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**Ex-Calif** · 18-06-2014, 18:48

I am a big pontificator and disseminator of advice around here.

It's a whole 'nuther story doing it for yourself...

I have 30 amp engine alternator and added 40w of uncontrolled solar. In my haulout (now refit) - I am going to rewire the boat. May as well make a wish list and design a new electrical system.

To make the boat more utile I am planning to add a/c - sleeping in marinas with no wind around here is too hot and sticky - so add shore power and a $400 a/c.

If I am going to be in a marina for 3+ days at a time add a battery charger to run the DC loads...

While I am at it upgrade the solar from 40w to 100w (a long time plan)

Battery bank due to space limits is going to remain 3 batts at about 210 a/h total. Might be able to get "taller" batts and up to around 300 a/h in the future.

Haven't finalized the energy budget but I am pushing at least 50a in a marina (more lights less nav) maybe similar underway (more nav less lghts) and a lot more on the hook (lights at night nav all day)

So I spent 8+ hours reading threads and doing internet searches for gear.

As I work the wish list using "top of the line stuff" that is "largely" over capacity for my needs I realize that I can soon exceed 50% of the value of my boat just for an electrical system I like - groan...

Take a simple decision like a charger - 15a oughta do it - at least 2 channel (house and start) But wait! In a marina for 3 days. Probably gonna need more lights chargers, iPads etc. for a lot longer than my daysail-deplete the bank-charge up all week cycle. Shoot maybe I need 20a so I can run all the stuff. What about a 30? So an initial $180 charger I drift into the $400-$500 range - yikes! - Big bucks for 4-5 "marina" trips a year! What 20-25 days (counting one longer trip) a year?

Ok - let's think about switching a bunch of stuff to LED - kaching!

Solar - 100w. Definitely gotta add a controller. MPPT? PWM? Reread all the smart guys web pages. They don't agree. The RV guy says pooh on MPPT for less than 600w (if you can't get past all his ranting and pick out the nuggets) Mainesail appears to be an MPPT advocate as are many around here, as am I - but now I am spending my boat bucks. Is the MPPT worth the boat bucks "in my case?"

Conotrollers are 'spensive.

Ok, now I got $800 or so in solar, $400 or so in a charger - Gotta get a monitor right ($450 worth of batteries to protect) - kaching!

My boat is "dramatically" underfused and underbussed (many wires direct to battery) add a couple of 300amp fuses (house and start), distribution busses, wiring, lugs j-boxes, expanded switch panel (too many shared loads at present) - $500-$800 in just this stuff...

Ok wire it all together - Hmmm... Charge the house and the start batt. Need switching to parallel them together - Solar and alternator underway, charger when plugged into shore. Maybe just add an ACR - kaching...

I will figure it out and design a system then I am going to ask opinions around here - stay tuned.

What I am learning is that it is easy to tell others what to do on a forum - harder to navigate these waters for real...

Oh - and add to all that the sourcing problem - We don't have West marine or Jamestown here. Can't run down and fondle all this gear. Gotta buy it on-line and ship it to a family member for trans-shipment or ship direct. Returns are a problem and forget to order something and you wait 2-3 weeks...

Oh - final tidbit - The RV guy (in the fine print) says get the battery monitor first - operate that for a while and see exactly what you use and do - then plan your supply system. I like this idea (and will likely start advocating it) but too late - my boat is disassembled and on the hard.

It would be great to have everything off, turn on a cabin light and see exactly what the discharge is. Turn the VHF on and see what the stand-by draw is? What does Otto really draw "on average?" The complexity I am finding with the energy budget is that the loads are either "rated" loads or a guess.

<sigh>

**skipmac** · 18-06-2014, 19:25

Yes, sigh. Sounds very, very familiar. Have been going through the same process for the last 4 years overhauling my boat. I think it just inevitable that any boat job is like opening Pandora's Box. More electric stuff needs more battery, more battery needs more charger, new this needs a new that to run it but why get the cheap this or that when a few dollars more gets you the good one.

At least in my case the plan is to live aboard and cruise for a few years so I can kind of justify the cost more so than for occasional weekend on board.

End of the day forget logic and whether or not it's cost effective. It comes down to how much you like the boat and how long do you plan to keep it.

**carstenb** · 19-06-2014, 00:10

I can only agree with the idea of installing a battery monitor BEFORE blowing all your bucks on the rest of the sytem (yes - unfortunately too late for you - live and learn)

I recently installed a battery monitor on my boat. Jesus was I wrong about what the various gadgets on my boat uses. The monitor lets you, as you noted, turn on one gadget at a time and see what happens.

Now you can make an accurate list of what you use and therefore what you need in the way of charging, batteries etc.

