Setting up Classic on a Houseboat

[Rzelred1]

Greetings everyone,  I recently installed a Classic 150 with 6-190 watt Eopolly panels at 72 volts in,  to charge the 12v battery system. I wired in the WBJ on the negative shunt that is between the battery negative and the input to the 12v to 120v inverter.   In this configuration when reading the WBJ info I am reading my amps to load, when reading the Classic info I am reading the charging amps, volts & watts  and  battery volts. It is my understanding that I can set my Classic to increase the charging output when it sees a rise in amps to load by going to the Advanced Menu and selecting "Shunt".

The issue I have with this is the WBJ shunt is just before the dc/ac inverter and it cannot see the Classic charging amps from the solar panels. By selecting "Shunt" will my Classic look at both input and output amps and increase charging when load increases even though battery voltage is near the Float mode?

[dgd]

The issue I have with this is the WBJ shunt is just before the dc/ac inverter and it cannot see the Classic charging amps from the solar panels.

would a simple solution for this be connecting the -ve output from the Classic to the side of the shunt that goes to your inverter? - and disconnecting it from the battery or bus or wherever it connects to now
Then the WBjr would be reading the amps in/out to the battery.
The Classic would automatically adjust the charging current when it sees a larger load on the shunt.

dgd

[Vic]

Rzelred,

In the Advanced menu,  when you select "Shunt",  you are telling the Classic  to use the current reading from the WBjr,  and NOT use the internal Shunt that is inside the Classic.

Vic

[Vic]

This is a link to a diagram of a  MidNite e-panel:
http://www.midnitesolar.com/pdfs/epanelManual.pdf

On page 15,  is a diagram. It shows the way you should wire the Shunt  to the battery negative,  and the returns from the CC,  etc,

You may have a good diagram,  or an e-panel already,  but if not that might help.    Vic

[Resthome]

The issue I have with this is the WBJ shunt is just before the dc/ac inverter and it cannot see the Classic charging amps from the solar panels.

would a simple solution for this be connecting the -ve output from the Classic to the side of the shunt that goes to your inverter? - and disconnecting it from the battery or bus or wherever it connects to now
Then the WBjr would be reading the amps in/out to the battery.
The Classic would automatically adjust the charging current when it sees a larger load on the shunt.

dgd

dgd is correct you only want one negative cable going to the battery and the shunt needs to be located in that cable. The other side of the shunt should be all your negatives.

[zoneblue]

I wired in the WBJ on the negative shunt that is between the battery negative and the input to the 12v to 120v inverter.

The shunt must be between the bat- and *everything* else.

In this configuration when reading the WBJ info I am reading my amps to load, when reading the Classic info I am reading the charging amps, volts & watts  and  battery volts.

It takes a bit of getting your head around this... the classic output registers a positive reading on the WBJr. The inverter on its own makes a negative reading. Combined the reading is Classic amps less inverter amps . This can be either negative or positive depending on which is larger, which is the net charge current, or battery draw.

It is my understanding that I can set my Classic to increase the charging output when it sees a rise in amps to load by going to the Advanced Menu and selecting "Shunt".

Your muddling a bunch of things here. The classic always provides exactly the amount of amps it needs to a) power the loads, and b) charge the bank. The charging will take precedence, and the bank will provide any shortfall, and all of this depends more on how much sun is, and whether the controller is maxed out or not.

The WBJr, and shunt setting you refer to are about Ending Amps, or EA for short. This is a method to terminate absorb. If you have a WB you should use EA, and use shunt, yes. This has nothing to do with powering the loads, just triggers the transition to float more accurately than relying on the classic internal amps reading which can be confused by loads. Perhaps this is what you getting at and theres a language barrier.

The issue I have with this is the WBJ shunt is just before the dc/ac inverter and it cannot see the Classic charging amps from the solar panels. By selecting "Shunt" will my Classic look at both input and output amps and increase charging when load increases even though battery voltage is near the Float mode?

[Rzelred1]

Thanks for all the replies. Amazing how much I have learned about solar in the llast few months. I reviewed the diagram and I am connected on the battery negative at the shunt which is then connected to the inverter so this looks correct. I do see the Controller charge amps and also the WBJ amps going to load. My thoughts here are when you step onto the houseboat the batteries are fully charged and then you start turning on refrigerator, appliances, etc,. At mid day the panels can produce maximum power but the Controller is at or near "Float" mode due to the Volts on the batteries are at the Float setpoint.  It looks like the batteries draw down 50 to 100 ahrs before the Controller switches to Bulk mode and then I get behind the curve for the day.  Is the reason for this feature to increase charge rate when volts are at or near the "float" mode.  That is what I would like to do so I do not use more amps than are charging at the beginning of a fully charged cycle when batteries will be used the most at mid day.   I am trying to minimize the use of my generator and have the panels/batteries provide the power.

[Vic]

Hi Rzelred,

When the Classic is in Float,  usually that means that the batteries have been fully charged.  If any additional power demands  can be supplied by the PVs,  the Float voltage will be maintained,  and no power will be taken from or supplied to the battery bank.

Batteries Accept charge current.  At a given voltage and State Of Charge,  the batteries will only draw (Accept) a certain amount of current,  regardless of how much current the CC (in this case) could possibly supply form the PV modules.

