Meeting 12 volt power requirements

[Petercatterall]

I've had lots of good advice from you guys on this and other subjects.
It is noted that all our requirements are different but I thought that I would set out my proposed way ahead for comment/advice.

1, change my old AC11 alternator for an A127 ?
2, Possibly then consider a Sterling or similar 'smart' regulator ?
3, Fit a 15amp solar panel and regulator for top up whilst away ?
4, scrap the 3 way fridge (which was not vented) and replace
with a 12 volt compressor chest which I will also use
in my camper van.?
5, buy a 'Halfords type' charger say 25amp and just clip on when
required ?
6 Buy a 'cheapo' small (say900watt) generator for use with small hand
and for emergency starting.
7 Will consider bigger solar panals later in the season.

Bear in mind that I have no money and like things simple!

Is this a reasonable stratagy.

 

[Talbot]

If you have little money (know the problem) why are you considering changing the fridge for one that doesnt work as well. Yes the 3 way jobs dont work well on 12v and use lots of power, but they do work well with LPG. I have had one fitted for the last 17 years and been very happy with it. You do have to consider how to vent, (and while doing this make sure you clean the soot out of the circular tube at the back of the fridge and it will work much better)., but this is not an impossible problem.
The money saved will allow the purchase of a bigger panel, which will be much more effective, and you will actually use less electricity anyway cause you wont be trying to run a cool box. You will need a regulator for this, but best to buy one that will fit the amount of panel that you want later.

 

[seacat]

An A127 was fitted to my last boat and delivered loads of amps.
I fitted a Sterling regulator and was so impressed I am fitting one to my new boat.
I have a Waeco (I think thats the right spelling) fridge/freezer - depending on how far you wind the thermostat - which also works brilliantly (cooling beer, tonic, milk butter - in that order) providing there are enough battery volts to start it, which is where the more powerful alternator and Sterling regulator come in. Providing the battery bank is big enough (min. of 1 x 110ah - 2 x is better)) and engine can be run to top up the battery then we have found fridge power consumption to be not a problem.
Not sure how this is done on no money though. Please tell me - we're broke too with lots to do (and buy on the 'I want' list)

 

[roger]

I have the Waeco fridge kit (supply your own box and it works well. Whatever fridge system you use make sure you have enough insulation 35mm. of polyurethane as minimum.
Chargers with transformers are usually voltage sensitive. With a lot of foreign electricity being nominal 220 v and lower at the end of the pontoon an ordinary charger may be disappointing. The smart chargers are much better.
If you just want emergency engine start then one of those portable power packs might be adequate. They are smalll and cheap.

 

[aidancoughlan]

number (5) - "buy a 'Halfords type' charger say 25amp and just clip on when required ?" I dont know what a Halfords type is (is it a car charger?), but if its of interest... I've been looking around at 'smart' chargers for shorepower charging, and the cheapest smart charger I've seen is sterlings pro-budget at £99 - from the detailed sterling blurb I got at the boat show, this seems like a full multi-stage charger @ 20amp, except you clip on with crocodile clips & it only charges one bank at a time.

ps. A question for anybody with the Sterling or Adverc regulators - How long does it take to get into the later phases of charging? ie. apart from overcoming voltage drop in split-charge diodes, how much advantage is the 'smart' part of the regulating - how long do you have to run the engine to get into the later phases.

 

[halcyon]

If you fit a relay unit instead of diodes, you get rid of the volt drop problem, then your into do I need a smart regulator if I don't reach the smart bit.

Brian

 

[Joe_Cole]

[ QUOTE ]
Is this a reasonable stratagy.

[/ QUOTE ]

I do wonder if you are overdoing it a bit, but without knowing what you are trying to achieve or what problems you are having at the moment it's hard to comment objectively.

 

[john_morris_uk]

The voltage drop problem across splitter diodes isn't a problem so long as you have a voltage sense wire back to the alternator.

The question as to how long a Sterling (or any other smart charger) tales to get into the absorb phase is not dependent on the charger but on the physics of the battery. The surface charge of the battery is very quick - high amps and fast - the next phase is slower because the electrons and the chemical reaction have to migrate through the outer layers of the battery plates.

The thing that smart chargers are good at is ensuring that the battery is charged at as high a rate as possible whilst monitoring the voltage to ensure that damage doesn't occur.

The physics of a Halfords type transformer-rectifier charger are stacked against you charging a battery bank in a very fast and efficient way. It will work, but it isn't very fast.

 

[pvb]

The one thing you haven\'t mentioned....

The one thing you haven't mentioned is increasing the size of your domestic battery bank. Adding extra batteries to the domestic bank is the most cost-effective upgrade you can make to a boat's electrical system. A bigger battery bank accepts charge more readily, and (for a given use) will last longer because the batteries are not discharged so deeply.

 

[Joe_Cole]

Re: The one thing you haven\'t mentioned....

Not necessarily. Adding more batteries won't be any use unless the power input to the battery bank is sufficient. A properly balanced system is essential if the batteries are to give their best.

 

[Thistle]

Isn't the cheapest solution to reduce your electrical needs? Can you get rid of or do without a few gadgets so that the existing system will provide all the amps you need?

