When we were deciding on what we wanted out of our electrical system, we realised that there isn’t a ton of information out there. The information that is out there is primarily from America, which can be confusing for all including us. With an Electrical trade and some Excel know-how I’ve done my best to put together a bit of a guide to help my fellow Australians navigate these treacherous waters, patriotic right!
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How big of a battery do I need to run all my stuff?
Say no more, I’ve channelled all of my Excel wisdom to create a power audit spreadsheet that should answer this question and a few more.
Wait, what is AGM or Lithium?
Essentially it depends on your budget, available space and weight carrying capacity.
An AGM battery is cheap, heavy, large and has a 2–5 year lifespan
A Lithium battery is by comparison initially expensive, lighter, smaller with a 10+ year lifespan.
***There is a difference in efficiency between the two as AGM’s can only be discharged to around half of their rated capacity, in short 200Ah of AGM = 100Ah of Lithium.
Heaps of people make these things, who do I choose?
Don’t be too fooled by advertising, batteries are pretty simple bits of gear. Google and check the reviews, as the cheap and nasties will definitely show themselves. For the most part there isn’t a huge variation in price, if there is a supppper cheap battery, its exactly that; cheap.
Since we had a bit of cash to splash during the rebuild of Huey, and were limited with our space, we opted to go Lithium.
Although initially expensive, long-term they are about as cheap when you factor in the difference in life span. When I compared an AGM setup we were going to need about a square meter of space and it would be around the same weight as I am. For comparison our Lithium battery is around ¼ of the size and weight, which let us reclaim some space and save some cash on fuel. We chose to go with Enerdrive, as the reviews were amazing, they have fair dinkum 5 year warranty and are Australian owned. The ePOWER B-TEC 200Ah Lithium is the exact model we bought; we love it since it has onboard electronics that tell you the state of charge via an app on your phone. It also tells us the charge/discharge rate, which lets us know how well the solar is working or how much load we have on at the time.
What’s an ACDC/DCDC Charger, which is for me?
An AC-DC charger transforms Grid power to 12V for batteries
A DC-DC charger regulates Solar/Alternator power to 12V for batteries
You’ll want a DC-DC charger regardless, it will charge your battery while you drive and will switch to solar (if you have it) while you aren’t on the move. Go for one that is around 40A+, as most alternators in cars will pump out around that. If you intend to stay at caravan parks most of the time, you may want an AC-DC charger so you can also charge from a powered site, if your solar system is abundant or you prefer to stay in national parks and free camps it won’t get much use. Being the millennial eco-friendly tree-huggers that we are, we like the idea of being self-sustainable. We have a large solar panel on the roof of Huey, that could keep us fully charged for days without driving, so we skipped out on the AC-DC charger. We stuck with Enerdrive and went for the 12V 40A DC2DC+ Battery Charger. Since the battery was quite a hefty investment, we thought it was important to have a charger designed specifically to feed it. The 40A model can handle full noise from Huey’s alternator and sunny days with no worries. Again, it has 5 year warranty which is nice.
How big of an inverter do I need?
If you haven’t already navigated through the Power Audit I’ve made, It’s all in there. What you do want to take note of though, is not only the size but the type. If you plan to run a Laptop or other device with a bulky block looking thing halfway along its cable, you’ll need whats called a “Pure” or “True” Sine Wave Inverter. In a nutshell, it provides a cleaner power output that doesn’t overwork that power supply block, or worse damage your device. They are a bit more expensive but are worth the extra cash.
Since we already had most of Enerdrive’s system in Huey, we chose to follow suit with the ePOWER 600W True Sine Wave Inverter. 600W was ample for us, since we really only need it for the laptops and stick blender. It was bundled together in price with the other gear.
Do I need solar and if so, how big?
The bigger the better, if you have vacant roof space you may as well use it. A 40A DC-DC charger should be able to handle it on sunny days with ease, even with that gaping hole in the ozone layer. The Power Audit spreadsheet should tell all about sizing.
Mono-Crystalline and Poly-Crystalline, whatever that means?
Mono-Crystalline are good quality, efficient panels. Poly-Crystalline are pretty much outdated, older tech now, avoid if possible.
Solid or Semi-Flexible?
Solid panels have the edge when it comes to efficiency and are cheaper too. There’s really no need for a semi-flexible unless you need to reduce weight, or can’t effectively mount the solid types.
We initially had a solid panel, but actually had an issue where the weight would cause the pop-top to sag when it was up. I got tired of the reduced headroom inside, so we decided to fork out for the semi-flexible style. It’s a 350W Mono-Crystalline panel from Solraiser, it hasn’t missed a beat. We also have an Adventure Kings 200W solar blanket in Huey in case it’s shady just to get a bit more juice.
Cabling & Protection
What sized cable/fuses do I need?
The manufacturer’s instructions should show everything you need to know for the wiring. It’s important that you don’t go smaller than specified. If there is a long run of cabling, it might pay to go up a size to negate a thing called voltage drop, Google it. Most cable, lugs and fuses can be found at any automotive retailer. Some brands like RedARC make kits and are complete overkill for price in our opinion, but do make it easy if you have no idea what you’re doing. We found sites like MyGenerator have most of what you need and is great quality gear. Keep in mind that if you install an inverter, hard-wiring out of the 240V side into a powerpoint will need to be done by a licensed electrician, or you can just plug an extension lead into the socket to avoid that. in Huey we used MIDI fuses over DC circuit breakers and keep spares in Huey. It's also important to not that ventilation is a critical part of any electrical installation; our system is installed in a small space under the bed, with enough ventilation to prevent overheating.
REQUIREMENT – Have I included everything I plan to run in the power audit to get accurate data?
AVAILABLE SPACE – Have I measured up my space to ensure I can fit the gear in there?
VENTILATION – Will that same space allow enough ventilation for that equipment?
ACCESSIBILITY – Can I access this area if I need to replace something?
COST – Do I have the bucks for this?
WEIGHT – Do I need to get the weight down? Should I go Lithium?
If you consider all of these things before you pull the trigger, you won’t go wrong. Hope this helped!