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ebs001 05-04-2013 08:44 AM

Battery Charging
We would like to be self-sufficient when we are cruising and away from shore power for extended periods of time. Our usage runs about 5 amp hours per hour or 120 AHrs per day. Currently I have a D400 wind generator but zero solar.

The D400 does an excellent job of charging when the winds are in the 20Knot and up range and easily keeps up with our electrical demand.

According to John at svHotwire the rule of thumb for solar panels is to divide watts by 3 to get amp hours. So I am looking at 4X140W which should provide a theoretical output of 160 AHrs per day on a sunny day and no shadows.

I am looking at options and would appreciate others input.

1. Install four 140 Watt solar panels and keep the D400. Two would be fix mounted over the bimini and two tiltable fore and aft over the dinghy davits Because the D400 and solar panels would be mounted in the same general area of the boat, at times shadows from the wind generator would reduce the solar panel's efficiency.

2. Remove and sell the D400. Install the same four 140 Watt solar panels. Then I have very little charging on cloudy days. We seemed to have very few of those days this season and not many days windy enough to have much charging.

3. I also have a radar dome mounted on a tower on the starboard aft corner opposite the wind generator tower . This also may cause shadows. I am going to remove the radar as I rarely if ever use it. My cruising grounds are Florida and the Bahamas so surprise fog is never a problem and I don't plan to do night cruising.

4. At anchor we make water almost every day for a couple of hours and bread with a bread maker every few days. This involves running the generator during that time and the 120volt charger puts in about 15 amps per hour of running.


Zanshin 05-04-2013 09:14 AM

Re: Battery Charging
One factor is what sort of batteries your main bank uses and how many Ah total capacity they have. The charger with just 15amps sounds very undersized and your generator is underloaded (15A @ 12V is only 180Watts of load for your genset, the watermaker probably draws more).

Both the D400 (which I had on my previous boat and loved) as well as the solar panels can only put as much energy into the battery bank as it will accept; and acceptance rates above the 85-90% fill level of the bank are much lower than when the bank is only 70% full and this makes a big difference in how full your batteries really get.

Often the big loads come in the morning or at night. If your bank was 90% full in the morning then the solar plus wind might take most of the day to bring it up to 96%. On the other hand, if the bank had been 60% full in the morning on the same day, it might have been brought up to 85% since the bank would have been able to take the higher daytime charging current.

ebs001 05-04-2013 10:00 AM

Re: Battery Charging
The battery bank is 450Ah flooded. The charger usually goes to the absorbsion stage and so the input is 15 to 20 amps. Bulk would be closer to 35 to 40 amps where it should be until 80% or so but it switches earlier to absorbsion thus the 15-20 Amp figure. The generator is capable of 16Amps at 120 volts and can handle the full capacity of the charger and run the bread maker and freezer with ease.

I understand your point about input rate depending on the state of charge. My intention is to keep the batteries between 60% and 80% occasionally to 100% charged. This would give me 150Ahrs per day to play with and also allow the batteries to accept a full input from the solar array through the controller.

The D400 does an excellent job when the winds are in the 20 Kn range. I have been sitting on a mooring ball for the last couple of days with very strong winds and it has easily kept ahead of our energy demands. It's also very quiet so one's hard pressed to know it's working. The question really becomes is there sufficient wind in my cruising area to justify keeping it and how much will it compromise the solar panels output.

btrayfors 05-04-2013 01:58 PM

Re: Battery Charging
Your 450AH flooded batteries will accept 90-110 amps when 50% discharged. As Zanshin said, your battery charger is WAY undersized.

For the type of things you say you do (run the 2000 watt genset every day for 2 hours), I believe the easiest and least costly solution for you would be to get a battery charger which could put out a lot more amps. This would cost $500 of so for a first-class sophisticated charger (e.g., the Sterling/ProMariner Ultra series) or about $250-300 for a very capable charger which could do the job (e.g., one of the Iota DLS chargers).

Figure out what the bread maker and water maker draw together, then figure how much additional load the genset will handle easily, and get the largest capacity battery charger which will draw about that much current.


ebs001 05-04-2013 05:30 PM

Re: Battery Charging
I am not interested in talking about the charger and the generator. The charging by the generator/charger is incidental and occurs because I am running the watermaker and or bread maker. I am trying to get away from using the generator for charging not become more dependant.

