Real-life energy production

[stoutwench]

When we began designing our charging system several years ago, I found that reading about other cruiser's systems to be the most help.

I would like to ask that those who are cruising, share their system configuartion.

This is ours:
Boat: Brewer 42
Persons aboard: Two adults

Batteries: AGM We chose AGM because of their slow discharge rate. We are away from the boat 5-6 months annually.
~House Bank = 4 - 6v Total 420AH
~Starter = 1 - 12v 110AH
~Windlass = 1 - 12v 110AH

The three battery banks are tied together with a PathMaker 3 Bank Battery Combiner. We find that this set-up works very well.

Charging system components:
~110 Balmar Alternator run to starter battery
~Two Kyrocera 120 watt solar panels run through a BlueSky Solar Boost 2000E to the house bank
~Shore power run through a TrueCharge 20amp charger to house bank
~Honda 2000 gas generator that we plug into the shore power inlet

Average daily power consumption: 120AH
Largest power draws at anchor: A-B 12v refrig = 65AH
Largest power draws underway: Furuno AutoPilot & Furuno Radar

How often we run engine just to charge batteries: never
How often we run generator: every third day if sunny....every other day if cloudy.

How can our system be improved: add more batteries to house bank

Problems with existing system: When we motor (60% of the time), all three banks are full in 2-3 hours, then any energy that could be produced by the alternator can not be stored. We plan to increase the house bank to 630AH.

Other thoughts:
~We added 3" additional insulation to our refrig and freezer
~Put a thick towel over your frig/freezer lids while not in the galley

Hope that this is helpful!

Roger

[sailingdog]

Umm.. you can't fully charge a battery bank from 80% to full in only three hours, even with AGM batteries.

[stoutwench]

Originally Posted by sailingdog

Umm.. you can't fully charge a battery bank from 80% to full in only three hours, even with AGM batteries.

Umm..that's odd..my regulator and my battery monitor seem to think that we do it all the time...but then I didn't actually put a stop watch to it. I'm certain that those who read the post will get the general idea.

But...thanks for the excellent input SD!!!!! Well done!!!!

Roger

[sailingdog]

You're welcome... just remember all batteries used in the marine industry, wet-cell, AGM, and gel cell, will have lower charge acceptance rates as they become more fully charged... While getting an AGM up to 80% is pretty quick, getting it to 100% is about the same as charging a wet-cell or gel-cell battery from 80% to 100%, IIRC.

That's why many cruisers size their banks so that they only use 30% of the capacity, since they don't always get up to 100% when they're charging them. Getting up to 80% and discharging them 30% still leaves the batteries above the critical 50% charge mark.

[stoutwench]

Originally Posted by sailingdog

You're welcome... just remember all batteries used in the marine industry, wet-cell, AGM, and gel cell, will have lower charge acceptance rates as they become more fully charged... While getting an AGM up to 80% is pretty quick, getting it to 100% is about the same as charging a wet-cell or gel-cell battery from 80% to 100%, IIRC.

That's why many cruisers size their banks so that they only use 30% of the capacity, since they don't always get up to 100% when they're charging them. Getting up to 80% and discharging them 30% still leaves the batteries above the critical 50% charge mark.

I agree completely. We never get our batteries to 100% while at anchor using the solar panels or the Honda 2000. We generally operate in the 60% to 90% (achieved by running the Honda in the am, then letting the solar panels take over). But when we motor, I have on numerous occasions had the Xantrex Battery Monitor show full and the alternator output drop.

Either way, above 80% or fully charged, the alternator is best utilized if the house bank is larger (during the bulk charging stage)....correct?

SD....how is your system configured?
Roger

[Valiente]

So my idea to essentially replicate Stoutwench's set-up, but with three Lifeline 8Ds (765 Ah), one 12 v 1100 CCA start battery and one 12 v 110 Ah deep cycle for the windlass should cover things, assuming I have about the same usage?

Because that is the sort of thing I'm moving toward, once I stop having the nightmares in which half a dozen SolarStiks on my stern all burst into flames...

[sailingdog]

Stoutwench-

I have a much smaller boat than you do would be my guess. My house bank is only two T105 golf cart batteries and gives me 225 AH for the house bank. The boat is a 28' trimaran, and is a bit more weight sensitive than your monohull is. Most of the lighting is LED, mainly converted using LED-replacement bulbs, and I do have two 130W solar panels for on-the-hook charging...

As for your xantrex... it will show a significant drop once the batteries reach over 80% charged...

[camaraderie]

Roger... Your Balmar should be going into stage 3 float charging after a couple of hours of stage 1 & 2 charging...In a bank as small as yours, the Xantrex might be showing less than an amp of charge but I doubt it is really getting to 100% charge. If you read the Xantrex manual...the fourth green flashing lite does NOT mean 100% charged...it is some calculation off the capacity...but that is nitpicking. You only really need to get to 100% once every couple of weeks or so and I'm sure the Honda and your passive stuff gets you there.

From what you've described...I would FIRST get a larger battery charger so you can use the full output of the honda. 20amps at 14.2 volts is only 285 watts vs. the 1600 your honda puts out. You could be running a lot less.
Another couple of T105's would also be nice but it sounds like you guys are doing fine.

Valiente...sounds good to me though my suggestion for a designed from scratch system would be to put a small separate charger up at the windlass battery and keep it out of the system. No need to run all those heavy cables to the front of the boat.

[stoutwench]

Originally Posted by camaraderie

Valiente...sounds good to me though my suggestion for a designed from scratch system would be to put a small separate charger up at the windlass battery and keep it out of the system. No need to run all those heavy cables to the front of the boat.

camaraderie

The problem with a seperate charges is that it requires either a seperate charging source or a battery switch. With a combiner there is no need for either. All the charging sources can be run to any of the banks and the charge is automatically shared. Just a personal preference. I dislike switches....one more thing to remember. Only one cable to run to the front with the combiner. If you use a battery switch to have the alternator as a charging source, you still must run the cable.

Good point on the size of my charger. When I decided on the 20amp, I had no idea that I would be adding the Honda. I had only anticipate solar and the alternator while cruising. Thought that we would only use the 20 amp charger while plugged in at a dock where it has all night to work.

Roger

[Valiente]

Originally Posted by camaraderie

Valiente...sounds good to me though my suggestion for a designed from scratch system would be to put a small separate charger up at the windlass battery and keep it out of the system. No need to run all those heavy cables to the front of the boat.

Ideally, no, I wouldn't want to. While it's a no brainer to run a separate charger (I already have a perfectly good 20 amp WM spare about four years old), I do wonder how I can use excess capacity in my (future) solar panels to keep said battery charged when I'm on the hook. I wouldn't object to running all the panels through a second MPPT to just that battery, with the idea that hauling the anchor is, under normal circumstances, not going to happen that often in the same day. Several days of sunlight should keep it topped up, and the wires from the panels run forward are much less expensive and large than tying in the house banks to the windlass.

This isn't a huge deal, however, as I'll have both a Honda 2000 and the manual windlass handle as backups.