The ideal backup for solar systems is a dual battery bank. A lot of solar systems
grid tied are doomed to failure because at any time the power companies can
reject the power or at least reject paying for it at a reasonable rate, also when the
grid fails they are without power anyway.
THe way to go is to have a solar system with two battery banks so that if
one becomes fully charged the other bank then gets charged, like on days away.
With a regular PV and battery system the panels can only replace what is
taken out so a second bank can act as a buffer on low use full sun days both
banks get fully charged and only one is used minimally, then if it rains for a
while there is double the energy available. Discretion is the key, if there is
days of rain coming then cut back on use so both banks are charged and ready.
Also with this method batteries are treated better because one bank can be
used while the other charges from the excess, if consumption on the main
bank being used starts to drop the voltage from float V (as Vela explained) then all the energy can be
directed back to it to minimize the discharging of it.
Grid tie systems that charge a battery bank are available but expensive.
A single bank solar system does not charge and discharge at the same time.
The load either uses less than the solar panels produce and the batteries
keep charging with less power or it uses more than the panels produce and
the batteries give up power, like when a cloud goes between the sun and the
panel.
I think any pulsed system that draws from a battery during part of the cycle
and charges it during another part of the cycle is also doomed to failure
because of battery abuse, they cannot do that, it's almost like applying AC to
the battery. But it would be entirely possible to draw off 1 amp and recharge
with 10 amps during the respective cycle portions, if the battery is sized
accordingly as Vela also explained. But the battery will suffer an early failure,
batteries are expensive and quite toxic.
Cheers
grid tied are doomed to failure because at any time the power companies can
reject the power or at least reject paying for it at a reasonable rate, also when the
grid fails they are without power anyway.
THe way to go is to have a solar system with two battery banks so that if
one becomes fully charged the other bank then gets charged, like on days away.
With a regular PV and battery system the panels can only replace what is
taken out so a second bank can act as a buffer on low use full sun days both
banks get fully charged and only one is used minimally, then if it rains for a
while there is double the energy available. Discretion is the key, if there is
days of rain coming then cut back on use so both banks are charged and ready.
Also with this method batteries are treated better because one bank can be
used while the other charges from the excess, if consumption on the main
bank being used starts to drop the voltage from float V (as Vela explained) then all the energy can be
directed back to it to minimize the discharging of it.
Grid tie systems that charge a battery bank are available but expensive.
A single bank solar system does not charge and discharge at the same time.
The load either uses less than the solar panels produce and the batteries
keep charging with less power or it uses more than the panels produce and
the batteries give up power, like when a cloud goes between the sun and the
panel.
I think any pulsed system that draws from a battery during part of the cycle
and charges it during another part of the cycle is also doomed to failure
because of battery abuse, they cannot do that, it's almost like applying AC to
the battery. But it would be entirely possible to draw off 1 amp and recharge
with 10 amps during the respective cycle portions, if the battery is sized
accordingly as Vela also explained. But the battery will suffer an early failure,
batteries are expensive and quite toxic.
Cheers
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