Swap out Atkinson charge controller for Victron MPPT

[mdtravelers]

In my 2016 26U I have the factory installed solar package which includes the Atkinson PVCMD25D charge controller and 160W solar panels. My questions is can the Atkinson charge controller be "swapped out" with a Victron MPPT charge controller without much hassle or is there more to it than reconnecting some wires and mounting the bigger controller.

Thanks for any clarifying information, I cant seem to figure this out by reading some of the other posts.

[AirMiles]

This could be an easy swap by just connecting the existing wires. BUT, I would add a cut off switch on the yellow wire coming into the Victron controller, 6 gauge wires between the Victron controller and buss bars and a 40A breaker on the positive 6 gauge wire. Here is a collage of pictures documenting my installation using the parts I suggested above:

http://www.airforums.com/forums/f448...ml#post2167314

[mdtravelers]

Thanks for the info. and other ideas. So, I don't see this as being highly technical and would plan on buying the SmartSolar MPPT 150/35 (because I may upgrade to 400W solar), Eaton Series 187 Marine Rated Circuit Breaker (50amp), Blue Sea Systems Manual Battery Switch - m-Series and 6 gauge wire.

I'm guessing the battery switch (cutoff switch) isolates the solar panels? Any surprises I might encounter??

[AirMiles]

Originally Posted by mdtravelers

Thanks for the info. and other ideas. So, I don't see this as being highly technical and would plan on buying the SmartSolar MPPT 150/35 (because I may upgrade to 400W solar), Eaton Series 187 Marine Rated Circuit Breaker (50amp), Blue Sea Systems Manual Battery Switch - m-Series and 6 gauge wire.

I'm guessing the battery switch (cutoff switch) isolates the solar panels? Any surprises I might encounter??

My Victron 100/30 works perfectly with my 400W of solar. It will put 30 Amps of charge on the batteries under perfect conditions.

Yes the cut off switch is to isolate the solar. I would cover the solar panels with towels while working on this wiring so the wires aren’t energized. Also disconnect the negative battery cables and unplug from shore power. You don’t want anything to be energized!

Also look closely at how I connected the 6 gauge wire to the busses. I used add-on lugs for the thick wire. Like these: https://m.lowes.com/pd/BURNDY-2-Coun...ugs/1000080279

[uncle_bob]

Hi

The MPPT can be directly swapped out for the existing controller. There is zero need to change any wires at all. The existing wiring is way oversized for what it is doing. Put anther way - does going from 1% loss to 0.00001% really matter when there are 10% losses elsewhere?

There is also zero need to put in a cutoff switch just because you went to MPPT. It is every bit as safe as the existing controller (likely much more so). You have the ability to disable from the app (if it's the smart version) or from the panel (if you wire up the "dumb" version).

All that said, if you want to put in cutoff switches go right ahead. To be fully effective a cutoff needs to be at the power source (= at the solar panels).

========

If you want a full list of what to do, this is at least a start:

1) Put one on the battery to the rest of the trailer (double pole of course)
2) Put one on the 120V input to the charger / controller
3) Put one on the 12V output of the charger /controller
4) Put one on the input to the MPPT
5) Put one on the output from the MPPT
6) Put one on the charge line from the 7 pin
7) Put one on the shore power input to the trailer

Be sure they all are clearly labeled and accessible from the outside of the trailer. Also put duplicates on the inside of the trailer in at least two accessible locations. One can never be too safe. In addition put lights on all of them to tell you which are active and which are cut off .... Possibly hook them all to a fire alarm system and have them all automatically shut off. To be even more safe, make them all relays so they can mount right at the power source. Then power those relays off an independent power system and put shutdowns on it as well ..... Each and every one of the above *will* make you more safe.

=====

You are at risk simply getting out of bed in the morning .... equally you are at risk if you never get out of bed. Welcome to life on planet earth.

Bob

[AirMiles]

If the design I shared is good enough for AmSolar, it’s good enough for me. My design came from AmSolar with the purchase of their equipment. Here is a picture of one of their installations, from their blog, with identical equipment placement : https://amsolar.com/solar-panels-for...untain-aire-40.

[waninae39]

My Victron 100/30 works perfectly with my three solar panels

i put a cut off switch on the solar side.
that why i can work on the MMPT, with no power coming in

[waninae39]

this winter, i will an a third cut switch

it will cut off power the the front of the aS
THUS NO POWER FOR THE up/down moter or the power plug for the moving equipment

[mdtravelers]

I just got a quote from AmSolar to upgrade my factory 160W (2 80W panels) to 340W. Question I have is a SunRunner Signature MPPT 40 amp controller is spec'd and costs $1000 (cost includes disconnect, breaker and associated hardware). That cost is a bit more than installing a Victron 100/30 or even 100/50 MPPT controller and associated equipment and hardwire. Does anyone know why the SunRunner might be recommended? I feel like it would have to provide a lot more benefit over the Victron to justify the price difference.

Thanks.

[lewster]

Howdy!

I would use the Victron controller, as that his the only one that I have been using for the last 2 years. You can't beat the quality!!!

Originally Posted by mdtravelers

I just got a quote from AmSolar to upgrade my factory 160W (2 80W panels) to 340W. Question I have is a SunRunner Signature MPPT 40 amp controller is spec'd and costs $1000 (cost includes disconnect, breaker and associated hardware). That cost is a bit more than installing a Victron 100/30 or even 100/50 MPPT controller and associated equipment and hardwire. Does anyone know why the SunRunner might be recommended? I feel like it would have to provide a lot more benefit over the Victron to justify the price difference.

