Problems with 12v solar system on my camper - Perth-WRX.com

Pimpreza · #1 07-01-2014, 01:15 AM

As above, I've recently fitted two 12v solar panels to the roof of my Transit van, one 200w & one 100w running in parallel, I should be getting around 15 - 17v but I'm lucky to get 11.8v at the batteries and low 12's at the panels, I've used 10mm sq cable which is more than big enough and it's about 2.5m from the batteries (2 x 130ah gel) to the panels.

My son in law is a sparky and he came over today and it's got him bamboozled also, everything I've done seems right but it's either the eBay panels which are the same brand but from different suppliers or ?????, all suppliers have good feedback and I sent off a question to them today.

I'm also having problems with my inverter, it's a 2000/4000w unit but it's somehow getting negative whatever the voltage in the battery is showing on a multimeter & it'll spark on contact with anything that's earthed to the body if the body of the unit touches earth though it works fine( I.E. if I put the multimeter between one of the body screws and the vehicle body it'll show something like -12.4v)......... well it did until we connected the control box today, now the control box beeps and shuts down the inverter which means I can't run my 240v fridge off it any more so I have to be plugged into mains, run the car for a couple of hours a day or run the generator so if anyone knows about this stuff or knows someone who does please let me know..............I'm supposed to take off on Sat.

On it's first trial run last week up at Lanno & Cervanties.

Couldn't do without a Subaru part or two so it's got a Foz seat with a swivel base and a couple of lap belts on the lounge in the back.

Cervanties.

Rossco · #2 07-01-2014, 01:49 AM

What are you using as a voltage regulator/isolator on your solar panels?
What brand & Model of panel are they?

As far as your inverter goes - Do you have a good chassis earth? The beep is a low voltage alarm.
Are your 130ah batts wired in to the rest of the transit or are they isolated?

Alternate · #3 07-01-2014, 12:02 PM

If they're 12V panels in parallel, why are you expecting 17 volts?

Not trying to be a smart arse, just a query

Pimpreza · #4 07-01-2014, 02:32 PM

Alternate.......because that's what they usually put out which is why you have a regulator to control them.

Ross.........They are Chinese (like the vast majority these days) Solraiser models SMP-ST-100w and Solraiser SMP-ST-200w, bought on Fleabay from two different suppliers at different times thought they were both sent from New Aim over east.

The regulator is a Solar 60 also from Fleabay and the inverter is a 2000/4000w unit which I'm also having problems with, works fine connected to the battery's without the regulator but if it touches earth on the body of the car it will spark???????

The 2 main battery's are brand new 130ah gel and work fine but being a Transit it also has 2 x 70ish ah battery's under the drivers seat, the working battery is isolated from the starting battery as soon as the ignition is switched off, it's a great system and as soon as I start the car you can hear it click in and see it charging all battery's as I have a voltage gauge in the cig lighter....it charges at about 13.6-8, this is enough to pretty much fully charge them after about 2hrs driving

The solar panels were hooked up to the regulator for the first time yesterday as it seemed pointless when I installed them because they were only putting out such a pissy charge ( I just hooked them straight to the battery's ) but it's made no difference apart from not letting the inverter work.

The regulator was showing 74% full last night when I tried to get the inverter to work, I had my 20ah charger on them for a couple of hours, I'll see if longer will help.

Just seems strange that both panels are bad yet from different shops and other people I've spoken to have had no probs and had them charging up to 19v

Willing to travel and pay for repair, I'm onto both suppliers but doubt I'll have much luck with them, one didn't even have a copy of the purchase (both have 99.6 & 99.7 rating so hopefully they will help).

WhiteRX · #5 07-01-2014, 03:19 PM

The solar panels will only put out battery voltage, as the battery charges the voltage will go up but with that size solar panels you will never get the battery voltage up that high. The voltage at the regulator should be battery voltage once the regulator is charging. What amp meter are you using to measure charge current

Pimpreza · #6 07-01-2014, 05:33 PM

Son in law used his meter with the big loop at the top, I was measuring volts with mine which is just a DS one but as it stands I just want them to charge the batteries, the only thing drawing off the whole system is the fridge which draws 132w when it's running so from a full charge overnight when the fridge is running less than 50% of the time the 300w of pannel should be able to replenish what's been used with a full day in the sun, the system is plugged into mains during the day and evening atm and only switched to battery overnight until 10am ish.

