Is it true that since a panel puts out say 18+ volts, that will cook the battery. So you put the voltage through an MPPT.
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MrM1
I'm Here, But I'm Not All There
It's magic
So you are saying that the extra volts goes to more amps for charging?
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An MPPT controller will take the power (watts) from the panels and convert into the charge voltage and corresponding amps. The incoming voltage/amps is largely irrelevant as long as the incoming voltage is at least 1V-5V higher than the charge voltage.
Example:
Let's say you have 500W of solar panels and due to the current solar conditions the panels are producing 350W. Your 12V MPPT charge controller may be setup to charge at 14.4V. This means the MPPT will take the 350W and produce 14.4V at 24.3A.
Simple answer is yes.
www.solar-electric.com
What is Maximum Power Point Tracking (MPPT)
An MPPT, or maximum power point tracker is an electronic DC to DC converter that optimizes the match between the solar array (PV panels), and the battery bank or utility grid. To put it simply, they convert a higher voltage DC output from solar panels (and
www.solar-electric.com
Thanks. So I should buy panels that have a high Vmp number based on the same Wattages?Simple answer is yes.
What is Maximum Power Point Tracking (MPPT)
An MPPT, or maximum power point tracker is an electronic DC to DC converter that optimizes the match between the solar array (PV panels), and the battery bank or utility grid. To put it simply, they convert a higher voltage DC output from solar panels (and
I want to use 2 100W panels in paralle on a 12v system. The HQST panels at 100W have a Vmp at 20.3 each.
Ampster
Renewable Energy Hobbyist
The other thing, not mentioned is that many charge controllers can be programmed for custom voltage and all of them will shut off or go into float when charging is finished.
efficientPV
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As temperature of the panels increases (you are almost never at 25C) the voltage drops. Any wires or fuses cause a voltage drop. So, running higher current with panels in parallel near battery voltage may not be a good idea unless there is shading. Running two 100W panels is often far more expensive than a higher wattage grid tie panel of 30-37V. I want to get rid of all my 100W panels, they are a waste of space.
MichaelK
Solar Wizard
What would happen is that even with the raw solar connected directly to the battery, the battery as a load would drag the voltage of the panel down to what the battery wants to charge at. So, if you connected the panel to a drained battery, the voltage would drop from 20V to ~12.0V. As the battery becomes more and more charged, the voltage will rise to around 14.4V or so.
But, one the battery is fully charged, the continued flow of electricity is going to by used to boil off the water in the electrolyte, finally damaging the battery. This is why you have to have a controller if you just want to walk away.
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