MPPT Solar Controller Install

T

Tim Porter

Active member
Joined
May 31, 2021
Messages
26
Fluid Motion Model
R-23 (Sterndrive)
Hull Identification Number
A235723
Vessel Name
Scout
Want to upgrade PWM solar panel controller to MPPT on my c30. Anybody have installation guidance or better yet step by step “how to”? Fairly handy but could easily turn a 1 hour project into a day figuring it out on my own.
 
First, I am not an electrician or electrical engineer. This is what I have done, twice now, to install from scratch or upgrade an existing anemic solar system.
1. Buy MPPT controller based on your desired solar panel size (not necessarily what you have today) CAREFULLY READ INSTALLATION MANUAL FOR THAT CONTROLLER AND FOLLOW THOSE INSTRUCTIONS - ESPECIALLY IF THEY DIFFER FROM ANYTHING STATED BELOW!
2. Buy a resettable 15 amp circuit breaker like this one
https://a.co/d/0OpqoYk
3. Locate existing solar controller
4. Determine if you have enough existing wiring length from solar panel to new MPPT installation location to use that or if you need to add additional correctly gauged wire to reach your new mounting location
5. Cover solar panel with thick blanket
6. Pull solar circuit fuse near house battery
7. Remove both positive and negative wires from controller to house battery bank. Keep them apart and taped off so they don’t make contact with anything else.
8. If you have the Morningstar SunSaver Duo also remove the wires from the controller to the engine battery and cap them off
9. Remove the wires from the solar panel to the existing solar controller. Tape the ends off for now
10. Remove the old controller
11. Mount the new MPPT controller in the new mounting location
12. Mount a resettable 15 amp breaker near the new MPPT controller
13. Connect the positive and negative wired from the house battery bank to the correct output terminals on the new MPPT controller
14. Reinstall the fuse next to the house battery bank. IT IS CRITICAL TO DO STEP 13 and 14 BEFORE CONNECTING ANY WIRING FROM THE SOLAR PANEL TO THE CONTROLLER. The controller must “see” the house battery current before being connected to the solar panel.
15. Connect the negative wire from the solar panel to the negative input terminal on the MPPT controller.
16. Connect a properly gauged wire from the positive input connector on the MPPT controller to the resettable circuit breaker. Keep the breaker off for now
17. Attach the positive wire from the solar panel to the other terminal of the 15 amp circuit breaker
18. Turn the resettable 15 amp circuit breaker on
19. Remove blanket covering solar panel
20. Measure current coming into and out of MPPT controller. If zero out of the controller check to make sure you have not reversed the wires coming from the solar panel to the controller. On some FM installs the black wire was positive, not negative as per convention.
21. Set your controllers charging profile to match your battery type (flooded, AGM or lithium)

Notes: This assumes you are keeping your existing solar panel. If upgrading the panel too you need to ensure all the existing wiring will handle the current delivered by the upgraded solar panel.

PS: included in this thread is a photo of my install on our 2017 C-28. FM did reverse the wiring coming out of the solar panel on our boat. https://m.facebook.com/groups/cwboats/p ... tid=S66gvF

I think that’s everything. If anyone has additions or corrections please chime in!
 
Martin from Channel Surfing has a great video on changing out the solar controller. I swapped mine out with a Victron 100/30 unit like he did and changed out the solar panel from a 160W to a 220W.

Easy upgrade! The Victron won't charge the starter battery like the MorningStar, so you'll have to cap off the wires to from the controller to the starter battery.

https://youtu.be/2NAqsXN8BDk
 
Brett,
Two things I would do differently than Martin showed in his video.
First is that FM installed the Morningstar SunSaver Duo on Martin’s boat inside the starboard cockpit locker. That’s a really, really bad location as Martin later found out. I’d definitely recommend installing the new solar controller in an area that can’t ever get wet. You want your solar controller in an always dry environment even if that means adding additional wire to the system. In the R-25 Classic I mounted my completely new install solar system controller in the cave. In the C-28 the controller was mounted on a covered panel in the cave and I kept it there.
Second is that I installed a resetting circuit breaker on the positive lead from the solar panel to the controller near the controller. This allows you to easily and completely shut down the entire solar system with the flip of the breaker switch.
It also protects the wiring from the controller to the panel in the unlikely event of the panel shorting out.
I should also add that, like Martin shows in the video, I too pulled the blade fuse going from the Morningstar controller to the engine battery near the battery in addition to capping off those wires at the controller end.
 
The Victron 100/30 is a popular MPTT choice and it has IP43 water protection. It isn't waterproof but seems like it's probably enough to be in a locker outside.
 
FlagShip":ttjt9nvs said:
Martin from Channel Surfing has a great video on changing out the solar controller. I swapped mine out with a Victron 100/30 unit like he did and changed out the solar panel from a 160W to a 220W.

Easy upgrade! The Victron won't charge the starter battery like the MorningStar, so you'll have to cap off the wires to from the controller to the starter battery.

https://youtu.be/2NAqsXN8BDk
Click to expand...

I removed those wires altogether going to the engine battery when I upgraded to 400w of solar and the 100/30 controller, as they are redundant. The ACRs will charge the engine/thruster battery in any case once they open, so not sure why FM wired it that way.
 
Watson1987,
I guess I’m going to have to respectfully disagree that an IP43 rating for the V/E controller is adequate water protection for that factory mounting location. A IP46 rating maybe. You don’t want to have an electrical fire back there while in heavy seas and a scupper that’s not keeping up with the water entering the cockpit.
 
my Victron is in the cubby below the AC DC panel on the inside.

I installed a rated switch between the controller and panel to help with items 13 and 14 below. this needs to be turned off before any changes to house battery cables are made.
 
