Solar Effectiveness - Great Lakes

[StuM]

You all knew this was coming!

Bob: > we get an average 1KWh charge per day

Rod: > 650 Wh / sunny day (just a slip in your case, you knew that. )

[ramblinrod]

Originally Posted by StuM

You all knew this was coming!

Bob: > we get an average 1KWh charge per day

Rod: > 650 Wh / sunny day (just a slip in your case, you knew that. )

Now that's funny. After I posted I thought OMG the UoM police will come after me, but I was doing a buck forty on the 401, and thought better of editing it.

Thanks for diligently calling on us to be more accurate stating Units of Measure. ��

[marty9876]

Many thanks for all the input. I had not thought about the longer days compared to the tropics, nice offset to some degree.

To address some questions - boat has refrigeration. Leaving the panels on over winter keeping the batteries topped off and running a small fan would be great. Seems risky, something going wrong and draining the batteries but I'm sure there is a solution for that. The cost of fixed is daunting to do right with the metal work ($2500?)

Part of my desire for for this is electrical independence and the peace and solitude that comes with that. Challenge, as pointed out, is making the best use of the boat dollars one has and the risk/reward for electrical independence for weekending/week long stints is tough to swallow.

[Boatwright]

"the real week spot in my system in Ontario was the psoc walk down due in part to lead acid batteries inability to accept a high rate of charge"

??? Lead-acid batteries will accept a high rate of charge. The limiting factors are battery and alternator temperature, and battery cable voltage drop. Lead acid batteries actually prefer higher charging currents -- low current charging contributes to early sulphation. Most so-called deep-cycle marine batteries are nothing more than relabeled auto batteries. True deep-cycle batteries such as those used in golf carts, solar systems, and cruising yachts have much thicker plates, and are designed to deliver moderate currents of 50 to 100 amps over longer periods, tolerate deep discharge cycles, and also to accept similar charging currents.

I suspect your battery charging problem is with the typical automotive type voltage regulator unfortunately found on most "marine" alternators. These regulators are designed to recharge automotive type batteries. They will deliver high current for a short time to recharge after starting, quickly taper off to a low current, and to provide voltage regulation with the engine running and with typical auto vehicle loads.

Unfortunately with these regulators, for sailors who want to use available alternator output to recharge in a reasonable time, a house battery discharged to 12.4v - 75% will quickly take a surface charge, the system voltage will climb to 13+v, and the regulator will taper off to a trickle. The result is long charging times, chronically undercharged and eventually sulphated batteries.

After installing larger alternators (still with auto type regulators) in two different cruising sailboats, and true deep-cycle Trojan batteries, we still had the same problem. We finally invested in a quality Fluke DC AmpClamp ammeter to figure out what was going on and discovered that with the batteries at 75% (50AH discharge), ten minutes after engine start the alternator was only putting 5 amps into the batteries. After 30 min, 2-3 amps!

Solution: SMART VOLTAGE REGULATION. You can go with a high quality Balmar setup which includes their proprietary smart regulator $$$$. Or as was chosen for our problem a quality aftermarket alternator with a Sterling smart regulator and battery isolator $$. This regulator also comes with battery and alternator temp sensors. With a 105 amp rated alternator this system delivers 60-70 amps to the batteries at fast idle from our 18hp Volvo, and in 30 minutes brings the batteries up to a true full charge after a typical day at anchor.

The reason solar works is 200 watts of solar on a sunny day will deliver 50 AH or more (equivalent to many hours of engine time with an auto type regulator) . Also AGM batteries will not by themselves solve the problem for all the above reasons. Both battery types have advantages and disadvantages.

FYI: Sterling has several informative videos on charging and batteries on YouTube. Search: "Sterling Power Limited".

[ramblinrod]

Originally Posted by Boatwright

"the real week spot in my system in Ontario was the psoc walk down due in part to lead acid batteries inability to accept a high rate of charge"

??? Lead-acid batteries will accept a high rate of charge. The limiting factors are battery and alternator temperature, and battery cable voltage drop. Lead acid batteries actually prefer higher charging currents -- low current charging contributes to early sulphation. Most so-called deep-cycle marine batteries are nothing more than relabeled auto batteries. True deep-cycle batteries such as those used in golf carts, solar systems, and cruising yachts have much thicker plates, and are designed to deliver moderate currents of 50 to 100 amps over longer periods, tolerate deep discharge cycles, and also to accept similar charging currents.

