# Electrical Power Recharging Options for Extended Cruise



## TSOJOURNER (Dec 16, 1999)

OK - I know this has been discussed in various places on these boards, but from the various separate discussion threads I really haven''t been able to draw a conclusion as to which option would be best for me. 

I am generally a weekend cruiser. However, in April I plan to depart for an extended 6 to 9 month cruise of the Bahamas, East Coast, Maine, and Nova Scotia. 

My electrical system consists of a house bank of 4-6 volt lead acid (golf cart) batteries and a separate dedicated 12v battery for starting. Capacity of the single house bank is 440 AH. I have an 3 step recharger and a high output alternator. I also have a Heart LINK 10 monitor attached to the system, so I am very well aware of my overall electrical usage and the draw of each electrical item in my boat. 

When sailing on the weekends I don''t use refridgeration and my daily power usage is about 30 to 40 AH per day. The banks recharge completely during the weeks with a small solar pannel I have. However, if I use refrigeration (which I will want on the cruise), it adds an additional 50 AH per day.

I''ve seen a lot of comments about the efficiency of a high output alternatior for recharging batteries. I have not found that to be the case. If the batteries are 110 amps down and my alternator is rated at 55 AH, it will not take 2 hours to recharge - in fact it will take much much longer due to the three step regulator. So - I don''t view using the alternator as a real option.

Both solar pannels and wind generators are expensive - I figure it would run me about $1,200 for either one. After the cruise I will not really need either one - so I''m not anxious to add either to the boat.

That leaves the good old gas generator. Honda makes super silent 1000 watt and 2000 watt generators that sell for about $850. I figure I could run the generator twice a week while at anchor - plug it into my shore power outlet and charge through the 3 step AC charger on board. Also, since I don''t have an inverter, the generator gives me options to use my onboard AC or plug certain AC powered items directly into the generator. Obviously, I would need to carry gas for the generator - but I could do this with jerry jugs lashed to the deck. The additional advantage of the generator is that I could sell it on EBAY at the conclusion of my cruise and recoup most of the cost (vs the solar pannels or wind generator where that would be harder to do - in addition to the fact that these two options would leave "scars" as they would be permanently installed on the boat).

So - I''m thinking about going with the generator.

Does anyone have thoughts, comments, suggestions? Am I wrong in the way I''m looking at anything here?

Thoughts, comments, suggestions?

Thanks in advance.


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## GordMay (Dec 19, 2002)

What you propose is exactly what worked well for me, over 9 years in Bahamas.
Unless your Fridge is really well insulated, I suspect that it may use more than 50 AH/day in southern (80 degree) waters.
Good luck,
Gord


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## TSOJOURNER (Dec 16, 1999)

Gererators are a viable alternative. I would like to point out that your 55 Amp alternator is not really high output by today''s standards. You might consider upgrading to a a 100 to 150 amp alternator. This would should cut your charge time by half. You will probably never end up with 100% charge for the reasons you already know but most people find 85% sufficient.


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## TSOJOURNER (Dec 16, 1999)

Thanks for your reply. 

Actually, the alternator is rated higher (it might be 100 AH or so - if they make them at that rating. I used to know exactly what it was). 

Still I find that the regulator slows the charging considerably. If I''m 60 AH down, my LINK 10 may show the batteries charging at 45 AH for a while, then the charge rate may drop to 20 AH for a little while, then 10 AH...I would think with a larger alternator I would still have the same regulator issues to prevent frying the batteries.

Should I expect not to be able to bring the batteries back to full charge using the alternator? It would seem - given the regulator - it might take 4 to 5 hours to top off the last 20 amp of capcity since the regulator may only permit a charge rate of 5 AH when the batteries are nearly fully charged...

Thanks


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## TSOJOURNER (Dec 16, 1999)

What type of regulator do you have? The smart regulators from Ample Power and others are supposed to do a much better job than traditional regulators. I don''t speak from experience yet, but will shortly be buying an Ample alternator (~$500) and regulator (also ~$500).


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## TSOJOURNER (Dec 16, 1999)

I have a Balmar high output alternator and matching Balmar regulator....


