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Old 05-12-2014, 23:24   #16
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Re: New Solar install

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Originally Posted by hapibeli View Post
Thanks Matt.
First, I read the Yamaha's manual and I see that I was misinformed by the previous owner. The manual states "The "Both" position should not be used unless neither battery has sufficient power by itself to start the engine"...

I need to get down to reading all of the Yamaha material I was left with.

...

Cool. I've never owned a boat new enough to still have the manual! Most of my boats would have had the operator's manual on stone tablets or perhaps a papyrus scroll.

42 pound plus frame is not a heck of a lot of weight but, depending on the hull shape, you mind find you need to adjust the boat trim after installation particularly if the panel sits outside the waterline of the boat. Could contribute a little to a hobby horse motion in some conditions too but now I am just being neurotic.

Enjoy all those lovely electrons!

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Old 05-12-2014, 23:55   #17
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Re: New Solar install

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Originally Posted by hapibeli View Post
Thanks Matt.
First, I read the Yamaha's manual and I see that I was misinformed by the previous owner. The manual states "The "Both" position should not be used unless neither battery has sufficient power by itself to start the engine"...
if you don't put it in both while running the engine. only the battery chosen will get charged. and the 2nd one won't.
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Old 06-12-2014, 00:33   #18
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Re: New Solar install

A 250 watt panel should generate about 17 amps. I have a 20 amp controller that produces 20 amps with 300 w of panels. The rough guideline I use is to divide the watts by 15 v (what I set my controller to bulk charge at) and you'll get the amps. In your case, 250 w/15v = 16.7A.

Something to consider, batteries are not like buckets, you don't just pour power into them. They are more like a leaking air tank, you have to compress the energy in via voltage, the higher the voltage (for about 2 or 3 hrs) the more power will be stored in the battery. Check the mfr website of your batteries to find out the correct charging voltage, you might be surprised at how high it is. Many people think that 14.4v is fully charged, but that's really only about 80% charged. Considering that you shouldn't discharge below 50%, you're only getting 30% usable cap. and not getting the other 20% due to low charging voltage.

I just installed 6 x 6v Interstate golf cart batteries for a guy, and the Interstate site states absorption voltage should be 7.75v for 2 to 4 hrs. That works out to 15.5v, and that voltage has to be maintained for 2-4 hrs or they're really not fully charged. Once fully charged, the difference between 50% of cap. and 30% of cap. is 40% more than you were getting before, which is a huge difference.

This guy's system I'm installing is using 3 x 230w panels in series connected to a Tristar 60 amp MPPT controller. We should be getting about 45-46 amps during peak hrs and close to that for most of the day. He runs the blender a lot as well as a lot of lights and stereo at night, so he wanted plenty of power without having to fire up the genny or worry about running low.

That's something I learned on my trailer. Install more batteries and solar power than you'll use, and you'll always stay between 60% and 100% charged, with the corresponding long battery life, even with cheap batteries that cost 1/2 of Trojans. I usually get 5-6 yrs out of a set, and I'm horrible about keeping up on the water. Many of my customers that I install these battery/solar/inverter/charger setups for don't even keep their trailers past 2 or 3 yrs. They sell off the old one, buy a larger one and call me to add more batteries, solar and an inverter/charger all over again.
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Old 06-12-2014, 15:31   #19
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Re: New Solar install

Thanks Matt, SOCalled Max, et al! I've got a request in to the Mfr's site for a wiring diagram for the new controller.
Dirk
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Old 06-12-2014, 16:12   #20
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Re: New Solar install

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Originally Posted by hapibeli View Post
Thanks Matt, SOCalled Max, et al! I've got a request in to the Mfr's site for a wiring diagram for the new controller.
Dirk
Aren't the connections clearly marked? They should be.

I've also had very good luck (so far) with a cheap $100 20A MPPT controller from Eco-worthy. Usually a $100 controller isn't something I'd even consider, but I saw a video review of it on youtube, and it is surprisingly well built, better than controllers that cost twice or 2.5x as much. The entire board has a thick, smooth conformal coating, and all connectors are gold plated which even some $600+ controllers don't have. In a corrosive salt water environment, gold plated connectors are nice to have. So far, I've installed 3 and one of them I'm abusing in my own trailer with 410w of solar panels attached to it, even though it's only rated for 300w. It simply goes to 10% over current, then throttles itself there.

