Electrical System

[Charlie]

Hello All:

I'm trying to decide on how to set up my charging system. I have 4-6 volt golf cart batteries and I'm assuming about 440 ah. I don't know what my consumption is going to be. I have 8 cabin lights, GPS, Windlass, am going to add 4 fans, anchor lights, running lights, VHF, SSB, and a washer/drier and two rambunctious kids. I also have a watermaker that is engine driven but I was thinking of converting it to run off of either 12v or 120v. The previous owner said that the W/D ran off of a 1200 watt inverter. I don't believe him.

Here is my dilema. The boat is 1000 miles away and I don't get to sail her very often - - enough --.

I looked at adding a high output alternator but since my engine is still under warranty am limited to an 85 amp Hitachi. I don't think it will put out near 85 when hotprobably closer to 50. Also the cabling running from the engine room to the batteries would need to be upgraded. When all is said and done I figured that it would be better to add a genset and a 3 phase battery charger.

Here's my reasoning.

1) With an average consumption of 150 amps a day it would take two to three hours to charge the batteries. That is alot of hours to put on an engine just for charging.

2) The genset I'm looking at only consumes 1/5 of a gallon an hour. (don't know if it is truebut that's what they say)

3)The cabling reqd. to run from the engine compartment (where the genset will be kept) to the batteries a distance of about 15' would be #8 or #10 wire for the genset to a smart charger positioned within a few feet of the batteries. The cabling for the alternator would be 2/0.

4) The genset (Next Generation ultra compact 3.5 kv) is capable of running Air Condi 16000 BTU. Don't have Air but may want it some day.

5) It's nice to have 120v to run tools, vaccum, W/D, trash compactor, coffee maker etc.

6) I can use electric heaters on the boat while I keep it in cold climates (It is going to stay in Sidney, BC for at least a year before we go south.


Okay go ahead and poke holes in that reasoning. I can take it.

So assuming my reasoning is sound (and even if it isn't) what kind of smart charger would you install. Ample Power, Xantrex, Iota, or ?

[btrayfors]

Charlie,

Nothing wrong with your reasoning. Makes sense to me.

I have a similar setup, though with a 110A Balmar alternator on my Perkins 4-108, and a Balmar MaxCharge regulator.

I also have a newish NextGen 3.5KW generator...about 2.5 years old. It's in a sound compartment, and has been very reliable. Much more reliable than an older and smaller Kubota-based DC generator I had for 12 years or so.

Only observation I'd make is that the four golfcarts and 440AH is probably not quite enough. I had the same for awhile (and, in addition, a separate 220AH golf-cart battery bank dedicated to my windlass), but since I added another two house batteries to give me a total of 675AH I'm much happier. I get about 3-5 years out of the Trojan T-105s.

Re: a battery charger, there are a couple of ways to go. If you're thinking of just a charger, one of the best and least expensive is the Iota series. They actually make battery chargers for a number of other "brands", are extremely well engineered, have a very good frequency tolerance (good for use with generators), and have an advanced pulsing circuitry which extends battery life. They come in different sizes: 15A to 90A, and you can combine two identical models to double capacity. For your setup, I'd suggest either a 75A or a 90A model. You can find them on eBay. Associated Industrial is a pretty good vendor. Be sure to get them with the optional IQ-4 regulator which makes them a smart charger.

If you want to get a bit fancier, you might think about a combined inverter/charger. Some of the larger inverters have large smart chargers integrated. Not sure I can recommend Xantrex these days; have heard some not-so-nice things about their products recently, and their engineering staff. The best one available is the Victron, made in Holland and not well known in the U.S. I lucked out last year and found a brand new one here for half-price: a 2,500 watt pure sine wave inverter with an integrated 120 amp smart charger. This unit is absolutely top shelf: I've never seen such engineering on U.S. products. Being a ham with lots and lots of electronic gear, I've seen plenty, and NOTHING comes close to the Victron. My friend and colleague has two of them aboard his 60-footer.

Just a few thoughts....

Oh, yes..almost forgot: I have two air conditioning units, a 16,500BTU unit and an 11,000BTU unit. The NextGen can easily run either one of them and, in a pinch, can actually run them both for a short time.

For planning purposes, though, I'd de-rate the NextGen a bit to factor in heat, especially when in the sound-shield and in a hot engine compartment. Figure a maximum load of about 25 amps @ 115VAC.

Bill

[Charlie]

Thanks Bill:

I didn't make it very clear but I do have a inverter its a heart 1200 watt. Have to run through some more tests to see if it works. I'll have a chance to do that in January. Good to here you like the Next Gen. I'm going to put it in the engine compartment so I don't see a need to get a sound enclosure. I'm going to be repowering at the same time as I add the genset so when I have the engine pulled I'll put in all new sound proofing and such.

Have a question off topic--trying to decide how to test for shorts and or bad wiring on my new to me boat. It is 25 years old but built to a good standard. I am thinking of buying a megger to test for shorts. I can use it at home as well. Or should I just test for voltage drop?

[btrayfors]

Charlie,

Amazing coincidence: I had a Heart 1200 watt inverter for many years, before I replaced it with the Victron. It's sitting on my workbench now, waiting to go to my son who just bought a 42' sloop.

Mine has a built in 45A charger with an adjustable voltage knob on the front. It worked well, but puts out a lot of RFI (radio frequency interference), and is undersized for my 675AH house battery bank, except for dockside use.

Two thoughts:

1. If you're gonna repower anyway, why not install a bigger alternator on the engine and a smart regulator? I can't believe there's no way to get around the "warranty" issue on the engine. This would certainly be a lot cheaper than the generator you're planning, and might be sufficient depending on your style of cruising. And, even if you are going to install the generator, it's a very good idea to have a high output alternator.