I suspect your battery charging problem is with the typical automotive type voltage regulator unfortunately found on most "marine" alternators. These regulators are designed to recharge automotive type batteries. They will deliver high current for a short time to recharge after starting, quickly taper off to a low current, and to provide voltage regulation with the engine running and with typical auto vehicle loads.

Unfortunately with these regulators, for sailors who want to use available alternator output to recharge in a reasonable time, a house battery discharged to 12.4v - 75% will quickly take a surface charge, the system voltage will climb to 13+v, and the regulator will taper off to a trickle. The result is long charging times, chronically undercharged and eventually sulphated batteries.

After installing larger alternators (still with auto type regulators) in two different cruising sailboats, and true deep-cycle Trojan batteries, we still had the same problem. We finally invested in a quality Fluke DC AmpClamp ammeter to figure out what was going on and discovered that with the batteries at 75% (50AH discharge), ten minutes after engine start the alternator was only putting 5 amps into the batteries. After 30 min, 2-3 amps!

Solution: SMART VOLTAGE REGULATION. You can go with a high quality Balmar setup which includes their proprietary smart regulator $$$$. Or as was chosen for our problem a quality aftermarket alternator with a Sterling smart regulator and battery isolator $$. This regulator also comes with battery and alternator temp sensors. With a 105 amp rated alternator this system delivers 60-70 amps to the batteries at fast idle from our 18hp Volvo, and in 30 minutes brings the batteries up to a true full charge after a typical day at anchor.

The reason solar works is 200 watts of solar on a sunny day will deliver 50 AH or more (equivalent to many hours of engine time with an auto type regulator) . Also AGM batteries will not by themselves solve the problem for all the above reasons. Both battery types have advantages and disadvantages.

FYI: Sterling has several informative videos on charging and batteries on YouTube. Search: "Sterling Power Limited".

Our opinions differ on this.

My understanding is that standard lead acid batteries only accept 25% of their capacity in charging rate, when HUNGRY.

So if one has a 400 A-hr standard lead acid bank, the maximum acceptance rate is 100A, WHEN SEVERELY DISCHARGED.

As the SOC increases the charge rate decreases.

I liken it to a hungry man set before a feast. Initially, he devours food quickly, and as his hunger is satisfied, he consumes more slowly, until the last few bites he can force in are painfully slow.

If one has a 400 A-hr bank with a Hitachi 80 A alternator with internal regulator, at 50% SOC they are likely to charge at a rate of 50 A-hrs, for the first hour, bringing them up to 62.5% SOC, for the next hour 40 A-hrs, bringing them up to 72.5% SOC.

Having a larger alternator or smarter regulator for charging above this point, doesn't do much good, because no alternator is going to put in more than about 30 A-hrs for the next hour, and even less after that.

Trying to charge batteries fully with any alternator, while sitting on the hook, is a fools game of diminishing returns hour after hour. While motoring or motor sailing all day, any alternator will bring the battery up to 80% or a little higher.

So, if one uses the alternator for Bulk charge only, (up to 75%) and solar for the balance, the big alternator with smart regulator does little for the money paid (which could be up to $3000 by the time engine mods and installation are considered.)

If one uses alternator only (regardless of size and type) it will be a rare day on the hook to bring the bank up above 80% from 50% (unless one just loves the sound of the diesel running while at anchor).

Whereas if one leaves in the trusty Hitachi internally regulated alternator, and puts half that money into a solar charging system, they are way better off, charging to 100% most sunny days.

If the current alternator is significantly under 80A, then a higher output alternator isn't a bad idea, definitely for a live-aboard, but for a weekend and vacation warrior, I would still go 400W solar vs 200W solar and high output alternator, if the choice had to be made due to budget concerns.

For a weekend and vacation cruiser (with daily consumption above 50 A-hrs), I recommend focusing on solar before other energy production methods, for the basic reasons that it is solid state (non-mechanical), low maintenance, silent, and effective. The only real drawback is the need for unshaded real estate for mounting.

If one is using batteries with higher charge acceptance rates (AGM, GEL, or L-ion) then a high output alternator is warranted (for full-time anchored live-aboards and cruisers, (where these technologies are readily available for replacement when needed).

I have yet to see compelling evidence warranting a change from 12 Vdc batteries to 6 Vdc batteries for most marine applications, or from a stock alternator to a high output smart one, for 6 or 12 Vdc standard lead acid batteries.

