Solar voltage output

Burgo1 · Veteran Member

Solar voltage output

Aus-Kiwi · Guru

Mine is up around 18v . Before reg . On sunny day ..

Burgo1 · Veteran Member

Thanks for that what amount to battery should there be ? I must admit it's been doing my head in !!

Aus-Kiwi · Guru

On my reg it's between 12.2 and 13.7 volts . AGL batteries .. Depending on day ? ( sun) and SOC .

Burgo1 · Veteran Member

I've got wires coming out of reg from battery 1 to one battery in a bank of two batteries only 1.4 volts it's a 20 amp red arc reg . I will read instructions again to ensure I've got it set right .

Aus-Kiwi · Guru

1.4 v or 14v ? Unless it's the solar voltage ? Overcast ..

Jaahn · Guru

Hi smile

Sounds like you should go back to basics and start again. Disconnect the solar panels and the battery(s), and the reg.

Read the manual first. Then measure the voltage of the panel output wires, next the battery voltages while sitting with no connection to anything.

Normally connect the reg to one battery first, check the connection is correct, then connect the panel to the reg.

THEN report back here with the voltages and say what happened when you connected these two up to the reg . before you do any other connections.

Jaahn

-- Edited by Jaahn on Tuesday 1st of November 2016 11:49:56 AM

PeterD · Guru

Burgo1 wrote:
Hello all, I have a portable set of 160 panels, the question is what amount of volts should be going to regulator ? I'm reading 14.3 in winter cloud free sun light.

You are not very clear here. Have you separated your regulator from the panels? It is difficult to read the input to the regulator on many panels, how are you getting to the input? I suspect you may be getting your terminology a bit skew.

The important thing is to see what output you get from the regulator into the battery. If your battery is flat enough for the panel to be charging it with full output from the panel there will be very little voltage drop across the regulator. It will be acting as a near short circuit with the series pass transistors turned hard on. Depending on the style of transistors used in the regulator you may only be able to read 0.3 to 0.8 V across it. That would make your 14.3 V feasible. If the battery is severely discharged and the battery voltage down to 10 to 12 V then the panel output voltage will only be the 0.3 to 0.8 V above the battery terminal voltage.

Solar cells (and thus panels) are not near constant voltage devices like batteries:

Solar Cell Curves.jpg

The above curves explain how a cell operates. The maximum a cell puts out is around 0.6 V, that's why there are 36 of them in a panel to get enough voltage to charge a battery. Follow the green line. If you will measure 0.6 V across it (21.6 for a panel.) When you draw a bit or current from the panel the voltage across the cell will drop. If you are charging your battery flat chat and the battery terminal voltage is only 13.5 V and you have a quality regulator with 0.3 V drop across it the input voltage of the regulator will be 13.8 V. That would have dropped the cell voltage to around 0.4 V and the cell would be producing roughly 1.2 W (which is a little down from its 1.35 W theoretical maximum potential.)

Dick0 · Guru

Hi Burgo,

If you have a bank of 2 batteries set up then you will see which is the + and the - for that dual setup.

The regulator will be clearly marked solar input + & - and the charge output to battery + & - will also be clearly indicated.

You may have all connected correctly except the connection to the dual batteries.

14v solar input to regulator should give you around 12v to 14v output charge depending on condition of batteries.

I have two fixed solar panels rated at 200w each. They output up to 22v depending on solar conditions but output from regulator is anywhere from 12.5v to 14v.

macka17 · Guru

Hi.

The average Panel. with output at outlet wires. around 17.3v on average.

String your wires to regulator, and you should be getting,
out of regulator to battery. 13.2 to around 13.6/7 (and more, regulated)
Any less than 13.2. your wire from/to. Is either too long. or tooo thin.
Go thicker.

Amp outputs, Generally tend to go up in 40w panel increments.
40/80/120/160/200w with a few in between.
Ampages, generally are. 40w/2.2a -- 80w/4.4a -- 120w/6.6a, etc. etc.
ALL amps are "ish" on the ends. varying. But generally pretty close to.
24/48v Grid panels are different again.
Most regulators will give adjustments for different types of battery.
Which normally adjust max voltages in to cover max charge rate.

Peter_n_Margaret · Guru

Depends on the panels...
Nominal 12V panels can be between 17 and 21V, depending on the panels and the solar irradiance levels. Mine are about 20V typically.
But panels can be much higher voltage output than that, but to get the best from them you will need an MPPT controller.

The solar controller determines the voltage to the batteries. That can vary from 13. something on float to14.9 for bulk charge into AGMs to over 15V for equalising a wet cell. The type of battery will determine the optimum voltage and the controller should be set for that to get the best rate of charge and the longest battery life.
Take close notice of your battery makers recommendations.

Cheers,
Peter

Aus-Kiwi · Guru

Have to ask ? Is there regs on each panel ?

PeterD · Guru

Aus-Kiwi wrote:
Have to ask ? Is there regs on each panel ?

You are not clear. Do you mean regulations or regulators? People who use colloquial language will frequently be misunderstood. When asking questions or giving answers you should use the queens English.

If you mean regulators, I think the major difference between portable panels and panels sold for permanent is whether they have regulators. Regulators would not be attached to panels sold for permanent installation. Portable panels will probably have regulators in the kit even if they are not glued to the back of the panel.

Back to the original question the question is what amount of volts should be going to regulator? The voltage will depend upon the regulator. If you have an MPPT regulator working flat out then the regulator will attempt to hold the panel output at its maximum power point (remember the maximum power output and the Vmpp will vary with the panel temperature, the higher the temperature the lower will be the MPP and the Vmpp.)

If you are using a PWM regulator, when it is working at full capacity there will be very little voltage lost across the regulator, its series pass transistors will be switched hard on. The voltage into the regulator will be around 1/2 V higher than the battery voltage. If you system will charge very well discharged batteries you could see well under 10 V into the regulator until the battery receives a bit of charge. The voltage from the panels will be that voltage plus the voltage drop along the wires from the regulator to the panel. That state of affairs will remain as the charger goes its bulk charge. During the bulk charge the battery terminal voltage will rise until it gets to the absorption stage set voltage and then the battery charge current will commence to reduce. As the current reduces the voltage across the regulator will commence to rise and thus the panel voltage will rise at much the same rate. When the battery charge rises to near full charge the current will drop to near zero and the panel voltage will rise to near its open circuit voltage.

Aus-Kiwi · Guru

You know what I mean . Whatever ? Check ? Using two or so inline will confuse main reg .