Magnum Inverter/Charger Design Tradeoffs
FYI The Magnum Inverter/Chargers are very good but cost tradeoffs in the design were made. I discovered the following on my ME2012 (2KW inverter and 100A charger) and these cost tradeoffs were made ac...
Forum Discussion
CA Traveler wrote:BFL13 wrote:Since it's a basic autoformer I would expect minimum wave form change.
Does the Variac's voltage adjustment make up for the poor wave form of the built-in gen being the cause of the apparent lower voltage? IE, even with a higher voltage, would it still be a poor wave form, so the charger still would not do full amps?
The Variac won't change the wave shape much and will heat up with a really bad wave shape. Also, a Variac is not what most RV owners think of when you say "Autoformer." A Variac is an adjustable autotransformer. An autoformer is a regular transformer with two different windings(really a buck/boost transformer) hooked up as an autotransformer. All the current flows through the windings of the Variac, so you'd need a high current variac. The pictured variac is a 3 amp variac. You'd need a 10A variac at least and that would be about $150. A 10% boost 60amp/ 20% 30amp buck boost transformer would cost you under $100. The buck boost transformer has small gauge wires for the input (carrying max less than 30A) and dual heavy gauge wires for the output capable of carrying 30A. The difference is that in the autoformer/buck-boost, all the current is not carried by the primary. In the variac, the primary and secondary wiring are the same (it's an autotransformer, so there is no true secondary wiring) and the wire diameter is not enough to carry the max current.
Depending on your charger output current, you might not need 30A or 60A (the buck boost can be wired either way), but a buck boost transformer would still be the cheapest way to go.