By the way - changing everything to LED is worth it. The "bulbs" last almost forever (no more need to cary all those spares) and your usage goes way down.

Good luck - I'm facing somewhat the same issues as I prepare our boat for a circumnavigation (sigh)

Salted · 19-06-2014, 00:25

Hi Ex-Cali,

Where might I also get an a/c for $400 please? thanks!

**Ex-Calif** · 19-06-2014, 00:53

Quote:

Originally Posted by Salted

Hi Ex-Cali,

Where might I also get an a/c for $400 please? thanks!

Unfortunately not a marine a/c. In our "walmart" equivalent I have found portable units like these -

7001 - 9001 - Portable Air Conditioners - Air Conditioners - Air Conditioners & Coolers - Heating, Venting & CoolingÂ*at The Home Depot

One states no need to vent it but I don't believe them and will design a vent.

The other non-marine item I am installing is a Coleman 12v "cooler" fridge. I actually already have that and it's been on the boat 3 years with no issue other than it kills the battery after a day and I need to run the engine alternator if it does continuous duty for 3 days straight.

Even if the A/C only lasts a few years I OK with that.

I am trading marina fee + ~$120 night for a room for marina fee.

On a yearly basis I am saving $2400 by sleeping on the boat. Some things can become consumable.

I am giving up most of the port settee to build cabinetry for the a/c and the fridge which I will now mount on it's back as a top loader - this way I can also add block ice if I want. Will have to siphon the water out though.

Oh yeah - As I hear the scampering of the scientists on the way to tell me about non-marine Alternating current items on board and how dangerous shore power is, I have considered GFI, polarity, stray currents - I just haven't reconciled myself on how fancy I get with the A/C power yet.

Seriously I am willing to hear cautions but I won't commit to "doing it right - damn the cost."

Part of me just says -

Carry the a/c portable drop it on the foredeck in port - Run a cord from shore power to the foredeck and in a two hole power strip plug in the a/c and a 600w inverter. Switch DC loads to inverter at shore and forget the charger and all it's complexities (and cost)

Where's that Excederin bottle...

Salted · 19-06-2014, 01:11

yup, thanks Ex-Cali,

I was figuring it was one of those portable jobs, but I've not come across any locally for S$400, not even US$400. Neighborhood shop prices are around S$7-800-ish for a 9-10k btu?

**Ex-Calif** · 19-06-2014, 01:18

BTW here's the Coleman.

Amazon.com : Coleman PowerChill Thermoelectric Cooler with Power Supply (40-Quart) : Coleman Coolers Dc : Sports & Outdoors

It does have some serious drawbacks.

- It is continuous duty and the motor runs continuously
- It says 4amps @ 12v. 96 amps a day - yikes! But I honestly don't know what it really draws
- Run for days straight it will likely end up failing
- It only professes to draw down the temp 40f from ambient and it's really hot here

Here's what I have learned about it and what I plan to do.

- It does keep stuff (food) at an acceptable temperature - We generally have a cooler on board for ice and drinks
- I have a simple LED battery voltage gauge that plugs in a lighter socket. After 10 hours my 140 a/h house bank will be down in the red - Auto, instruments, stereo, VHF and fridge all drawing. That's like 7 amps/hr and based on the stuff running seems about right.

Things that will help

- Block ice in quart bags to help out - no water cleanup
- A simple timer that cycles the thing off and on?
- incorporating some sort of insulation in the back that I am planning to make?

Again this boat is a weekender/campervan. Not an ocean cruiser/liveaboard.

I can deal with some compromises.

**Ex-Calif** · 19-06-2014, 01:23

Quote:

Originally Posted by Salted

yup, thanks Ex-Cali,

I was figuring it was one of those portable jobs, but I've not come across any locally for S$400, not even US$400. Neighborhood shop prices are around S$7-800-ish for a 9-10k btu?

Oh - I just note you are in Singapore.

They have them in Giant. My boat interior is really about 7 X 20 X 5 = 700 cu ft.

I am planning to get a 7-8,000 btu unit from Giant and on sale are around $399-$450 Sing.

I go to Sebana Cove and Nongsa regularly - when the boat is together - LOL. And sleeping on board is miserable. I have slept on the hook up the Johor River and there is just enough breeze (depending on time of year) to sleep - but Marinas? Forget it.

**Dockhead** · 19-06-2014, 01:58

Familiar story indeed

And I have found advice of others on here to be incredibly valuable when I faced similar questions.

First of all, like most boat things, you will have to put aside a realistic budget to do it right. Or better not start. You won't be able to do this for a few hundred bucks.

