Simple Solar For A Simpleton

[Dsanduril]

Given the cost of controllers, I'm inclined to have the controller for the 320 W panel, and feed the 140 W panels in directly to the battery bank.

I personally don't see a problem with that. It will require a little active management of your system. Put a DC rated switch or circuit breaker in line with the 140W panels. That will allow you to disconnect the panels if the batteries get full. If you wanted to get fancy later you could put in a voltage sensing relay that would disconnect them at 14.4 and reconnect them at 13.8. I'd only go that far if you find yourself having to turn off the solar because your batteries are overcharging at the end of the afternoon

You may want/need to alter your generator scheme, you will generally want to run in the evening, to give the sun as much of a chance as possible to charge the batteries. Once you see how the solar behaves you'll have a better idea of how much, if any, generator charging you want to do in the morning. Otherwise, top up each evening after the sun has done its work.

MPPT controllers that I think might fly:

Xantrex XW-MPPT60-150

MorningStar TS-MPPT-45

These all have the capability to deal with the power and the voltage. The question to ask each manufacturer is the minimum voltage for MPPT. Since your panel is rated at 54V, I would want them to be able to track down to at least 50, and preferably 45. There is some limit to how far the controllers can track, all of these are rated up to 140-150V input. For the MorningStar I found a graph in the manual that shows operation from 13 to 98 Vmp, so that looks OK.

No recommendation, I haven't used either one.

[goboatingnow]

Originally Posted by Dsanduril

Vic,
....
What can happen is that if one charger/controller starts first, it may raise the voltage into the 13.8-14.2V (typical) range while in acceptance charging mode. When the second charger/controller comes online it may see this as the batteries being fully charged and move into reduced power float mode. This can usually be dealt with by monkeying around a little with the float and acceptance voltages on the controllers (like setting the smaller controller to have both float and acceptance at 14.4V).

.....
$).

Two charge controllers will not interfere. During bulk mode both will contribute max power. During absorption mode one will do all the work , so what. If one goes into float mode it has no effect on the other and the battery voltage remains in absorption mode. Chargers /controllers can't " pull" the voltage down, electrically that's not what happens.

Dave.

[Dsanduril]

Originally Posted by goboatingnow

Two charge controllers will not interfere. During bulk mode both will contribute max power. During absorption mode one will do all the work , so what. If one goes into float mode it has no effect on the other and the battery voltage remains in absorption mode. Chargers /controllers can't " pull" the voltage down, electrically that's not what happens.

I disagree, and that's not quite what I'm saying. I'm saying that charge controllers will push the voltage up (actually, charging does that).

Imagine that one set of panels is in the sun. The voltage on the system goes up to 13.8 or so in bulk mode.

The other panels are not charging for some reason (maybe a switch is open). Then they come online. The second charge controller fires up and sees the voltage at 13.8 or 14. Depending on how it is configured it may believe the batteries are at float state, not in bulk state, and go directly into float, wasting most of the available energy.

Some controllers go briefly into bulk at startup as a test, others do not. I've actually seen this condition occur and have had to work around it to get everything charging at maximum capacity. It's not that hard, but it does need to be watched when putting multiple controllers on a single system.

Doesn't look like Vic is going there, so maybe moot.

[noelex 77]

Originally Posted by VirtualVagabond

Given the cost of controllers, I'm inclined to have the controller for the 320 W panel, and feed the 140 W panels in directly to the battery bank.
It's my understanding that this should be ok because we're not likely to over charge the battery bank.

Vic

You will need to monitor the voltage and disconect the 140w bank when the voltage gets high. It you leave them connected they will overcharge the batteries.

The trouble is sooner or later you will forget. The battery cost is much higher than the regulator cost.

[noelex 77]

Originally Posted by goboatingnow

Two charge controllers will not interfere.

I agree with this.

[goboatingnow]

Originally Posted by Dsanduril

I disagree, and that's not quite what I'm saying. I'm saying that charge controllers will push the voltage up (actually, charging does that).

Imagine that one set of panels is in the sun. The voltage on the system goes up to 13.8 or so in bulk mode.