Yes I could get a battery charger that charges at 20% to 40% of C but a Mastervolt 100amp charger is $2,200. It's just not going to happen. I know of no one who has a charger that charges in that range even though there are some who have larger battery banks.

btrayfors 05-04-2013 07:38 PM

Re: Battery Charging
Hmmmm.... how about $143?

Iota DLS-55 12 volt 55 amp regulated battery charger

Wouldn't hurt a bit to lose the attitude, either :-)


ebs001 05-04-2013 07:55 PM

Re: Battery Charging

Originally Posted by btrayfors (Post 1025622)


Wouldn't hurt a bit to lose the attitude, either :-)


Yes, you are right. My apologies.

ebs001 05-04-2013 08:09 PM

Re: Battery Charging
btrayfors, very good price on battery chargers, thank you. The Iota chargers are significantly less expensive than anything I have seen offered for sale at Defender, West or Broken Leg Dave. The only problem I see and I may have missed it, is that they don't have equalizing capabilities which I think is very important.

btrayfors 05-04-2013 09:54 PM

Re: Battery Charging
Not trying to complicate your life, here. Rather, it seemed from your description that you run the genset every day anyway, so the thought was that you almost certainly have enough power left over to run a healthy-sized battery charger for those two hours, so why not take advantage of it?

Two things about the Iota's.

1. They are not approved for marine use. However, when fitted with the IQ-4 accessory ($15) they are VERY good multi-stage chargers for the money, and there's a full line of them from about 15A to 90A capacity. I have two of them, one on my boat and one at home, both maintaining a bank of Trojan T-105 batteries. They have run 24/7 for at least five years. I've installed a bunch of them on customer's boats as well. I don't think the lack of marine certification is a big deal, especially if you have a diesel boat. I've talked to Iota engineers and they say there's really nothing to worry about; under normal conditions, there's no spark generation. But, fact remains, they're not marine rated and the marine business is such a tiny part of Iota's business (which is mostly solar and industrial) that they're unlikely to seek such certification anytime soon.

2. You're correct: the Iota's do not have a true equalization cycle; what they call "equalization" really isn''s only a high absorption voltage. One strategy might be to use an Iota to pump as much power back into the house batteries as possible with the genset while you're cruising and use your existing charger -- if it has an equalization cycle -- for equalizing periodically when at dockside.

One very nice thing about the Iota's is that they'll take "dirty power" from generators in stride. My 55A DLS-55/IQ4 model runs just fine on my little NextGen generator which has a very dirty output until loaded while my high-end Victron MultiPlus won't even take the genset's output until I load it down!

No matter. You can still find marine-rated top notch chargers for around $500 or less, though. Again, the Sterling and ProMariner Ultra series are about the best ones out there for the money these days, and they DO have a true equalization cycle, and are programmable.

These come in sizes up to 60A. Here's a 50A model for $459. These can also be fitted with a remote control panel if you need that.
Sterling Power Pro Charge Ultra 12V 50A Marine Battery Charger 3 Banks | eBay

MaineSail has an excellent tutorial on his website re: installing one of these. I've thoroughly tested them in my shop, and have installed several on client's boats....they are really wonderful chargers. One very nice feature if you plan to go abroad is that they'll take "worldwide power", i.e., you can plug them into 240VAC 50 cycle current and they'll handle it just fine.


xort 05-05-2013 08:00 AM

We have an air breeze which puts out about half the d400.
We added 2 140w solar panels to our bimini
We supplement with 2 40 amp chargers off the generator
Plus engine charging
We consume way over 100 amps per day
It's impossible to make comparisons because the wind, sun, motoring are SOOO variable. Plus we have a dual refer system, engine drive + 12v so we get refer chill when motoring.

Reading your description, I would add 2 solar panels and the iota charger and see how you do. You can add more panels and remove the wind gen later.

BTW, I'm surprised at your comment that you don't get much out of the d400. Are you sure it's working right? Let me know if you're selling!

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