Solar.... getting volts but no amps????

[NYSail]

Hello all

so playing with new boat stuff. I hooked up a 175 watt panel yesterday.Did a basic program of controller ( battery type / 12v). Immediately volts went from 12.5 to 13.0, however did not have change in amps and according to my monitor, my batteries were still being depleted.
What would cause this.....

thanks
Greg

 

[JohnShannon]

Well the fact that the battery voltage increased would seem to indicate charging is occurring. Are you sure the solar is being added on the correct side of the current measurement shunt?

So my vote is the panels are working but you have a measurement problem.

 

[NYSail]

I will double check that as I did attach the neg to the shunt buss-bar rather than directly to the battery.

thanks

 

[Davidasailor26]

Sounds like the right place for the negative.

What other loads were running at the time? Where does the voltage sensor read, the negative bus or the battery terminal?

 

[Hayden Watson]

The charger should attach the the load side of the shunt. the only connection that you should have on the battery side of the shunt is the cable to the negative terminal and the battery side wire of the twisted pair to the meter.

 

[Capt jgw]

Was it sunny or cloudy, and any shading on the panel? One little shadow on the panel and it won't work. Does your charge controller have a readout showing volts and amps to the battery? Mine does, and it never agrees with the monitor. Monitor shows net charge, after all the loads have been subtracted. Sometimes the load is more than the panel is producing, so the net is a negative number.

 

[SycloneDriver]

From my experience under normal conditions a solar panel will produce 75% of its rated power. So a 175 watt panel will produce 131 watts. Your a little further north so I would expect less. As others have said shading greatly reduces output, so does heat. If the panel was producing 130 watts at 13 volts that would be 10 amps. If you had more than 10 amps of load on the boat at the time your battery would be depleting.

Give us a little more detail on the equipment and the install.

 

[NYSail]

I went through mppt charger and it appears to be reading and producing correctly. I think that my 10+ years old Xantrex linklite might not be functioning properly. It has happened before when I had to unhook batteries while on a trip. Started acting normal when I got home plugged in charged overnight And Then synced the monitor/ batteries.

Greg

 

[Will Gilmore]

Immediately volts went from 12.5 to 13.0, however did not have change in amps

Does this mean that the amp reading was the same as the previous configuration or are you saying you get a voltage jump at zero amps?

.
I'd be concerned about a zero amp rating, but why would you expect the amperage to go up? This is your current. An increase in voltage doesn't have to come with an increase in amperage. It could come with an increase in resistance. Maybe your wire size is too small or too long or the terminals don't have good contact.

With an increase in voltage, you still are seeing an increase in wattage or is that not so either?

-Will (Dragonfly)

 

[Davidasailor26]

I'd be concerned about a zero amp rating, but why would you expect the amperage to go up? This is your current. An increase in voltage doesn't have to come with an increase in amperage. It could come with an increase in resistance. Maybe your wire size is too small or too long or the terminals don't have good contact.

I think he means the amperage, as measured by the shunt, didn’t go down. The shunt measures the current being provided by the battery, or being pushed into the battery when charging. The current provided by the solar should offset the current being provided by the battery. So depending on the amount of the load the measure current draw from the battery should either decrease (solar offsetting but not keeping up with the load) or go negative (solar proving more than the load is drawing.

One more thing you could do to troubleshoot - use a multimeter to measure the voltage across the shunt. The voltage should change when solar turns on. Without solar it should be a few mV, with the load side being the higher voltage. With solar it should be either less mV, or the battery side will be the higher potential. Since you’re reading 13V I think you’re actively charging the battery, so I’d expect to see the battery side of the shunt higher.

 

[Brian D]

Unless you have a shunt between the solar panel controller and the battery I don't think you will see what the panels are doing. Normally your shunt will be after the battery, between the battery and the distribution panel. And, if you are not putting any load on the battery you won't see any current flow. Key is LOAD. Now unless I am not understand what you are trying to do, maybe a diagram of your system would help us.

JMHO

 

[NYSail]

So again pardon my ignorance with electric. Wires go from panel to controller (10 amp fuse for +), controller to battery (fuse for +). So I thought I would see amps go up..... again today voltage read 13.0 on battery monitor. my reference is my alternator..... when I turn engine on with 50% soc I see volts go up to setting and amps as high as 100. No obviously I don’t expect to see this performance but though I would see some positive charging. Soc is not bettering under solar.

Was trying to trouble shoot this weekend but will call tech dept in morning to work things out.

Thanks
Greg

 

[JohnShannon]

If your battery voltage is going up then the panel is charging it. Battery voltages don't rise on their own. You can check by throwing a blanket over the panel and see if the battery voltage goes down, repeat as many times as necessary to convince yourself that sun on the panel= higher battery voltage.

If there is a wiring error and you don't measure the charge current from the panel. Then your charge current will incorrectly read zero, and likely your SOC won't change because the charging current is not being measured.

 

[NYSail]

There is voltage going to the battery. Today I will turn off all loads and see what is coming through in regards to amps.

Thanks!
Greg

 

[Captain Larry-DH]

I will double check that as I did attach the neg to the shunt buss-bar rather than directly to the battery.

thanks

Greg, Is it possible you attached it to the wrong side of the shunt? That would produce the behavior you described.
When charging from solar you should see a positive amps reading if your charge current is exceeding your load current, or your load (negative amps reading) would be reduced by the amount of charge if load exceeds charge current.

 

[dLj]

What are your loads? Can you simply turn them all off and just let the panels charge the battery? That may help to see if the installation is correct.

dj

 

[Maine Sail]

What side of the shunt is your solar controller negative output connected to??

 

[SouthernYankee]

Hey All, first solar panels are rated at the voltage they output, usually 18+ volts (volts pre controller), thus 175 watt = Volts x Amps, or ~ 9 amps. Secondly, charge controller will not output amps if it senses that batteries won't accept a charge (i.e. full), it will be working in trickle mode which is ~13.5 V @ ~1 amp (depending on charge controller). Lastly you can always get it to out put by putting demand on your system, e.g. turn on your water pump, refrigerator etc, and you will see the charge controller respond in kind and output amps to match the load. If you don't have a reliable amp meter hard wired, try using an dc amp clamp meter.

 

[SycloneDriver]

Hey All, first solar panels are rated at the voltage they output, usually 18+ volts (volts pre controller), thus 175 watt = Volts x Amps, or ~ 9 amps. Secondly, charge controller will not output amps if it senses that batteries won't accept a charge (i.e. full), it will be working in trickle mode which is ~13.5 V @ ~1 amp (depending on charge controller). Lastly you can always get it to out put by putting demand on your system, e.g. turn on your water pump, refrigerator etc, and you will see the charge controller respond in kind and output amps to match the load. If you don't have a reliable amp meter hard wired, try using an dc amp clamp meter.

Not true with an MPPT controler. Example, my RV has 2 100 watt panels wired in series. The voltage at the controller is often in the high 30s. I often see charging currents of 10 amps and sometimes 14.

 

[Ron20324]

Not true with an MPPT controler. Example, my RV has 2 100 watt panels wired in series. The voltage at the controller is often in the high 30s. I often see charging currents of 10 amps and sometimes 14.

I have 2 switches to change the panels from series to parallel. If a panel goes bad, switch to parallel to use just the one good one.