Gavin brings up an excellent point about having a fuse/circuit breaker between the solar panel and the V/E solar controller. Always stop the flow of electricity between the solar panel and the controller before disconnecting the controller from the house battery or when removing battery cables from the house bank batteries. A blanket over the solar panel may not be enough. Not doing this may cause the internal fuse inside the controller to blow.

Also make absolutely sure you are connecting the wires from the house bank to the correct polarity output terminals on the solar controller. Per V/E: “Reverse battery polarity can in rare occasions be accompanied with a blown battery fuse (one that is located in the battery cable). But in most cases the ultra-fast internal fuse inside the solar charger will blow to ensure a proper fail-safe situation. This internal fuse will usually blow before the external fuse blows. The internal fuse is located in a non-serviceable area of the solar charger. It is not possible to replace or repair this fuse. This fuse will only blow in case of an internal fault, and replacing the fuse will not fix the internal fault.”

The V/E controllers have internal protection if you reverse the polarity of cables from the solar panel to the controller. You will not hurt the controller if this happens but you will get zero charging output from the controller.
 
scross":30hhh381 said:
Watson1987,
I guess I’m going to have to respectfully disagree that an IP43 rating for the V/E controller is adequate water protection for that factory mounting location. A IP46 rating maybe. You don’t want to have an electrical fire back there while in heavy seas and a scupper that’s not keeping up with the water entering the cockpit.
Click to expand...

In addition, make sure your scuppers are clear so water can drain before overflowing and running across the solar controller.

I smoked my Victron 100/30 in heavy seas in Johnstone Strait. I smelled it long before I found it.
This is the conditions I was in at the time. So much water was falling into the cockpit from the bow.
https://youtu.be/FXfiLxqndk4
 
scross":etydzke0 said:
Brett,

Second is that I installed a resetting circuit breaker on the positive lead from the solar panel to the controller near the controller. This allows you to easily and completely shut down the entire solar system with the flip of the breaker switch.
It also protects the wiring from the controller to the panel in the unlikely event of the panel shorting out.
Click to expand...

The only way to really shut down the solar panels is to throw a dark colored blanket over them, or do the work at night. They always output voltage otherwise, even dark cloudy pouring down rainy days.

The Victron 100/30 has an internal fuse on the PV (solar panel) side. It's not a user replaceable fuse. So if it blows, the unit is toast and must be replaced. I blew that fuse in Johnstone Strait. No damage to my panels, no damage to the conductor that goes to the panels. I replaced the Victron 100/30 and I'm back up and running.

Installing a fuse or circuit breaker between the panel and the solar controller is not a bad idea, but it's also not required. The short circuit amperage for my 400 watts of solar is 6.6amps per panel. Hooked up in series, it's 6.6 amps. If I hooked my two panels up in parallel it would be 13.2 amps. The wire is 10awg which can easily carry 30 amps. So a short circuit wouldn't hurt the conductor. This is why there's no fuse on that conductor to begin with.
 
for me its less about damage but an easy way to turn off power from panel to controller if batteries are disconnected.
 
I have a circuit breaker after the MPPT to my batteries. Main reason is to turn off power to my batteries. Also, since it could be up to 30a, to protect the wire from a power source.

I use one of these: https://www.amazon.com/gp/product/B07D7VHJYK/

But I have been thinking about putting something between the panel and the MPPT because I'm always leery about just using a blanket.
 
I just unplug the MC4 connections at the solar panel to disable power to the MPPT Controller. Simple and easy. I do have a 30A breaker between the Controller and batteries.

I have 2 x 200W panels wired in series.
 
Second is that I installed a resetting circuit breaker on the positive lead from the solar panel to the controller near the controller. This allows you to easily and completely shut down the entire solar system with the flip of the breaker switch.
It also protects the wiring from the controller to the panel in the unlikely event of the panel shorting out.
Click to expand...

Did the same. Works great.
 
Belated reply but thanks for the excellent discussion on solar controller upgrade. Great stuff. If I go with single output Victron, the ACRs will take care of the charging engine battery but doesn’t that assumes no DC load is using solar? Feel more comfortable if engine battery getting charged regardless of DC load since engine battery charging won’t start until house bank charged. I might be missing something here. Have at it.
 
The only reason I can think of to care about the engine and thruster being charged from solar is extended (months) of storage on a trailer without being plugged in. Agm batteries will self discharge about 3pct a month.

Or on an older boat that has the 24/7 fuse block wired to the engine battery and not the house bank. And if this is the case, I’d recommend moving the 24/7 fuse block to the house bank. (It’s a 15 minute mod to do this.)

I completely rewired my boats charging electrical system to support Lifepo4. (Lithium). With 400 watts of solar, none of it touches the engine or thruster on my boat. Solar feeds the house bank only.

I have a Victron battery sense widget on my engine and thruster battery. It’s like having a volt meter hooked up all the time. I look at my phone and can see engine and thruster battery voltages. It also gives me voltage history (over time). They’re always above 12.8volts even when we sit at anchor for days.

Here in Juneau, we’ve been at the dock for 4 days. I don’t run the battery chargers (I have one charger for the house, and one for eng and thruster. I run neither). I plug in for shorepower to run 120 volt loads. But I let the 12 volt side run off solar and battery. Eng and thruster batteries sit idle. They have no boat loads that run off them.


Sent from my iPhone using Tapatalk
 
The acr approach works.

All depends on your house loads.

I have a 340w panel. I don’t often use all the solar power during the day. The rest is into the thruster and engine battery.
 
You must log in or register to reply here.

  • Tugnuts.com is the community hub for Ranger Tug, Cutwater, and Solara owners. Since its inception in 2008, the Tugnuts forum has grown into an active and thriving community of more than 9,000 members. It serves as both a meeting place for the best boating community online, and an invaluable archive of information.

  • User menu
Back
Top