Full Disclosure - I sell and install marine batteries, high output alternators, wind generators, solar charging systems, and all associated equipment.

[Boatwright]

Rod,

The Sterling system overcomes the surface charge problem by analyzing the battery state of charge at the beginning of the charging cycle, and then applying a constant current level for a calculated time. It overrides the internal alternator regulator and applies the necessary field current according to its own algorithm. It only tapers the charge current at the very end of the charging cycle. In practice we are seeing 90%+ SOC after a 30 - 60 minute charge cycle with a 105 amp rated alternator which is putting out 60-80 amps at a fast idle. The daily energy budget with all LED lighting and no refrigeration is ~40 AH / day. The system is working so well we are considering adding 12v refrigeration.

My understanding is the Balmar system uses a similar design. Advanced design AC dock-power chargers also use this strategy during their bulk charging phase. Our dock charger puts out 30 amps during bulk charging.

You are correct about the 25% rate of charge. The battery bank is 4 T-105 Trojans rated at 400+AH -- so no problem there.

[ramblinrod]

Originally Posted by Boatwright

Rod,

The Sterling system overcomes the surface charge problem by analyzing the battery state of charge at the beginning of the charging cycle, and then applying a constant current level for a calculated time. It overrides the internal alternator regulator and applies the necessary field current according to its own algorithm. It only tapers the charge current at the very end of the charging cycle. In practice we are seeing 90%+ SOC after a 30 - 60 minute charge cycle with a 105 amp rated alternator which is putting out 60-80 amps at a fast idle. The daily energy budget with all LED lighting and no refrigeration is ~40 AH / day. The system is working so well we are considering adding 12v refrigeration.

My understanding is the Balmar system uses a similar design. Advanced design AC dock-power chargers also use this strategy during their bulk charging phase. Our dock charger puts out 30 amps during bulk charging.

You are correct about the 25% rate of charge. The battery bank is 4 T-105 Trojans rated at 400+AH -- so no problem there.

Any smart charging system, maintains a constant charge current (limited by the maximum batteries will accept) during the "bulk" charging stage (to about 75 or 80% of charge.)

At 50% SOC (~12.2 Vdc resting), the max your bank will accept is less than your 105 A alternator can deliver. The batteries just won't accept that much.

As the SOC increases, (the batteries become less hungry) the acceptance rate decreases, so at 60% (~12.3 Vdc resting), 105 A is less warranted, 70% (~12.4 Vdc resting), even less yet, and so on.

The smart regulator switches to the "Absorption" (constant voltage) stage (around 80% SOC, ~12.5 Vdc resting), the charge current starts dropping off even more dramatically. It is at this stage (or sooner) that you are better to shut down the engine and top off with solar, rather than continue to charge with any alternator, smart or otherwise.

The gains you claim to be experiencing at a high SOC with your alternator, are highly unusual.

I'm not suggesting for one second you are not being untruthful, but perhaps mistaken in your SOC or charge rate beliefs.

For example, you have not stated in this post what you believe your SOC is when starting the engine.

If the bank was fully charged via shorepower, you have a 400 A-hr battery bank, and are consuming 40 A-hr per day, you are only discharging to 90% SOC (12.6 Vdc resting) in 24 hours. That you are still at 90% SOC after 30-60 minutes of alternator running, is clearly the indicator that your alternator is adding very little.

If you were at 80% SOC to begin with (~12.5 Vdc resting) and after 60 minutes you were at 90% (~12.6 Vdc resting) SOC, that would mean that in that hour, your alternator only put in 40 A-hrs, which even for a 105 A smart regulated alternator, sounds very high approaching 90% SOC.

Even maintaining standard lead acid at 90% SOC on a regular basis, and rarely bringing them up to 100% is terrible for batteries. Which is why, solar is almost essential, if you are not connected to shore power.

An alternator, standard auto type, or high output with smart regulator, is just no good at topping up batteries, unless motoring 8-12 hours day every day.

This is why given the budgetary choice of:

A) Dumb 80 A alternator with 400 W of solar
B) Smart 105 A alternator with no solar

I would recommend option A) every single time.

Of course if there were an option

C) 105A alternator with 200W (more expensive than option A or B)

..this would be a possible solution.

However in my opinion, option A) would still be the preferable solution.

In your case, with 40 A-hr day consumption and 400 A-hr storage, you could ride out 5 no sun days (extremely rare except in UK spring or BC winter) before hitting 50% SOC, and on a sunny day, you would produce 2.5 times your consumption, so the batteries would be back up to 100% in just 2 days.