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## Nereus32 (Jun 23, 2002)

To completely charge a battery off an alternator can take a long time, provided it is properly regulated, which yours is (and should be). I am having success with letting my alternator bulk charge and supplimenting the rest of the process with solar panels. My hundred amp alternator can really put a load on my engine, but after the output drops below 30 amps, there isn''t that much of a draw, and I don''t like to run the engine with a light load. Besides, I don''t motor that much, so my alternator rarely completes the charge process, which isn''t good.

So, unless you are planning on motoring hours a day, your regulated alternator, while essential, won''t completely charge your batteries on its own.

I like to diversify, so I am going with multiple technologies (regulated alternator, ac inverter/charger, solar panels, and possibly wind in the distant future). One of those little Honda generators seems to be an excellent and inexpensive solution that I am considering myself. Small enought to stow, yet big enough to tickle my battery charger.


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## jack_patricia (May 20, 2001)

Stormer, you''ve got a basically suitable electrical system for your passage plans but I think you misunderstand how a hicap alternator & lead acid batteries work and therefore think you have needs which in reality might not exist.

The charging regimen you describe is exactly what is supposed to happen, and having a hicap alternator (let''s assume it''s a small frame 100-110 amp unit, with perhaps less output at max temp) does not provide for rapid, full bank charging, something I get the impression you think should be available and adviseable. This isn''t suitable because the lead acid batteries can''t sustain it. One you''ve passed the bulk rate charge, the batteries are what dictates the acceptance rate of charge; this will be true whether you''re working off a generator, alternator or whatever else you might use (so long as you care for the batteries properly).

Given that you have the typical ''100 amp/day boat'' and especially with your cruise plans - frequent docking/anchoring at times (engine running), perhaps the occasional plug-in, routine living aboard and cruising - you should IMO be fine using the 50-80 rule. This refers to the fact that you don''t really want to draw down the house bank below 50% in order to max the lifespan of the bank, and you don''t want to charge much above 80-85% of bank capacity simply because the efficiency of doing so becomes less and less (just as you describe). This 30-35% ''band'' of your 440AH bank is roughly 140-150 amp hrs, or about 1.5 days of average electrical consumption with refrigeration before a charge is required, followed by an initially high bulk rate charge (I would expect your system would charge a 50% full bank at the 80-90 amp rate; if it doesn''t, your alternator is overrated or your regulator isn''t doing it''s job) that should put most of another day''s electrical capacity back in your bank within one hour.

This is where alternative energy comes in, as the process described above introduces a slowly dropping curve with slowly increased battery charging times in order to insure the 50% capacity level is never exceeded. But for a finite cruise period such as you anticipate, and with moving the boat being a norm, I agree that the purchase of ancillary charging sources is probably not needed...and that would include a generator.

However, if you consider a generator, realize that it might not be controlled by your regulator (this can be a real problem with smart systems and dumb generators) and you''ll likely have to bypass that system entirely and connect the generator directly to the house bank.

Don''t think you should be working from 100% capacity ''down'', but rather expect that you''ll be oscillating between 50-80% capacity, at which point you might conclude as I do that there isn''t a problem you need to solve.

Good luck on a safe, enjoyable cruise!

Jack
(last BB post before losing normal web access; follow-ups should go to the email address above)


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## TSOJOURNER (Dec 16, 1999)

Make sure the gen set you buy is a honda EU2000i... on deck gen sets need to be quiet, or you will be an outcast in any spot with more than one boat, yours.

The EU1000i is not big enough, the EU 2000i is just right.


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## Vasco (Sep 24, 2006)

The Honda 2000 would be your best bet BUT you'd better have a battery charger large enough to charge your bank without running the Honda all day. I have a 100 amp smart charger with mine. I would not get anything less than a 40 amp smart charger. A buddy of mine had a Honda 2000 but only a 20 amp charger and he wondered why his batteries were always down. With your usage and bank your batteries would be down 50% in two days. You have to remember that when you're at anchor you end up with about 35% of your battery bank available because that last 15% takes forever to pump back in and it's just not worthwhile. It's best to just use the top 50% before recharging. Longer battery life. With the Honda and a 40 amp charger you'll still be running it every day for at least a couple of hours.


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