Solar regulator query

[Keithy P38]

I've got a 140w folding solar system (2 X 70w panels) with a PWM regulator (10a).

I've only noticed issues with the new P38's Aux battery, which is AGM 90ah. I had no issues with the previous P38's SLA Aux battety, which is 105ah.

Basically, and I'm unsure/worried, the voltage at the AGM battery is quite high when the panels are hooked up. I'm talking around the 17 to 18v mark.

The load is a 50L Waeco fridge set at reasonable beer-chilling temp.

I don't normally keep a virgin-daughter type eye on things, seeing as this P38 is new to me I like to make sure it's getting what it needs.

Is there an issue with the regulator perhaps?

One time it was doing this on a discharged battery, which at the time I really appreciated, however it also did it to a practically full battery, and I'm worried I'll do some damage.

Thoughts?

I'm pretty much a novice trying to get my head around the issue as I've had the battery discharge overnight for no apparent reason, twice now, with a small fridge being used in winter and conservatively.

On the previous P38 I ran a larger 78L ARB fridge with less food and beer inside, and not once did I wake to anything less than 12v (even in summer), but also had no problem charging it back up at 13.8v from the solar regulator.

The panels and regulator are 1yr old now.

Cheers
Keithy

[Homestar]

The voltage does sound a bit high IMO, and you shouldn't flatten a 90ah battery overnight with a fridge that size - not even close. I can get nearly 3 days out of my 100ah running a 38l Engel - with nothing charging it.

Someone will be along shortly to add some more detail hopefully.

[carlschmid2002]

I can't help you with the high voltage but I do know that Waeco fridges have an issue where they stop running rather early and you think the battery is flat. I had this issue on my dual battery setup on my Defender. It didn't happen if I had it plugged into the inverter on 240V. It happened using cigarette lighter plug. I have just had my Waeco serviced by an authorised service agent in Mount Louisa. You can find him on the Waeco web site. It was freezing my beer as well. Hopefully all fixed now.

[JDNSW]

The regulator should not allow the voltage to exceed a 'float' voltage, typically under 15v, and if the voltage ever exceeds this, it indicates either a fault in the regulator or possibly in the wiring (or a faulty voltmeter).

As a result of the over voltage, it is possible the battery is already damaged (a charging voltage over about 14.8v usually indicates a faulty battery), or there may be a bad connection at the battery.

Get someone who knows what they are doing to check it out.

John

[isuzu110]

My brother-in-law had a similar issue. It turned out that the battery in his multimeter was slightly flat, leading to the multimeter over-reading the voltage. When the 9v battery was changed, everything was in spec.

Could your issue be that simple ?

[PhilipA]

I have 120Watt panels running through a GSL 10 amp MPPT regulator.

I have in the circuit a ABR watt/amp meter after the MPPT .

Batteries are 130AH AGM plus Optima 760CCA Blue top.

My voltage runs up to about 14V then cuts to float.

Running 40l Engel.
I usually connect the panels on the first morning so get about 7amps with batteries at about 12.4+, but have seen 8 amps when I couldn't use the panels first day because or rain and battery voltage was down to 12.

17Volts seems to me to be far too high , but how did you measure? with the batteries connected? I cannot see how this could be so as the voltage would reflect the battery voltage not the input voltage, and I think you would have Lucas style smoke if the batteries were at 17 volts.

Regards Philip A

[Keithy P38]

Thanks for the replies guys.

I have two ways that I measure the battery voltage as this is happening (should have mentioned it earlier). I use a multimeter and I have a voltage gauge mounted in the rear (where the aux battery is located). Both tell the same story.

I'll take them camping with me this weekend and see if it's the same story, and I'll try the panels on the old man's deefer as well to confirm if the problem is my end or the panels/regulator.

Cheers
Keithy

[Keithy P38]

What I've noticed this weekend is that I get a high voltage (17v) when the panels are in full sun. If I partially shade the panels, it regulates around 13.8v to 14.2v. By partially shade, I mean 1/8 of one panel shaded with a towel.

For the time being ill roll with it as I've got no time between now and a 12 day trip.

Can anyone decipher why it regulates when one panel is partially covered?

Has kept my battery in good health all weekend.

Cheers
Keithy

[85 county]

sound like a problem i had.

battery no water in it, went flat.

solar panels after regulator 17V, boiled of the battery

do not use the salar now

[85 county]

in the sun, disconnect the panels from the battery.

check voltage before regulator and after regulator


after regulator it should never be above what is normal charge for a wet cell battery assuming your regulator has the option fore wet or dry, some thing to check