Factory installed solar; swapping PMW controller for MPPT?

DesertDweller

Hello all.  For those of you with factory installed solar panels on your T@B, have any of you successfully swapped out the older PMW solar controller (mounted under the driver side bench seat) for the newer Victron MPPT controller, but keeping the factory installed panel?  The reason I want to switch is to have a solar controller with working Bluetooth transmission of battery status.  I understand from reading threads on this forum that the Victron models actually have working Bluetooth transmission.  The dealer and I have tried getting the PMW model to connect with the appropriate iPhone apps, but no joy.  

ScottG

Not quite an answer to your specific question, but I don't think the panel cares what kind of controller it feeds into, so long as it is rated for the maximum capacity of the panel.

DesertDweller

@ScottG Thanks for the response.  That was my (uneducated) assumption as well.  What prompted my request for actual experiences is when I proposed the described swap to Creed at NuCamp via an e-mail, his response was to describe the difference between PMW and MPPT and then he advised not doing the swap.  I am hoping to get a clarification from him why he would not recommend the swap as the reasoning is not obvious to me.  In the meantime, if others actually did the swap without adverse consequences, that would be useful to know.

Sharon_is_SAM

https://www.victronenergy.com/solar-charge-controllers

It would be helpful to know what panel you have as they change things up from time to time.  Your maximum input voltage and maximum output current will help determine which controller you need.  See the link below.  I agree with Scott.  Should be an easy swap and the built in Bluetooth for monitoring is sweet.  We have a generic PWM controller with a BMV battery monitor with their original Bluetooth that was not built in.  We have found it to be very useful.

DesertDweller

@Sharon_is_SAM Thanks for the link.  Yes, that is the type of unit I would like to swap with.  I do not know the particulars about the factory installed panel on my T@B.  I was hoping Creed would be able to get that info to me.  

ScottG

On a related note, I'm not quite following the logic here. If the PWM controller is supposed to work with Bluetooth, but doesn't, what's to ensure the MPPT controller will? It seems to me the Bluetooth connectivity issue and the PWM vs MPPT processing are unrelated .

With regard to charging capability, there are some advantages to MPPT, by my (admittedly limited) understanding is that you may or may not benefit from from those depending on your particular set-up and exposure conditions.

Sharon_is_SAM

@DesertDweller,  Other folks have reported similar problems with getting the factory supplied PWM controller Bluetooth to work, so I understand your frustration.

@ScottG, I think everyone with the Victron products have had great success using the remote function (Bluetooth), hence her interest.  It has nothing to do with the fact that it is MPPT other than Victron does not have a smart controller in their PWM version.  I agree that there is limited advantage to the MPPT in this application, except that the Victron smart products actually work!

ScottG

Ahh, I didn't realize we weren't talking about two Victron controllers. Seeing as how I have no desire to be in constant communication with anybody, let alone any thing, I should probably just stay out of these conversations.  ;-)

So, back to my original point...  I can't see any reason why swapping out the controller--regardless of the impetus for doing so--should pose any sort of problem. If you determine the rationale for why nuCamp advised you as they did, I'd be curious to hear it.

DesertDweller

@ScottG @Sharon_is_SAM ;  Sharon has summarized the situation well.  But the current controller I have is not a Victron.  It is another brand.  It looks like this.  



Sharon is correct that forum members have had mixed results with the BT function with this unit notwithstanding that the BT symbol is visible on the LCD display (not in this picture, though).

I will pass on anything I hear from Creed.  In the meantime, maybe someone who has actually done the swap will chime in.  

Sharon_is_SAM

@DesertDweller, I have not heard of anyone swapping these out as the solar option is rather new.  It should be a no brainer swap with 2 wires (+/-) coming from the battery and 2 wires (+/-) coming from the panel.  Easy peasy.  Check for a Victron online manual.

