Solar panels - connection to batteries

[Momentum M]

SPECS:  Solbian flexible -1/8'' thick - about 4lbs - 22''X59'') velcroed on my bimini,137W, 24V.
             I've got this Off, One, both & Two batterie selector.

The panel will be installed next w-e.  I've run the cable from the top of the bimini, goes down along side with the backstay, enter the boat near the A/C shore power plug....all the way to the controler (Genasun GV-10) located in the batteries compartment (2-4D, no starting bat).  From the controler I've got 2 fused pigtails going to my 1ST bat (+ & -).  The neg of both bat are linked together so this is not a problem.

Now the real question is  that if I connect the Pos pigtail from the controler to the Pos of that batterie 1 ...the panel will be charging only that batterie...Right?
Now if I move the batteries selector switch to Both.....will I be charging both batteries? (meaning the solar panel output, to the controler, to the batt One...then to the selector and back to batt Two) 
Obviously if I move the selector to Two...then no charging from the panel....only number One will  be charged.

Since I'm far from having enough electrical knowledge to know if this will work I'd appreciate any comments.

By the way, my CDN vendor is of no help...is answer was to go on the internet....

Thanks in advance.

[Ken Juul]

Assuming one of the reasons you have the solar is to keep your batteries up when away.  As you have it wired now, bat 1 will be charged constantly.  Battery 2 will only see a charge if the bat switch is in both.  The easiest way I see is to add an ACR or echo charger to the solar circuit after the controller.  Then the if the battery needs charging it will get it.  You could also add a second pigtail to the second battery and put switches in each pigtail.  You would have to manually select 1, 2, or both batteries that way....probably not the best solution.  Or you could wire it through the 1-2-both switch instead of directly to the battery, but then the switch would have to be on to charge the battery.

I'm sure Mainesail or Stu will have a more elegant idea.

[patrice]

Hi,

Not that I'm good with electricity, but one thing to be carefull when doing your connections.
And specialy if you will be going from one batterie to the other.
On my MPPT controller, it is marked to make the connections to the batterie BEFORE making the connection with the solar panel.
The controller must have power to it before.
Check yours to see if same thing, so if you plan on going from one batterie to the other, unplug the + of the solar panel before changing from bat 1 to bat 2.

This is the pain I do for now, until I get the ACR.  To isolate the 2 batteries from each others.  Because I have an old and a new one as house.

[mainesail]

You could also add a second pigtail to the second battery and put switches in each pigtail.  You would have to manually select 1, 2, or both batteries that way....probably not the best solution. 

This is not a good idea. You should never have even a remote possibility of "paralleling" banks with undersized wire..

If you want the GV-10 to charge two banks a combining relay or battery to battery charger such as an Echo or Duo Charge is the best solution. If you don't want it automated you'll need to use the BOTH position of the batt switch....

[Ken Heyman]

I find it easier to just "parallel"(with bagttery cable) my two battery banks in the battery box. I have my 22.5 watt solar panel fused and connected to a regulator so as not to overcharge the batteries when away for an extended period. It is connected to bank number 1. Yes, in the alternate I could turn the selector to "Both" but prefer not to have my electrical system on when away. That said,we are comparing the effort of turnng a switch to that of  connectiing a battery cable. I need the additional exercise.
Ken

[Stu Jackson]

Serge,

You've got 2 big batteries with no start bank, and I think you use them alternately, not both together unless you're charging.

The easiest way to have ONE charging source charge BOTH banks is to leave your 1-2-B switch on BOTH when you leave the boat.  The downside of this is that you have the power ON when you're gone.  (When running the boat, you most likely start the engine on BOTH and only use 1 or 2 once the engine is off.)

But unless and until you install more equipment, that's the only way to make the solar panel charge both batteries.

Your future plans should include

1.  Keeping only these two batteries:  At the very least, buy an ACR (automatic combining relay) so that you can run the solar wiring to battery1 which will automatically connect battery 2 WITHOUT leaving the 1-2-B switch on BOTH when you're away from the boat.  For running the boat, you could continue to do what you're doing, since the alternator output (AO) is still most likely going to the C post of your 1-2-B switch.

2.  Consider a system upgrade to add a small reserve battery and combine your two existing batteries into a larger house bank, and relocate the AO from the 1-2-B switch to the house bank, and use the ACR between the house bank and the reserve bank.  The details of how to do this are discussed in detail in the "101 Topics"  Electrical Systems 101   http://c34.org/bbs/index.php/topic,5977.0.html

You have three basic choices for choosing an ACR:

1.  Blue Sea ACR  (www.bluesea.com)  which does NOT limit current and is appropriate for your two big batteries, since you'll want as much charging current going to the second battery as possible.  It will also work if you add a reserve battery. Another choice is a Combiner (http://www.yandina.com/), which I have on our boat, a very good, reliable automatic relay with a lifetime guarantee.  Ours has been working flawlessly since 1998.

2.  Echo Charge (Xantrex) - This limits current to 15 amps.  It may work for your two battery arrangement, but know that since it limits current it will take longer to recharge the second battery until you move to the reserve battery setup, in which case it is exactly what you want.  The Echo Charge is a great, reliable piece of equipment.

3.  Duo Charge (Xantrex) is like the EC but can be programmed to charge different battery chemistries.  If you stay with wet cells, it's really unnecessary and costs more.  I worked with the late Past Commodore Jon Schneider when he bought his, and afterwards he admitted he really didn't need it, and EC would be just fine.

Good luck in your decision making process, keep us advised, we're here to help.

[Momentum M]

Thanks so much..great help!!!  It looks like I'm going to go with the Bleue Sea System ACR.  I've got a lot to read before the w-end.  I'll take some pictures of the installation (including the panel mounted on the bimini) and tell you how I finally connected everthing.

Again thanks  a million 

Serge

[Ron Hill]

Serge : Are you really charging at 24V from your solar panel ??

[mainesail]

Serge : Are you really charging at 24V from your solar panel ??

No, the Vmp of the Solbian 137W panel is 24V but he is then sending this to a Genasun GV-10 MPPT controller which converts the extra voltage into usable current at 12V battery charging voltages. Most all 12V nominal solar panels are between 16V and 26V Vm and this is why controllers are almost always necessary.....

[Momentum M]

Along with the panel (other post) here's the way that it was connected via an ACR.  In the installation instructions/diagram it shows a fuse on both sides....so I went with 2 X 100A fuse/block using no 4 elect cable.  The power from the controler (turning the 24V into 12V) is wired (again 10A fuse) directly to main switch  positive C (off-1-both-2 switch).  Again I'll let you guys know how it work out.
Regards
Serge