MPPT controller location

[Grichelli]

We are probably 50% done at this point. I have ran the wire from the bimini top, down the backstays. Install some scantrust glands on the top of the transom where the rail is connected. This was much more problematic than initially thought as we found a stainless plate and could not use the factory screws provided with the gland. Ran all 4 wires through the corrugated tubing. Fortunately Catalina has 2/3 extra tubes that go underneath the head and come out by the battery compartment, this made the job much easier. Installed the MPPT on the aft wall of the settee right next to the battery compartment. This is as far as we got. Next weekend we plan on taking the bimini down to figure out how to install the panles to it, finish the wiring at the MPPT and the battery. I will be installing the MC4 connector fuses right after the solar panel.

With regards to the wires on the back stay. After everyone thought out input I understand the danger of having moisture trapped, the new idea is to wrap the backstay with sunbrella. This should let any of the air dry any moisture that comes in through the stay. Thoughts? Reasoning for this is to protect the wire from sunlight, and also keep the wife happy with the esthetics.

 

[dlochner]

I will be installing the MC4 connector fuses right after the solar panel.

Fuses always go close to the unregulated power supply to protect the wire. The fuse should be at the battery or positive bus bar. The solar panel is a regulated power supply, i.e., there is a maximum about of current the panel can provide, so it is easy to properly size the wire. The battery is an unregulated power supply, meaning it will dump all of the energy in the battery through a short which will melt wires and cause fires.

With regards to the wires on the back stay. After everyone thought out input I understand the danger of having moisture trapped, the new idea is to wrap the backstay with sunbrella. This should let any of the air dry any moisture that comes in through the stay. Thoughts? Reasoning for this is to protect the wire from sunlight, and also keep the wife happy with the esthetics.

Sunbrella does not breathe. If you have used duplex wire there are are 2 layers of insulation for the sun to eat through before the wires are damaged. Replacing some wire is a lot cheaper than replacing rigging. Chafe may be a bigger issue, the stays will move a little, the Bimini frames don't move. The frames are fatter and can better hide the wire or put them under the Bimini so there is less UV exposure.

 

[Maine Sail]

Close to batteries but out of the way of corrosive fumes. Without knowing which MPPT hard to advise further?

 

[Grichelli]

Close to batteries but out of the way of corrosive fumes. Without knowing which MPPT hard to advise further?

Two victron MPPT 75|15 with two sun power 100W with possibly adding two more 50W panels in the future.

 

[leo310]

I use 2" velcro strips to hold down my solar panels on the bimini . Yes it holds been in 35kt with no problem.

 

[Grichelli]

Blue Seas MMPT controllers should be installed in the same area as the batteries as they temperature compensate the charging voltage by using the ambient temperature in the compartment.

My understanding is that all MPPT controllers should be installed as close as possible to batteries, also to reduce loss from he wires traveling unnecessary distance.

 

[dlochner]

My understanding is that all MPPT controllers should be installed as close as possible to batteries, also to reduce loss from he wires traveling unnecessary distance.

Line loss can be compensated for by increasing the size of the wire, that is not the reason Victron recommends placing the controller in the same compartment as the battery.

Battery temperature affects charge acceptance rates, higher temps reduce charge acceptance rates. In order to provide a proper charing profile the regulator/controller needs to know the battery temp to adjust the voltage for efficient charging. The ideal way is with a temp sensor on the battery, for simplicity, Victron has an ambient temperature sensor and uses that to adjust the charging voltage. Placing the controller outside of the battery compartment will yield an inaccurate estimate of battery temp which will affect the charge rate. As MaineSail noted, the controller should not be placed where it would be affected by off-gassing from the batteries.

Take a look at the photo of my controllers. They are in the same compartment as the batteries and are not too close to protect them from off gassing. (which is unlikely given the batteries are sealed). For convenience I attached the controllers to a piece of starboard to make installation easier and then attached the starboard to a bulkhead.

 

[Grichelli]

I use 2" velcro strips to hold down my solar panels on the bimini . Yes it holds been in 35kt with no problem.

I live in south florida where in the mooring field we have sudden storms with 50+knt winds. That will likely not work for us.

 

[Grichelli]

Line loss can be compensated for by increasing the size of the wire, that is not the reason Victron recommends placing the controller in the same compartment as the battery.

Battery temperature affects charge acceptance rates, higher temps reduce charge acceptance rates. In order to provide a proper charing profile the regulator/controller needs to know the battery temp to adjust the voltage for efficient charging. The ideal way is with a temp sensor on the battery, for simplicity, Victron has an ambient temperature sensor and uses that to adjust the charging voltage. Placing the controller outside of the battery compartment will yield an inaccurate estimate of battery temp which will affect the charge rate. As MaineSail noted, the controller should not be placed where it would be affected by off-gassing from the batteries.

Take a look at the photo of my controllers. They are in the same compartment as the batteries and are not too close to protect them from off gassing. (which is unlikely given the batteries are sealed). For convenience I attached the controllers to a piece of starboard to make installation easier and then attached the starboard to a bulkhead.

View attachment 213568

i don't have a flat surface in the battery compartment , i am hoping the adjacent locker has similar conditions considering it's only separated by a half inch wall and there is a two inch hole that connects the two compartments.

 

[dhandzy]

I mounted two flexible 100W solar panel to the Bimini. Wires ran down the Bimini tube, port side, and neatly wired tied so it does not look too bad. I agree that attaching it with heat shrink to the back stay will invite crevice corosion as that will limit O2. By laying out the wire carefully against the tubing and using several gray fex ties, the routing looks ok.

