Thanks, gives me food for thought.

I'll have to look closer as to how much fiddling the PCB could easily take.

What I have and what I intend to do.

As mentioned one 72W solar panel.

The solar panel will charge a 12V or 24V battery bank.
The solar panel when in operation will also directly power 4 * 50W LED=20
arrays. The arrays require 32V @ 1A5, they will be connected in=20
series/parallel ~ probably.  I've tested the arrays on my bench power=20
supply and provide more than adequate brightness running at 26V resulting=20
in approx 800mA current requirement each. Hopefully the under running will=
=20
make them last longer, perhaps. I'll have to look up Russell's treatise on=
=20
that.

Sadly the arrays, aren't too happy at 24V. The datasheet voltage is nominal=
=20
32V

So the controller will need to.

1. Via MPPT provide a direct output of 30v @ 2A.
2. Sense if the battery requires charging and charge to the correct=20
profile.
3. With PV off (night time) switch battery to the MPPT inverter to provide=
=20
26 - 30V @ 2A.

4. Inverter will need to be SEPIC or buck-boost.
5. Isolation to disconnect battery or PV via FET or latching relay.
6. Sense battery temperature as part of charge/discharge regime.

I suppose I could make the system 24V output and then boost at the LED=20
array to 30V.

I'm thinking of using used but in working order UPS batteries.

Colin
--
cdb, colin@btech-online.co.uk on 2/02/2014
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On Sun, 2 Feb 2014 19:16:33 +1300, RussellMc wrote:
:: Here's the schematic, if you want to have a think now

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