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-   -   Solar charge controller (http://www.cruisersforum.com/forums/f14/solar-charge-controller-145178.html)

kbudd 26-04-2015 06:16

Solar charge controller
 
I recently ordered a 120W solar panel to keep my batteries charged up while on my mooring. I have a house bank of 2 Gp 31 AGM batteries for a total of 180 Ahr. My charging is by a Balmer 80 amp alternator, a 40 amp shore power charger and a Honda eu2000 generator for emergencies. My question is in regards to a charge controller for the solar panel. As it will only produce around 5 amps, I don't think I need anything too sophisticated. Looking on ebay I see MPPT charge controllers anywhere from $20 for a chinese made unit to several hundred dollars. I know you generally get what you pay for but realistically how much should I spend for one? Any suggestions for a particular model? Thanks in advance.

nimblemotors 26-04-2015 10:11

Re: Solar charge controller
 
MPPT controllers will get more power out of a '12v' solar panel,
than connecting the panel directly to the batteries, which essentially is what a "PWM" controller does.

socaldmax 26-04-2015 11:36

Re: Solar charge controller
 
Quote:

Originally Posted by kbudd (Post 1810165)
I recently ordered a 120W solar panel to keep my batteries charged up while on my mooring. I have a house bank of 2 Gp 31 AGM batteries for a total of 180 Ahr. My charging is by a Balmer 80 amp alternator, a 40 amp shore power charger and a Honda eu2000 generator for emergencies. My question is in regards to a charge controller for the solar panel. As it will only produce around 5 amps, I don't think I need anything too sophisticated. Looking on ebay I see MPPT charge controllers anywhere from $20 for a chinese made unit to several hundred dollars. I know you generally get what you pay for but realistically how much should I spend for one? Any suggestions for a particular model? Thanks in advance.

I've had great success with a 20amp MPPT controller made by Eco-worthy.com. It has a great display, lots of menu options, full charging voltage control in .1v increments, great build quality (fully conformal coated PC board and gold plated connectors) for only $102 delivered anywhere.

Check your solar panel Voc to make sure it doesn't exceed the controller's max. input voltage (this is necessary for any solar controller.)

You might find a cheaper true MPPT controller, but it's kinda doubtful when you get under $100, and this one is very well designed. I have no affiliation, but I've installed 5 of them so far and they are all working great.

kbudd 26-04-2015 12:31

Re: Solar charge controller
 
Quote:

Originally Posted by socaldmax (Post 1810435)
I've had great success with a 20amp MPPT controller made by Eco-worthy.com. It has a great display, lots of menu options, full charging voltage control in .1v increments, great build quality (fully conformal coated PC board and gold plated connectors) for only $102 delivered anywhere.

Check your solar panel Voc to make sure it doesn't exceed the controller's max. input voltage (this is necessary for any solar controller.)

You might find a cheaper true MPPT controller, but it's kinda doubtful when you get under $100, and this one is very well designed. I have no affiliation, but I've installed 5 of them so far and they are all working great.

Thanks much. Exactly the information I need.

socaldmax 27-04-2015 13:16

Re: Solar charge controller
 
Quote:

Originally Posted by kbudd (Post 1810483)
Thanks much. Exactly the information I need.

You're very welcome! Please give us an update on how you like/dislike it when you get it, or if it ever fails, please post up! I've recommended this unit to quite a few people and all of the input so far has been from me. I'd welcome thoughts from others good or bad, just to get info from someone besides just myself.

Also, go to your battery mfr's website and check what the recommended bulk charging voltage is. A lot of times, it's somewhat higher than most chargers are set for and most people think. A lot of people are out there with their batteries charged up to 14 or 14.4v and they think they're fully charged, when the mfr recommends 14.9 or 15.2v or something like that. In essence, they're not charging to 100% and discharging to 50%, they're only charging to 80% and leaving 20% unused, which is actually 40% of usable capacity. I adjusted my solar controller bulk charge voltage up to the mfr's recommended, and started seeing voltages like 13.6v at midnight, after drawing 20 amps ever since sundown. Even with heavy furnace usage in the winter, my batteries were barely discharged by morning, when the solar started recharging again. I've got 475 watts of solar panels on an RV and even though I use a lot of power (inverter on 24/7, powering 3 TVs, 2 DVRs, large suround sound stereo, charging power tool batteries, lights, large fans, etc) my batteries would end up fully charged by 930 or 10 am even in the winter, with the sun low in the sky and the solar system producing 1/2 of it's rated power. I ended up with so much excess power, I bought a 40 lb/day ice maker that runs off my inverter. I start it up at breakfast and shut it down at sundown, by then it's made about 22-25 lbs of ice. The only time I start the genny is when I'm running the microwave or A/C.

Just something to think about, if you choose to add 1 or 2 more panels. *wink*

newhaul 27-04-2015 13:37

Re: Solar charge controller
 
We use the cheapie pwm 30 amp that came with the panels have a 20 amp spare that was under 30 bucks when the original fails I will replace with a good mppt controller but regardless of what you get don't go less than 20 amp ( leaves room for expansion).however with there being little cost difference between the 20 amp and 30 amp units go big


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