How to put Solar, Wind, Alternator into AGMs

[beebopbogo]

I'm on a Cal 39 looking to set up for extended cruising. She's always charged from shore power and engine power and I'm looking to add solar and a drag-behind water turbine. I'd like to never need to top up from the engine. i.e. Only run the engine for propulsion or maybe once in a while to keep the oil splashed in the right places.

Two questions before I describe my system:
1) Will I have enough charging power to keep up with the loads?
2) How should I set up the charge controllers (and should I shell out money for an expensive PWM or will a cheap one do? I see a large range in prices on eBay/Amazon.)

Here's what I've got:
4 AGM house batteries (105aH each for 420aH @ 12V).
1 AGM engine battery
Fridge (or not?) I may not use the fridge, depending on power availability.
SSB
1 hour per day on the laptop
Sporadic cabin light use, all LEDs. (But we mostly use headlamps.)

Here's my desired power sources:
Shore power - installed already
Engine alternator - installed already
200W solar split between two 100W panels.
Drag-behind water turbine.
(I hate the sound and vibration of wind turbines, so let's forget that)

What about charge controllers?
I have a Freedom 20 Inverter/Charger for shore power.
I assume the alternator has an internal controller? (1978 Perkins 4-108)
Can I plug both solar and water turbine into one PWM Controller?

--I decided on PWM because I'm in the tropics with a small solar array and won't see much difference between it and an expensive MPPT. But will a PWM provide the appropriate bulk, absorb, and float voltages for my specific AGM betteries?


Thanks all!

[zboss]

You first need to find out how many amps are you using in a 24 hour period under two conditions:

At anchor: not hooked to shore power and having not run the engine for recharge.

I did my testing before adding alternative energy and just used power as needed without going out of my way to save energy. For example, we just leave the lights on until we go to bed. We don't turn off our water pumps or anything else when we go to bed, so we left these on.


When sailing:

I did my testing under worst case scenario... autopilot running, radar running, all the instruments running, all the running lights on, etc...


Until then, no one can answer if you will keep up with your consumption.

I am assuming you have upgraded your alternator. We moved up from a 70 amp alternator to a 165 amp alternator.

[beebopbogo]

I listed the only electric gear I will have on board and unfortunately am away from the boat before departing for Tahiti. So testing is out. Worst case I'll run the engine.

So I guess the main question is regarding the charge controllers. Separate controllers for the solar/turbine or one hybrid. Any suggestions on specific products that work well with AGM batteries?

Also, why pay $200 for a 30A PWM when there are $40 30A PWMs out there?


Sent from my XT1030 using Cruisers Sailing Forum mobile app

[tdoster]

The only time you have too much fuel on board is when you are on fire.

You can never have too much electricity.

Don't skimp on the controller(s). Batteries are too expensive. I like the Genasun as a really efficient MPPT and the BlueSky 2512i is well liked.

My school of thought is to have a controller for each source (wind, solar, etc.) and then can direct them in Parallel or segregate (switch) to banks as needed.

I was turned onto the DM 158's on this forum and highly recommend them. DM 158w solar panel, solar module 158w, 12V Solar Panel

Problem with cruising is it never stays sunny, so compliment with a good wind generator as most of the time you have either wind or sun. I agree, the sound is annoying, but when we use it, it is pretty crummy outside and when we need the power the most sitting below at anchor bored and reliant upon electronic entertainment, we don't hear it. The other side of that coin would be having to run the engine or genset and that just spoils quiet movie or computer time.

[Pete7]

Might be worth having a look at the "bang for buck" you get with the towed genny and see if doubling the solar might be more efficient. Certainly 400w would fill probably all your needs.

We have a 180w of solar and in strong sunlight this quickly makes good any overnight usage (averaging 30 - 40AH). However, in rainy or overcast conditions then we are in trouble after a few days as solar generates at best a 1/3rd under these conditions. Then its a case of running the engine for an hour or two to make up the shortfall and give us some hot water.

Pete

[botanybay]

Originally Posted by beebopbogo

I'm on a Cal 39 looking to set up for extended cruising. She's always charged from shore power and engine power and I'm looking to add solar and a drag-behind water turbine. I'd like to never need to top up from the engine. i.e. Only run the engine for propulsion or maybe once in a while to keep the oil splashed in the right places.

Two questions before I describe my system:
1) Will I have enough charging power to keep up with the loads?
2) How should I set up the charge controllers (and should I shell out money for an expensive PWM or will a cheap one do? I see a large range in prices on eBay/Amazon.)

Here's what I've got:
4 AGM house batteries (105aH each for 420aH @ 12V).
1 AGM engine battery
Fridge (or not?) I may not use the fridge, depending on power availability.
SSB
1 hour per day on the laptop
Sporadic cabin light use, all LEDs. (But we mostly use headlamps.)

