Impossible decision regarding charging

[Bob666]

Hi!

I am in a deadlock situation. I was hoping the nice community here could help me choose?

I need to do something about the charging = alternator + regulator + batteries.

Currently refitting a 37 feet sailboat. Going for ARC.

Current config:
Volvo Penta 2003 B with original 50 A alternator. 300 Ah housebank. Will add 400-500 W solar panels and possibly a wind generator.

Proposed config # 1:
An expert from the cruising community, well-known and reputable, recommends exchanging the original alternator for a Balmar, Mastervolt, Eletromaxx etc + external regulator and + temperature sensor.

Example:
Mastervolt - Innovative power systems<br>for autonomous use

While doing so, upgrade to at least 100 A charging current. Must reprogram the alternator or regulator (haven't figured out which, perhaps both), which, the expert states: requires high skills!

Most mechanics in Marina Workshops look puzzled and "never heard of the idea" (so how find somebody to do the reprogramming?). Not many other long distance cruisers recommend this, at least not ones I've been in contact with.

Proposed config # 2:
Keep current alternator. Purchase the Sterling up to 130 A:
Alternator to Battery Chargers up to 130A | Sterling Power Products

Recommended by long distance cruisers and forums. More often recommended than config # 1.


Ambition level:
Or should I write "budget and time constraints".

Not much up to the task of programming stuff, don't really know how to. Not much up to the task of modifying engine mounts for a Balmar, Mastervolt etc alternator. Unless absolutely necessary.

Ambition level says go for Sterling. But if config # 1 is way much better than # 2 I just might go for that. Also, I am not that interested in electrical systems. Want to do things right but at the bare minimum. Everything electrical should work 100% automatically.

People in forums mention building their own charging systems including shunts at the battery side to measure current etc. Great, but don't have time or interest.

Which config (#1 or #2) is more KISS by the way?

I can imagine a config # 2 B by the way. There exists upgrades to the original alternator, 70 A and 100 A. Same mounts!

Would I be better off with one of those + Sterling? Or is the idea of Sterling that the original alternator will do? But shouldn't I get faster recharge of drained batteries with more current, eventhough there is a Sterling unit?

Cheers

[woodenboats]

More than a hundred of my customers chose #2 or #2b - never heard of an unhappy customer. Upgrading the alternator may reduce charge time, but do not overestimate the effect.

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[sailorboy1]

I would do option "3".

Upgrade you battery bank to something closer to at least 500AH so you have more storage to take advantage of your proposed 400-500W of solar and possible wind generator. Start with the solar only till it is proven to yourself that wind is even worth doing (I decided it wasn't).

Then go cruising!

The only time the higher output alternator will really help is if you didn't have sun for a few days and then decided to run the engine to recharge. In which case a higher output alternator would speed things up, but only till you got to around 80-90% state of charge and then the batteries are only going to accept what the 50 amp alternator can provide anyway.

I have 460AH battery bank with 290W solar and that does 90+% of my electrical needs and that is with the refrigerator on all the time. If I were to sail for days and not have any sun I would have to run the engine, but that's not normally the case.

[Adelie]

So with 300 a-hr capacity you should be drawing the battery down 150a-hr max before recharging.

Assuming no solar or wind charging then bulk charging by the alternator stops at 75% so you will run the 50a for 90min before tapering off charge rate. A100amp alternator would save you 45min every time you need to use the engine to recharge. A bigger alternator will not speed up absorption or float charging unless you go to Lion batteries which is a whole different situation.

If you are consuming 50a-hr/d then you need to recharge every 3rd day max, 75a-hr/d every 2nd day, 150a-hr/d every day.

So what happens when you add solar panels? Let's say you add 400w nameplate capacity. The rule of thumb is that daily amp-hours produced from solar panels is 25% of name plate capacity in watts. With a new MPPT controller you might get that up to 30% or so. Let's stick with 25% here, it's a conservative value to plan from.

So with 400w solar you get 100a-h/d supplied on average and you wouldn't need to recharge ever if you average 100a-hr/d consumption. In reality there will be low sun periods where you fall behind and here will be periods when you have extra demand which will also cause you to fall behind. Let's say once a week you need to recharge to keep from falling below 50% so you are saving 45min once per week by getting a high capacity alternator.

But really it's less than that because you may incur added battery maintenance and system maintenance with the higher capacity. But the big one is can you get parts in remote locations or will you spend lots of time dealing with shippers and customs (as well as money for duty) if you get the higher capacity? There is something to be said for equipment that can be fixed locally in 3rd world countries.

A lot will depend on you usage, if you have A/C really you need a dedicated generator (2kw or so).

If you have a refer that's well insulated and not too large you may be able to keep usage under 100a-hr/d.

With a large or poorly insulated refer you'd probably have to be conscientious about the rest of your power consumption to stay under 100a-hr/d.

Unless you had pretty high demand I would stay with the stock alternator with a dumb regulator, with spares for each, bump the solar to 500w if you can find convenient mounting and if you can find the space bump the batteries up to 400a-hr.

If you are a moderate demand user with no refer you should be just fine with the current system.


A house is but a boat so poorly built and so firmly run aground you would never try to refloat it.

