Wiring a New Mastervolt Power Charger

[mkendrick]

After 10 years my Guest 2610A battery charger died and I am replacing it with a Mastervolt Charger on my 25'.

What do i do to make this conversion work?

 

[Sunbeam]

Can you be a little more specific? Is there a certain step in the installation instructions for the new charger that is confusing? Is there something about your current installation that seems "off" as compared to the new charger?

It's not that I can't think of anything (or things) that could be confusing, but it's just hard to answer your question because it is so general. I'm sure lots of people here could help :thup

 

[thataway]

Which Mastervolt charger? Most of them are individual bank charging. So you hook up the + (red) to pos. to the battery, and - (black) negative to the battery. As I recollect my master volt had terminals, and I used #10 - #12 (depending on distance) wire to each of the battery, with separate pos and neg. I would do each battery separately. For each end of the wire I crimped on the appropriate size terminal, Fuse the each wire within 7" of the terminal--with a water resistant, in line fuse. I like the type which is rubber, and uses the spade connector, which you can coat the spades with dielectric grease.

One would assume that you have at least 2 if not 3 batteries. That you got at least a 25 amp charger.

 

[colbysmith]

Just purchased the Mastervolt Chargemaster 12/25-3 and will finish installing it today. Yesterday I rewired everything for the charger, using 8 gauge wire between the charger and the batteries, one a 10 foot run of wire, the other about 15 feet. 8 gauge is probably a little over kill, but the old wire was 10 and 12 gauge. The old charger was installed underneath the aft dinette seat above the water tank, in a horizontal position. I'm making a new mounting board that will sit beside the water tank so when I open the cabinet door, it will be right there, towards the front of the compartment. I'll take some photos later. The question I have is in regards to the ground terminal on the charger. The users manual doesn't show it hooked up in the diagram, yet at one point talks about a connection to the boats safety ground thru the hull. The confusion exists due to the terminology being used for the grounding wire in the ac power cord. They refer to PE/Ground in both cases. Also, on the old Guest charger, it's negative 12 vt terminal was also connected to the galvanic isolator. I'll need to research this a bit further to see if that was simply allowing a connection to the battery negative terminal from the isolator.

To simplify, I'm wondering how others have connected that ground terminal on the Chargemaster, or if it's even used.

And, does the Galvanic Isolator need to be connected to the batteries negative post as well. (The same isolator terminal that is also connected to the A/C ground system.)

Late note. After doing a bit of quick research, I don't see any reason for a connection between the galvanic isolator and the boats 12vt system. Looks like it should just go between the incoming "earth" ground wire from shore power, and "earth" ground terminals in the boats a/c electrical system. Colby

 

[thataway]

Do not change the way the galvanic isolator is installed. There needs to be one single point in the boat where the galvanic isolator green wire to the boat's "ground", is tied to the common DC ground. Normally this is the engine block.

Do not connect the green wire to the negative battery post. In your case, don't connect the "ground" terminal of the charger to the negative battery post.

When you connect the battery charger AC input it will have white (neutral), black (hot) and green (ground) to the 110 volt system.

I did not connect the "ground" terminal of the Mastervolt charger. If I did it would have been to the engine block--common ground point--which is in direct contract with the water.

 

[Jake]

If I might slip in a related question. On a boat with an ACR dual battery type of setup, the installation of the charger would be the same as on a boat without the ACR? You would still use a dual bank charger hooked up directly to the two batteries? Hope this makes sense.
Jake

 

[thataway]

If I might slip in a related question. On a boat with an ACR dual battery type of setup, the installation of the charger would be the same as on a boat without the ACR? You would still use a dual bank charger hooked up directly to the two batteries? Hope this makes sense.
Jake

Yes and no. With the "smart chargers" which treat every battery individually, you want to disable the ACR. This can be done in several ways. Some have provision for a switch to allow this. Some you can put a switch in line.