In your case, with a 400+ A-hr bank, and daily consumption of only 40 A-hrs, I would recommend the stock alternator and 200 W of solar. Only on overcast days, would the smart alternator be of any benefit, being slightly reduced run-time. If you were tempted to go to a high output alternator, I would steer you to adding 200W more solar, for a fraction of the cost, zero noise, less wear an tear on your expensive to replace diesel engine.

Beware that those selling "Marine Stuff" are motivated to sell "their" marine stuff. For example, if a supplier manufactures and sells alternators at high margin, and resells or rebrands solar and/or wind at low margin, rest assured they will promote the alternator solution above all else.

I make about the same margin on everything I resell.

Installation for any solar, alternator, or wind solution is about the same, so I have no other motive than what solution is likely to result in the best value to the customer (based on initial cost, ongoing cost, performance, reliability, maintenance, and comfort).

Solar beats high O/P alternator, hands down, almost every time, for a typical size, lead-acid battery bank on a cruising boat.

[StuM]

Originally Posted by ramblinrod

Any smart charging system, maintains a constant charge current (limited by the maximum batteries will accept) during the "bulk" charging stage (to about 75 or 80% of charge.)

...

Solar beats high O/P alternator, hands down, almost every time, for a typical size, lead-acid battery bank on a cruising boat.

+1

You've explained the situation very nicely.

To me this is the crux of it:

"If the bank was fully charged via shorepower, you have a 400 A-hr battery bank, and are consuming 40 A-hr per day, you are only discharging to 90% SOC (12.6 Vdc resting) in 24 hours. That you are still at 90% SOC after 30-60 minutes of alternator running, is clearly the indicator that your alternator is adding very little."

[Boatwright]

Hi again,

With our energy budget and 400 + AH battery bank we typically have to recharge every three days when we see resting voltage down to 12.4v.

I am unclear as to why you think 90% + SOC (12.7v) is bad for batteries if a high current bulk charging cycle starting at a 75% SOC is followed. Keeping batteries around <90% all the time could lead to sulphation - but we're not doing that. We do also do an occasional 100% balancing charge cycle when motoring with no wind.

I understand that standard voltage regulators start tapering as soon as battery surface charge brings up the system voltage, resulting in chronically undercharged batteries -- but we're not doing that either.

I also understand the benefits of solar -- just don't like the panels cluttering up the aft end of the boat.

You really should check out the Sterling eqpt.

[CharlzO]

I'm just going to jump in, since I missed it I think. I don't know the in's and out's by any means. However, my first question to the OP, was your energy budget, and what you anticipate your needs to be during your trips.

I had mine on Ontario, and used a cheaper Renogy 100w rigid panel on my stern rail, feeding a pair of GC2 batteries from Sam's Club (golf cart batteries). I mainly weekended when I was there, and used it for LED cabin lights, a 7" chartplotter and VHF radio that were both on constantly, and then using a 12v outlet to charge phones and an inverter to run a 24" LED smart-TV to stream at night or for others to watch underway. The only time I ever even started to run down, was after I inadvertently caught something on the wiring into the controller and pulled a wire loose, and even then didn't realize until my VHF turned off on me. But even then, it had been that way for a few weekends of use, and those batteries held up. And the solar had no issues topping me off easily through the week when I wasn't using it, if it hadn't already by Sun evening.

But that's also with no fridge, and not using a huge draw of everything else. So mileage will vary, but given an appropriate sized array for your energy usage, I'd see no reason why it shouldn't be fine throughout the season.

[admiralslater]

in my post #13 I neglected to mention that I am powered by 2 9.9 Yamaha ob as originally specd by PDQ .They produce almost nothing but great torque and reliability with no fuel usage . That is the reason that I am going to switch to a high acceptance battery and get a bigger smarter Bc. I am on a mooring with little access to shore power .My usage is very in relation to capacity (50%) I Don't really want to increase the bank size due to weight considerations.

[ramblinrod]

Originally Posted by admiralslater

in my post #13 I neglected to mention that I am powered by 2 9.9 Yamaha ob as originally specd by PDQ .They produce almost nothing but great torque and reliability with no fuel usage . That is the reason that I am going to switch to a high acceptance battery and get a bigger smarter Bc. I am on a mooring with little access to shore power .My usage is very in relation to capacity (50%) I Don't really want to increase the bank size due to weight considerations.

