No PV voltage coming from solar controller

skyote

I have searched the group for possible solutions but have found none so far that worked for me.  I have a 2021 Tab 320S BD with an MPPT 75/10 SmartSolar controller.  On July 17th, shortly after buyying this trailer,  I replaced the the stock battery with a Renogy lithium 100ah self-heated battery.  My charger brought it up to 80%, then the solar topped it off as expected.  It worked great for two days, then the solar stopped charging.  The Victron app shows voltage, but no current to the battery, nor current load from the battery.  While running the roof fan, fridge and lights, the Renogy app shows -6.6a current, but 0 from the Victron app.  The suggestions I have read so far include checking fuses at the battery, and the controller, (all are good) and checking the connections at the battery and controller (also good).  I am still getting good charge to 80% from the charger, but nothing from solar.  I am posting photo of the app, battery and controller to see if anyone spots anything I have overlooked.  It worked great until it didn’t.  Thanks in advance!

Yoshi_TAB

Hi, 

The solar charger won't start charging until the solar voltage is +5V above the battery voltage.  That won't occur until there is enough sun energy on the panel.

skyote

With full direct sun, the voltage only gets up to 17-18v.

Yoshi_TAB

Can you post the History screen for the two days it worked

Is it possible you toggled the slider to turn off the charger (on the set up scrren)

skyote

Grumpy_G

Looking at the pic of the Victron it appears nothing is connected to the load terminals. The controller won't show any load then. 

The 5V difference is something I find a questionable design decision by Victron. I understand the thinking, a typical RV PV panel has 20V open circuit voltage and they want to make sure the controller has enough of a voltage range to measure for the power tracking. But smaller panels can be marginal with the 5V requirement. Once the controller gets going it works down to a 1V differential under load so lowering the starting differential to 3 or 4V might not be a bad idea. 

Do you know the specs for the panel on the trailer ? 

skyote

I do not know the specs, sir.  It is the stock panel for the 2021 320 BD.  105W, I believe.  I don't understand the 5v requirement. To me, that says my battery would have to drain to around 15% (12.5v) before the charger would kick in.  So how does solar top off the battery after it reaches 80% with the DC charger?  I am still learning.

skyote

Right now, about half the panel is getting direct sun and this is a shot of my app screen.  

Yoshi_TAB

"With full direct sun, the voltage only gets up to 17-18v."

Once it does get to the +5V, it does not have to stay there to continue to charge. But at least 1V above battery voltage.

I have the same set up and will get to over 20V.  The battery does not have to drain, but the solar voltage does have to be +5 to begin charging, that's just the way it functions.

You have 17.14 with it partially shaded.  Can you swing your TAB more into the sun to test it.

If that's not it, hopefully someone can help...

skyote

Thank you.  So, if i take it off shore power, and run the refrigerator and fan until it drops down to 12.5% or about 15%, the solar should kick in?  I haven't seen it go above about 17.7v.  I appreciate your help!

Yoshi_TAB

You could do that to test it, but that is a pretty big drop(12.5V) for a lithium battery.  I would first see if you can shuffle your TAB to bring in more sun (or wait until the sun moves a bit) and see if you can get it to the +5V which will kick in the charge.  Your almost there at 17.14V.

pthomas745

You changed to a new battery.  Did you change the Victron solar controller to lithium settings? Show us a shot of your battery settings on the SmartController page.

And: solar controllers are a bit choosy about how they want to be hooked up.  The battery should be connected to the solar controller, and then the solar panel should be connected to the controller.

Show us the battery settings for your controller.  Try "resetting" the controller by: removing the negative cables from the solar controller for the panel and the battery input.  Reconnect the battery first. Then the solar panel.

The phrasing for the "load" and "current" gets a bit screwed up.  The "load" section of the solar controller with the two connections is only used in fairly specific situations for small 12V uses.  If you haven't been into the manual and jumped through several hoops for proper use of the "load terminals", those numbers will always be zero.

The "battery current" section of the controller is the number of: current going into the battery to charge, and current going out of a battery while the battery is in use (denoted by a negative number).

If you have not changed your settings from a lead acid battery, the solar controller is seeing a full battery and will not charge.  (A full lead acid battery is 12.6v or so.)

rfuss928

In the OP photo, ti appears there are no lights lit on the Victron controller.  That means there is no battery voltage at the controller terminals (or the unit is dead).
Check the voltage at the battery connection.

skyote

I did change the user defined battery to Smart Lithium.  
The Victron has a slow blinking blue light.  i also have the Renogy DC Home app that shows the same voltage as the Victron.

skyote

Right now I have full sun on the panel and it only gets up to 17.6-17.7v

Horigan

Is the solar panel relatively clean?

skyote

I would say so.  Here is a current pic.  The trailer is facing north, but the sun is pretty much overhead.  

Yoshi_TAB

Hi,  

Another source I find helpful is  :  Vehicle Mounted Systems | DIY Solar Power Forum (diysolarforum.com)  Lots of knowledgable people there.

I'm not sure how much differecne it makes, but my float and absorption voltages are both set to  13.90 V. (I have Lion batteries).  Also my Battery preset is also set at "User Defined"

I've reached out to these folks when I noticed minor peeling of the clear coat.  They were helpful.

105W Flexible Vehicle Solar Panel - OK4WD

skyote

Thank you for your help and the links, Yoshi.  I notice one spot on the solar panel where the previous owner may have knicked it with a tree limb.  It looks to have just peeled back a small, maybe 1/4" x 3/4" area of the top skin.  It doesn't look too bad.  

