Association Forum - Solar Charge Controllers MPPT vs 3 stage

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Solar Charge Controllers MPPT vs 3 stage

New Topic

Topic Locked

Printer Friendly

Author

Topic

C25OBrien
1st Mate

Member Avatar

USA
44 Posts

Initially Posted - 03/09/2010 : 11:03:35

My boat will most likely be on a mooring this season so solar power looks to be my best bet. Has anyone had experience using the MPPT style controller versus standard 3 stage controller? It is my understanding that the MPPT can trade volts for amps and vice-a-versa when the panel is generating more or less than 14.4 volts to charge a 12V. Has anyone used these and do you feel the efficiency gained is worth the more expensive price tag of the MPPT controller? I'd rather have a smaller "footprint" on my panel and boost it's efficiency wherever possible.

-Chris OB
Cool Yer Heels
1980 C-25 SR/FK L-Dinette
Sag Harbor, NY

Edited by - on

islander
Master Marine Consultant

Members Avatar

USA
4024 Posts

Response Posted - 03/09/2010 : 11:38:22

I did a quick research on MPPT controllers. Very expensive

but it seems to be not worth the cost for systems under 200 watts.
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The MPPT (Maximum Power Point Tracking) charge controller is the shining star of today's PV systems. These controllers actually detect the optimum operating voltage and amperage of the solar array and match that with the battery bank. The result is additional 15-30% more power out of your array versus a PWM controller. Although the MPPT controller is more expensive than its PWM counterpart, it is generally worth the investment for any solar electric system over 200 watts. <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
Are you planing on using a 200 watt panel?

Edited by - on

C25OBrien
1st Mate

Members Avatar

USA
44 Posts

Response Posted - 03/09/2010 : 11:48:00

NO! The boat is to get away from society, no 50" Plasma on this boat. I am currently looking in the 40 watt range (or 18x2). I will be using lights (LED in cabin), Stereo, VHF (not all the time), Depthfinder, and 12v chargers for cell phones. Does anyone have input on whether a 40 watt panel would be sufficient for this? Mostly 3 day weekend sailing so the panel would have 4 days to recharge the battery. Also, does anyone have input on a particular brand of panel or charge controller that they think is a good value?

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 03/09/2010 : 12:58:44

I have 3, 11 watt United Solar flexible panels. I do not use a controller. But then, I only use them during long term cruises. I have a voltage regulator that I could use, if desired.

I find 33 watts is sufficent to live aboard indefinitely away from shore power (during summer months).

This is with autopilot, fish finder, GPS, marine stereo, halogen lighting, invertor with some use of laptop computer.

If I try to use my electric cooler, this is not enough charging.

I have 2, wet cell, Group 24 batteries.

My outboard puts out charging current, and with this I would probably not even need the solar panels during a long cruise. My old OB did not have a charging circuit.

I would think for your application you could get by with 10 watts to 20 watts.

I don't think any expensive controller is required. I don't even use the $30 voltage regulator I bought with my panels.

Edited by - on

C25OBrien
1st Mate

Members Avatar

USA
44 Posts

Response Posted - 03/09/2010 : 13:11:08

Thanks Jim, that's encouraging as i was not excited to spend $500 on a solar set up. The boat came with 1 small flex cell that read @ 14.4 on the voltmeter, however i do not know the wattage of it. I am debating on setting up 2 batteries or not. Do you feel the 33w is enough to keep both batteries up to sniff? I currently have 1 Deep Cycle Group 27 and i do not have an alternator on my yamaha 8hp. Also, do you recommend a place to buy the Flex cells? Brand?

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5368 Posts

Response Posted - 03/09/2010 : 19:52:39

I just got a pretty good deal on a 20W panel on Amazon - $85.00

"An HQRP 20W Mono-crystalline Solar Panel 20 Watt 12 Volt in Anodized Aluminum Frame."

This will replace my failed 18W solar panel.

While it is not a flex cell and it is rigid, with this and my 18W panel, I should be able to power everything but a 4 Amp cooler chill-pad.

So, with 38W and a group 24 battery, I calculate my load as follows:

Suppose I use 1/2 of my full 78 AH on a weekend, so that's 39AH. To replace it, I need to deliver about 2 A for 24 hours (some is lost) or some combination of Amps and Hours.