The other panels are not charging for some reason (maybe a switch is open). Then they come online. The second charge controller fires up and sees the voltage at 13.8 or 14. Depending on how it is configured it may believe the batteries are at float state, not in bulk state, and go directly into float, wasting most of the available energy.

Some controllers go briefly into bulk at startup as a test, others do not. I've actually seen this condition occur and have had to work around it to get everything charging at maximum capacity. It's not that hard, but it does need to be watched when putting multiple controllers on a single system.

Doesn't look like Vic is going there, so maybe moot.

Nothing is wasted per say . if the battery is capable of accepting charge from both panels it will do so. Once in absorption, generally the battery is taking less then either panel is outputting. The panel energy is being wasted but not due to the controllers.

Dave

[tartansail]

I recall seeing mention of the Solbian flexible panels earlier int this thread. We're in the market for supplemental charging and were thinking of solid panels above the Bimini. Our biggest drain is refrigeration which is its own topic, but we thought that two hundred watts of solar should give us what we needed. We were at the Newport Boat Show today and spent a good bit of time with Bruce Schwab going over the Solbian panels. Other than the price, these are very impressive. Light and plenty flexible to conform to the shape of our bimini. Bruce is a good guy that we've crossed paths with before so I tend to trust his numbers. The 100 amp panels are rated at 17.5% efficiency. He sells them with Genasun controllers. They will ship them with zippers so that all that is needed is to sew the other half of the zipper into the canvas and do the wiring. This seems too good to be true. Has anyone actually used these panels? Any thoughts on the Genasun controllers?
Thanks.

[noelex 77]

Originally Posted by tartansail

I recall seeing mention of the Solbian flexible panels earlier int this thread. We're in the market for supplemental charging and were thinking of solid panels above the Bimini. Our biggest drain is refrigeration which is its own topic, but we thought that two hundred watts of solar should give us what we needed. We were at the Newport Boat Show today and spent a good bit of time with Bruce Schwab going over the Solbian panels. Other than the price, these are very impressive. Light and plenty flexible to conform to the shape of our bimini. Bruce is a good guy that we've crossed paths with before so I tend to trust his numbers. The 100 amp panels are rated at 17.5% efficiency. He sells them with Genasun controllers. They will ship them with zippers so that all that is needed is to sew the other half of the zipper into the canvas and do the wiring. This seems too good to be true. Has anyone actually used these panels? Any thoughts on the Genasun controllers?
Thanks.

The Gensun controlers are one of the best lower cost controlers. Some of the Solbian panels have a very low Voc so will only work with the very small number of controllers that will boost voltage, or when combined (in series) with other panels. Gensun is one company that makes regulators like this.

The panels look like a useful alternative option, but generally rigid panels are much cheaper and panels like this are only worthwhile where the flexibility is essential.

Durability has been an issue with this sort panel, but I have no experience of this particular brand.

[VirtualVagabond]

Well, the solar panels have arrived and we'll be fitting them during this next week.
The fun one is going to be getting the big panel set up on the davits. It weight 60lbs and I really don't want to drop it in the river!
We're working out the best mounting arrangement at the moment and will use a switch on the 140 watt panels so we can isolate them.

In the end I've ordered Tristar - MPPT - 45 controller. It was one of the controllers mentioned in a few places here and Morningstar recommended it for the 320 watt panel specs too.
After hunting around I managed to find one for $409 including shipping.

I guess we're almost there

Vic

[atoll]

Originally Posted by VirtualVagabond

Well, the solar panels have arrived and we'll be fitting them during this next week.
The fun one is going to be getting the big panel set up on the davits. It weight 60lbs and I really don't want to drop it in the river!
We're working out the best mounting arrangement at the moment and will use a switch on the 140 watt panels so we can isolate them.

In the end I've ordered Tristar - MPPT - 45 controller. It was one of the controllers mentioned in a few places here and Morningstar recommended it for the 320 watt panel specs too.
After hunting around I managed to find one for $409 including shipping.