You want the ACR hooked up "normally" when running with the engine. Of course some of the modern engines, have two charging circuits-and act more like the "smart chargers"

 

[san juanderer]

Thataway-
In your second and fourth sentence you refer to "ground terminal of charger",
would this be the chassis terminal ?
In your first sentence, the single point in an outboard engine boat would be at what place in the wiring ?
thanks

 

[colbysmith]

Thanks Bob. Looks like I may need to do a little more work. Using the 8 gauge wire was a pain, at least with the terminals on the Chargemaster. In fact, I pretty much stripped out one of the 12vt + set screws so not using that terminal for now. (Only needed two anyway. The problem is, the heavier gauge wire doesn't allow the set screw to set in very far. I did add solder to the ends of the wire, as opposed to crimping butt ends on. But in retrospect I probably would have been better off just leaving the wire alone. The users manual calls for the crimp on ends, and in fact the short 10 gauge wire they provide already has those ends crimped on. Again, in retrospect, 10 gauge wire would probably have been best, but I ran the 8 gauge due to the length of run and to insure I could get the full amperage out of the charger. I will either need to run a separate wire to the battery's negative post from the boat side of the galvanic isolator, which I'd prefer not to do, or find a way to splice into that 8 gauge wire from the charger all ready going back to the battery. FWIW, the A/C wire on the charger uses the European color coding. Brown is hot, Blue is neutral, and green/yellow stripe is ground. I've got that all hooked up properly, with the hot and neutral wires going thru the switch (the marine switches I have cut the circuit for both the hot and neutral lines), and the ground attached to the ground bar that is connected to the boat side of the galvanic isolator.

So at this time, the isolator has nothing connected to the d/c system. Colby

I did run a wire from the boat side of the galvanic isolator to the earth ground pin at the bottom of the charger. Sounds like I should just remove that wire all together.

 

[thataway]

Thataway-
In your second and fourth sentence you refer to "ground terminal of charger",
would this be the chassis terminal ?
In your first sentence, the single point in an outboard engine boat would be at what place in the wiring ?
thanks

The terminal which I refer to is the silver one second from the left side (first is the power cord, then the Ground terminal, then 3 reds, each to a battery, and finally, the black wire to common negative.


"Chassis", might normally refer to an RV or car frame, I suspect you know that to be the metal "chassis" of the battery charger. This is correct. ABYC Section E refers to this. The wire connected would be the common ground system in larger boats which would go directly to a point which had contact with the water. On my C Dory, I have not used that terminal, since I have no "ground" or "bonding system". We find this "grounding" to be almost essential when there is HF radio in the boats.

ABYC E-11 in part:

"11.18.1. DC Grounding
If a DC grounding system is installed, the DC grounding conductor shall be used to connect metallic non-current-carrying parts of those direct current devices identified in E-11.17.2.3 to the engine negative terminal or its bus for the purpose of minimizing stray current corrosion..."

There are many more parts of ABYC section E.
E- 1.2 "DEFINITIONS
a. Ground - A surface or mass at the potential of the earth's surface, established at this potential by a conducting connection (intentional or accidental) with the earth, including any metal mea which forms part of the wetted surface of the hulL
b. Bonding The electrical connection of the exposed, metallic, non-current carrying parts to the ground (negative) side of the direct current system.
c. Common Bonding Conductor An electrical conductor, usually running fore and aft, to which all equipment bonding conductors are connected.
d. Bonding Conductor A normally non-current-carrying conductor used to connect the non-current- carrying metal parts of a boat and the non-current carrying parts of direct current devices on the boat to the boat's bonding system.
e. Engine Negative Terminal - The point on the engine at which the negative battery cable is connected...."

The DC Negative, ground, bonding and 110 ground system, should only met at one point--and generally that is an inboard engine block. With an outboard, this can be a single point near the outboard, and so connected to the outboard bracket. Many of our C Dorys do not have this done. It is a point of controversy in small boats.

Colby. I used #10 wiring in my boat--my run may be a bit shorter, but #10 wire will easily carry 25 amps anywhere you want in the boat with no more than 10% voltage drop. Yep, I know that you want to get everything out of the charger you can...but the 25 amps, or 22.5 amps, if you happen to have that max voltage drop with a 50 foot round trip run...is only going to be there for a short part of the charging period. OK--what did you do about the fusing?