2. For troubleshooting your electrical system, yes, you certainly could use a good digital multimeter. Fluke makes several models which aren't too pricey, and which are reliable. For guidance on the overall system, I can highly recommend Nigel Calder's book, the "Boatowners Electrical and Mechanical Manual, 3rd Edition". If you don't have this already, be sure to get it: it's "the bible".

Good luck,

Bill

[Charlie]

Thanks for the reply Bill:

What a coincidence on the equipment we have. I have two digital multimeters one is an AEC (made in Korea) clamp on that reads 600 amps DC - hope I never see that number on my meter- and the other is a Sperry. I saw your post on SSCA about the accuracy of multimeters (after I bought the AEC)and how a small percentage of inaccuracy would make quite a difference on a twelve volt system. Started me thinking I should spend the money on a Fluke.

I am also considering buying a megohmmeter b/c it will let me test the insulation of individual wires and I am under the impression that it will tell me about bad crimps etc. Gord May's thread on Ohm's Law made me think about the fire hazard of bad wiring and I've already found some splices that are so badly corroded that they won't operate the switches.

[DeepFrz]

Hi Charlie;
It's been a long time since I have used a megger but I don't think they have much use on a boat except maybe to test the AC wiring. Firstly, all equipment has to be disconnected or you will likely destroy it, possibly including switches (talking about 12 volt ccts.). I think that a good digital VOM as Bill describes and an infrared thermal gun should be all you need.

A good visual check for corrosion to start with and then a thorough testing of the ccts feeding your high current devices, such as bilge pumps, autopilot, masthead lights, cabin lighting, alternator, starter and windlass (to name a few) will get you started and feeling confidant. Systematically check all ccts and replace any splices and connections that show any sign of deterioration, using the methods that Gord May has detailed above.

As noted in the linked article good splices don't have a detrimental affect on the cct. so it may not be necessary to replace your wiring when a cct. needs repair. If it ends up to short you can splice in a section to give you the length that you need.

By the way, you might want to practice making a few splices and testing them out before you tackle the boats wiring. For cleaning connections you can use the 3m abrasive pads, just be careful you don't remove all the tinned plating.

The thermal gun can be used to check the connections in a cct. under load for any heat buildup. A calibrated torque driver will allow you to tighten the screw connections without breaking the screws and a coating ot anti corrosion spray on your electrical panel will keep things in good shape for a while (after you have finished the testing and repair).

It is a whole lot of detailed work which is probably why the electrical system gets neglected on so many boats.

Have fun, and good luck.

[Charlie]

Thanks Deepfrz:

I might cause more problems than I find with a megger. The infrared thermal gun sounds like a good plan. The heat build up is what I am worried about. I'm looking forward to this little challenge.

[GordMay]

Charlie:

I got your PM, and thought I’d reply publicly, as you pose excellent questions, which are generally relevant to all of us with “older” boats.
As I no longer do consulting [and certainly not for free ] I’ll keep my comments more general, than specific.

Originally Posted by Charlie

“... I have a new to me boat that was built to a good standard in 1985. I have found a few connections that were so corroded that they didn't work. After reading your article I am concerned that some of the wiring on the boat may have high resistance and therefore be a fire risk. What is the best way to tell whether or not it is necessary to replace the wiring, circuit breakers, and other electrical components.

These are the ideas I have formulated so far:
a) Test for resistance on each wire?
b) check for voltage drop on live wires?
c) Its that old it should be replaced or
d) is there something completely different.
Wheels has suggested using a megohm meter to test the insulation. I was wondering if that would also test the splices and terminals.

Also can you recommend a specific brand and model of crimper. I don't want to think about it. Also do you know where you can get the shrink wrap terminals at wholesale prices?

If
~ the ‘85 boat was truly built to “good standards”
~ and the “few corroded connections” were truly few in number
~ and located in “vulnerable locations” (bilges, battery boxes)
you may not have a generalized wiring problem.

It’s difficult to advise, without examining the boat, when a complete electrical refit might be justified or required. Notwithstanding, I’m not generally in favour of “stop-gap” repairs, unless a discrete etiology (for the fault) is self-evident.

A boat built to “good standards” would have tinned marine wire, of adequate gauge (both unlikely, but possible in 1985), tinned terminal blocks, terminals, & etc (not bare Cu), dedicated Negative return wires (no “commons” nor Gnd. returns), among many other “quality” features.
These features should be visually apparent, and wouldn’t require extensive technical testing. “Bad” wiring is a bit like pornography, hard to define - but I know it when I see it. If the wiring doesn’t look right, it almost certainly isn’t.
A simple “look & pull” test might reveal bad terminations.
(My Wire Sizing Chart < http://www.cruisersforum.com/gallery...age.php?i=1321 >gives minimum “Pull-Out” force for differing wire sizes).

Like DeepFrz, I wouldn’t recommend a megger for amateur use.

By definition, Wholesalers generally only sell to the trade (those selling to users being Retailers). I do recall an earlier CF discussion, which revealed some excellent West Coast sources.

Any “rachetting” crimper should suffice, but the best model might be one offered by the terminal manufacturer.

I listed some recommended products at the end of the “Ohm’s Law ...” article
< http://www.cruisersforum.com/forums/...read.php?t=372 >

and some links to on-line catalogues at
< http://www.cruisersforum.com/forums/...ead.php?t=6043 >

HTH,
Gord

[Charlie]

Thanks Gord:

I appreciate your comments. Perhaps what I need to do is look at the boat's wiring with your comments in mind. I've purchased a non touch thermoneter and will use that to identify any particuilarly blatant problems with the wiring. The places where I did find corrosion were not in the bilge. One of them was the wiring of the switch for the propane solenoid (located in a protected area of the lazeret) and two others were the cigarette lighter sockets (also not in extreme corrosive areas)