- Thread starter mechman
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HughF
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- Work: Dorchester, Workshop: Corfe Castle, Wife's place: Frome
48v nicad system (68v absorb set point). We were in float by 1pm iirc. No diversion loads yet, only had the panels installed since the Christmas break but been on battery/inverter/diesel for 7 years now. Outback vfx3048e flexware500 setup I built and installed myself.
Best day so far:
Best day so far:
That explains the low output. The down side to an off grid system is that once the bats are full you stop collecting energy.
My system is:-
3000va-120amp-12v-16amp pass through relay inverter charger (Victron Multiplus)
FM80 outback
4350ah 12v battery
1200 wp array
with 6kVa genny back up
All self installed.
Been 6 years ish now
HughF
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Mechman, just some info for you. Solar panels have an open circuit voltage (with no load connected) and a voltage at which they produce the most power (like the volt/amp curve of a welder). This voltage is called the maximum power point.
A decent (maximum power point tracking) charge controller will attempt to load the solar panels up so the voltage drops to the maximum power point, so you get the most power (watts) from the panels. The charge controller then lowers this voltage to charge the batteries. You see in my picture, the peak panel voltage was 127v, the peak current was 30.4 amps and the maximum power was 1.91kw.
There was a lot of sun that day so we made 5.1kwhr (units) of electric.
A decent (maximum power point tracking) charge controller will attempt to load the solar panels up so the voltage drops to the maximum power point, so you get the most power (watts) from the panels. The charge controller then lowers this voltage to charge the batteries. You see in my picture, the peak panel voltage was 127v, the peak current was 30.4 amps and the maximum power was 1.91kw.
There was a lot of sun that day so we made 5.1kwhr (units) of electric.
Thanks for that, I'm still reeling a bit from all the good info from the members.
Let me guess, inverter came cheap and determined system voltage? 48v is nice
Nail - head.
Well not this inverter but the one before it & the first 6 x 2v cells.
Looking at updating to a 48v unit & dropping 6 cells off the battery. Will be looking for new cells in the next year or two as well.
Selling the old inverter charger, 6 cells & outback FM80 would pay for the new inverter (or poss two, three would be nice to get 3 phase but would want it re-configurable to all single phase too) which will also do the solar.
All of this is true, however a good MPPT controller costs lots & panels are cheap.
You could have an extra 1000 watts for the cost of a good controller.
I used to just recommend using MPPT charge controllers.
Now I am more flexible.
HughF
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Must say, I've been very pleased with the vfx3048e, it has worked perfectly since day 1... Doing it again I would buy midnite solar mounting hardware instead of genuine outback (it takes up a load of space), but I would probably stay with this inverter brand. I have no experience with Sma or xantrex to comment on those.
Landy Lad
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Ive got a 150w bosch panel on my transit with a dual controller, with 90% of the charge going to the leisure battery that usb sockets, 12v sockets, inverter etc, and 10% going to the main battery just to keep him topped up when the vans not used. I have used sikaflex to fix the brackets to the roof and the panel to the brackets and don't think anyone would be able to it off in a hurry. Over the last couple of days with the sun we have been having both batteries have been charged to max and are on float charge. Bought the panel, controller and mounting brackets off eBay for around £150 from memory.