As batteries are charged during Bulk,  the voltage of the battery will rise.  When the Absorption voltage is reached,  the voltage is held constant by the CC,  and the current that the batteries will accept tapers,  by changing internal impedance of the battery,   NOT because the CC decides to supply less current to the batteries.

So when your batteries have reached Float,  additional power demands on the inverter will come from the PVs via the CC.  When the demands for power  exceed what the CC can supply,  the Float voltage cannot be maintained by the CC,  so,  the demands for power that cannot be supplied by the PVs will come from the battery,  and the battery voltage will decrease -- the CC will show Float MPPT.  If the battery voltage descends to/below the ReBulk voltage that you have set,  a new Bulk stage will start,  but this may not do any added battery charging if the sun is fading in the afternoon.

Does this help or confuse?   Vic

[dgd]

...sorry, just to confirm how you have the shunt connected...

One side of the shunt ONLY goes to the battery, absolutely NOTHING else is connected to this side of the shunt.

The other side of the shunt has the connections to the inverter negative AND the Classic negative and any other devices that need to connect to negative.

Is this what you have?

dgd

[zoneblue]

Your batterys will only discharge if your afternoon loads exceed what the solar, and classic can provide. Little or nothing about the voltage setpoint will change that. Therefore rebulk is only useful in certain particular applications.

If you havent already get yourself a DC clampmeter, and watch and learn. Before no time your a solar addict like the rest of us.

[Resthome]

Thanks for all the replies. Amazing how much I have learned about solar in the llast few months. I reviewed the diagram and I am connected on the battery negative at the shunt which is then connected to the inverter so this looks correct.

It would help if you would indicate where the Shunt is located on you diagram. Right now I see two negatives connected to the batteries. One from the inverter and one from the Classic. If this is the way you have it wired and the Shunt is in the wire coming from the inverter then you need to move the Classic negative to the inventor side of the shut. ONLY ONE Negative cable to the battery from the shunt. EVERY thing else need to be on the OTHER side of the shunt.

[Rzelred1]

Sorry about the delayed response, work keeps getting in the way. Ok so it sounds like I have my CC negative connected at the wrong spot on the battery negative. I will move it to the inverter side of the shunt. Thank you Vic for the explanation on how the CC charges the batteries and how it tapers off when reaching the voltage setpoint. I had a good understanding of that and was looking for verification. The real issue that was perplexing me was watching the load amps and charge amps at about the same level when starting at 1oo% charge on the batteries and then slowly the AHr's remaining would decline over the next few hours when I expected it to maintain a full charge with full sun. Will relocating the CC negative cable help this issue? 

Does the generator negative cable also need to be attached at this place on the shunt?

I have 1140 watts of solar and with full sun so far I have not seen more than 550 watts charging. The batteries have not been below 80% on a sunny day yet.  I was told that I would probably not see more than 50 to 60% with efficiencies and my setup of panels on a flat roof, "houseboat".   Does this sound about right.     

[Resthome]

Sorry about the delayed response, work keeps getting in the way. Ok so it sounds like I have my CC negative connected at the wrong spot on the battery negative. I will move it to the inverter side of the shunt. Thank you Vic for the explanation on how the CC charges the batteries and how it tapers off when reaching the voltage setpoint. I had a good understanding of that and was looking for verification. The real issue that was perplexing me was watching the load amps and charge amps at about the same level when starting at 1oo% charge on the batteries and then slowly the AHr's remaining would decline over the next few hours when I expected it to maintain a full charge with full sun. Will relocating the CC negative cable help this issue? 

Yes. All you are seeing with the way it is wired now are what ever the loads and charging are from the inverter if the Classic is set to read from SHUNT. If the Classic is set to read Classic internal shut you will see the charging from the Solar but not any load. The rule to see NET AMPS in and out of your batteries is to have ONLY ONE negative wire from the batteries to the SHUNT. All other Negatives go to the other side of the shunt.

Once you have the Shunt with the WBjr wired correctly you can monitor the WBjr Amps with the Local App. Once your batteries reach Float you will see little WBjr Amps but the other amps shown as amps out will be going to loads on the boat.

Does the generator negative cable also need to be attached at this place on the shunt?

Yes. If you want to see true NET AMP going in and out of Batteries.

I have 1140 watts of solar and with full sun so far I have not seen more than 550 watts charging. The batteries have not been below 80% on a sunny day yet.  I was told that I would probably not see more than 50 to 60% with efficiencies and my setup of panels on a flat roof, "houseboat".   Does this sound about right.   

Your panels have a spec of MAX Power of 138.9 watts. @ 20 C. Temperature variations will effect this. The hotter the panels are the less power you will get. If you want to see what you can get out of them. Turn on the microwave for a load. The solar will try to provide all the power it can to supply that load, but the load will be greater than the solar. So you will see max solar power for the temperature and sun intensity at that time on the Classic status. 50% is a little on the low side typical is 70% to 75% from what I have observed. Make sure there are no shadows from antennas or other devices being cast on the panels.

Remember with no loads the solar will only put out what the batteries need to reach the voltage set points and will then start to tapper off to maintain that voltage set point.