Need Help/Advice

[upnorth]

Hi to Everyone! Recently joined this forum as everyone seems quite knowledgeable on here and I am hoping someone can guide me in the right direction as I am currently lost!? Please bear with me as I have essentially no knowledge with regard to solar systems and am just starting out. I recently had an off-grid system installed at my cabin consisting of ten 310 watt Canadian solar panels(total 3100 watts), a Samlex power 3000 W inverter, and a midnight classic 250 charge controller, and 4 Rolls 6v AMG batteries.

This was not an inexpensive system and I tried to go with good quality gear. Everything was hooked up by a friend who is an electrician. The system was hooked up to the batteries right out of the box and everything was working great. The cabin is located in Northern Saskatchewan and I would say the panels would receive about 6 hours of direct sun/day this time of year. I decided to go with this size of system for future use but currently the only real draw on the system currently was a microwave used infrequently, a coffee maker, and 6 or 7 led lights.

The System was fully functioning 2 weeks ago and then we received a huge blizzard here in Saskatchewan which covered the panels completely in about 10 inches of snow with temps around -5 F, and I was not there to clean off so there was no power being generated. I then arrived at the cabin a couple of days ago and the whole system is completely dead, no power, and no display on inverter.

From my understanding the batteries are large and good quality and I am very surprised they were completely drained in that amount of time with no draw on them (other than the inverter I guess).

I want to get the system up and running again and I only have a 3000w Yamaha generator so I am thinking my only option is to try and charge the batteries with it. I have looked up how to actually do this and haven't been able to come up with an appropriate method to charge it. One article I read stated that you need to plug into the AC outlet on the generator and then connect to the battery?? It said to run a proper 240 volt or 120 volt battery charger off the generators AC output, however, this article was from Australia. lol. Is this correct?

Basically I am hoping someone can give me advice on what type of charger I can get to charge the batteries up again off the generator because I don't think there is enough sun exposure to do it, and also why the system drained so quickly??

Thank you very much in advance for anyone that can offer any advice!!!!

 

[Hedges]

Start with a volt meter, measure battery voltage.
An inverter ought to shut off for low battery voltage to protect it.

With sun on the PV panels, the charge controller ought to start charging them again. But if batteries are drained too low, it may not want to start.

You can commonly find battery chargers for 12V, some also do 6V. If you can find one for 24V it would charge the entire bank at once.

Here's the little battery charger I use for individual batteries:

4 Amp Fully Automatic Microprocessor Controlled Battery Charger/Maintainer

Amazing deals on this 4 Amp 12V High Freq Battery Charger/Maintainer at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

That's only 4A, 50W, and you want something much faster.

How many Ah are your batteries? What is their desired charge rate? (probably 1/10th their capacity, 0.1C to charge in 10 hours.) Look for a battery charger of that current. If you are present and can tend to it, you can stop the charging well before full charge (have a target voltage in mind). Then PV charging and regulation can take over.

If you have to charge two batteries at a time because you don't have a 24V charger, then charge both pairs to the same voltage, so they have equal state of charge before returning the system to service.

 

[digitalsteve]

You first need to verify how the batteries are wired. Best to take a picture and post here, if you do not understand series and parallel connections. Then we can tell you what voltage the charger has to be. Your yamaha generator should be able to do the job. If the batteries went dead and then froze, they might be cracked and should not be re-used or charged. AGM batteries can work at -40f so you are probably OK.

 

[Hedges]

I'm assuming you have the inverter, not the inverter-charger

Inverter Charger for Marine, RV, Fleet, Off-Grid | Samlex America

Samlex EVO Inverter / Charger is an inverter, battery charger and transfer switch - ALL-IN-ONE device. Perfect for marine, RV, commercial fleets & off-grid.

www.samlexamerica.com

3000 Watt 12V Pure Sine Inverter/Charger | EVO-3012 | Samlex America

3000W 12V Pure Sine Wave Inverter/Charger with 130A Battery Charger + 70A Transfer Switch. Marine grade, heavy-duty power for rv, boat & off-grid. Lithium compatible.

www.samlexamerica.com

 

[Hedges]

You first need to verify how the batteries are wired. Best to take a picture and post here, if you do not understand series and parallel connections. Then we can tell you what voltage the charger has to be. Your yamaha generator should be able to do the job. If the batteries went dead and then froze, they might be cracked and should not be re-used or charged.

You're right, looks like those are probably 12V not 24V. Plenty of 12V chargers around of all sizes.

 

[Hedges]

A Samlex manual I found says low battery shutdown 10.2V (for 12V system)

https://www.samlexamerica.com/documents/manuals/SA-1000K_SA-3000K_Manual_Mar2010.pdf

That is way below 0% charge for my brand of AGM batteries.
A system ought to shut off at some reasonable depth of discharge. My inverters shut off at 80% discharge, and give a signal to shed all non-critical loads at 70%.