Yoshi_TAB

Hi,

Other people have experienced a bit of peeling on the top clear skin.  I've been told by a few sources (one was the link I sent)  not too worry about.  They did recommend to trim any hanging rough edges back , like trimming a cuticle back.  The website has a recommended adhesive if there are large spots.

 I would post on the Solar forum and see what answers you get if nothing comes from this forum.  There are some smart solar folks on this forum..maybe they have not seen this post yet.   

It seems to be working to some degree, as you are getting up to 18V.  As someone suggested, it maybe worth cleaning it with a soft cloth and mild soap just to know it's clean. 

Also, are the settings those recommended by Renogy?  It may matter with the battery chemistry.  I would contact Renogy.

I also like the suggested idea to confirm the voltage at the controller with a meter.  Put the meter probes on both the PV and battery on the controller +/- just to confirm what the app is saying.

If you do facebook, here is another place to post your issue:  Victron Energy | Facebook


Let us know what you find when you get it working.

skyote

From what I have gathered, Renogy specifies 14.4v for both absorption and float.  The voltage reported on the Victron app matches what i am getting from the renogy battery Bluetooth app, so I believe it is accurate, but I will confirm tomorrow.

skyote

Also I did climb up and cleaned the solar panel with distilled water and a microfiber towel.  It didn't make any difference.

Marceline

skyote said:

Thank you.  So, if i take it off shore power, and run the refrigerator and fan until it drops down to 12.5% or about 15%, the solar should kick in?  I haven't seen it go above about 17.7v.  I appreciate your help!

I’m a little confused by this comment. If you’re trying to test your solar panel you shouldn’t have the camper connected to shore power. The solar controller is going to read the voltage from your converter or charger(?) as the voltage at the battery (13.43v above). You have at least one reading of 18.3v on the solar panel so assuming that voltage, if you disconnect from all other power sources the controller will kick back in as soon as the battery reads 13.3v.  Then it will bring it back up to float at 13.5v. 

Yoshi_TAB

 Hi,

A few ideas/thoughts;

In your later post, the battery voltage went up to 13.43 from 13.22.  What did the SOC indicate on the Renogy app?  That is almost fully charged.  Did the SOC read closer to 100%?  Maybe the battery is fully charged.  That would be one reason the solar controller is off in addition to the +5V requirement.  On my Shunt app (like your Renogy app), it needs to be calibrated at 100% when the battery is known to be fully charged.  Maybe the SOC is not right?

 If you are comfortable removing wires, just to check,  can you you remove all the connections to the battery and  check the battery voltage with a multimeter confirm the voltage matches the readouts of both apps?  

Although you can have multiple sources  to charge a battery (converter/charger and solar).  I do like the idea of the other poster to remove the charger out of the loop and just have your solar connected to the battery and see what it does/reads.  I think if you turn off the battery switch, the solar controller is wired directly to the battery (that is how my unit is wired)

I would , as you plan, double check the voltage settings for the renogy battery.  If they are not right, I believe the controller may think the battery is fully charged when it's not.

MPPT solar charger manual (victronenergy.com) (section 9.2.4-9.2.9  battery not charged)

Did you know...why the MPPT charge controller starts 5Vdc above the battery voltage? - YouTube

skyote

This morning, with shore power disconnected and after running yesterday afternoon and evening with refrigerator and fan to bring the battery down, the battery is now at 22% SOC @12.9v.  The multimeter readings at the Victron terminals match what is shown on the app and the battery itself is consistent with the disconnect on or off at 12.95v (with cables still connected). It also matches with the Renogy app voltage.   I am in the shade until later today, then I should be able to get 5Vdc above to see if solar charging kicks in.

Yoshi_TAB

Hi, 

Hopefully that will work.

I'm sure you know, but just to confirm, since you are running at -3.24A to power your DC items (assuming the battery switch is on) you will have to at least generate  that many solar amps to power those devices and then, any excess, (once it's gets back to zero) will be used to charge the batteries.  So if your DC items are on, it may take a bit to fully charge your batteries via solar.   

LucaJones

It looks like there might be an issue with the mppt controller or its settings. Double check the controller's configuration and consider reaching out to the manufacturer for support.

Also ensure all connections are secure.

pthomas745

I still would disconnect the solar controller and reconnect it with the battery connected first.  The Victron should be registering that current draw the same way the Renogy app is.  This is independent of what the charger may be waiting for.

Marceline

pthomas745 said:

I still would disconnect the solar controller and reconnect it with the battery connected first.  The Victron should be registering that current draw the same way the Renogy app is.  This is independent of what the charger may be waiting for.

 I concur. I think the Victron app should also show -3.24A from the battery. 

Nevermind. The post below is correct. The solar controller readout only shows flows from the controller to the battery. I have a SmartShunt and mostly look at that so I got a little muddled there. 

ColMag

I believe the solar controller cannot know what current is being drawn from the battery. VictronConnect's line under Battery/Current would list the current going into the battery from the controller, if there was any. This stuff is always confusing to figure out.

Yoshi_TAB

Hi,

The victron and the renogy current flow should match if the battery switch is off (i.e no loads going to DC items).    If the battery switch is on, I agree the solar controller will not know what is being drawn from the battery (which is why a shunt wired into the negative current flow is needed)