M116A3 Build

[lfhoward]

john61CT,

Do you consider Renogy 100 watt mono panels to be of decent quality? I am thinking they are good quality.

I do. I especially like their Eclipse line of monocrystalline panels, which is what I got in 2 solar suitcases. You can get regular rectangular 100 watt Renogy Eclipse panels for less money than the foldable suitcase models.

[John61CT]

They are strictly a relabeling / distribution /marketing outfit, do not actually make anything.

I used to hear fantastic stories about great customer service, in recent years not so much.

Not saying their products are bad, but certainly not professional level best of breed, they cater to mass market consumers who think everything can and should be bought on the internet.

. . .

Panels suited to the excellent Victron MPPT are 40+ Voc rated.

Otherwise the watts output per sqft and cost per watt would be my main criteria, rigid framed for longevity, warranty fuggedaboudit

If no good value specialist supplier nearby

best found from local installers or intermediary with some surplus from big projects.

[MickinOz]

A few questions re: your solar system.
Those Renogy folding kits appear to come with a charge controller. Have you by-passed this to feed "raw" power to the Victron controller?
How is the dual Victron set up wired to the battery, do you only use one system at a time?
My Renogy Rover MPPT controller needs to "see" the battery voltage.
If you have two chargers in parallel do they confuse each other with regard to battery voltage sensing?
I haven't read all your thread - there simply are not enough hours in the day to read everything I find interesting, so I hope you'll forgive me if you covered all this.

[MickinOz]

Yes, Victron very purposefully prevents the charging circuitry of the SC from powering up until significant energy levels are being produced.

Like all quality MPPT, they are designed to work with quality higher voltage panels

not the low voltage consumer grade ones sold through big box retail or over the internet.

The voltage has nothing to do with the quality, and vice versa. Pretty easy to buy a low voltage/high quality panel.
It's horses for courses.
The high voltage ones are generally for rooftop solar installations on houses, and the quality level of those usually ranges from woeful to acceptable.

If Victron impose a 5 volt differential, they are actually defeating one of the reasons for having an MPPT - eking out a little more power from a low voltage panel in low light conditions such as at the end and start of the day.

[John61CT]

No low voltage panels don't give enough swing room to really benefit from the MPPT optimization algorithms, hence even the el cheapo 75/15 model handling only 250W allows for 70Voc panels.

Minimum should really be 21Voc, might as well just go PWM otherwise, unlikely MPPT would squeeze out even 10% extra.

Get a bigger improvement changing to Sunpower cells

Actually a mobile context do everything possible, watts per sq ft is critical when you only have maybe 150 sq ft total.

[MickinOz]

Have you actually read the Victron manual?
I won't get into a full blown discourse on it, because there is a point where you may as well just have a PWM.
However the Victron looks for battery V plus 5V to start, which is achievable in surprisingly low light from a panel that isn't flowing any current (I've measured a few).
But, once it has started, it only needs battery V plus 1V to run.

[lfhoward]

A few questions re: your solar system.
Those Renogy folding kits appear to come with a charge controller. Have you by-passed this to feed "raw" power to the Victron controller?
How is the dual Victron set up wired to the battery, do you only use one system at a time?
My Renogy Rover MPPT controller needs to "see" the battery voltage.
If you have two chargers in parallel do they confuse each other with regard to battery voltage sensing?
I haven't read all your thread - there simply are not enough hours in the day to read everything I find interesting, so I hope you'll forgive me if you covered all this.

Thanks everyone for the lively discussion. I’ll try to answer Mick’s questions here:
1. My first solar suitcase came with a PWM charge controller that has a lithium setting, but no adjustability. The second one I got is the panel only. I bypassed the PWM charger to send all the power from both panels in series directly to the Victron MPPT mounted inside the trailer. I have a waterproof CNLinko coupler on the side of the trailer for the solar wires.
2. The Victron components can all see each other because they form a bluetooth network. Thus, both charge controllers get to know the voltage and temperature readings taken at the battery by the BMV712 monitor.
3. It is fine to use two charge controllers at the same time because they don’t interfere or fight with each other. This should be true even without the Victron network.
4. No worries! Happy to answer questions.

[MickinOz]

Cool.
With both of them being networked, should all be good.
I wouldn't put my money on point three with some of the dumber controllers out there, though.

They wouldn't "fight" as such, but I'm betting a lot of non-networked stuff would simply mis-read the battery voltage and underperform.

[lfhoward]

Cool.
With both of them being networked, should all be good.
I wouldn't put my money on point three with some of the dumber controllers out there, though.

They wouldn't "fight" as such, but I'm betting a lot of non-networked stuff would simply mis-read the battery voltage and underperform.

Thanks, and fair enough. I changed “would” to “should” under point 3 for future people reading this.

[MickinOz]

I'm in a bit of a debate with myself at the moment.
I have a big 250W panel that has only seen the sun just to confirm it works.
It would take up the entire roof area of the teardrop, but with my Renogy controller it should put in about 16 amps allowing for losses.
Trouble is, I hardly seem to need it.
With my 105 amp hour battery only powering LED lights and the tv, and my penchant for mostly overnight trips, hardly seems worth fitting.
All the loads go through the controller since I decided to put the fridge back in the truck and go with a cooler, and last trip I used 12AH.
I recently went to a garage sale and scored one of those 120W folding kits, with a MPPT controller and an extension lead with anderson plugs at both ends for the princely sum of $50 Australian. Doesn't appear to have seen the sun much either.
I also scored a very nice electronic charger for $3 the other day.
With these two recharge options available, I'm dithering over fitting the big panel.

[featherliteCT1]

lfhoward,

Have you been able to test how far away from your Victron device you can be with your phone and still read Victron data on your phone?

For example, it would be nice to be able to be driving down the road and to look at your phone as you drive to see what is going on with your electrical system.

Also, what is the operating system for your phone (i.e., Apple or Android or whatever)?

Thanks!

[bdosborn]

The Vmp of 17.6 of one panel would mean the battery would have to be discharged to 12.6 volts before the charger would kick in (likely with lead acid batteries but not my new LiFePO4 battery).

At the risk of belaboring a point, the panel will be disconnected by the controller so the PV voltage it's sensing to start charging is Voc, not Vmp. Your panel's Voc is up over 21V and that's a fairly typical value. It doesn't take much light for the panel to get to Voc; I get 12.5V when I turn on the garage lights. The victron controller will start charging a LiFePO4 with just about any modern 12V PV panel, you don't need to worry about that 5V difference.
Bruce
P.S. Parallel PV controllers is no big deal, I've been running them for years. Just make sure they are both set to the same battery charge parameters when you install them.

[bdosborn]

Have you been able to test how far away from your Victron device you can be with your phone and still read Victron data on your phone?

Mine worked in the truck if I had my phone held up so it could "see" the trailer through the rear window. I got a new phone with a better Bluetooth radio, I need to see how well it works.
Bruce

[bdosborn]

My 210 watt roof panel from Continuous Resources just arrived. That’s a couple of weeks earlier than expected! Nice!

I've been eyeing those, let me know what you think of it...
Bruce

[featherliteCT1]

Mine worked in the truck if I had my phone held up so it could "see" the trailer through the rear window.

Thanks for the informative feedback