I find that this chart from the West Marine Catalogue is the easiest to use. I also keep the Blue Seas charts laminated, handy for work on wiring.



Colby--I would not be "splicing" at any point. What you say, is that C Dory grabbed the most convenient point on the boat, to tie the 110 V "ground" on the back side of the galvanic isolator, to tie into the battery charger negative terminal. Not a good idea, but C Dory has frequently done that. I would set up a common point and not use the battery charger. This could be a single negative terminal, back by the batteries, and could include any hull bonding, negative battery cable, ground chassis, lightning ground, and the "ground" green wire from the isolator. As it is now, there is no protection in the boat. If you want to just take this to a thru hull fitting that would suffice such as a head discharge or the raw water wash down intake. If you wanted to do that on the battery charger, then you would use that "Ground terminal"--but have to set up a bonding system--/ground system etc...That would involve wire from the engine, the negative terminal of the battery, bonding thru hulls, etc...

Don't worry guys, this is one of the most controversial of all points in wiring a boat which has 110 V and an isolator, bonding. ground etc systems....

Yes, Colby I am aware of the European wiring system: When we cruised Europe it seemed as if I had to made a different pigtail for every marina we hooked up to for several years. I ended up with a box of different connectors. I had a 4 KW step down transformer, to get 110 volts for some appliances. Many items would not work with the 50 hz current frequency.

Finally one way to get # 10 wire to the smaller terminal of the Mastervolt charger, would be to use the male round fitting "bullet connector: and swage that to the #10 wire. (or if you had to use #8, cut a few strands off, so it will fit into the #10 fitting. Fill the end of the bullet connector with solder....probably easier to just cut some wire strands off the #8 (or use a step down crimp from 8 to 10 for your fuse holder, and then use the #10 wire...) Fusing the end of any of these with solder, and using heat shrink on the wire just before the connector, is what I do.

 

[colbysmith]

Bob, after reviewing your reply and doing a little more googling I think I sort of understand all this a little bettter. First off I did have to do some splicing back by the batteries to install inline fuses. I used those type that take a flat blade fuse and have a rubber cap. Unfortunately they use a 12 gauge wire but are rated to 30 amps. But very short run of wire so shouldn't restrict much current. I'm pretty sure my outboard has a grounding wire to its stern bracket and the engine should be grounded from the batteries negative terminal. I think I will just leave the chargers earth ground pin attached to the galvanic isolator and redo the 12vt negative line out of the charger so that it is also attached to the isolator. That will require a splice but with a proper connector I'll make it work. The end result will be both the boats a/c ground and d/c ground will be connected to the outboard motor. Im not sure why it's not a good idea to tie the systems together at the isolator. In the end it's all still connected to the engine by the lead going back to it. Rather all have their own individual wire or share a wire it still ultimately is terminated at the engine. Colby

 

[san juanderer]

Totally agree that this topic is controversal when mixing 120v and 12v electrical systems on a boat. It is not an ideal situation !

I have a Pro Mariner 1250P installed on my boat. This is a 50 amp charger,selected to charge a 430 ah house bank.

To quote from the installation manual; "Bonding stud A.K.A. Chassis Ground - This stud is connected to the boats bonding system as well as the Negative Bus Bar. This conductor is permitted to be one size smaller than the DC positive conductor. In the case of a DC to case fault, this conductor is critical in carrying the fault current to trip the fuse or breaker, the AC ground CAN NOT handle high DC amperages."

alan

 

[thataway]

I think I will just leave the chargers earth ground pin attached to the galvanic isolator and redo the 12vt negative line out of the charger so that it is also attached to the isolator. That will require a splice but with a proper connector I'll make it work. The end result will be both the boats a/c ground and d/c ground will be connected to the outboard motor. Im not sure why it's not a good idea to tie the systems together at the isolator. In the end it's all still connected to the engine by the lead going back to it. Rather all have their own individual wire or share a wire it still ultimately is terminated at the engine. Colby

