A Dual Battery to nowhere, melting dangers, overcharging, undercharging and flat Lithium "drop-in" batteries. But wait, there's more. So much more.
Our clients came to us with a freshly purchased 2nd hand caravan, of which the seller boasted was equipped with a "full lithium battery system upgrade" and adequate solar charging but the batteries kept going flat.
We discovered an ineffective DIY “drop-in” lithium battery system which had zero lithium compatible equipment attached such as chargers, solar controllers, battery monitoring and vehicle charger.
For further reading about this see our article "Solving Drop-in Lithium Battery Dramas". A single roof top solar panel formed part of this system, incapable of providing adequate charge even if it the Solar Controller had been Lithium specific, due to its size and undersized cabling.
Having corrected the caravans' shortcomings, we turned our attention to the tow vehicle, a Ford Ranger, for attachment to the caravan. A more dire scenario revealed itself before us, in all its glory.
With the brief to run two Fridges from the vehicle, a Dealership had undertaken a Dual Battery installation.
The Dealership's Auto Electrician installed:
1 x 40A AGM battery under the rear seat. Why? Because that's what size battery fit the space. A 40A AGM battery is entirely inadequate to keep two fridges running.
A 40A vehicle battery charger, which meant the battery was receiving excessive charge over the manufacturers 10A recommended maximum charge rate. Too much current generates heat and damages the battery.
The absolute best part of this though, was there were no sockets installed so the fridges couldn't be plugged in!!!
So all that's achieved is a 40A Dual battery under a seat which can overcharge but can't run anything! Truth truly can be stranger than fiction.
Having travelled to another location after the Dual Battery install, our clients took the Ford Ranger to an Auto Electrical business and requested fridge sockets be fitted, along with an Anderson Plug to charge the caravan batteries whilst driving.
The Auto Electrical business installed:
A 50 Anderson Plug to the rear tow bar, using 6mm Auto cable instead of at least 8BS cable, which is kind of like trying to force a garden hose amount of water (electricity) through a straw. The connection was made live, instead of switching the connection to the ignition to turn on/off with the key. This means that when the caravan is plugged in, its batteries continue to draw power from the vehicle start battery even when the vehicle is not running. Perfect way to flatten the vehicles' battery.
A 30A Blade Fuse to the 50A Anderson Plug. A 30A blade fuse is not suitable for an item capable of 50A's of power so the fuse will melt or blow in excess of 30A's, terminating the connection.
Two fridge sockets tapped off the Anderson plug instead of installing them on their own separate circuit with individual fuses. If that aforementioned fuse blows, two fridges and caravan battery charging cease working, unless the vehicle start battery goes flat first, in which case the vehicle stops too! Imagine that scene on the side of the road in the heat and the red dust of our remote and beautiful north! If you made it that far.
So on completion of the Auto electrician's work, we have a Ford Ranger with two fridges drawing constant power from the essential start battery in addition to Lithium caravan batteries also desperately trying to pull charge!
"But what about that 40A AGM Dual Battery under the seat?", we here you say. That's still there, overcharging and unable to run anything. And we thought we'd seen it all.
We resolved the Ranger by installing The Lithium Box (TLB) 100/40 Small, the most compact in our RV Lithium Systems portable range, which happily runs their 60L Kings fridge and 40L Engel. We also replaced the cig socket on the Kings fridge with an Anderson plug for a secure connection to TLB Small because Cig sockets tend to fall out with vehicle movement.
TLB 100/40 Small is also capable of running camp lighting, charging devices and running 12v accessories.
For easy removal of TLB 100/40 Small, we built a custom aluminium base plate for mounting.
The Dealership removed the "Dual battery system" and refunded our clients' money.
The Auto Electrical business refused to admit there was any fault in their work.
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