I have 2 x 120a/h deep gel batteries.I run 2 x 70 watt panels,I find at times they just keep up with our power consumption in the motorhome over a few days ,and have had a blackout once. If I was to add another panel,do I have too match up the 70watt panels or can I go a bigger panel e.g 200 watt.Thanks
bill12 said
03:10 AM Jun 24, 2013
As long as your reg is upto it,add as many as you can. I reckon you can,t have enough.I have 2 80w panels, and would like more. I willget more when I can. If you have the room , get more. Bill
goldcoaster said
11:59 AM Jun 24, 2013
Thanks Bil, my reg..is 30amps, should be allright !!! My panels are portable not fixed so room is not an issue,plenty of storage.
justcruisin01 said
07:03 PM Jun 24, 2013
goldcoaster wrote:
Thanks Bil, my reg..is 30amps, should be allright !!! My panels are portable not fixed so room is not an issue,plenty of storage.
The two 70's will give you around 9amps.
the 200 will give around 15amps so your 30amp reg is ok.
JC.
goldcoaster said
12:39 AM Jun 25, 2013
Thanks JC,can I ask how you calculated the amps.
justcruisin01 said
04:15 AM Jun 25, 2013
goldcoaster wrote:
Thanks JC,can I ask how you calculated the amps.
Watts divided by volts = amps; less 10/15% loss.
Eg; 120 watts divided by 12 volts =10 amps; minus 1/1.5% loss = 9/8.5 amps.
This loss is a natural loss due to the way the system works, nothing wrong with the equipment.
This calculation is at peak performance of a 120watt panel.
JC.
Peter_n_Margaret said
05:59 AM Jun 25, 2013
Many (but possibly not all) regulators will not be damaged if they are fitted to panels which deliver more power than they can handle, they will just "waste" the excess. Alternatively it is possible to use a shunt and have a small regulator control more panels than it can handle directly. The Plasmatronic regulators can be arranged to do this, probably others too.
Cheers, Peter
mr glassies said
02:43 PM Jun 25, 2013
hehehe im putting 4x 200 watt panels on my roof
dibs
Cruising Cruze said
06:35 PM Jun 25, 2013
@ mr glasssies
And how many Batteries you put in MMATEEE
next time when we camp beside you Mate, my battery will be charged in 10 minutes if I hook onto your system
Cheers John
Plendo said
05:01 AM Jul 3, 2013
Please be careful about how you configure your solar panels, it varies depending on the type of controller you are using, and a few important parameters.
Please let me try to explain:
Pulse Width Modulation controllers, or PWM for short, manage the voltage being supplied to the battery by pulsing the signal on and off. For example if they need to supply say 14.6V to charge a 12V battery, and the voltage from the solar panels is 21.9V, the signal would be on for two thirds of the time. These controllers also manage current in the same way, so they use frequency and pulse width to shape the output. The negative, is that a large part of the unused power is wasted.
Multi Point Power Tracking or MPPT, is the new kid on the block, it works in a very different way, it tries to optimise the power from the panels, then inverts it and rectifies it to achieve the correct output voltage (vastly simplified explanation). The advantage of MPPT is the efficiency, the disadvantage is the cost.
PWM works best with the panel voltage just above the target voltage, MPPT is most efficient when the voltage is high. This means you configure your panels differently for each type of controller.
For PWM you tend to buy panels to suit your system and to arranged them in parallel, thus keeping the voltage close to your system voltage, the number of panels you have is typically limited by the current capacity of your controller.
For MPPT you arrange your panels in series in matching strings, with the number of panels in a string limited by the maximum input voltage of your controller. You then connect the strings in parallel.
There are many more considerations when building a solar system.
Many of the existing solar systems could achieve more, and often people spend far more than they need. Please consult a specialist to ensure your system is properly designed and balanced, both within itself, and with your battery bank, otherwise you are likely to waste money.
I have 2 x 120a/h deep gel batteries.I run 2 x 70 watt panels,I find at times they just keep up with our power consumption in the motorhome over a few days ,and have had a blackout once. If I was to add another panel,do I have too match up the 70watt panels or can I go a bigger panel e.g 200 watt.Thanks
The two 70's will give you around 9amps.
the 200 will give around 15amps so your 30amp reg is ok.
JC.
Watts divided by volts = amps; less 10/15% loss.
Eg; 120 watts divided by 12 volts =10 amps; minus 1/1.5% loss = 9/8.5 amps.
This loss is a natural loss due to the way the system works, nothing wrong with the equipment.
This calculation is at peak performance of a 120watt panel.
JC.
Alternatively it is possible to use a shunt and have a small regulator control more panels than it can handle directly. The Plasmatronic regulators can be arranged to do this, probably others too.
Cheers,
Peter
dibs
And how many Batteries you put in MMATEEE
next time when we camp beside you Mate, my battery will be charged in 10 minutes if I hook onto your system
Cheers John
Please be careful about how you configure your solar panels, it varies depending on the type of controller you are using, and a few important parameters.
Please let me try to explain:
Pulse Width Modulation controllers, or PWM for short, manage the voltage being supplied to the battery by pulsing the signal on and off. For example if they need to supply say 14.6V to charge a 12V battery, and the voltage from the solar panels is 21.9V, the signal would be on for two thirds of the time. These controllers also manage current in the same way, so they use frequency and pulse width to shape the output. The negative, is that a large part of the unused power is wasted.
Multi Point Power Tracking or MPPT, is the new kid on the block, it works in a very different way, it tries to optimise the power from the panels, then inverts it and rectifies it to achieve the correct output voltage (vastly simplified explanation). The advantage of MPPT is the efficiency, the disadvantage is the cost.
PWM works best with the panel voltage just above the target voltage, MPPT is most efficient when the voltage is high. This means you configure your panels differently for each type of controller.
For PWM you tend to buy panels to suit your system and to arranged them in parallel, thus keeping the voltage close to your system voltage, the number of panels you have is typically limited by the current capacity of your controller.
For MPPT you arrange your panels in series in matching strings, with the number of panels in a string limited by the maximum input voltage of your controller. You then connect the strings in parallel.
There are many more considerations when building a solar system.
Many of the existing solar systems could achieve more, and often people spend far more than they need. Please consult a specialist to ensure your system is properly designed and balanced, both within itself, and with your battery bank, otherwise you are likely to waste money.