Newby - Solar System for Farm Questions.

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Re: Newby - Solar System for Farm Questions.

Postby Gordon-Loomberah » Sat Jan 30, 2016 6:09 pm

There appears to be a few short circuits in that diagram, but it looks like 6 paralleled strings of 2 X 125A 6V batteries, to give you 750AH 12V.
Generally you'd want to be able to charge them at about C/10 or 75A if possible for best battery health, but your PWM type charge controller is limited to 60A, so you'd want 800-1000W of PV panels, and they need to be wired up correctly, and of the right voltage, so as not to waste too much of their output.

FarmerBrown wrote:Q1) What does ripple volt mean?


It's when there is a bit of AC in the DC voltage, which shows up as a ripple when viewed on an oscilloscope, or a wavering analogue meter around the DC voltage. You can get that from an AC source that goes through a rectifier, but doesn't have any capacitors on the DC side, ie not smoothed. You can also see it with a non-constant load.

State = Bulk
Bulk 14.0V Float 13.4V
Q2) What do the last three mean?


I'm assuming these are the saved settings, as it was night time
Set point voltages in the charge conotroller.
Bulk is charging at maximum charger output
(Absorb is constant voltage charging, when the current gradually decreases as the battery approaches full charge.)
Float is the voltage maintained to keep it at 100% state of charge.

Bulk charging doesn't actually have a fixed voltage, but if it bulk charges then goes to float, it is a simple 2 stage charger, and your batteries may never get to full charge. You'd need to check battery specs, but 14V seems a bit low to be transitioning to float.

Q3) Why did the fan go instantly and the battery temps rise so rapidly?


The inverter is probably designed to do it so that it doesn't overheat. Battery temps always rise under load, and they rise faster under higher loads.
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Re: Newby - Solar System for Farm Questions.

Postby FarmerBrown » Sat Jan 30, 2016 7:29 pm

Solar diagram.pdf
(99.64 KiB) Downloaded 385 times


Thanks for bringing the short circuits to my attention.

I have revised diagram to suit. Assuming there are 3 active and 3 neutrals going into the inverter because i didnt take the bottom cover off.

So would it be a better option to get a charger controller capable of 75A instead of 1000W worth of panels? Is that an option?

Really enjoying the solar journey so far and great site by the way!
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Re: Newby - Solar System for Farm Questions.

Postby Gordon-Loomberah » Sat Jan 30, 2016 10:52 pm

The wires from the batteries will be positive and negative, rather than active and neutral, which is AC terminology.

There really should be large fuses between each battery string and the terminals on the inverter, and also a DC circuit breaker between panels and charge controller, and charge controller and batteries, and also fuses on each string of panels if you increase the array size.

1000W is probably about all that charge controller can handle- you need to check specs, but if you get a larger controller to handle 75A, you still need more panels. More panels will get you through cloudy weather with less need for a generator, and bring your batteries up to charge quicker- handy when there isn't much sun in winter.

If looking at a new charge controller, it is worth thinking about a MPPT type, which will typically get you about 30% more energy from your panels, which can be arranged differently to reduce losses by running at a higher voltage in a string of 2 or more.
At some stage, if you can, it would be worth charging your batteries to full, then disconnecting all loads and charger, and the paralleling cables (with care!), leaving them at rest for at least a couple of hours to settle, then measuring each 6V battery's voltage with a good quality digital multimeter, and recording them. You can pick if there are weak ones there now, and it gives you a baseline for next time you do it, in say 12 months time.
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Re: Newby - Solar System for Farm Questions.

Postby rasco » Mon Sep 12, 2016 4:37 pm

For your information: Rich Electric (Invertek) which includes Supercombi etc inverters was handled by Jacar.
They have dropped Invertech products so there is no longer any Australian support.
I have a Supercombi 3000VA 24v unit in my motorhome that is on its 3rd failure.
1st was under warranty that Jaycar - Electus(their distributor) fixed but the 2nd failure I had to repair myself.
The current fault (Inverter Overload again) I have replaced 3 15000mf Capacitor that blew off the circuitboard tracks, plus 3 Mosfets and 3 biasing resistors. Still a problem there but too hard to trace without circuit diagrams that Invertek - Rich Electric won't release.
So its all bad news in OZ.
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