(Sorry if this seems a rather facile reply but I do believe that unless you think carefully about your present and future needs, the system you end up with may still not be able to cope.)

 

[fireball]

It does sound like your asking if a 5 ton lorry is enough .... enough for what? From what your describing it sounds like your going to be living aboard the boat....

The last boat we (ok father-in-law) had had a single leisure battery and a spare car battery pulled from a cavellier whose crank shaft broke, these were charged (when we actually got the alternator wired up correctly*) by a volvo MD5a .. the boat was used most weekends and powered a GPS unit, depth gauge and lighting as well as starting the engine and was more than sufficient for the boats needs....

Why do you need to change your alternator? Is it because you were changing to a 12v coolbox?
why do you need a smart regulator? if your short on funds then judicial switching of the batteries is sufficient and lasted us ok...
if your on a 3 way fridge - why change - just sort out the vents, a 12v cool box isn't as versatile and more hungry on the power.
I guess you want the halfords bit when you've got shore power ... handy bit of kit, but really nessersary?
900w generator?! Jeeze - we spent a night in Gunwharf, Portsmouth and a training "Ship" berthed on the outside, it had generators running ALL NIGHT - with the radar going and gawd knows what else ... why? Because they couldn't be arsed to turn it off? - anyway ... erm - with solar panel and smart regulators and halfords dubary ... is this really nessersary? You've got a s*dding great generator with your engine and new alternator ...

It does sound like your intending to live aboard this boat - in which case you might well need all that ...


*the leisure battery lasted for 1/2 season starting the engine before it gave up - this was after a full charge on-shore charger to no charge at all and cranking the engine for some time at each start ....

 

[William_H]

As already commented on a lot depends on whether you are living on board and if so at a marina with shore power or on anchor. If not living full time on board then how often will you visit. Solar is great for those who go for long periods without visiting as it can keep batteries healthy. The low power of solar is not worth the trouble/expense if you are living aboard or visiting frequently. Certainly not if you have shore power available. So shore power is cheapest and best. Engine charging provides a lot of power but if you don't want to run the engine for long periods ie you sail a lot or remain at anchor then a smart charger will reduce the engine run time if it is run just to charge the batteries. On shore power a cheap Halfords charger is fne but needs to be carefully managed and will not be a turn on and forget. providing you have a dedicated /isolated engine start battery a 900 watt generator is not necessary.
So I suggest you wait for summer and start using the boat in the manner you expect to continue to do so with just your engine driven alternator and isolated batteries. I do agree a compressor fridge will be far better than the absorbtion type certainly more powerfull quicker to get cold. Add a shore power charger if you have shore power available and see how you go. Monitor voltage current and usage closely. The next step if you find you have flat domestic battery is to add another battery then if necessary the smart charger. Only if you need to leave unattended for long time should yopu consider solar and then probably no regulator.
I think the regulators are a con. On a reasonable sized battery a manageable solar panel could never danmage overcharge the battery.
regards will

 

[Anonymous]

Will, I suspect you misread his post...he is talking about fitting a 15A solar panel -which is very large and must be used with a regulator as the open circuit volts of these panels can be as high as 19V so there is sufficient potential to continue charging at high levels with a battery voltage in excess of 14.6V. I would have thought that a 15A panel would be very useful even for a liveaboard. It's a serious piece of kit. Unless he meant a 15W panel (i.e. around one amp) but even then I wouldn't want to leave it unattended without a regulator.

David

 

[Petercatterall]

Sorry, yes I did mean 15watts, I thought that the regulator was advisable if not essential.
One of my concerns is that I'm going onto a mooring this year,no shore power and I want to self reliant any way!
The small genny is not intended to be permanently on the boat but perhaps I would take it if I was able to spend a long period aboard this year.
Thanks to all for the advice

 

[pvb]

Re: The one thing you haven\'t mentioned....

Almost without exception, leisure boats have insufficient domestic battery capacity compared with their charging ability (and their needs). Many owners spend hundreds upgrading alternators, expecting a 90A alternator to push 90A into a couple of weary 110Ah batteries - it won't. My point was that the most cost-effective upgrade is adding extra batteries. Traditional concepts of the "ideal" ratio between alternator and battery bank size are unproven; it's possible to greatly increase the battery bank size with only beneficial results.

 

[Anonymous]

Re: The one thing you haven\'t mentioned....

I totally agree with one proviso....it is essential to get a full equalising charge into the batteries every few days - i.e. 14.3V for an hour or so. That's hard to do on most sailing yachts unless you have regular shore power, solar/wind, or are prepared for you and your neighbours to suffer the generator running for hours.

 

[Gordonmc]

Could you outline your venting arrangement, please Talbot.
I have a twoway which I only use on 12v. Although I got the fitting kit with the fridge, I couldn't work out a way of venting without putting another hole in the hull or deck. I did think of running a pipe and tee-ing onto the Taylors 28mm chimney. Would that work?

 

[Petercatterall]

I have the same problem, plus there is a fair amount of heat going up the 'flue' on gas. I was concerned about that and the length of vent to get the fumes outside in a reasonable position.
I use mine on 1 volts and it is very power hungry so decided to go for the compressor chest option. Cant work out why a 12 volt compressor is so expensive though.