T&T: Sine vs Modified Sign Wave Inverters

[Ken Ongemach]

Well, I guess we have to go thru this every couple of years.... The sign vs
modified wave noise came up when Prosine was a separate company, from Zantrex,
as a Marketing ploy.

As a designer of on board power systems for 28 years & supplier of Marine
Power equipment, I will say that there is NO advantage in one over the
other... What IS important, is reliability, & the ability to operate a full
loads. Forget about looking at the output on a scope. It will just scare
U...Except for cheap, small chargers, for charging little power screwdrivers,
we have found no marine loads which will not operate on  Heart Freedom units
including computer loads. If U could see how some of these units are used in
commercial service, U would cringe, operating under a load of fish, etc.

As in choosing electronics, stop reading the damn adds & getting into esoteric
discussions of features.. If U want reliable batteries, alternators,
regulators & electronics, go down to the local commercial dock, talk to
commercial captains & ask them what works & what doesn't... If their equipment
fails, they don't eat!

Electrical systems on boats are probably the confusing systems on a vessel..
As anyone on this site or other sites can easily see..

As an example, people running off to AGM & Gel Batteries, for no reason other
than they don't understand that a battery is a chemical, not a mechanical
device.. These batteries introduce a whole new set of variables &
characteristics to the system, that must be accounted for when designing a
balanced power system.. I've heard all kinds of reasons for using these
batteries, and paying the extra cost.. But in most cases after talking to a
client, it boils down to " I don't want the check the batteries".. Trust me,
its not worth it..

The 2nd most asked for item is massive ampacity alternators... like "200 amp
gotta be twice as good as  a 100 amp unit" There is MORE to consider, when
sizing an alternator than .."How many days do U want to run without charging"
to size the battery bank &" How long do U want to run the Eng. or Gen. to
recharge.".

Always look at the system as a whole, when adding, or modifying a power system
& seek the advice of a good electrician, technician or power system
designer... It is very easy to just try to throw money at a inadequate system,
but most times, it doesn't solve the basic problem..

As an example, an insurance co. hired me to do a survey on a vessel which had
a battery explosion which almost completely destroyed the vessel.. Upon
investigation, the owner had added a 3rd set of GC-1 batteries & Switch to
extend his time between charges... This is a common change... What the owner
didn't do, was add fuses in line with the new & existing batteries.. Adding
the 3rd set increased the fault current available to a level which is higher
than ratings of normal recreational switches.. As such, when the bank faulted,
it was impossible to tell what caused the fault, the fault current tried to go
to infinity & the battery(s) exploded... The insurance did not pay due to a
bad design....

Ken Ongemach BSEE
MACH V