Second, I suggest you set priorities. Very first I thing I would do is get rid of every incandescent light on the boat, including nav lights. In my opinion it is idiotic to work on increasing capacity before you've rationalized consumption. The other big consumer is refrigeration, and if you have a power hog reefer system, you should correct that before going on to supply side questions. "Power hog reefer system" means refrigeration which uses an air cooled condensor and/or which is poorly insulated. If you have to change it out, I would go for one of those cold plate systems with the controller which freezes the cold plate when system voltage shows there is abundant power. In my opinion the best water-cooled condensor system is the Isotherm SP which uses direct seawater cooling of the condensor without a seawater pump.

Next question -- do you need an inverter or not? I don't know how you use your boat, but as I live on mine at least 1/3 of the year, I find the inverter to be absolutely essential. It means you have constant AC power on board to run the household, which for me includes microwave, nespresso machine, kettle, vacuum cleaner, multiple charging devices for all kinds of electronics, power tools, etc., etc., etc. Mine is on 24/7 and I have uninterrupted AC power, BUT -- I have battery capacity for that (420 amp/hours x 24v, equivalent to 840 in 12v). You'll have to decide yourself whether an inverter makes sense considering existing or desired AC consumers versus existing or feasibly increased battery capacity.

If you do decide you want an inverter, then I strongly suggest that it should be integrated with the charger. You then get a whole useful world of control over your power, especially, the ability to control the amount of AC power you take from shore power or generator and to supplement that if necessary with inverted battery power.

On a small boat like yours, you can probably cover any power needed at anchor or on the mooring with a Honda suitcase generator, a cheap, easy, and convenient power source. Just set it up on the swim platform and run it once or twice a day to charge batts, maybe at the same time you have heavier AC loads. Here the power limit function of a charger/inverter is extremely valuable.

If you decide to stay spartan and do without an inverter, then of course you will save a lot of money and complexity. Even Victron battery chargers without inverters are cheap; the Sterling ones are also supposed to be good. You will want enough capacity to charge your batts at a reasonable rate, especially if you plan to use a generator of any kind. So the charger should really be 20% C or so; with a smaller bank maybe even 25% C, so maybe 30 amps with your present bank (which I would increase if it's not outrageously inconvenient or expensive, if I were you).

As to busses, panels, and so forth -- do not skimp. Any weak link in the system will bite you in the butt at some point. Make sure you have a master fuse in the system somewhere -- usually in the negative side of the main battery box. It will be irritating to have to make an investment into this invisible part of the system, but do it if you have to.

As to battery monitors: I have found the amp-counting kind to be fairly useless for determing state of charge. The shunt which measures the current for such montors allows them to tell you the momentary consumption provided there's no charging going on at that moment. This is a somewhat useful datum. But if all you need to know if how much individual items of equipment consume, you are much better off putting a DC clamp meter on the individual item. So if you decide to forego that type of monitor, you will avoid having to install the shunt, which is a PITA which requires you to cut one of the main battery cables, and you can use the Smartgauge monitor which analyzes voltage patterns to give a much more accurate estimate of state of charge. I don't have one of these, but I am convinced that this is the superior system for monitoring batteries, after having evolved from a few years of using an amp-counting shunt-type Victron monitor to throwing that away in disgust and moving to analyzing voltage patterns myself by looking at a simple volt meter, which has given me much better results. I am planning to install the Smartgauge when I get around to it. If you go this route, don't buy it from Balmar, who sell it with their usual markup; rather buy it VAT-free by mail order from one of the UK distributers. Here is the mfg website: SmartGauge Electronics - Homepage

Don't forget to think about isolation transformers, if you're going to be hooked up to shore power a lot. I have the Victron one; avoid it -- it's crap. At least the one I bought; maybe they've been improved.

Getting electrical power right is very satisfying as it really transforms life on board -- if you spend a lot of time on board and really live. If you don't -- just an occasional night at anchor or odd weekend in some marina -- then maybe it's really not worth screwing around with too much. Only you can decide that.

**Ex-Calif** · 19-06-2014, 03:02

Excellent post and intellectually I agree with you on just about everything.

One key is use of the boat and other goals. This is a weekender/week at a time "campervan" and I can rough it a bit.

Think of it as an RV with 80% RV Park hook-up time and 20% off-grid (3-day stretches)

Goals

- Improve the safety of the electrical system - I am underfused and underbussed for sure
- "Very" comfortbable sleeping at marinas 25 days /yr
- Comfortable for 3 days at a time on the hook (max 5) - Spacewise I can't provision or keep ice longer than that (assuming 2 people) and after that it's no longer "fun" - it's survival.
- Learn about these systems - Honestly I can go more minimalist than this but at this "size boat" I can buy a 15 or 20 amp charger instead of 60amp one and be making "cheaper mistakes. 100w of solar and PWN vs. 1000w of solar andn MPPT. Foul up a $400 battery bank instead of a $1,000 one

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