[Capt. Arnaud]

I would also go for option 3.
Have as much as LED lights as possible, this will make a big difference in consumption at night when the solars don't generate power.
500W of solar is a lot so make sure that your battery bank is big enough to store the energy otherwise you will spill a lot of generated power during the day.

[tkeithlu]

I've self-installed the Balmar alternator AR-5 regulator combination and programmed it to my large battery bank. The programming is not wonderfully user friendly because you are doing everything with one reed relay and a pencil magnet, but if you read the instructions carefully and plan ahead it's doable. The biggest trick was extending the period of time that the alternator charges away at 14.7v to match size of the battery bank. As delivered, I think that was 14 minutes, not several hours as I needed. You can do it.

[Adelie]

Originally Posted by Capt. Arnaud

500W of solar is a lot so make sure that your battery bank is big enough to store the energy otherwise you will spill a lot of generated power during the day.

Excess power supply is a minor problem. Excess storage could be a problem. If your supply is marginal for the amount of demand, you will be constantly using the battery in a partial state of charge (PSOC). PSOC use leads to sulfation, Gel and AGMs are especially vulnerable but even regular FLAs don't like it. They all like to be topped up to 100% as often as possible.

If money is an issue and you can only get an extra battery or panel but not both then get the extra panel.



A house is but a boat so poorly built and so firmly run aground you would never try to refloat it.

[StuM]

Originally Posted by Adelie

So with 300 a-hr capacity you should be drawing the battery down 150a-hr max before recharging.

......

Unless you had pretty high demand I would stay with the stock alternator with a dumb regulator, with spares for each, bump the solar to 500w if you can find convenient mounting and if you can find the space bump the batteries up to 400a-hr.

If you are a moderate demand user with no refer you should be just fine with the current system.

I agree with these conclusions. Excellent analysis.

[Rapanui]

I would agree with the consensus analysis except for one thing, the OP says he is going for the ARC. Daysailing and at anchor he should be fine. He has not indicated what other consumers he has but when he is sailing 24/7 there will be the potential additional loads of instruments, chartplotters, autopilot etc all presumably working 24/7 as well. That could easily be another 100+ Ahr/day on top of fridge etc. 500W of solar would not keep up with that on its own so the OP will be faced with running the engine periodically to keep up, or increase solar, or power conservation measures. Running the engine early in the morning when batteries are at their lowest charge and highest acceptance would work, but he would need a plan B if the engine or alternator packed up.

[Neptune's Gear]

Just another note. The Vp 2003 standard has a single v belt. To change up, and go over about 80 amps alt, you'd have to change the belt system to twin or to a flat belt.
Personally I would go to a direct fit, hot rated alt of about 80a with a smart charger, and leave the belt as is. Charging performance is WAY better, when you need the alt to do it, and you will.
I have a 2003T, and this is what I've ended up with. But I only have 250W solar and wind. 400 AH house bank. Works pretty well, now done over 30,000 NM with this setup. Pretty happy with it.

[Sandero]

I suggest...

smart charger regulator, 100 amp alternator, large capacity batts, solar and or wind...with monitor... maybe engine drive refer instead of 12v.

[out42]

Feels to me like the OP might do well to consider a towed generator rather than potentially tricky alterations. On the ARC power use will be continuous and if the boat is big(ish) then the drag of a towed generator will be relatively minor. They are not as noisy as windgens and can be lifted out of the water if the solars are doing their job.

[coastalexplorer]

Hello,

All this electrical explanation is very interesting, My red seal qualified electrician sailing buddy Peter all ways says "Do not trust me to wire a flash light". So my comments are about the 2003 Volvo Penta. Now granted that mine is an early model which would have been an 'A' as opposed to a 'B' which is a designation that they did use to differentiate.

Thus my first point is that unless they changed it on the later versions the accessory drive pulley on the crank shaft has four bosses already tapped to bolt on a second pulley so that two alternators can be run. this course of action thus would not upset the revolutions counter.

My second point which I discovered by experience is; That it is the impulses from the standard alternator that work the rev counter on the standard Volvo control. Since the alternator that came with the engine when I received it was determined by Colin's electric of Vancouver BC to be non repairable. Colin supplied an A C Delco 104 amp alternator which was cheaper than the Paris/Rhone Valeo Volvo replacement.(55amp/hour?)

Back at the workshop this did not run the rev counter, So I sent it back for modification. (this is a point that I understand the OP Bob666 was asking about?) So when I collected the alternator back big surprise the rev counter needle moves but the result did not look believable.

Consultation with Volvo Canada gave the specifications for the pulley dimensions. Colin changed the pulley to the closest one he could find. I ordered one from Volvo, for $36 but ended up sending it back because it can not be fitted to the different manufacture of alternator. To obtain a perfect reading I will have to either have one custom machined, or live with the minor error. because is is not only the 76 MM diameter that is important: as it is the profile of the Vee grove that has to match also.

(check your transmission spline to damper fit. Good insurance to call Next Wave Marine systems Inc for a sure drive)

https://www.dropbox.com/s/eixuwb7c85...drive.mp4?dl=0

[Fuss]

how many amps does your fridge and freezer use in 24 hrs?


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[mitiempo]

Originally Posted by Fuss

how many amps does your fridge and freezer use in 24 hrs?

Don't you mean amp hours?

Nomenclature is important.

A 2 amp load uses the same 2 amps in 1 minute as it uses in 24 hours.