I completed some more enhancements to the Kimberley camper trailer this week by adding 2 additional lithium batteries and a DC/DC charger.
When we purchased our Kimberley Kamper (Special Edition) camper trailer in 2013 we had four 40 Ah batteries installed. Lithium was, and continues to be, an expensive option for a camper trailer, most opt for AGM. Even Kimberley, pioneers in this space no longer offer lithium as an option in their current camper trailers; only caravans.
So why choose lithium in the first place?
- They weigh much less than any other type of battery of equivalent capacity, typically 102 Watt Hours/Kg vs 30 Watt Hours/Kg for AGM. Our 40 Ah Lithium weight 6 Kg; an equivalent AGM would be twice that weight.
- They have a greater depth of discharge so a greater percentage of the capacity can be utilised. Compare 50% depth of discharge of AGM with 30% for lithium Iron Phosphate. Some argue that lithium can be safely used at 95% depth of discharge.
- Can charge much faster and can discharge high currents safely.
- Have a longer cycle life if maintained correctly.
- They are still very expensive compared to AGM.
- They require dedicated charging systems.
The 2 additional batteries takes our total capacity to 240 Ah which gives us lots of headroom if there are poor solar conditions such as bad weather or shady campsites. We spent 5 months on the road in 2014 with the 4 original batteries and never connected to the mains, however Northern WA in the dry season represents ideal exceptional solar conditions.
When we purchased the trailer in 2014 I was always a little disappointed it did not come fitted with a DC/DC charger in the trailer to manage the DC power coming from the car alternator when the engine is running. I considered fitting one, however could not find one with a lithium charging profile and we were short on time before heading off on the big trip.
With the addition of 2 new batteries I decided to have one fitted and after much research, decided upon an Australian made DC-DC Charger by GSL model (NGBC1222). It charges at 22 Amp, has a lithium profile, has a small form factor and retails for around $300. We already had a isolator installed in the car to disconnect the main battery when the engine stops, so only need one to be fitted in the trailer. We tested it for the first time on our recent camping trip and we now get a full 18-20 Amps when on the road. The existing hard wired solution rarely did better than 6 Amps and never charged the batteries to full charge.
Combined with the install of the new Victron solar MPPT charger we now have all our 12v power needs covered.