Thanks.

[uncle_bob]

Originally Posted by mdtravelers

I just got a quote from AmSolar to upgrade my factory 160W (2 80W panels) to 340W. Question I have is a SunRunner Signature MPPT 40 amp controller is spec'd and costs $1000 (cost includes disconnect, breaker and associated hardware). That cost is a bit more than installing a Victron 100/30 or even 100/50 MPPT controller and associated equipment and hardwire. Does anyone know why the SunRunner might be recommended? I feel like it would have to provide a lot more benefit over the Victron to justify the price difference.

Thanks.

Hi

340 W at 12V is just over 28A. That makes a 100/30 a bit "tight" for what you are trying to do. The 40A or a Victron 100/50 would be a bit better bet. Yes it's more expensive ...it's not *that* much more ...

Bob

[waninae39]

Victrom MPPT is the way to go. the have many makes and models sizes. Plus they can talk to other victron parts for an "integrated monitoring" system

Yes, add a series shut off switch and a breaker inline with the SP.this is for safety and ensure that you can work on the MPPT without getting zapped by the SP if light falls on them

[AirMiles]

Originally Posted by uncle_bob

Hi

340 W at 12V is just over 28A. That makes a 100/30 a bit "tight" for what you are trying to do. The 40A or a Victron 100/50 would be a bit better bet. Yes it's more expensive ...it's not *that* much more ...

Bob

I have used my Victron 100/30 Smartsolar Controller with 400W of solar for 100 days of boondocking over this summer and have never hit the 30 Amp maximum limit of the controller. I have posted over 70 of my 100 days of usage on my Solar Show & Tell thread.

Here is a link to thirty days of my solar boondocking experience in July, the month when the sun will produce more PV than most other months. http://www.airforums.com/forums/atta...9&d=1532444176

Using my actual production data, my daily maximum PV Power was divided by my daily minimum battery voltage. The result of this calculation is the maximum Amperage my Victron 100/30 could have possibly produced that day.

Days Max Min Max
ago PV Volts Amps
0 67 12.36 5.42
1 198 12.26 16.15
2 238 12.55 18.96
3 211 12.38 17.04
4 244 12.00 20.33
5 190 12.60 15.08
6 214 12.38 17.29
7 264 12.35 21.38
8 206 12.29 16.76
9 198 12.25 16.16
10 176 12.33 14.27
11 136 12.33 11.03
12 206 12.57 16.39
13 244 12.48 19.55
14 298 12.46 23.92
15 184 12.37 14.87
16 261 12.57 20.76
17 325 12.14 26.77
18 271 12.48 21.71
19 212 12.45 17.03
20 239 12.47 19.17
21 140 12.43 11.26
22 293 12.27 23.88
23 171 12.52 13.66
24 170 12.58 13.51
25 266 12.55 21.20
26 235 12.31 19.09
27 60 12.00 5.00
28 176 12.69 13.87
29 90 12.69 7.09
30 64 12.69 5.04

As you can see by this analysis, the Maximum Amps that could have been produced on any single day was 26.77. The typical day was below 20 Amps. Plus, those of us with solar know that you seldom would get maximum PV at minimum battery voltage. When the sun comes up, the PV starts at 1 Watt and slowly adds Watts as the sun rises. As the Watts are slowly increasing, the battery Voltage is also increasing in Bulk Mode. By the time the sun gets anywhere near maximum PV, the battery will likely be in, or near, Absorption Mode at 14.4V. Even my 400W of solar divided by 14.4V is only 27.8 Amps. Therefore a Victron 100/30 is more than adequate for 400W of solar panels.

P.S. Its not that my solar system cannot produce 30A under perfect conditions with low battery voltage and high solar production. I have documented my system is capable of producing 30A in my Solar Show and Tell thread by forcing the necessary conditions. http://www.airforums.com/forums/atta...4&d=1526491969

[mdtravelers]

Thanks for the great information. After this planned upgrade (from the factory installed system) I might boost the system to 600W in the future so the 100/50 controller might be god to do now but......... I think I'll definitely go with the Victron and save around $400.

[AirMiles]

Originally Posted by mdtravelers

Thanks for the great information. After this planned upgrade (from the factory installed system) I might boost the system to 600W in the future so the 100/50 controller might be good to do now but......... I think I'll definitely go with the Victron and save around $400.

I love my Victron controller, especially the Bluetooth interface and networking. If you are contemplating adding wattage, buy a big enough controller for as much solar as will fit on your roof. Solar panels are addicting!

On that subject, I thought 200W of solar would have been adequate this summer when the sun was high in the sky and the days were long. But like Uncle_Bob has stated, more solar is needed in the fall when the days are shorter and the temperatures are lower (furnace use). It took all of my 400W, plus a generator boosting on a few rainy days, to keep my batteries fully charged over the past 30 days of boondocking.

[uncle_bob]

Hi

The bigger question is if you want to run the various components of the system right at the max. For a lot of this stuff staying below about 80% of the ratings is a pretty good idea.

Bob

[mythbuster88]

Originally Posted by AirMiles

... Solar panels are addicting!

...

I find LiFePO4 batteries even more addicting.

[jgbagley]

Originally Posted by lewster

Howdy!

I would use the Victron controller, as that his the only one that I have been using for the last 2 years. You can't beat the quality!!!

I am trying to do this same replacement; however it looks to me like there is no negative cable wired to the Atkinson coming from the Zamp roof mounted solar panels. Any suggestions as to what I might be missing?