12V DC or 240V AC generator

There was quite a comprehensive thread on floating neutrals some time ago (maybe 12 months ago now). The main electrical issues that concern me are the possible consequences of the live neutral (isolation issues with switching and neutral to earth shorts, etc), the evidence I have seen from tests that RCD's may not work reliably in floating neutral systems, plus (rightly or wrongly) they are banned for safety reasons from many work sites.

The floating neutral is not the same as one finds when an isolating transformer is installed on a boat. When an isolating tranformer is installed on a boat the "neutral" on the boat side should not be left floating (although it sometimes is) like it is in the on shore use of an isolating transformer for powering a power tool or whatever. The recommended practice is to ground the on board side neutral to give a three wire grounded neutral system on board (which is required in any event for the boat's own AC generation (eg from generator or invertor).

The shore side earth when on shore power connects only to the transformer's primary side shield - this also means that as the boat's AC earth is isolated from the shore power one, the boat side neutral to earth connection does not have to be switched open circuit when on shore power as is the case if an isolating transformer is not used.

In the end, I have not fussed too much about exploring the floating neutral matters myself because the fuel (especially while refuelling) and carbon monoxide dangers put the small petrol powered generator's use completely out of my consideration too, apart for perhaps occasional powering of maintenance tools if at a dock or permanent mooring and no other supply.

Regards

John

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To not clutter the article above with some raw data, informational input is shown below for the just have to know tech types.
&#; Largest boat dedicated charger available (12vdc - 60amp) produces only 30 amps (apx.) of charging power when run of off the boat's 120vac generator.
&#; Largest boat dedicated inverter/charger available (12vdc - 150amp) produces only 80 amps (apx.) of charging power when run of off the boat's 120vac generator.
&#; ZRD dedicated DC Generator produces 220 amps @ 12vdc in example, but it is available in many other voltages and amperages.
&#; ZRD dedicated DC Generator solutions do not require additional equipment in order to charge batteries or power large DC Loads.
&#; ZRD dedicated DC Generator solutions may produce up to 6,667% more amperage available for battery bank charging (1,250% for largest inverter/charger available).
&#; The ZRD ZDCGE Generator solution typically requires only 7% of the engine run time a 30amp boat charger requires in order to charge (36% for 150amp inverter/charger).
&#; A simplified overview of the above may be explained in the following 2 examples:
  » A ZRD DC (Direct Current) Generator vs. a Standard 120Vac (Alternating Current) Generator has a 10 to 1 run time efficiency for typical overnight air conditioning use. Next, a ZRD DC Generator vs. a Standard 120Vac Generator has an apx. 4 to 1 run time efficiency for fuel consumption. The Resultant Total efficiency is up to 40 to 1 now. If you were to have a larger oversized AC generator (like many do), this number may easily exceed 100 to 1. Add in ZRD's forward thinking throttle control, and efficiency soon doubles (200 to 1) or triples (300 to 1) by not needing to run a generator at full RPM all the time. AC generators have no option to do this feature - They MUST BE RUN at FULL RPM whether 1% or 100% of amperage output is required.

» While cruising at anchor, charging the house battery bank using the installed standard shore charger running on 120Vac power supplied by an AC Generator (no shore power available) it has an efficiency reduction of 9 to as low as 25 or more to 1 compared to when that same charger is powered via Reliable Good sourced 120VAC shore power. Now, add in the engine run time required 1hr (DC Generator) vs. 3 or more (120Vac Generator) and the efficiency comparison changes to 27 or 75 or more to 1. Don't forget the apx. 4 to 1 run time efficiency for fuel consumption and the Resultant Total efficiency for comparison may easily reach 108 (or even up to 300 or more) to 1.
&#; The current battery bank condition (not charge state) is an item one always needs to be aware of and is one of the most misunderstood situations. Regardless if the batteries are old or new, but are worn out from improper charging or maintenance, they will not be able to handle any load beyond a few amps.

A small load

of a few amps (10-25) is

usually possible from a dead battery bank

for many years after the batteries have died. However, if a large load is applied, the batteries will immediately notify the boat operator that the batteries are in fact dead and are unable to supply the required higher demanding load. This is why the only way to know if your battery bank is still good is to have an installed battery monitor (gives months of advance notice) and test it regularly with an actual load meter. See the following FAQ that shows a load meter.

A Conversation regarding cheap portable generators.

Since the ZRD DC (Direct Current) Generator was introduced, we have received wonderful reviews and feedback. Although in a very small minority, we have received a few questions similar to the following. Read their thoughts and our view regarding the underlying fundamental principles on different ways to approach a solution.

I read the ZRD FAQ on "Why choose DC (Direct Current) over AC (Alternating Current) when Selecting a Generator?". The case you put forth makes sense for traditional AC diesel generators. It does not address the Honda series which is what everyone seems to be going with. I have one even though I'd much rather have a built in diesel. Sure, they are not marinized, but they're inexpensive and they work well. I would love to be able to just turn on a switch and run a generator, No pulling cords to start, rigging shore power cords, etc., filling gasoline tanks and schlepping them around. The Honda uses more fuel than my dingy. I just wanted to let you know that ZRD is missing a significant portion of the cruising community by ignoring the Honda phenomenon.

