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jim w
Guest
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 Posted:
Sun Jan 09, 2005 8:09 am Post subject:
charging a 12V battery from a 48V dc source? |
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I need to get 12V from a 48V Solar (PV) system. The 48V is charged by 4
12Vdc PV panels, into eight 6V batteries.
I have a need for 12Vdc. I could just use a power supply on the AC side
of the inverter, but that seems like a waste of power
(48Vdc->inverter->transformer->regulated_PS).
Would it be reasonable to build a DC-DC drop-down switcher?
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Madhu
Guest
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| Posted:
Sun Jan 09, 2005 9:58 am Post subject:
Re: charging a 12V battery from a 48V dc source? |
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A DC-DC converter is the way to go. ETA-USA (http://www.eta-usa.com/)
for one has a bunch of 48VDC input converter modules and using them is
simplicity itself. Likewise you can do a search of 48VDC input DC-DC
converters and come up with a lot of products that would match your
needs. I would not use the inverter-transformer method.
Madhu
jim w wrote:
| Quote: | I need to get 12V from a 48V Solar (PV) system. The 48V is charged by 4
12Vdc PV panels, into eight 6V batteries.
I have a need for 12Vdc. I could just use a power supply on the AC side
of the inverter, but that seems like a waste of power
(48Vdc->inverter->transformer->regulated_PS).
Would it be reasonable to build a DC-DC drop-down switcher? |
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SteveB
Guest
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| Posted:
Sun Jan 09, 2005 12:57 pm Post subject:
Re: charging a 12V battery from a 48V dc source? |
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I don't suppose you could just take +12v direct from the 2nd battery up the
chain, a problem would be that the lower 2 batteries would get discharged
quicker than the top 4, so rotation would be needed to even things out.
"jim w" <jim22@trlp.com> wrote in message
news:Bn0Ed.2699$9a4.755@fe06.lga...
| Quote: | I need to get 12V from a 48V Solar (PV) system. The 48V is charged by 4
12Vdc PV panels, into eight 6V batteries.
I have a need for 12Vdc. I could just use a power supply on the AC side of
the inverter, but that seems like a waste of power
(48Vdc->inverter->transformer->regulated_PS).
Would it be reasonable to build a DC-DC drop-down switcher? |
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ComTech
Guest
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| Posted:
Sun Jan 09, 2005 9:58 pm Post subject:
Re: charging a 12V battery from a 48V dc source? |
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You're right a switcher would be the best way to go.
But there is a cheap and dirty way of doing things. You could put a power
resistor in series to your load. You would calculate the resistor by R = 36V
/ max current then calculate the wattage for the resistor. Again it is
really dirty and you should use zener and capacitor, but then I would try
the switcher.
Best of luck to you,
Comtech
"jim w" <jim22@trlp.com> wrote in message
news:Bn0Ed.2699$9a4.755@fe06.lga...
| Quote: | I need to get 12V from a 48V Solar (PV) system. The 48V is charged by 4
12Vdc PV panels, into eight 6V batteries.
I have a need for 12Vdc. I could just use a power supply on the AC side of
the inverter, but that seems like a waste of power
(48Vdc->inverter->transformer->regulated_PS).
Would it be reasonable to build a DC-DC drop-down switcher? |
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