Posted by Ecnerwal on November 30, 2006, 11:02 pm
My head hurts.
For the better part of 3 years I've been creeping towards getting a
power system together - partly I take a long time researching stuff,
partly the longer I wait the more money I have (on the other hand, the
price of copper wire has roughly tripled).
I'm about to get it ordered.
I have been, based on early input from helpful folks here, leaning
strongly towards a 48V system. Smaller wire, smaller breakers, fewer
parallel strings in the battery for a given storage capacity and battery
size. Since I'm starting from scratch I don't need to match any existing
equipment, and I'm leaning to the "do it pretty much all with AC from
the inverter" approach as being cheaper than having various DC
appliances which are costly and rare (putting the cost into more
generation due to slightly lower efficiency - but I have other reasons
to want plenty of generation capacity - workshop loads, etc).
However, the pesky conundrum of a PV array that will, on the one hand,
charge a 48V bank effectively (in the hot season), and won't on the
other hand, fry the charge controller (in the cold season) is making me
seriously reconsider 24V as a system voltage.
--
Cats, coffee, chocolate...vices to live by
Posted by Solar Flare on November 30, 2006, 11:18 pm
24 v is nowhere. Go 48 for the capacity or 12 volt for the
availability with automotic circuits everywhere.
Most MPPT I have seen will accept from 50v to 120 vdc for a 48v bank.
> My head hurts.
> For the better part of 3 years I've been creeping towards getting a
> power system together - partly I take a long time researching stuff,
> partly the longer I wait the more money I have (on the other hand,
> the
> price of copper wire has roughly tripled).
> I'm about to get it ordered.
> I have been, based on early input from helpful folks here, leaning
> strongly towards a 48V system. Smaller wire, smaller breakers, fewer
> parallel strings in the battery for a given storage capacity and
> battery
> size. Since I'm starting from scratch I don't need to match any
> existing
> equipment, and I'm leaning to the "do it pretty much all with AC
> from
> the inverter" approach as being cheaper than having various DC
> appliances which are costly and rare (putting the cost into more
> generation due to slightly lower efficiency - but I have other
> reasons
> to want plenty of generation capacity - workshop loads, etc).
> However, the pesky conundrum of a PV array that will, on the one
> hand,
> charge a 48V bank effectively (in the hot season), and won't on the
> other hand, fry the charge controller (in the cold season) is making
> me
> seriously reconsider 24V as a system voltage.
> --
> Cats, coffee, chocolate...vices to live by
Posted by wmbjk on December 1, 2006, 9:49 am
On Thu, 30 Nov 2006 23:18:17 -0500, "Solar Flare"
>24 v is nowhere. Go 48 for the capacity or 12 volt for the
>availability with automotic circuits everywhere.
12V? That's hilarious Gymmy Bob. Got a photo of any of those
"automotic" circuits?
Lawrence: Ron's advice hit the nail on the head.
Wayne
Posted by SJC on November 30, 2006, 11:42 pm
I would go with 48v. I have heard of systems using the Sunnyboy intervers
at 200v, but I don't think I would like to have that high voltage DC around.
> My head hurts.
>
> For the better part of 3 years I've been creeping towards getting a
> power system together - partly I take a long time researching stuff,
> partly the longer I wait the more money I have (on the other hand, the
> price of copper wire has roughly tripled).
>
> I'm about to get it ordered.
>
> I have been, based on early input from helpful folks here, leaning
> strongly towards a 48V system. Smaller wire, smaller breakers, fewer
> parallel strings in the battery for a given storage capacity and battery
> size. Since I'm starting from scratch I don't need to match any existing
> equipment, and I'm leaning to the "do it pretty much all with AC from
> the inverter" approach as being cheaper than having various DC
> appliances which are costly and rare (putting the cost into more
> generation due to slightly lower efficiency - but I have other reasons
> to want plenty of generation capacity - workshop loads, etc).
>
> However, the pesky conundrum of a PV array that will, on the one hand,
> charge a 48V bank effectively (in the hot season), and won't on the
> other hand, fry the charge controller (in the cold season) is making me
> seriously reconsider 24V as a system voltage.
>
> --
> Cats, coffee, chocolate...vices to live by
Posted by Eeyore on December 1, 2006, 3:53 am
Ecnerwal wrote:
> However, the pesky conundrum of a PV array that will, on the one hand,
> charge a 48V bank effectively (in the hot season), and won't on the
> other hand, fry the charge controller (in the cold season)
Where's the rpoblem ?
Graham
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> For the better part of 3 years I've been creeping towards getting a
> power system together - partly I take a long time researching stuff,
> partly the longer I wait the more money I have (on the other hand,
> the
> price of copper wire has roughly tripled).
> I'm about to get it ordered.
> I have been, based on early input from helpful folks here, leaning
> strongly towards a 48V system. Smaller wire, smaller breakers, fewer
> parallel strings in the battery for a given storage capacity and
> battery
> size. Since I'm starting from scratch I don't need to match any
> existing
> equipment, and I'm leaning to the "do it pretty much all with AC
> from
> the inverter" approach as being cheaper than having various DC
> appliances which are costly and rare (putting the cost into more
> generation due to slightly lower efficiency - but I have other
> reasons
> to want plenty of generation capacity - workshop loads, etc).
> However, the pesky conundrum of a PV array that will, on the one
> hand,
> charge a 48V bank effectively (in the hot season), and won't on the
> other hand, fry the charge controller (in the cold season) is making
> me
> seriously reconsider 24V as a system voltage.
> --
> Cats, coffee, chocolate...vices to live by