This sounds as if you are going to make one ground point at a "splice connection"--how are you gong to do this with a single connector? (Somewhat rhetorical question because there are several ways, but not all best practice) You will then have a second point somewhere at the motor/motor bracket. Gives the possibility of a ground loop. Also if the isolator fails, there is the possibility of AC current flowing thru this wire--and thus a very dangerous situation. The path of least resistance is important. Also a ground fault interruptor should be installed, if not already done.

quote from an Oct. 15, 1996 article by Stan Honey in Practical Sailor:

AC Ground

See Practical Sailor August 15, 1995 for a detailed treatment of the green wire. The best solution is a heavy and expensive isolation transformer. The acceptable solution (for the rest of us) is to install a light and inexpensive Galvanic Isolator in the green wire, between the shorepower cord socket on your boat, and the connection to the boat's AC panel. Then, connect the grounding conductor (green) of the AC panel directly to the engine negative terminal or its bus.

Note that this meets the ABYC recommendation. In choosing Galvanic Isolators, make sure that you select one that has a continuous current rating that is at least 135% the current rating on the circuit breaker on your dock box. Certain Galvanic Isolators (e.g. Quicksilver) include large capacitors in parallel with the isolation diodes, which in certain situations theoretically provide better galvanic protection. Unfortunately, these units cost substantially more than conventional Galvanic Isolators. If you feel like spending real money on galvanic isolation, you might as well do it right and buy an isolation transformer.

I think the answer to why a separate connection, is that you want the path of least resistance to the "ground=water", in case stray AC current gets into the DC system (thru the galvanic isolator)...Thus a separate green wire to this single point--the engine bracket or block. How does AC current get thru that isolator? The diodes can fail/short. (Reason that an isolation transformer is a better answer--but rarely used because of cost and size of the transformer.)

Colby--I assume that the galvanic isolator is in series with the green wire between the plug into the boat, and the green wire going to the AC panel. (Stan Honey suggests the wire from the green wire common point on the AC panel, to the single point ground.) There is then a wire from the "boat" (after the isolator) side of the isolator to the negative on the old battery charger. We are talking about that wire--which really should be directly to the single point at or near the motor. The isolator goes in series interrupting the green wire. The "out" wire of the isolator goes to the AC panel and buss bar where all of the other green wires are attached. Then a wire goes from that point to the common ground--engine block. It sounds in your case as though there are two wires off the galvanic isolator side which goes to the AC panel--one going to the negative wire of the Battery charter--that wire should be going to the single point engine block...

In case you don't know who Stan Honey is--he is known in the boating world as a expert navigator, and having done the tracking/TV model/graphic feeds for the Americas Cup boats. In the Football world, he is the guy who invented the technology to put the overlay of the first down line (yellow) line of scrimmage, etc on the TV broadcast. (His wife Sally Lindsay Honey is a sailing legend in her own right--yachtswoman of the year 2x.)

 

[san juanderer]

The 120v system on your boat is most likely wired with 14-2 marine romex wire, which is rated at 15 amps. It could be 12-2 wire, which has a 20 amp rating. So the "green" ground wire would have to carry the amperage of a dead short of the DC positive wire to the charger case, at the point which you connect the case grounding stud to the galvanic isolator.
Many galvanic corrosion problems in marinas are caused by battery chargers failing while owners are absent.

 

[thataway]

Many galvanic corrosion problems in marinas are caused by battery chargers failing while owners are absent.