 

[upnorth]

Thanks very much for your input guys. I really appreciate it. Unfort the guy I bought the package from has not been helpful at all.
My Dad is still up at the cabin and has been warming it up with the wood stove. He said about an hour ago that the midnight charge controller display is finally on and I have attached photo of display showing batteries at 7.8 volts. I will also attach photo of battery hook up and specs.
My Dad also said the Samlex inverter just started making an alarm noise and said “overload” so now I definitely don’t know what’s going on! Lol. He shut the inverter off. Not sure if it is just finally defrosted enough?

 

[upnorth]

Here are the specs on the batteries.

 

[Hedges]

Despite that Gordian knot of cables, I think I can make out that the batteries are series/parallel for 12V 800 Ah.

S6-460AGM-RE | Rolls Battery

rollsbattery.com

Recommended charge rate is 85A per string, just over 0.2C
Twice that for your two strings, so 170A charge rate is good. Probably you won't have such a charger, so anything you can get.
(unless the charge controller wakes up and starts doing its job.)

Inverter was supposed to shut off at 10.2V, don't know why it went lower. Unless that was the effect of getting cold after being discharged. Seems like warming up raised it a little so electronics turned on.

Of course a car and jumper cables might also charge it, but there is the risk of killing your alternator, not worth the risk.

You need a low battery shutdown.
The data sheet does show 600 cycles to 100% DoD. If it wasn't damaged by freezing it might still have a long life.
Needs to get recharged, but I suppose while cold that slowed chemical degradation. Charge it now.

 

[digitalsteve]

I agree with Hedges, you have a the batteries arranged for a 12 volt system, so a car battery charger can get you going, but the panels might also do it, if you keep the inverter off until the batteries charge up. Could take quite a while, either way (days maybe). Good luck. If you put a charger on it, to be sure you are across the 12 volt system, connect the charger to the battery terminals that have 2 cables on the same terminal.

 

[Ryang]

If the inverter is off, there should. Be 0 draw on this batteries. What happens when the sun is next on the panels? What does the charger show ?

 

[Steve_S]

Well, 1st things 1st. If the batteries are NOT 100% flat and did NOT freeze your still ok... empty & frozen is very bad ! and time to cry in your overheated "Red Cap Ale". Warm up the batteries till they are at least 5C temperature... Then you can charge them up safely without much worry.
You don;t mention if your Samlex is an EVO or another model. IF it's an EVO, you can use it to charge the battery back up from the Genset.

We are Canadian so 120V charger it is. You can use a Car Charger with an AGM setting to bring up the batteries but that will be slow because of the capacity they have.... at least if you can get them to keep the Classic awake then the solar will charge them up. A good External Charger capable of pushing 50A up are not cheap and for such batteries 50A is minimum. This is where the difference between buying an EVO versus the standard inverters really cuts across the $ lines.

The inverter, even if ON, should have cutoff with the Low Volt Disconnect, verify that it is set correctly.
The Classic will want to "see" the batteries sitting at, at least 10V and the temp sensor will tell it to compensate if needed (default is 5mv).

BTW, do not use a vehicle with jumper cables to try & charge those, unless you have a spare alternator handy and/or are ready to have it replaced along with possibly the vehicle computer should things go really bad. It happens I've seen it myself (fortunately I'm not the victim of that stupidity).

BTW: this is the level of charger IF you want to go external for at least 40A: Schumacher SC1353 6/12V Wheeled Battery Charger Canadian Tire
Alternatives ? Got a Princess Auto handy ? Possibly TSC can do better... or if you have a car mechanic buddy...

Samlex 12V/50A Charger: 50 Amp 12 Volt Battery Charger *UL Listed* | SEC -1250UL (samlexamerica.com)
Amazon.ca "ouch": Samlex Solar SEC-1250UL SEC-UL Series 12V Battery Charger: Amazon.ca: Automotive

Hope it helps, Good Luck.
Steve

 

[upnorth]

Thanks again for everyones help/advice! Really appreciated!

I just got an update from my Dad at the cabin and he said it is a cloudy day but panels still seem to be charging the batteries and the display says they are up to 11.8 volts with the inverter off. He tried with the inverter on and the lights in the cabin turned on!

Unfortunately the Samlex inverter is not an EVO model which now that I understand it a bit better I am pretty disappointed with. Would have been nice for sure but this option wasn't even presented to me. I may look at getting the Can Tire battery charger Steve_S recommended - thanks for the link to the exact model! Very helpful indeed! Dumb question though, how exactly do I hook the cables up to charge? I know Digital Steve said to hook it to connect the charger to the battery terminals that have 2 cables on the same terminal, but is this any 2 terminal in the overall set of 4 batteries? Bottom of battery 1 on the left and top of battery 3 in the above battery bank photo???

Also in the future, when I leave the cabin for a few weeks with these very cold winter temps, what is the best thing to do? Turn off inverter and leave the system as is, then plan on having to warm cabin up for a couple of days before use? If the batteries are charged fully when we leave, the cold itself is enough to discharge the batteries on its own I would assume? I thought if the panels were still feeding power into the system the batteries would not loose their charge, but they obviously have. Prob not a good idea to show up next time and right away plug charger into generator and try to charge batteries up as they will be really cold?

Take the 4 monstrous batteries with me and put at home in heated garage (would like to avoid this if possible)?

