Charging Systems

[Hurleyburly]

If I've got a system with two 110Ah 'leisure batteries' one 60Ah starting battery, 40 Amp alternator, wind generator and 2x 30ish Watt solar panels what do I need in between to control it all in the way of regulator / monitor ?

Just starting to think about liveaboard electrical supply, so any advice appreciated.

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[mdrifter]

How about an Adverc running from the alternator to 3 output diode splitter? LVM do a "dual battery" (+add-on for 3rd battery) charge controller for their Aero/Aqua gens - this has a dump load to prevent overcharging from Aero/Aqua and if can also be used simultaneously to control Solar Panel output via Schottky diode(s). LVM may send you circuit drawings...

For "shore" supply: Solatek 30A spike/surge suppression and lo/hi voltage monitor feeding 30A/100mA RCD to, say, 2 MCB's of, say, 16A & 10A. Use 16A for "ring" circuit and 10A dedicated to 12V charger/power supply such as HiTec 12V/25A.
Google with "solatek" for their web site.

Now for the "contentious" bit: do not connect the shore ground/earth, use only shore L & N. Have a separate hull "ground plate" used only for AC ground/earth - do not simply wire AC ground/earth to your anode.

Perhaps there should be a sparate thread about AC earth/ground on boats....I don't know enough about it but have seen anodes where the Zn was pristine and the bolts wasted...and 3rd immersion heater being installed...

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[AlanPound]

I'd reckon on the Adverc smart Alternator regulator. Adverc have some useful material on their web site, including circuit diagrams of various configurations, including multiple battery, and both single and twin alternator setups.

http://www.adverc.com/technical/technical-boat.asp
http://www.adverc.com/technical/technical-twin.asp

But I would certainly not recommend leaving the earth connection off. If galvanic isolation is your concern, then buy a galvanic isolator, or alternatively, use a big fat bridge rectifier (connect one AC pin to ship earth, and one AC pin to shore earth (leave and - n/c), and parallel the bridge rectifier with a small value Mica or similar capacitor for RF grounding) in series with the earth ship-shore connection.

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[snowleopard]

first figure out your battery requirements, i would think 220 AH is a bit on the low side. basically aim to have the total electrical demand for 24 hours equal to 1/3 of the domestic battery capacity. the biggest battery eater is refrigeration.

secondly, run the domestic batteries in parallel as a single bank, not as two separate banks. the reason for this is that your batteries will last a lot longer being 1/3 discharged each day rather than 2/3 every other day. any more than 50% discharge drastically reduces battery life.

finally, use a smart regulator, run through a splitting diode, to charge both domestic and start batteries. adverc and sterling regulators have a sensor wire to measure the voltage at the battery. this compensates for the voltage drop through the diode. it should be connected to the domestic bank, not the start battery.

don't expect 40A out of a 40A alternator unless the battery is flat. you'll normally only see about half that during bulk charging.



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[Paul_H]

This stuffs common knowledge from a variety of souces, but how to choose between Adverc vs Sterling vs Driftgate etc. They all claim to be the badgers nadgers and belittle one anothers systems but they cant all be right.
What's folks experience with this stuff before I spend my hard earned on a dud.

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[stretch33]

Im' in similar position wirh regards putting all this together, l have 3 110 batts + 70 starter batt, got wind genny etc. Keep the info coming trying to glean as much as poss. Gives me brain ache reading all the bunf about makes of regulators, boosters etc.etc
Phil (electrically numb)

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[snowleopard]

don't know about the driftgate but here's the poop on adverc & sterling. strangely, they work on totally different principles:

sterling use a conventional 3-stage charging program, i.e.
1) constant current bulk charge, i.e. a 30A charger will provide a steady 30A until around 80% full
2) constant voltage charge to bring it up to 95-100%
3) float charge: hold at lower voltage to keep it topped up.

adverc pushes out a steady 14.4 volts, dropping it to 14.0 for 5 mins out of every 20 to reduce gassing. there is no float charge phase. this means that if running the engine for a long time you could cook the battery unless you put a load on the system to draw off a bit of current.

i have the adverc and despite having 2 x 55A alternators the best charging current i ever get is around 32A and once the batteries are 80% charged this drops to <10A

My sterling shore power charger which works on the same logic as the regulator does exactly what it says on the tin.

i had to scrap a bank of batteries after 18 months use. can't say whether the adverc is to blame, other people are quite happy with them.