I guess we're almost there

Vic

next thing you will need to buy is the cables,use tinned wire of the correct guage or larger due to the long run from the stern,but check the size of the terminal appature on the mppt before choosing wire as on some controllers they are quite small.
measure well for the lenth of cable and allow a fair bit extra for corners etc

make sure wire is well supported along the run as well to avoid chafe.
the cable ties that have a bridge that can be screwed into a bulkhead are use full for this.

when mounting aluminium panels on stainless it is a good idea to put a plastic gasket between to avoid corrosion as well.


i used these deck seals last time i fitted panels and can reccomend them
Scanstrut – Deck Seal

[tartansail]

Originally Posted by noelex 77

The Gensun controlers are one of the best lower cost controlers. Some of the Solbian panels have a very low Voc so will only work with the very small number of controllers that will boost voltage, or when combined (in series) with other panels. Gensun is one company that makes regulators like this.

The panels look like a useful alternative option, but generally rigid panels are much cheaper and panels like this are only worthwhile where the flexibility is essential.

Durability has been an issue with this sort panel, but I have no experience of this particular brand.

Many thanks. We're mulling options, but the reduced weight above the bimini and the ability to attach easily without another layer of frame are pretty attractive and mitigate the price difference for the panels themselves. The voltage boost of the Genasun shouldn't be necessary with our installation, but it does seem like a good feature if voltage is marginal.If we go this route, we'll let you know how it goes.

[Brogan007]

After reading all this....sounds like solar is in the same "boat" as diesel mechanics.... hire a pro right at the start. The level of education reqd to navigate the rediculous variety of inputs/outputs/voltages etc etc would seem to be beyond us mortals.
I'm in awe of the OP for still hanging in there....

[Tia Bu]

Originally Posted by Brogan007

After reading all this....sounds like solar is in the same "boat" as diesel mechanics.... hire a pro right at the start. The level of education reqd to navigate the rediculous variety of inputs/outputs/voltages etc etc would seem to be beyond us mortals.
I'm in awe of the OP for still hanging in there....

Oh, goodness, no! That's a formula for bankruptcy. This stuff isn't nearly as hard as it sounds- either the diesel mechanics or the electrical stuff. It makes more sense as you actually work through it. The original poster, with some free help from others on this forum, actually worked through a VERY complex, big-boat electrical problem in just a few weeks. And now he's quite knowledgeable on the subject and his system.

The alternative would be to take the boat to a boatyard, drop thousands and thousands of bucks for someone else to do the same head-scratching, and then the next time he has problems, he would have to pay someone to go through the same process, since he still wouldn't understand his system.

By the way, I've just lurked through this whole thread, trying to glean info for a new, old boat I'm starting to upgrade. There is some great information here. Thanks to all!

[VirtualVagabond]

Originally Posted by atoll

next thing you will need to buy is the cables,use tinned wire of the correct guage or larger due to the long run from the stern,but check the size of the terminal appature on the mppt before choosing wire as on some controllers they are quite small.
measure well for the lenth of cable and allow a fair bit extra for corners etc

make sure wire is well supported along the run as well to avoid chafe.
the cable ties that have a bridge that can be screwed into a bulkhead are use full for this.

when mounting aluminium panels on stainless it is a good idea to put a plastic gasket between to avoid corrosion as well.


i used these deck seals last time i fitted panels and can reccomend them
Scanstrut – Deck Seal

Thanks for the tips. We'll certainly be using gaskets between the aluminium and stainless.
I'll take a look at the Scanstrut site too.
Cheers,
Vic

[VirtualVagabond]

Originally Posted by Brogan007

After reading all this....sounds like solar is in the same "boat" as diesel mechanics.... hire a pro right at the start. The level of education reqd to navigate the rediculous variety of inputs/outputs/voltages etc etc would seem to be beyond us mortals.
I'm in awe of the OP for still hanging in there....

It's a tempting idea. It would be easier.
But I do like to try to get my head around this stuff if possible though, because if something goes pear shaped in the Pacific Islands I just may be able to find solutions... particularly if I can get onto the forum here and tap into the wisdom of the gurus