For someone who needs no more than 20 amps, or has a bunch of 300w panels and chooses to wire up a system with 1 controller per panel for optimum MPPT action, you really can't beat $100 ea. I'm considering a 3900w system with 13x300w panels and 13 controllers, with a couple of spares in case any of them go T.U. That should keep the lights on and the fridges cold. LOL
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Old 06-12-2014, 16:48   #21
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Re: New Solar install

Understand how 1-2-B switches and boat wiring works, then wire your solar panel to the house bank.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com
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Old 06-12-2014, 18:23   #22
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Re: New Solar install

Thanks for the links Stu...
By the way, I have NO shore power and don't intend to have it, which is one of our reasons for the solar array. We are moored at the Canadian Government Wharf in Cowichan Bay, but I'd likely only use a/c power to recharge my drill or driver if I were repairing something dockside.
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Old 06-12-2014, 19:32   #23
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Re: New Solar install

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Originally Posted by socaldmax View Post
A 250 watt panel should generate about 17 amps. I have a 20 amp controller that produces 20 amps with 300 w of panels. The rough guideline I use is to divide the watts by 15 v (what I set my controller to bulk charge at) and you'll get the amps. In your case, 250 w/15v = 16.7A.

Something to consider, batteries are not like buckets, you don't just pour power into them. They are more like a leaking air tank, you have to compress the energy in via voltage, the higher the voltage (for about 2 or 3 hrs) the more power will be stored in the battery. Check the mfr website of your batteries to find out the correct charging voltage, you might be surprised at how high it is. Many people think that 14.4v is fully charged, but that's really only about 80% charged. Considering that you shouldn't discharge below 50%, you're only getting 30% usable cap. and not getting the other 20% due to low charging voltage.

I just installed 6 x 6v Interstate golf cart batteries for a guy, and the Interstate site states absorption voltage should be 7.75v for 2 to 4 hrs. That works out to 15.5v, and that voltage has to be maintained for 2-4 hrs or they're really not fully charged. Once fully charged, the difference between 50% of cap. and 30% of cap. is 40% more than you were getting before, which is a huge difference.

This guy's system I'm installing is using 3 x 230w panels in series connected to a Tristar 60 amp MPPT controller. We should be getting about 45-46 amps during peak hrs and close to that for most of the day. He runs the blender a lot as well as a lot of lights and stereo at night, so he wanted plenty of power without having to fire up the genny or worry about running low.

That's something I learned on my trailer. Install more batteries and solar power than you'll use, and you'll always stay between 60% and 100% charged, with the corresponding long battery life, even with cheap batteries that cost 1/2 of Trojans. I usually get 5-6 yrs out of a set, and I'm horrible about keeping up on the water. Many of my customers that I install these battery/solar/inverter/charger setups for don't even keep their trailers past 2 or 3 yrs. They sell off the old one, buy a larger one and call me to add more batteries, solar and an inverter/charger all over again.

I have been looking at cells for a while now and cant seem to find any panels that generate any thing close to that at 250 watts. see below. can you direct me to the panles you are saying generate that many amps per hour.

PERFORMANCE UNDER STANDARD TEST CONDITIONS (STC)*
Maximum power Pmax
Open circuit voltage Voc
Maximum power point voltage Vmpp
Short circuit current I
sc
Maximum power point current I
mpp
SW 250
250 Wp
37.8 V
31.1 V
8.28 A
8.05 A
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Old 06-12-2014, 20:43   #24
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Re: New Solar install

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Originally Posted by scuba0_1 View Post
I have been looking at cells for a while now and cant seem to find any panels that generate any thing close to that at 250 watts. see below. can you direct me to the panles you are saying generate that many amps per hour.

PERFORMANCE UNDER STANDARD TEST CONDITIONS (STC)*
Maximum power Pmax
Open circuit voltage Voc
Maximum power point voltage Vmpp
Short circuit current I
sc
Maximum power point current I
mpp
SW 250
250 Wp
37.8 V
31.1 V
8.28 A
8.05 A
Sure!

The example you posted is fine.

It produces 8.05A @ 31.1V = 250.3 watts.

When connected to an MPPT controller, it's going to convert 31.1v down to 15V to charge the batteries. In the process, it's going to consume a couple of watts, so let's say you get an output of 248 watts to the batteries. 248 watts/15v = 16.53 amps.

It's kind of like a gear reduction. You're converting a higher voltage to a lower voltage, but the power isn't lost so the amperage must go up. A reduction gear takes a higher rpm, converts it to a lower rpm for more torque, but the same amount of work is still getting done, just at a lower rpm.

Does that make sense? Sometimes it's hard to explain. It makes sense to the writer, but not always to the reader.
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Old 07-12-2014, 06:31   #25
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Re: New Solar install

So is it the type of controller that is allowing it to make more amps because it is cutting the volts down.

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Old 07-12-2014, 06:40   #26
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Re: New Solar install

Ok just looked up what is a mppt controller. Awesome. Thanks. Very good explanation..

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Old 07-12-2014, 11:05   #27
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Re: New Solar install

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So is it the type of controller that is allowing it to make more amps because it is cutting the volts down.

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I think converting would be a more accurate term, it's converting a higher voltage source to a lower voltage, higher amperage output. They "sweep" the array every few seconds to determine the optimum voltage for the panels for max. current, this power point changes as sun intensity changes, or the panel gets partially shaded. That's why I feel MPPT solar controllers are a good investment for max. solar harvest, in addition to some of them having more advanced battery charging adjustability and capability.
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