DesertDweller

@Sharon_is_SAM ; I agree that it should be a relatively easy switch, but my only concern was when Creed advised against it when he, I, and the dealer could not get the existing unit's BT working.  I think I ought to have Creed clarify his hesitancy to such a swap before I become my own guinea pig.   

Sharon_is_SAM

Yes, you need to clarify.  Could be he is hopeful the Bluetooth fairies will wake up and you will save yourself the headache and $$!

DesertDweller

Yes, saving $$ would be good, but I boondock a lot in the summer in the forest.  There will be shade from the pine trees and where I store my trailer in the summer there is no shore power available to me.  So, the solar panel is the primary battery recharger.  With my prior trailer I was able to recharge via a solar suitcase unit (chasing the sun with it).  But, I sold that unit with the old trailer since the T@B had the roof mounted unit.  I have no experience with how effective that roof mounted panel is under my summer camping conditions.  So, having good information about battery usage and condition is worth any extra $$ I may have to spend.  

ScottG

DesertDweller said:

@ScottG @Sharon_is_SAM ;  Sharon has summarized the situation well.  But the current controller I have is not a Victron.  It is another brand.

...

Along the same line as my previous comment, I don't think the solar panel cares what brand of controller you have either. The controller is the brains of the operation; the panels themselves are pretty dumb.  :-)  

Not sure why you were told the swap was ill-advised, but sometimes "no" is the safe answer when what you really mean is "I don't know."

I'm looking forward to a more detailed explanation. I can see in your case why you want to make the swap.

DesertDweller

I had a very nice conversation with Creed this morning.  Part of the reason for his hesitancy about the swap is that when nuCamp switched solar panel suppliers (from a company called SunPower to one called Sunflare).  The new company recommended the use of the Victron controllers.  He was also unaware of anyone having done this sort of swap before.  He told me that he would be forwarding my swap proposal to "R & D" to get their input.  Stay tuned.  

N7SHG_Ham

I think NO was the safe answer, as long as whatever controller you have can handle voltage and current from whatever panels you have it will work. I built a system for my cargo trailer and bought whatever parts I wanted and it has been working for 14 years. If you want the Victron controller and it meets the electrical output of your panels I would say carry on. I can't imagine it wouldn't work as I doubt the actual electrical output from your old panels would be much if any different than the newer panels.

DesertDweller

I tend to agree, but I appreciate that nuCamp is being cautious as I will be depending on the solar panel setup almost exclusively during the April-September camping season.  

At any rate, Creed and I e-mailed some more and he has asked the Sunpower folk if they know of any reason why their panels would not be compatible with a Victron controller.  Perhaps Sunflare's preference for Victron was simply a preference for MPPT over PWM rather than something else, and Sunpower has the opposite preference or no preference at all. 

When I hear what they have to say (and any reasoning), I'll decide what my next step will be.  I will pass on anything I learn.  

ScottG

DesertDweller said:

...
At any rate, Creed and I e-mailed some more and he has asked the Sunpower folk if they know of any reason why their panels would not be compatible with a Victron controller.  Perhaps Sunflare's preference for Victron was simply a preference for MPPT over PWM rather than something else, and Sunpower has the opposite preference or no preference at all. 
...

I'll bet a nickel you're on to something here. The increased performance of the Sunflare panels touted in this recent discussion make me wonder if they are not better able to utilize the MPPT technology, hence the recommendation. Beyond that speculation, the technical details are outside my pay grade.

Regardless--as you also suggested--the recommendation for the use of certain controllers with Sunflare panels in no way translates to a recommendation not to use those controllers with other panels.

jkjenn

Victron has some smart charging features that are likely to improve the performance of their panels in lower light situations, which they tout as one of the benefits of their technology. 

From their website:

The intelligent Load output function prevents damage caused by running batteries 'flat'. You can configure the voltage at which SmartSolar disconnects a load - thereby preventing excessive drain on your batteries. And here's the clever bit: SmartSolar will attempt a 100% recharge every day. If it can't - during periods of poor weather - it raises the disconnect voltage, daily, until it achieves success. We call this feature BatteryLife because it maintains the health, and extends the life of your battery.