Solar panels were measured at the panel with nothing attached and at the battery while hooked up.

Understanding this shit is way beyond me, never dealt with it before and I've still got to install my reversing camera and two way radio.

Rossco · #7 07-01-2014, 05:44 PM

A solar panels currency is current (amps) @ 12volts – so you are going to need some method of measuring current rather than the panel voltage. Some solar regulators have a display that will tell you how much current is coming from the solar panels at any point in time (assuming of course that the regulator has been installed correctly and that you trust this reading).

If your regulator does not have a “Charge current reading”, you are going to need some other method of measuring this current flow.

Option 1 – Clip-on Ammeter.

This is by far the simplest and safest method of measuring the current flowing into your batteries from the solar panels. These little meters are able to measure the current flowing through a single wire by simply measuring the magnetic field around that wire. All you have to do is pick the right single wire and clip the meter around it. Note – if you have a pair of wires (going to the solar panel for example) you cannot clip around the pair – the magnetic field generated by the current flowing in the positive wire is cancelled out by the field generated in the negative wire. If you decide to buy one of these great little meters (expect to pay around $90 from Dick Smith/Jaycar) – be sure that it will measure DC current as well as AC current – not all do.

Option 2 – Standard multimeter.

Not difficult or dangerous … if you take care. To measure the current flowing through a wire, you must disconnect that wire and have the current flow through the meter. Effectively putting the multimeter in series with the wire.

Safety –

Make sure your meter is able to measure at least the expected current from the panels. If you have a meter that is rated to 10amps – don’t connect it to a circuit that you expect to see 20amps flowing in.

Once the meter is in current mode – NEVER put the probes across the battery. This is the fastest way to destroy the meter.

» Step 1 - place the multimeter into current mode (high current). This normally involves moving at least one of the probes to a different place on the meter AND selecting the AMPS scale on the selector switch.
» Step 2 – Carefully disconnect the positive cable that goes from the solar panels to the battery.
» Step 3 – Place one multimeter probe onto the terminal where the wire came from and the other probe onto the wire.

Your meter will now be reading the current flowing from the solar panels to the battery. Be very sure to put the meter back into volts mode when you have finished measuring the current.

The quick test

If you have more than one solar panel, you can very quickly check if each of these are working by simply covering them up one at a time. The current measured should drop by approximately the percentage of panels you have covered.

What should you be reading for a 12 volt system…?

Take the total number of watts of all the panels, divide this by 17 – this number is the approximate current you should see charging the batteries at midday on a sunny day.

Example – Your panels = 300w

300 divided by 17 = 17.6 amps - thus under ideal conditions you would expect to see around 17.6 amps of charge flowing from the solar panels into the batteries.

Post back what current you are seeing at Midday.

Pimpreza · #8 07-01-2014, 07:40 PM

Thanks for the detailed explanation but it went in one eye and out the other

(here are some pics of the set up) I'll get the son in law to read this, he should understand it better than I ever will.

You can just see the black spot on the bottom front bolt on the right of the cabinet which goes through to a steel wall where the inverter touched and sparked, it's just about impossible to get the wiring wrong and the batteries are all earthed and interconnected with Subaru battery wiring set ups so pretty sure they are strong enough.

This thing I just don't understand.

Battery set up, power & earth comes through the plywood wall on the left from the feeder battery and as you can see both battery's are individually earthed from the earths that were on the Subi cable setups

Pimpreza · #9 07-01-2014, 07:54 PM

The sparky son in law was using one of those loop meters yesterday and said it was getting sfa but can't remember what he said it was but 12v & solar isn't exactly his field, more industrial.

WhiteRX · #10 07-01-2014, 08:43 PM

What suburb are you in mate?

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