going lithium

I consulted my always-helpful friend Dan Morland at Battery World, Burleigh Heads and he suggested a remote auxiliary battery solution that I could remove after the trip without cutting into the Isuzu’s wiring loom and then re-purpose another time in another vehicle.

The starting point was a battery box that could be anchored securely behind the front seats, close to my Engel, or in the load bay of the D-Max. I chose the former location.

There are a number of these boxes on the market, but Battery World sells their own ones primarily for use in boats and 4WDs. The one recommended was made of tough plastic with a sliding lid and room to mount a DC-DC charger on the side, close to the auxiliary battery to ensure the maximum voltage from the cranking battery got through.

Of course, I then needed a battery, which could have been anything from 75AH AGM upwards. But not having one spare and wanting to ensure that the system worked, I approached Lithium-Ion battery specialists Enerdrive to borrow one of their latest B-Tec batteries.

I knew the quality of their products and the Australia-wide support they give from my experience with the lithium power system they tailored for my Trakmaster Pilbara off-road caravan.

Although slightly smaller and just 70 per cent the weight of a conventional AGM battery, Enderdrive’s B-Tec Lithium batteries have a higher energy density that makes them perfect for cyclic applications, with faster charging and discharging.

Enerdrive option

There are five batteries in the Enerdrive B-Tec range, which is popular with manufacturers of hybrid caravans and camper trailers because of their power relative to their size and weight.

The 12-volt B-Tec batteries come in 100AH, 125AH and 200AH models for RVs, while the 24v and 36v versions of the 100AH model are  primarily for marine applications. I borrowed a 12v, 125AH model, which was a little overkill, as a base 100AH B-Tec would have done the job perfectly.

Battery World and Enerdrive both recommended I controlled the current from the Isuzu’s cranking battery through an Enerdrive ePower DC to DC battery charger. With the ability to charge from different sources, this would allow the B-Tec to be charged from either the engine while underway, or via a portable solar panel when at camp. The choice is fully automatic, as both functions are controlled from within the unit itself without the need for external relays.

Battery World also mounted an Anderson plug to the outside of the battery case to make the connection of a portable solar panel easy and fitted an in-line circuit breaker to protect the battery in case a dead short occurred in the system.

During normal operation the ePower DC2DC Battery Charger will do a full charge cycle to float stage on the car’s battery bank with ability to choose either GEL, AGM, Flooded, Custom Programmable or Lithium via a simple adjustment. Once float stage is reached the charger transitions to a power supply mode to support any on-board DC loads.

If you forget to charge your lithium battery, unlike a conventional battery it will still deliver peak power until it drops to a predetermined low voltage level, when its internal protection system will switch it off before any damage occurs.

If this should happen, you can simply ‘kick-start’ it by bridging its positive terminal to that of another battery, for example via jumper leads. This is simpler now, with an addition momentary switch wired in as part of the latest ePower DC2DC installations and all you need to do is press and release this switch while the engine is running to re-set the battery.

But the point of this story is that my beer, our wine, our pre-prepared frozen ‘travelling meals and our precious seafood, all kept perfectly and were delicious.

Most importantly, my credibility as a savvy, cool, Outback traveller was maintained in the Browning household!

What does it cost?

The path I took to keep my portable Engel running on freezing was not the cheapest, but probably the most cost-effective way, in the long term.

The average price for a dual battery set-up in a 4WD these days is around $1500 drive-in, drive out. This includes the battery shelf, an AGM battery of about 90AH (anything more powerful will probably not he heat-proof under the bonnet).

I took the high road, which my mate at Battery World, Burleigh Heads says the majority of customers with ute canopy installations do, with my Enerdrive lithium set-up, which at retail prices would have cost about $1000 more, but this easily be justified...

The 125AH Enerdrive B-Tec Lithium battery gave me a longer run time than an equivalent AGM battery, as it still produces virtually undiminished power before its built-in BMS (battery management system) shuts it down to protect it from any internal damage;

It also recharged around three times faster than an AGM battery, and I could expect 10-15 years’ service life with the Enerdrive lithium battery, compared with 3-5 years with the sort of AGM you would get in a basic dual battery package set-up. The more you invest in the battery, generally the longer the lifespan.

The RRP cost of my set-up from Battery World was as follows, but keen shoppers could no doubt do better:

Enerdrive ePower B-Tec 125H battery ($1950, although I have seen the 100AH version as low as $1,329 online), Enerdrive DC2DC Charger ($520), Battery Box ($110), Enerdrive circuit breaker ($43), plus fitting cost, depending on vehicle.