Non comprendez?

If you are not on shore power (with a significant battery charger) and running outboards (without significant alternator) what charging system is going to benefit from high acceptance rate batteries?

On the rare occasion you connect to shore power?

Why not add more solar to meet your energy demands and keep your standard lead acid batteries topped up all the time.

[ramblinrod]

Originally Posted by Boatwright

Hi again,

With our energy budget and 400 + AH battery bank we typically have to recharge every three days when we see resting voltage down to 12.4v.

I am unclear as to why you think 90% + SOC (12.7v) is bad for batteries if a high current bulk charging cycle starting at a 75% SOC is followed. Keeping batteries around <90% all the time could lead to sulphation - but we're not doing that. We do also do an occasional 100% balancing charge cycle when motoring with no wind.

I understand that standard voltage regulators start tapering as soon as battery surface charge brings up the system voltage, resulting in chronically undercharged batteries -- but we're not doing that either.

I also understand the benefits of solar -- just don't like the panels cluttering up the aft end of the boat.

You really should check out the Sterling eqpt.

OK, so I am not on your boat, and can only use my prior experience and knowledge to apply to your scenario, but it just isn't adding up to me.

What I understand of your system is that you have a 400+ A-hr standard lead acid bank and starting from full 100% charge on shore power charger (12.8 Vdc resting) after 3 days of no power generation you have depleted the bank to 12.4 Vdc (believed resting and 70% SOC). This would mean that you have drawn off 30% of (at least) 400 A-hrs, or 120 A-hrs.

You then claim (by prior post) that your 105 A alternator with smart regulator is recharging your batteries to what you believe is 90% (12.6 to 12.65 Vdc resting) by 80 A-hrs in 30 to 60 minutes.

In my experience, this simply is not possible and defies immutable laws.

To charge that size bank by that amount with a smart alternator takes about 3 hours, due to rapidly diminishing acceptance rate of the batteries and the regulator transition to "absorption mode".

If your batteries won't accept the charge current your alternator is capable of delivering, you simply can't put it in that fast.

So I really do believe that your SOC values are incorrect. (Probably, what you think is 70% resting voltage to start charging, is actually loaded voltage (and resting voltage is closer to 75%), and what you think is 90% resting voltage at end of charging, (is actually closer to 85% charging voltage) meaning that you are only replenishing the bank by 40 A-hrs.

A 105 A smart alternator charging a 400 A-hr bank from 75% to 85% in about an hour, makes sense to me. 70% to 90%, not a chance.

If you only do this the odd weekend, and then recharge the batteries back to 100% on shore power, no problem. If you do this regularly and only charge to 100% occasionally, that is what is bad for batteries (irrecoverable sulfation).

This is why solar on the hook is so important, getting those batteries back up to 100% every day (or at least almost every day).

I am familiar with smart regulators in general but not Sterling Products in specific, but unless they have devised a way to overcome immutable laws, high (constant) current bulk charging stops at around 75% and declining current "constant voltage" stage runs from around 75% to 95%, then switching to float voltage (13.6) to 100%.

I completely understand dislike for the appearance of solar panels on a classic vessel and we are struggling to keep our 1975 Douglas 32, aesthetically appealing and yet make her comfortable for extended cruising. Therefore, a compromise is called for; flexible panels on a hard bimini aft of the boom, over the poop deck.

[admiralslater]

I will explain Ramblinrod. Our Pdq 36 was built with the usual comprises speed versus comfort etc. We chose speed, consequently many decisions went the direction of weight reduction. Including the charge system of 150 watts of solar going through an mppt to two 6 volt Trojans. We run the fridge from launch till haulout for about 100 amps in 24 hours. This of course is a poor set up. After learning more about batteries because of the Outremer I realized that an adjustment was needed. Since the LA will not accept high amps for very long straight solar was not going to work in this situation. However my thinking is that if I use batteries that c*n accept a big charge quickly I will be better off. I am thinking of either lifepo or the Firefly Carbon plate batteries. I installed 5 of the latter on the Outremer. The ability to recover from the PSOC that I will be operating in gives me the flexibility to keep the solar as it is. Putting on larger panels is doable but I would like to experiment with the other stuff first. My present batteries are shot and my 20 amp xantrex charger works fine but is to small and can't be programmed to meet modern battery profiles.

[leftbrainstuff]

We've only recently moved from Berkeley to Seattle. Solar effectiveness seems to be halved based on a month empirical evidence.

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