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[Alex_Blackwood]

Earlier this year my pal and I fited a Rutland 913? wind generator and a Rutland RWS 200 Charge Regulator to his boat, battery capacity a bit smaller on liesure side but similar on engine and same size alternator. The RWS 200 will charge two battery banks (Run your liesure batteries in parallel). It also has a connection for 60watts of solar power. As it also incorporates blocking diodes you can connect it straight to the batteries. It contains a shunt regulator which prevents the batteries from gassing and cooking!
The RWS 200 is available from RS components (rswww.com) you can also download the technical info from them as well.
Rutland are to be found at Marlec Engineering, Rutland House Trevithick Rd.
Corby, N,hants NN17 5XY. Tel 01536 201588. They do have a website but I don't have the details to hand.
We didn't use the solar connections but the system works well, although the geny needs 10knts wind to get about 2 amps charge. The 200 is about 300mm X 225mm.
I do however think that if you were living on board and had a constant heavy drain on the leisure batteries you could have problems keeping them charged via the wind geny and solar panels especially on dull days and light winds. You really need to balance your charge capacity against power drawn.

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[pvb]

Not sure about that...

The Sterling claims are a bit bewildering. I suspect they are trying to blind people with science, and that the products aren't as good as they reckon. For example, they claim that their alternator regulator is a "constant current" device (as you've said), but there's no way that the device can monitor the current. Also, you can't push current into a battery bank if it doesn't want to take it (as you've found with your system). The Sterling literature has a diagram showing that a 90amp alternator can pump a steady 95amp current into a 300Ah battery bank for an hour and a half; I don't believe this is a real world possibility.

On the other hand, the Adverc claims are quite straightforward. Their product is extremely well-respected by both private users and local authorities. You mention gassing, but if you use maintenance-free batteries it won't happen (because of their lead-calcium chemistry).

In your own case, I'd suspect your battery bank isn't big enough to benefit fully from your alternator capacity. I have a 660Ah bank, and rarely see much over 75A charging current from a 90A alternator with Adverc control. My batteries (Delco Freedom maintenance-free) are over 7 years old.

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[timevans2000]

I have a very similar set up as you. Two 110Ah caravan batteries (£45 each new), one 110Ah spare battery (I use domestic bank to start the engine), I have the standard Yanmar supplied alternator, what ever that is, no clever alternator controller. I have 2 Uni-solar 64 watt panels that give excellent output in poor sunlight. I have just ordered a Duogen and a new fridge (water cooled condenser).

I control the output of the panels using an electronic 4 stage controller. This is very effective ans we have never needed to charge the batteries with the engine in 2 years of cruising. The advise I have has is keep the solar regulator I have and just switch the Duogen on when needed. We also have a smart electronic battery monitor that permanently tells you input/output in amps and amp hours remaining

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[Phil]

What modern 240v requires an earth these days? Wouldn't a decent twin pole trip switch be perhaps even more effective, especially if going abroad where pos. and neg. are often the wrong way round as they tend to put a circuit breaker in both pos. and neg. feds as they don'y use ring mains as we do.

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[JEG]

I have some experience of electrical installations and would take the view that to omit the earth & rely upon the rccd is NOT sensible. Rccds are excellent, but infallibility is extemely rare [westminster excepted]. I recommend "boatowner's mechanical & electrical manual" by Nigel Calder.

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[saturn]

wow, i lived and worked (electrical industry)in med for 10 yrs and did'nt come across any incidences as you put it and if i was worried i would check it out before connecting. maybe its time sea boat installations were inspected in the same way as canal boats are,now thats really contentious.
reckon i will have to ask about a boats wiring before i accept an offer to "come aboard".
imho take care with 240 volt on a boat, i use common ground with a £70 galvanic isolator.
all the best.

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[mdrifter]

My system does have an earth/ground - it's just not the marina/shore one - the boat's AC earth/ground is to a below the waterline ground plate; it could just as easily be a separate lump of zinc or a copper plate dropped over the side and into/below the water, to which all AC earth/ground connections are made. Yes?? No???
I have heard that "people" just connect N and E/gnd together...that doesn't seem to be a good idea. The 30mA RCD has a "test" button regularly pressed...Of course 110V via an isolation transformer would be even better.

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[AlanPound]

Yes, you will get a ground of sorts from that - maybe (probably) even enough to trip a 30mA breaker. I think the aim though is to get the best quality ground, and the availability of a Marina supplied Earth connection *should* be the best choice (yes, I know they can't always get their Live/Neutral round the right way!)

Regarding equipment without earth connections - these are all so-called 'double insulated' devices, which have been engineered to be virtually immune from the possibility of an internal fault causing the external casing to become live (most often having entirely non-conductive cases). I can't quite envisage how you could make a boat like that...

... Essentially, the assumption is that the Earth and Neutral are connected together *at source* (ie. back at the substation or last step-down transformer). You should not have these connected together on the boat, as that would be a pretty sure way of causing stray currents and causing galvanic problems. (You can often measure a few volts of AC between Neutral and Earth wire.)

The only time you should consider connecting Neutral to Earth, is when you have an on-board Generator, in which case the connection will usually be made at the generator (so when you switch to shore power, you rely on the connection already made upstream at the supply). You probably don't need to think about this with an installed generator (as it should have been done at installation), but you will need to think about it if you use a small stand-alone petrol genny plugged into your shore cable (as it will usually have an isolated supply)...

Alan

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