ScottG

Assuming this is a beneficial feature unique to Victron controllers (as opposed to just marketing hype), it sounds like switching to a Victron controller could be an upgrade in and of itself.

jkjenn

ScottG said:

Assuming this is a beneficial feature unique to Victron controllers (as opposed to just marketing hype), it sounds like switching to a Victron controller could be an upgrade in and of itself.

I have not found that Victron hypes their stuff. Their products seem to deliver as promised. I got extraordinary performance from my controller when I spent about 3 months in my T@b.

DesertDweller

So, just an update.  I decided to be my own test subject and went ahead and swapped the black HP2440 PWM solar controller for a Victron Smart Solar MPPT 75/15.  Neither Creed nor I ever heard back from Sunpower.

It was easy to swap out.  The only hiccup was that the gauge of wire that went into the HP2440 slots was too thick for the Victron's slots.  So, I had some wire of a little less thickness and made a jumper wire for each of the four slots (PV and Battery; + & - for each.  The "load" slots had no wires.)  Seems to be working fine in the storage lot.  BT connected once I updated the Victron's firmware.  I won't be able to take "The Doghouse" (finally named my T@B!) out on a boondocking trip until next weekend.  So, we'll see how the Victron does then.

I am using the Victron's default charging settings as I did not see any preset setting for a sealed wet lead acid battery (supplied by my dealer).  I scoured the internet, but did not see any specific settings for recharging the battery -- a Centennial, 12 V, group 24 deep cycle with a rated reserve capacity (25 A) of 140 and a Draw Amp Hour @ 20 HR rate of 75.  (Not really sure what all that means, however). 

We will see how this battery does with the solar panels and the MPPT controller. 

Thanks for everyone for their comments. 

Sharon_is_SAM

@DesertDweller, for RV use, most folks use the 20 hr battery rate for determining available amperage.  So, you have 75 amps to start and you may know this already, but it is best to not use more than 50% before recharging as over time it will shorten the lifespan of your battery.  So, limit use 35 amps or so before recharging.  

DesertDweller

@Sharon_is_SAM. Thanks for the info.  That is helpful to know. We'll see how that works out this summer which is my heavy boondocking season.  

Sharon_is_SAM

@DesertDweller If you are a minimalist like we are, you will use very little amps.  We prefer Lucci solar lights.  We have the MaxxAir fan and the ARB which has little amp draw and we often recharge our phones and iPads in the car, so, no worries.

DesertDweller

@Sharon_is_SAM. I think you are right. When boondocking with my prior trailer we had no issues. I had a 90 watt solar suitcase and moved it around throughout the day. The only electric we used in that trailer were the LED lights, the propane refrigerator, whatever the hot water heater thermostat may have used, and very rarely the forced air heater. That last one drew a lot of current. We did charge our phones, too. I can’t remember the trailer battery capacity though. 

I doubt that I will be using the TV or stereo in the T@B, so I will probably use the same items in the T@B as I did in the prior trailer. I may want to use the Alde heat some more than I did the forced air heater though. And, the stock ceiling fan is tempting too. 

Sharon_is_SAM

And your Alde can run on propane, so no worries.

DesertDweller

@Sharon_is_SAM I assume the glycol pump uses some electricity, no? And, I forgot about the water pump as well .

DesertDweller

Another update:  Sunpower did eventually get back to Creed.  As several here thought, there are no issues using an MPPT controller, as opposed to a PWM one, with their flexible panels.  Hopefully the Doghouse will get a field test this coming weekend.  

rbrtm

What model Victron controller came with some tab 400s ?

GatorEgg

Solar seems baffling in the beginning.  I lived on a sailboat in the tropics for years with my electrical needs supplied totally by my solar.  Controllers do not control the panels.  Just what happens to the outputs.  Both types of controllers have pros and cons.  I'm not affiliated with them but the Renogy.com site has great  information on all areas for the interested.