Problem with 100 watt panels or something else. Random issue

Blindowl1234 · October 2023

About 5 years ago I put in a handful of solar lights outside, and in the house for use at night. Basically 15-20 watts of accent lighting. System is 12 volt and has 2- 100 watt Grape panels. Cheap 30A Chinese controller BSC3048. Last summer I noticed one of the panel surfaces appears to have surface cracks all over it. It was still working fine so I left it alone. Recently the lights which run for 6 hours after dark, started cutting on and off at a more or less random interval. This only happens after they've been working fine for about 3 out of the 6 hours. The lights come on for say around 2 minutes or so, then off for 1 minutes then repeat the cycle. That's just a guess as I've not actually timed it. At the end of the 6 hour programmed cycle they shutoff as normal for the night. I also noticed it seemed to be a problem when it rained. I figured water was shorting out the panel that was cracked. Well that's not it either, as I disconnected the cracked panel, and that night the problem was still there. It's random and I have no idea what to check next. I plan on replacing the bad panel which is currently unhooked. But its not the problem as far as I can tell. I'm wondering if possibly the controller is starting to have random issues? Almost appears that something is telling the panels its daylight when its dark...only randomly though. Any ideas? Don't want to just randomly start replacing parts. However its baffling me.

BB. · October 2023

Do you have a volt meter you can measure the battery voltage with?

-Bill

Blindowl1234 · October 2023

11 AM light rain and cloudy. Batteries show 13.2 volts. A few hours and they should be at float voltage

BB. · October 2023

Given poor solar conditions--It does sound like the system is capable of charging...

Just check the battery voltage when things "go south". In general, the solar charge controller/light controller should be responding to battery voltage. Both when controlling lights (low voltage) and when charging (actual charging of ~14.4 volts or so, and around 13.6 volts or so when floating--charging is completed (high voltage).

It is very possible you have two problems. The solar panel possible failure, and the battery just getting old (5 years of daily cycling is not a "bad" battery life)--As well as the battery getting stressed from the (possible) panel failure.

Eventually, you may want to get a simple AC+DC current clamp DMM (digital multi-meter)--If you don't have one yet.

https://www.amazon.com/UNI-T-Digital-Handheld-Resistance-Capacitance/dp/B0188WD1NE

The above is pretty inexpensive (for a current clamp meter) and will do pretty much any basic testing you need (voltage, current, resistance).

Once you have a DC Current Clamp meter, you can check the current from each solar panel and see if your panel(s) is good or not (test under full sun, each panel, and then compare current between them).

-Bill

Blindowl1234 · October 2023

BB. said:

Given poor solar conditions--It does sound like the system is capable of charging...

Just check the battery voltage when things "go south". In general, the solar charge controller/light controller should be responding to battery voltage. Both when controlling lights (low voltage) and when charging (actual charging of ~14.4 volts or so, and around 13.6 volts or so when floating--charging is completed (high voltage).

It is very possible you have two problems. The solar panel possible failure, and the battery just getting old (5 years of daily cycling is not a "bad" battery life)--As well as the battery getting stressed from the (possible) panel failure.

Eventually, you may want to get a simple AC+DC current clamp DMM (digital multi-meter)--If you don't have one yet.

https://www.amazon.com/UNI-T-Digital-Handheld-Resistance-Capacitance/dp/B0188WD1NE

The above is pretty inexpensive (for a current clamp meter) and will do pretty much any basic testing you need (voltage, current, resistance).

Once you have a DC Current Clamp meter, you can check the current from each solar panel and see if your panel(s) is good or not (test under full sun, each panel, and then compare current between them).

-Bill

Thanks Bill! I think I'm just going to replace the panel anyway and get an extra controller. I've got two or three multimeters around here. I checked voltages and amps etc...this summer. Hopefully sunny towards weeks end. Thanks Jeff

Blindowl1234 · November 2023

Blindowl1234 said:

BB. said:

Given poor solar conditions--It does sound like the system is capable of charging...

Just check the battery voltage when things "go south". In general, the solar charge controller/light controller should be responding to battery voltage. Both when controlling lights (low voltage) and when charging (actual charging of ~14.4 volts or so, and around 13.6 volts or so when floating--charging is completed (high voltage).

It is very possible you have two problems. The solar panel possible failure, and the battery just getting old (5 years of daily cycling is not a "bad" battery life)--As well as the battery getting stressed from the (possible) panel failure.

Eventually, you may want to get a simple AC+DC current clamp DMM (digital multi-meter)--If you don't have one yet.

https://www.amazon.com/UNI-T-Digital-Handheld-Resistance-Capacitance/dp/B0188WD1NE

The above is pretty inexpensive (for a current clamp meter) and will do pretty much any basic testing you need (voltage, current, resistance).

Once you have a DC Current Clamp meter, you can check the current from each solar panel and see if your panel(s) is good or not (test under full sun, each panel, and then compare current between them).