What do you guys think?

Thanks again!

 

[Hedges]

Fully charged AGM batteries can be left alone quite a while, like 6 months or more.
Turn off the inverter and any other loads. The inverter data sheet I read said it won't disconnect until 10.2V, which is too low.

You need something to automatically turn off inverter. Is its switch a stiff one that switches full current? Or a lightweight control switch? is there a connector for a remote? You might be able to add an external battery voltage sensor to control the inverter, or to control a relay. Does the Midnight charge controller have any control signal outputs that can be assigned "low battery disconnect"?

For charging, not just any two terminals. Some are 6V apart; you need 12V. The two wires going to inverter are 12V.

Lead acid is OK charging when cold. A good charger is temperature compensated and adjusts voltage; even cars have that. But batteries aren't supposed to get frozen, which can happen if discharged deeply and too cold. That may damage them irreparably, but at least get the ice inside melted before charging, whole battery above 32 degrees C if it was completely discharged.

There is a perfect way to wire four 6V batteries in series/parallel 2s2p so current divides evenly, and a less than perfect way. Can you produce a drawing showing your for batteries and exactly where each wire connects? Then we can review it.

 

[GSXR1000]

Thanks very much for your input guys. I really appreciate it. Unfort the guy I bought the package from has not been helpful at all.
My Dad is still up at the cabin and has been warming it up with the wood stove. He said about an hour ago that the midnight charge controller display is finally on and I have attached photo of display showing batteries at 7.8 volts. I will also attach photo of battery hook up and specs.
My Dad also said the Samlex inverter just started making an alarm noise and said “overload” so now I definitely don’t know what’s going on! Lol. He shut the inverter off. Not sure if it is just finally defrosted enough?

is that picture with the sun out? you should have at least 15v on pv (panels) more like 50 v with that set up. if no power in then no charging

you said it worked good for 2 weeks? what was yours watts when fist installed?
Sounds to me that the panels Never charged and you ran off your batteries for 2 weeks until they died... see what your PV voltage is.. maybe they are all in parallel so not enough voltage.... electrictricians don't understand series parallel much not in there trade.

 

[SolarQueen]

Ask your dad what the PV voltage is when he thinks it is charging. I'd love to know how the installer has the 10 panels wired. If 5 strings of 2, he wouldn't need the Classic 250, a 150 would have been fine. Not a big deal though, just less than optimal design. If 2 strings of 5, the charge controller is always going to be in overvoltage protection and never charge.

From what I can guess of your battery bank, it is wired as this drawing. The grey lines are ones I can't see and guessed, the black I am sure of. Bring a volt meter with you as well as the 12V charger, and measure the voltage at the points where I show the inverter is connected. Make sure it is in the 12V range to confirm the bank is wired right. You want to connect your charger to those points as well.

 

[GSXR1000]

Ask your dad what the PV voltage is when he thinks it is charging. I'd love to know how the installer has the 10 panels wired. If 5 strings of 2, he wouldn't need the Classic 250, a 150 would have been fine. Not a big deal though, just less than optimal design. If 2 strings of 5, the charge controller is always going to be in overvoltage protection and never charge.

From what I can guess of your battery bank, it is wired as this drawing. The grey lines are ones I can't see and guessed, the black I am sure of. Bring a volt meter with you as well as the 12V charger, and measure the voltage at the points where I show the inverter is connected. Make sure it is in the 12V range to confirm the bank is wired right. You want to connect your charger to those points as well.

if he wired 10 panels in parallel (which i am betting) that would be close to 100 amps on the pv wire. prolly #10 it would melt

 

[Hedges]

He tried with the inverter on and the lights in the cabin turned on!

Now that the test confirmed things are functional, he should turn the inverter off.

A 12V, 830 Ah bank is 10 kWh. It will take at least 4 sunny days to recharge with your 3100 W PV array.
After charging is complete and battery has settled to a "float" condition, use a meter to check voltage of each 6V battery individually. That will show how well balanced they are.

If not well balanced, a 6V battery charger like the HF one I linked could be used to bring up any low ones. Maybe powered off the inverter, like a perpetual motion machine, but really just a balancer. Might be tricky to figure out what is the best state of simultaneous charge and discharge.

I have an idea - by disconnecting one string of two 6V batteries (removing a single connection between them would accomplish that), they could each be full charge by the little 6V/12V AGM battery charger, powered from the inverter. Then, reconnect that string, disconnect the other, and charge each of those.

But rebalancing would only be needed if they showed significantly different voltages, which may not be the case.

 

[upnorth]

Ok I will attach a shot of the midnight display with sun on the panels. Also the diagram that was provided by the guy that sold me the system - I think they are wired as 2 strings of 5. The last diagram is a diagram my Dad did just now of how the batteries are hooked up. It seems to be charging the batteries so I would assume everything is hooked up ok??

What do you guys think??

 

[Steve_S]

I'm curious, at what angle & direction are your panels set to ?
Northern Sask is a BIG place and angles change drastically. Winter angles are no fun up here & further north. (I'm near Algonquin Park).