With each solar cell putting out, say 750 mA (0.75A), I need to charge the battery for 39AH / 1.5A = 26.5 hours. Given about 12 hours of charge time per day during the summer months, you can replace 39AH in under three days.

For a group 27 battery with 96 AH, you would typically expend 48 AH before you had to recharge. To replace 48 AH, using the above math, you'd have to charge for the better part of 3 days. Now, some days will be cloudy, so you might need 4, or even 5 days to replace the 48 AH.

With two group 24 batteries discharged to 1/2, you'd have to charge for 4-5 days and hope for clear weather. In that case, I'd want to either recharge using the engine alternator, use a shore power charger or go with higher wattage solar cells, 2 x 40W maybe or an 80 W solar panel.

In my research, the 80 watt cells are in the $400-600 range, but your regulator would also have to handle around 7 Amps.

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 03/09/2010 : 20:37:51

The Flexible solar panels are very nice. I can just throw mine on the cockpit seats, tie them to the handrails, or tie them on the boom. Boom works best. You can walk on them without damage. No mounts are necessary. They are not as efficent as fixed panels.

The panel puts out about 25 volts in direct sunlight. When you hook this up to your battery, the overall system voltage will go up a few tenths. When I get up to 14 volts I disconnect the system. For you, that's where a voltage regulator would come in.

During normal day sailing say over a weekend you use very little amp hours. All year long, I probably hook up my shore power and 2 amp charger once or twice. Motoring in and out of the slip seems to provide enough.

If you left a flexible panel plugged in during the week hooked up to a voltage regulator, I think you would be fine.

Here you see exactly what I have (on a big boat).

United Solar seems to be no longer selling these in the US.

Amazon . com seems to have a large selection. Google is your friend.

Edited by - on

C25OBrien
1st Mate

Members Avatar

USA
44 Posts

Response Posted - 03/09/2010 : 22:56:41

The small panel on the raised hatch in the above pic is similar to the one that i currently have. I would ideally like to go with these flex panels for versatility and durability, however the newer 'roll up' style is all i can seem to find and they are quite expensive. If anyone knows where to get the older style flex panels please let me know.

As of now, barring discovery of flex panels, i will probably go with the 20W panel that Bruce got from amazon and stick with my single group 27. Bruce- Have you received the panel yet? How does it look?

Lastly, I would like to still incorporate the small flex panel that i currently have. Is it possible to connect these 2 different types of panels to the same charge controller? If not I have a new-ish group 24 from my old boat that i could keep on board and use the small flex cell to keep topped off as a backup battery linked to the dual perko switch. I'm now just realizing, maybe that is my best bet anyways. I could link the small panel directly to the backup battery and only put the panel out when the charge was getting low (The PO did install a Voltmeter in the circuit so that would help a bit with monitoring the level). Then i would have the 20W panel hooked to the charge controller and the group 27. It's not ideal, but the only expense i would have is the 20W panel and controller, Amazon for 99 + 15 shipping for both. Any thoughts or concerns about this setup?

I feel like in the past I have worn batteries down very quickly with the ipod hooked to the stereo, i like to listen to music for extended periods on the boat. To clarify, i would not be using the "both" setting on the batt switch due to the age and size difference of the batteries, the smaller battery would just be maintained as a backup. Thanks for your input gents.

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 03/10/2010 : 10:05:24

I almost always have iPod on, stereo on, GPS on, Fishfinder on, autopilot on. The autopilot is a big draw. With 2 group 24s in "both" I think I could sail every Saturday and a couple of evenings/week for a month before I worried about charging the batteries.

That would not be true if I was spending the nights aboard. Then I would worry about it after a couple of weeks.

Edited by - on

britinusa
Web Editor

Members Avatar

USA
5404 Posts

Response Posted - 03/10/2010 : 18:41:20

Check Harbor Freight for Solar panel kit, might be worth buying the kit to get the panels. Not sure about the controller.

Paul

Edited by - on

DaveR
Master Marine Consultant

Members Avatar

USA
2015 Posts

Response Posted - 03/11/2010 : 07:03:57

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"> i do not have an alternator on my yamaha 8hp <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

That's to bad, an alternator is a great equalizer for a smaller solar panel.

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5368 Posts

Response Posted - 03/13/2010 : 16:12:35

My new 20W solar panel came in, and its a lot smaller than my amorphous silicon panel. Only problem now is I have to wait until the sum comes out to test it! We're getting a noreaster now.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.