-Bill

Thanks Bill! I think I'm just going to replace the panel anyway and get an extra controller. I've got two or three multimeters around here. I checked voltages and amps etc...this summer. Hopefully sunny towards weeks end. Thanks Jeff

Bill, Another question for you. I ordered another 100 watt panel and checked my 3 batteries. They're getting old, but using a simple hydrometer they're still ok. I've got a 30 foot run from my panels to the charge controller using 14/2 with ground. Everything runs behind the vinyl siding so not a weather issue there. I'm thinking of keeping the slightly damaged panel since it appears to be still working. I'll have three panels total. Amp rating on the sticker on the back of the 100 watt panels are 5.51, 5.51, 4.91. I'm sure I'm not producing the max rating amp wise, or 300 watts total either, in the real world scenario. I'm guessing however if all three panels were putting out max amp rating, I'd be at around 16 Amps? 14/2 is rated at 15 amps. Is my existing 14/2 ok or should I use12/2? I think my original problem was a loose wire on the controller. That problem is fixed. Just worried about wire size if I add the 3rd panel. Thanks!

Graham Parkinson · November 2023

14/2 is pretty skimpy. Even if the wire carries the current safely from 300 Watts, with 12 V panels you probably don't have much tolerance for voltage drop which will reduce ability to charge your battery. So worth it to run 12/2, it'll make your system run better.

Remember to fuse everything, especially on the battery side - even 12 Volts can cause fires if wires short somehow they can glow red hot for just long enough to melt vinyl siding and start a fire.

SteveK · November 2023

If you place a third panel in parallel and with your 14AWG wire you would have losses at ~21%. That's expensive. Getting to ~2% loss or less should be the goal. Even with 12AWG wire you will be losing ~13% of your precious gathered energy. 13% loss is better than 20% loss but 13% is still very high.

Here's a voltage drop calculator: https://www.southwire.com/calculator-vdrop

Blindowl1234 · November 2023

SteveK said:

If you place a third panel in parallel and with your 14AWG wire you would have losses at ~21%. That's expensive. Getting to ~2% loss or less should be the goal. Even with 12AWG wire you will be losing ~13% of your precious gathered energy. 13% loss is better than 20% loss but 13% is still very high.

Here's a voltage drop calculator: https://www.southwire.com/calculator-vdrop

So how to get it anywhere near the 2% is the big question. Guess I can I run heavier stranded wire like 10 gauge THHN ? I really can't shorten the wire length.

Blindowl1234 · November 2023

Graham Parkinson said:

14/2 is pretty skimpy. Even if the wire carries the current safely from 300 Watts, with 12 V panels you probably don't have much tolerance for voltage drop which will reduce ability to charge your battery. So worth it to run 12/2, it'll make your system run better.

Remember to fuse everything, especially on the battery side - even 12 Volts can cause fires if wires short somehow they can glow red hot for just long enough to melt vinyl siding and start a fire.

Probably will change to 12/2 on 10/2 on the wiring. Usually I don't have any issues with batteries staying charged so far since 2018. I checked last night and all the LED lights in total were using less than 1 amp. Today I'm going to check the voltage at the panels, and incoming voltage at the controller. Going to check amps as well. Maybe I can tell what kind of loss I have, probably more than I thought

SteveK · November 2023

Well, to get to 2% you'd need to stuff a 3awg wire below the siding.....def not suggested. I'd be OK with 2 fused 10AWG in parallel @ 30'. This would get you to ~4%. Need to keep THHN out of the Sunlight though.

That is if we are throwing NEC codes out the window anyways.....

Graham Parkinson · November 2023

Steve is meaning that for safety and to meet code, DC wire inside a house (ie under the siding) needs to be in metal conduit. Metal conduit will not burn and ignite surrounding materials if a short occurs.

Blindowl1234 · November 2023

SteveK said:

Well, to get to 2% you'd need to stuff a 3awg wire below the siding.....def not suggested. I'd be OK with 2 fused 10AWG in parallel @ 30'. This would get you to ~4%. Need to keep THHN out of the Sunlight though.

That is if we are throwing NEC codes out the window anyways.....

Well I got a 2nd mortgage ..well almost did, and got some 10AWG today. I remember when wire was a lot less expensive. By the time I got everything reworked it was almost sunset. The THHN is out of the sun...under deck rail, then straight to overhead in the garage. It will never see sun that's for sure. I was hoping about 4% give or take, so that's better than 21%. NEC codes well they went out the window with this small setup 8 years ago lol. Thanks to all for the help and tips

SteveK · November 2023

Second mortgage

At least it wasn't a first mortgage then we have to do a home inspection: "Quick, hide the batteries!"

I'm with you on cost. Every day I try to convince myself that less is more 'cept my lenders just don't seem to agree.....

Problem with 100 watt panels or something else. Random issue

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