From there, the wire has a drip loop then into a clamshell with hole through the transom and caulked into the port side rear locker.

My MPPTS Victron controller is mounted in the rear locker on the bulkhead between the rear and port side cockpit locker. The Victron has blue tooth, providing full information to my cell phone.

@SJN Would you mind sharing pictures of your setup, as I'm about to start the same project as well. I'd appreciate seeing how you attached the panels to the bimini, the clamshell access, the controller, etc. Many thanks.

 

[Grichelli]

@SJN Would you mind sharing pictures of your setup, as I'm about to start the same project as well. I'd appreciate seeing how you attached the panels to the bimini, the clamshell access, the controller, etc. Many thanks.

It’s not 100% done, need to finish wiring one MPPT, clean up the wiring, we need to put the velcro on the second panel, we need to make a cover for the wire for the wire from the panel to the part going down on the Bimini. Also just purchased 3 Victron agm batteries and will be replacing the one acid house battery.

 

[dhandzy]

It’s not 100% done, need to finish wiring one MPPT, clean up the wiring, we need to put the velcro on the second panel, we need to make a cover for the wire for the wire from the panel to the part going down on the Bimini. Also just purchased 3 Victron agm batteries and will be replacing the one acid house battery.

Thanks -- very clear! I see you put both MPPT controllers under the port settee -- I read that controllers need ventilation as they can heat up. Perhaps that's mainly true of PWM controllers and not as much with MPPT. Any thoughts about keeping them in a confined space?

 

[Grichelli]

Thanks -- very clear! I see you put both MPPT controllers under the port settee -- I read that controllers need ventilation as they can heat up. Perhaps that's mainly true of PWM controllers and not as much with MPPT. Any thoughts about keeping them in a confined space?

Actually the MPPT charge controllers only request to be installed vertically, and that they should be in a similar environment as the batteries in order to adjust charging based on room temperature, and not on top of the batteries in case fumes come from the battery. One last thing I forgot to say, which shaved a ton of time off installation of the wiring, under the head there are 4/5 tubes that come out at the battery compartment. Big ups to Catalina for this! Where I put the wire glands from the transom has metal under the gelcoat, this caught me by surprise and created some complications and the standard screws provided by scanstrut did not hold.

 

[dhandzy]

I have a 'standard' two-battery setup with one of those big red dials on the electronics control panel that allows me to choose to get all current for my DC needs either from battery #1, or from battery #2 or from 'both' (in parallel). So I cannot cannot the solar controller's output to both batteries as that would render the dial useless (the batteries would always both be used - I'd be putting them in parallel by connecting their positive leads together).

So I'm planning on connecting the output of the MPPT controller to one of the batteries and setting the dial to 'Both' so that the panel charges both batteries. This means that if I leave the dial to either "1" or "2" that only the battery connected to the panel controller will be recharged by the panel and, in that case, the other battery would not be charged by solar panel. I will just need to remember to set the dial to "both" to charge both batteries.

Does anyone do it differently or is this the best way to set it up?

 

[leo310]

What I have done is used an victron FET you could also use an ARC.

 

[Grichelli]

I have a 'standard' two-battery setup with one of those big red dials on the electronics control panel that allows me to choose to get all current for my DC needs either from battery #1, or from battery #2 or from 'both' (in parallel). So I cannot cannot the solar controller's output to both batteries as that would render the dial useless (the batteries would always both be used - I'd be putting them in parallel by connecting their positive leads together).

So I'm planning on connecting the output of the MPPT controller to one of the batteries and setting the dial to 'Both' so that the panel charges both batteries. This means that if I leave the dial to either "1" or "2" that only the battery connected to the panel controller will be recharged by the panel and, in that case, the other battery would not be charged by solar panel. I will just need to remember to set the dial to "both" to charge both batteries.

Does anyone do it differently or is this the best way to set it up?

I installed an automatic charging relay. I have the MPPT connected to the house battery, the ACR once receives enough steady voltage will charge both batteries. I always keep my switch to both off when away from the boat. Here is the one I have:
ACR

 

[Tom J]

I have a 'standard' two-battery setup with one of those big red dials on the electronics control panel that allows me to choose to get all current for my DC needs either from battery #1, or from battery #2 or from 'both' (in parallel). So I cannot cannot the solar controller's output to both batteries as that would render the dial useless (the batteries would always both be used - I'd be putting them in parallel by connecting their positive leads together).

So I'm planning on connecting the output of the MPPT controller to one of the batteries and setting the dial to 'Both' so that the panel charges both batteries. This means that if I leave the dial to either "1" or "2" that only the battery connected to the panel controller will be recharged by the panel and, in that case, the other battery would not be charged by solar panel. I will just need to remember to set the dial to "both" to charge both batteries.

Does anyone do it differently or is this the best way to set it up?

I would install the controller output to the common terminal on the battery switch, same as the alternator output. Then you can choose which battery to charge by solar. Be aware that at some point, the alternator may shut down as the solar continues to charge the batteries. You will know when your tachometer goes to zero, if you have a Universal engine.
I initially installed an ACR, because I had difficulty remembering which battery I had charged last. In the end, I just connected the MPPT to four golf cart batteries in series/parallel, and let the engine charge the separate start battery. I shut the ACR off, and haven't used it lately. The MPPT works so well, with 320W of solar panels, that I don't normally use the onboard charger at all.