I just purchased a home that has a complete solar system including a Midnite Classic 150. It was an estate sale so no one could tell me how the system was setup or how it works. My goal is to get the system running to the point it can charge the batteries and provide electricity to power outside landscaping lights and as backup power. I believe the system has been off for about a year. I believe it is a 5kw system (20 panels). There are 18 Marathon batteries connected in series and parallel (I believe). I am looking for some guidance on what to do first and/or what additional information I can provide to get me started. There are 2 batteries in the battery bank connected to a battery charger so I started with trying to charge these batteries (in progress). I have assumed that the previous owner had the system running "as is" in the past. I have attached a picture of batteries. Comments and input greatly appreciated.
Another picture
Another picture
Hi Buckmaster, Welcome to the Forum.
Guess that there were 16 batteries, but perhaps there were some problems with that battery bank, and perhaps someone simply added two additional batteries to try to use a minimal system, or to test other parts of the system.
Lead Acid batteries do not do well, when just sitting around, not getting fully charged, on occasion.
Those Marathons are AGM batteries. Some data:
https://www.batteryservicehub.com/product/marathon-m12v105ft/
It is probably a 24 Volt system (Inveerter needs 24 V nominal).
If you have a Multimeter, you could begin trying to measure the two batteries' voltages, that are on that charger, etc.
Heading off to bed, more later, Vic
I don't have much time now- but if it was me and those batteries are not good , I would invest in a lithium battery and also fix up any of the deficiencies in the system wiring.
You should start out by drawing out exactly what you have there with all the wire gauge sizes to breakers, etc.
That is the only way to begin to analyze what you have and how to fix or improve it.
Larry
Quote from: ClassicCrazy on October 27, 2022, 10:01:48 AM
I don't have much time now- but if it was me and those batteries are not good , I would invest in a lithium battery and also fix up any of the deficiencies in the system wiring.
You should start out by drawing out exactly what you have there with all the wire gauge sizes to breakers, etc.
That is the only way to begin to analyze what you have and how to fix or improve it.
Larry
If I were a betting man, I'd say those batteries are toast. As Vic mentioned, leaving lead-acid batteries sit without maintenance charge is a death blow. That being said, a lithium iron battery 24V @ 100Ah would set me back between $1500 to $2000 depending on where you look. Yeah, sure you can DIY with Chinese cells and so on, but let's talk about ready to plug in and go.
Now, that being said, four 6-volt golf cart batteries would give you 100Ahr (220 Ahrs with 50% depth of discharge) for about $400-$600 bucks, again your mileage will vary. However, golf cart batteries, or any flooded cell lead-acid battery, requires some maintenance. If you're not ready to go weekly checks of water, keeping the tops clean the dry, and doing a monthly equalization charge, then you should pass on lead-acid and go with the lithium.
Mike
... and, Buckmaster,
It could help the advice that you might get, it we knew more about the purpose of the power system:
Is this site completely off-grid (NO Grid power on the property)?
The loads on this system, especially large power users, like pumps, motors, heating and cooling (as in A/C).
Is this a full-time residence, weekender, of occasional escape use?
Et cetera, Vic
Buckmaster,
You mentioned that two batteries in the bank are connected to a charger.
Is the charger a 24v charger with one lead connected to a neg on one battery and pos on another battery?
Or is it 2 chargers connected to 2 different batteries?
Base on the pick it looks as if the entire array is currently wired up. 2 series of 9 in parallel for approx. 1000ah capacity.
Hence a 24v system.
Technically I suppose that if you separated the series, you could charge each 12v array with a 12v charger and then reconnect the series. Even with Lead Acid, I would think you would want to make sure you end voltage was close before connecting it back together.
If you have a 24V charger, then I would guess that you are connecting to 2 different batteries positive on one series negative on the other series.
As mentioned, if the system has been sitting stale for a year, the batteries are most likely shot. I won't offer opinion on batteries technology. Too many factors involved (cost, need, location, etc)
Good luck sir.
I have sketched up what I think your battery array is.
If you have time, would you be able to look at it and tell me if it is correct? If so, could you provide information on what the two boxes of question marks contain? I am assuming this is the battery charger(s)? Would you have spec on in (them)
Quote from: qrper on October 27, 2022, 12:53:20 PM
Quote from: ClassicCrazy on October 27, 2022, 10:01:48 AM
I don't have much time now- but if it was me and those batteries are not good , I would invest in a lithium battery and also fix up any of the deficiencies in the system wiring.
You should start out by drawing out exactly what you have there with all the wire gauge sizes to breakers, etc.
That is the only way to begin to analyze what you have and how to fix or improve it.
Larry
If I were a betting man, I'd say those batteries are toast. As Vic mentioned, leaving lead-acid batteries sit without maintenance charge is a death blow. That being said, a lithium iron battery 24V @ 100Ah would set me back between $1500 to $2000 depending on where you look. Yeah, sure you can DIY with Chinese cells and so on, but let's talk about ready to plug in and go.
Now, that being said, four 6-volt golf cart batteries would give you 100Ahr (220 Ahrs with 50% depth of discharge) for about $400-$600 bucks, again your mileage will vary. However, golf cart batteries, or any flooded cell lead-acid battery, requires some maintenance. If you're not ready to go weekly checks of water, keeping the tops clean the dry, and doing a monthly equalization charge, then you should pass on lead-acid and go with the lithium.
Mike
Mike
$1600 ( includes shipping ) right now will get you 5.1 kwh LiFePO4 lithium wall mount battery 48v 100 ah . complete with bms and communications ( and free monitoring software)
Now that I have lithium , they are fantastic compared to lead acid. They charge faster and will give much better performance than lead acid.
Larry
Thanks everyone for your feedback...I am learning as I go. I have tried to consolidate some answers based on what has been asked so far:
What is the purpose of the system: It is really an alternative source of power. The home is completely on the grid and will be our residential home once we have completed renovations. We were told the previous owner "sold" power back to the utility company but I see no evidence of any connection to the main house panel. My purpose for this system is to revive it to run outdoor lights (just over half acre) and to power the driveway gate - I would like to use it as backup power for power failures in emergency but the current plan is really "light duty" power for 12V outside lights.
For the current charger, I will find the name/model but I believe it is a marine charger which is connected to 2 batteries independently (it can charge 2 batteries at a time).
Thank you for starting the diagram - I will work on completing this to the best of my ability to get a better insight into the setup. As we are renovating the home, I am not living there but will get something together this weekend.
Thanks all for your input!
Sounds like fun. Reno's can be a blast I have done a few over the years some good. some not so much.
Our current place is from scratch ground up off grid for retirement. Coming along well but learning a lot along the way. :)
Keep us posted on the progress.