Here's my desired power sources:
Shore power - installed already
Engine alternator - installed already
200W solar split between two 100W panels.
Drag-behind water turbine.
(I hate the sound and vibration of wind turbines, so let's forget that)

What about charge controllers?
I have a Freedom 20 Inverter/Charger for shore power.
I assume the alternator has an internal controller? (1978 Perkins 4-108)
Can I plug both solar and water turbine into one PWM Controller?

--I decided on PWM because I'm in the tropics with a small solar array and won't see much difference between it and an expensive MPPT. But will a PWM provide the appropriate bulk, absorb, and float voltages for my specific AGM betteries?

Thanks all!

An unrelated comment... of you have the Borg warner transmission do not let it free spin for days. The older manual said it was OK, newer manual definitely not for more than a few hours.

Ate the reverse bearing in mine after running downwind for a couple of days. Stopped spinning... fired up the engine and appeared OK but had significant shavings in the oil 50 hours later and a 2500 dollar rebuild. Installed a max prop and the problem was no more.

[TDC]

My setup is very similar.

2 x 4D batteries for a total of 420ah
Perkins with externally regulated Balmar alternator 100amp
300w solar
Morningstar 20 amp pwm controller

My usage is also very similar and it is enough to run a small fridge. On a long trip it is not be enough to cover continuous autopilot so either run the engine or add a wind (maybe water) generator. Also have the freedom 20, but it never gets used as I don't usually spend time at docks, and avoid inverter use by using 12v car charger for laptop.

I recommend the Morningstar unit. 3 stage charging, temp controlled, and fully epoxy potted for marine use unlike the $20 ones, and at $90 was a whole lot cheaper than a MPPT one. One note is it only has two options for battery type, wet or sealed. Lifeline AGMs are robust and handle the wet settings but if you have another brand the sealed setting should be fine, albeit probably more conservative than necessary.

[beebopbogo]

Thanks for the info.

My AGM 8A31DT batteries accept the following voltage:
13.80-14.58V Bulk/Acceptance
13.38-13.56V Float

The Morningstar Sun Saver 20 provides the following voltages:
14.1V (sealed) or 14.4V (flooded) Bulk/Acceptance
13.7V Float

Would high voltage during the float stage cause a reduction in battery life? It's only 0.14V too high (13.56V required, 13.70V applied)

[Cheechako]

remember, most cruisers are at anchor maybe 85% of the time. The water device will do nothing for you.

[beebopbogo]

I'm cruising back and forth to Tahiti, so it would be nice to have on those windy cloudy days. But I can't find anything less than $1800! Guess I'll just have to run the engine...

Sent from my XT1030 using Cruisers Sailing Forum mobile app

[TDC]

Someone might correct me, but I wouldn't worry about the 0.14v difference. You'll always have some load- fans/fridge/anchor light/etc- so it won't stay there for long.

Honestly Id spend the money you were going to spend on the tow generator on more panels and maybe an MPPT charger. Side effect is the nicer charger will let you set any float voltage you want. Hard part is just finding a place for them. Can't help there!

[Beausoleil]

Rather than using a towed generator, do you have room to install a large pulley on the prop shaft and have it turn your spare alternator while underway? You do have a spare alternator, don't you?

If you have a fixed prop, or a feathering prop like a MaxProp, you can drive an alternator while sailing. You can tie in a switch on the field wire to disable it when running under engine power. The MaxProp has a nice feature where you "lock" the blades by shifting into reverse and shutting the engine down. Of course, you'll need an external regulator for that alternator...

Boat designer/builder/cruiser Steve Dashew goes so far as to add to his designs a second prop and shaft dedicated to driving an alternator for power. It sure beats towing a shark lure behind the boat!

[beebopbogo]

Ok, so if I add the prop-shaft alternator, where would I connect the positive wire into the charging system?

Let's test my asci art skills here:

Shore Power---F20 Controller---|
Eng Alt----Controller-----------|
Shaft Alt---Controller----------|
Solar-----Controller------------|---Battery Bank

So all four sources go to their dedicated charge controller, which all tie into one power terminal which leads to the battery bank.

The negatives from the controllers go to the negative terminal and on to the engine ground.

Sound about right?

[forsailbyowner]

No thoughts of windgen? It compliments the solar so well. When Im running reefed , its been stormy and overcast for a long time, and solar input has been minimal the windgens humming away back there keeping everything going.

[cwyckham]

Originally Posted by beebopbogo

Ok, so if I add the prop-shaft alternator, where would I connect the positive wire into the charging system?

Let's test my asci art skills here:

Shore Power---F20 Controller---|
Eng Alt----Controller-----------|
Shaft Alt---Controller----------|
Solar-----Controller------------|---Battery Bank

So all four sources go to their dedicated charge controller, which all tie into one power terminal which leads to the battery bank.

The negatives from the controllers go to the negative terminal and on to the engine ground.

Sound about right?

Yes, that looks right (well, the power from the alternators don't go through the controllers, they go direct and the controllers have a sense wire to the battery and control the field voltage, but same difference).