Addressing "ZRD is missing a significant portion of the cruising ..." For any community that is willing to sacrifice on important, significant issues strictly over price, ZRD's choice would be to bypass that community. ZRD will never provide an inferior solution in order to generate revenue - ever. ZRD always strives to provide the best proper solution or none at all. We have passed and will continue to pass on prospective customer opportunities in order to not have our name attached to an inferior solution they desire ZRD to manufacture or provide for them. We frequently tell customers that ZRD operates like the original Motorola from many years ago. Their company philosophy had at is root, "99% is not good enough". Look what happened to them when they compromised on quality just in an attempt to "compete on price" alone. The ZRD community understands our philosophy -

"You Deserve Us"

.

In addressing the Honda scenario, the prospect made the direct case for us logistically on why not to use a portable generator in his own . We do not need to expand on that any further, but if you understand how inefficient an AC Generator is, just observe how much less efficient than even that your boats 30 or 60 amp charger is when running on a Honda.

Unfortunately, the most significant item

he did not see at all and completely overlooked (because they are always blinded by price) was

Safety

. We have not mentioned safety directly for the same reason. It is so obvious, significant, and the backbone of everything ZRD does. ZRD will NEVER COMPROMISE on anyone's safety. This is a line in the sand for us - e.g. when a prospective customer wants an alternator for a gasoline engine without a spark arrestor or operates a generator all night with no one monitoring in case a malfunctions occurs that will endanger lives. The same mentality that will accept using a portable gasoline generator on a boat is the same thinking that does not wait 5 minutes for it to cool down before refilling when it runs out of gasoline. It probably ran out unexpectedly due to its not being monitored. I am sure they also only use it in calm conditions because it is as stable as being on land - NOT, even on a cat, ... I can go on, but it is apparently nothing they desire to hear, so why continue. Those of us that know, do not just do it, but Do it Better.

His and a few other emails are now addressed. This is an example of someone attempting to justify their "Wal-Mart" thinking - Cheaper wins over proper solutions. In the bigger picture and long run, ZRD solutions are the most economical when ALL factors are considered. This is the underlying problem in corporate business today. Any company run by an accountant(s) instead of a CEO that has a verifiable operational background and truly knows what he is doing is usually producing inferior products and is doomed to eventual failure. They do not know how to think or make decisions outside of a spreadsheet. They are incapable of incorporating intrinsic values and costs into it. Those costs and benefits are not easily quantifiable by accountants, but are known and valued accordingly by ZRD. ZRD will Never compromise on Quality or our customer's safety.

The case for a 120Vac Generator?

The answer is simple - If you desire or use your vessel as a

Floating Condominium

forever on the hook, never at a dock, used very little on the open water, continually consuming an inordinate amount of electricity to run all types of items and HVAC, with limited or non-existent supplemental solar and wind sources, have an

unlimited expense

($,$$$,...00)

budget

, have an

unlimited continual access to diesel

With competitive price and timely delivery, Sino Air Conditioner sincerely hope to be your supplier and partner.

fuel, and have

no concerns about the environment, wildlife, or climate change,

then a 120Vac Generator may be the solution you should choose.

The difference between the two sources of electrical power is in the total time and amount of power consumption you will require per day - 400Ah vs. over 1,000Ah.

To meet these non-cruiser higher consumption needs with a 120Vac generator, daily run time durations of 16 to 24 hours are required with its associated 15-25 gallons of daily fuel consumption, cost$, maintenance, noise, and obvious safety concerns.

ZRD manufactures DC Generators for most situations. If you have determined that you

"need"

a quantity of

electrical power

that is

beyond

what the

majority of "standard cruisers"

use, even after you have added supplemental electrical power in the form of solar panels and wind generator(s), you may seriously need to

consider

installing the ZRD model

ZDCGEUR (4Kw) DC Generator instead

of the usually selected ZRD model ZDCGE. This enhanced output model allows for continuous unlimited run time operations (similar to a 120Vac Generator), but without the extreme higher operating costs. And for those times that unlimited run time operations are not required, it still has all of the advantages of a standard ZRD DC Generator.

For very large vessels

(over 50' in length, typically over 60' or large catamarans) the

ZRD DCGDI may plainly be your solution of choice

. Again, in ZRD's opinion,

installing or using a 120Vac Generator should only be done in very limited situations

.

Generator or Genset?

The company is the world’s best 12v Dc Generator supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

The words Generator and Genset are often used interchangeably. A generator or genset, consists of electricity production components (typically a DC Alternator or AC Generator) combined with (connected to) an engine that provides the necessary rotational energy required for the electricity production components to produce their electrical output. This combination of components is called an engine-generator set, gen-set, or genset. Most commonly, the engine is assumend and taken for granted resulting in the combined engine with its electricity production component being called a generator. DC or AC is added for additional clarification as to which type of electricity is being produced.