Absolutely correct. However, I am not sure that the tying in of of the ground will entirely prevent these problems. For example, I had sold a sailboat --and there had been a near by lightning strike, while the new owner was still staying at my dock. A lobe of the strike came thru the water, blew (shorted) the diodes in the regulator/and alternator on the engine. The result of this was the full output of the 50 amp charger going into the bonding/ground system. The new owner called me, and one of the questions I asked was if the alternator was warm--he didn't think it was. When I got back to the house, about a week later--the prop, prop shaft, thru hulls, rudder shaft etc all had severe electrolysis--in a little over a week. The boat had an excellent lightning protection system--on the mast! It had a galvanic isolator, properly wired, but of no value in this case, Since the back feed was thru the alternator was the cause of the DC powered electrolysis. The boat had just been hauled before the sale, for a bottom job, and again for a survey as the sale progressed, so we had photos of the condition of all running gear and thru hulls. After turning off the power, the first thing I did was put my hand on the alternator--yes it was "Warm"!

San Juanderer, Although I agree with the wiring size, and rating, Most of the boats are wired with proper Marine grade, stranded, AWG, tinned triplex copper wire each wire insulated, separately in an enclosing vinyl sheath or jacket. "Romex" brings visions of house wiring, and solid wire--plus most modern code requires at least 3 wires to each outlet in the house: hot, neutral and ground (which is a bare solid copper wire run in the jacket) Again, I don't think it is the wisest choice to put the ground from the AC panel in the boat, directly to the Chassis terminal of the battery charger--the best place remains a common point near the engine, or some direct water connection...I believe "Romex" is a specific brand, although we commonly use that term to refer to many types and brands of household wiring cable--which should never be used in a boat: : Southwire’s Romex® brand Type NM cable.

 

[san juanderer]

Romex was used in the context of the wire being vinyl sheathing covered.
Pro Mariner installation manual clearly denotes the chassis ( case ) stud being wired to the DC Negative Bus Bar.
Boat, water, 120v and 12v bad mixture.
alan

 

[colbysmith]

Lots of good info here, I think... Giving this a lot more thought, I think I'm making this harder than it needs to be. The wiring directions for the Charger do not show any part of it tied into the Galvanic Isolator. Nor does it even show the "earth ground" terminal attached to anything. So I'll remove the wire I installed between that terminal and the boat side of the galvanic isolator.

Now back to the 110 vt system. Isn't the whole idea of the galvanic isolator to keep stray current from coming onto the boat thru the shore ground line, yet closes the circuit if necessary to allow the boats stray current to escape back to shore ground? There are very few things on our C-dorys that would conduct electricity to the water. The outboard motor is about it. Unless you have a chain only anchor rode. Our hulls are fiberglass. The only thing that normally uses both A/C and D/C that would possibly short circuit across those two electrical systems, would be our battery chargers. In which case if that happened, the D/C system is already grounded through the engine.

What would be more advantageous in the case of stay current from a short circuit would be the GFCI. That will stop the current flow. The isolator just allows current on the ground (green) wire to flow to ground.

In retrospect, I question why we want to tie our 12vt and 110vt systems together at all. Colby

 

[thataway]

Colby,
You have hit upon what I do in my boat...that is a float the 110 volt ground, and have GFI on the plugs. We use the Honda Generator as much as any source of 120 volts when cruising--and it has its own issues, with a semi floating neutral.

Yes, ABYC is optional--and one of the options is not to bond and tie things together. If you are going to tie them together, then do it properly.

There is a paradox, because if you use the hot, neutral, ground wiring to the Mastervolt battery charger, then you have tied the charger "chassis" to the neutral I believe.

The galvanic isolator prevents stray DC current and miss-wired boats (where the hot and neutral are reversed--and thus the neutral and ground, become hot--and this can cause dangers on your boat--because the marina or other boats on the same "leg" of the circuits have been miss -wired. I check the marina wiring before i plug into it--to avoid that problem. I know that my home wiring is proper.

Back to an isolation transformer is better, but large heavy and costly, so you rarely see it on small recreational boats.

Alan, Yes, the ProNautic series Manual, shows the case ground going to a "Main Grounding Bus to Engine negative" (sic-manual)--which also has a leg to the neg terminal on the battery. As per suggested in ABYC. However, the ProSport series, do not have a chassis ground and no chassis wire in that series. This is pretty much the way that the less expensive "wet mount" battery chargers are wired. Any negative connection is thru individual battery cables, and the 120 AC mains, is thru the power cord.