Parallel vs series

[Unpluggedone]

If you’re boiling a battery then things are about to get bad. You have sealed batteries if they are venting then it’s really bad. You need to turn off your Powermax AC charger and shutdown the SolarMPPT immediately. A battery can easily explode then things will short and the nice wooden storage area will catch on fire and bye bye bus.

Your systems design is not incorrect just one major error resulting in unequal charging legs and a failing battery. If your just learning take a deep breath and ask for someone who’s close to come look at it. A few tweaks and likely a new battery and you’ll be up and running. Ps get a fire extinguisher close now

[djdalfaro]

Not what you want to hear I'm sure, but as we now KNOW your batteries are not of equal wear. I would pull them all off, have them all trickle charged and load tested and try to sell the good ones. I think what you'll find is vastly varying capacities. They aren't the type of batteries you should be using in this situation anyways, so If you want to keep this setup you can buy (4) matching 6v deep cycle batteries in the highest ah capacity you can afford and install them in a single series configuration (these are common batteries). This is preferable to (4) 12v 2S2P. If you don't want to keep this weird separated setup you need to make a list of what you have, preferably with clear pictures and tell us what you're trying to accomplish and we can help design your system. Do not just replace a single battery. You'll end up in the same place.

[john61ct]

One of the huge longevity advantages to FLA deep cycling model units over VRLA

is the fact that you do not need to worry about that "boiling" toward the end of the charge cycle

in fact it's a good sign you are getting to the spec'd 100% Full point, which is absoljtely critical to longevity.

Not saying go higher than spec sheet **voltage** but no such thing as holding that CV stage too long, so long as you keep the electrolyte topped up.

Now AGM or GEL, you may hear that "boiling" before the 100% Full spec is reached - and for longevity that point must be reached, usually takes 7+ hours

but as noted you cannot replace lost electrolyte. That is why we say sealed units are "fussier" to care for, there is a much narrower window complying with the spec sheet profile but not holding CV / Absorb Hold Time too long.

Thus better quality full user custom adjustable charge sources are required, and then calibrated for that model batt and the current conditions, fairly challenging for newbies to get right.

With FLA you have a lot more leeway for proper care, they inherently last longer and are cheaper per Ah in the first place.

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club.

NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

[Kwest364]

Originally Posted by djdalfaro

OK... So from what I can see and ASSUME about your battery configuration, it will work to provide 24v. Yes, it's done weird, but if your batteries are connected the way I show below, the wiring is not the issue. Yes it could be improved, but it's nothing major. I'll explain.



If we consider (4) 12v 100ah batteries,
Most 2s2p systems are wired like this:

        24v 100ah
   ┌─────┐     ┌─────┐
 ┌─┤-   +├─────┤-   +├─┐
 │ └─────┘     └─────┘ │
─┤                     ├─   Total: 24v 200ah
 │ ┌─────┐     ┌─────┐ │
 └─┤-   +├─────┤-   +├─┘
   └─────┘     └─────┘
        24v 100ah

We do this because when batteries are wired in series, they each receive the same current through them. This results in longer battery life because they charge/discharge at the same rate. So while both legs may not receive the same current, the batteries in each leg receive the same current as it's pair. There are methods to TRY to keep the the current through each leg identical. If they are successful, then you're golden.

You can also wire batteries in 2P2S like this:

  12v 200ah   12v 200ah
   ┌─────┐     ┌─────┐
 ┌─┤-   +├─┐ ┌─┤-   +├─┐
 │ └─────┘ │ │ └─────┘ │
─┤         ├─┤         ├─   Total: 24v 200ah
 │ ┌─────┐ │ │ ┌─────┐ │
 └─┤-   +├─┘ └─┤-   +├─┘
   └─────┘     └─────┘

In this wiring configuration each 200ah pair receives the same current, which is then divided amongst the 2 batteries. This is less desirable because no single battery is in series with any other single battery. Sure there are methods to TRY to keep the current in each pair the same. These are the same methods I mentioned above, however instead of having to employ them once, now you have to employ them twice. So greater chance of non-equal charging/discharging.


Then we have your configuration.

  12v 100ah   12v 100ah
   ┌─────┐     ┌─────┐
─┬─┤-   +├─┬─┬─┤-   +├─┬─
 │ └─────┘ │ │ └─────┘ │
 │         │ │         │    Total: 24v 200ah
 │ ┌─────┐ │ │ ┌─────┐ │
 └─┤-   +├─┴─┴─┤-   +├─┘
   └─────┘     └─────┘
  12v 100ah   12v 100ah

In your configuration, no batteries will receive the same current. How much will the be off? Hard to say. It's more number crunching than I care to put in. What to do about it? As others have said, you need to find out what condition your batteries are in currently. Then ASSUMING THEY ARE ALL EQUALLY GOOD I'd modify the wiring to look like below. Do this by removing the two cables running vertically in the middle of your picture (one red, one black), and switch the red cable on the right side of the picture from the upper battery positive post to the lower battery positive post. That will give your system the best chance at even charging/discharging without much work.

   ┌─────┐     ┌─────┐
─┬─┤-   +├─────┤-   +├─┐
 │ └─────┘     └─────┘ │
 │                     │    
 │ ┌─────┐     ┌─────┐ │
 └─┤-   +├─────┤-   +├─┴─
   └─────┘     └─────┘

Thank you so much. When you say "switch the red cable on the right side of the picture from the upper battery positive post to the lower battery positive post", which red cable do you mean?
1. The thick red cable running from upper right battery + terminal thru fuse to inverter + terminal?
2. The red cable running straight to the shore power converter box? I'm guessing no,
3. Or the thin red wire running from my charge controller?

[Kwest364]

Ok, removed center parallel cables. What else do I have to do? Anything else I should move?

[djdalfaro]

Originally Posted by Kwest364

Thank you so much. When you say "switch the red cable on the right side of the picture from the upper battery positive post to the lower battery positive post", which red cable do you mean?

1. The thick red cable running from upper right battery + terminal thru fuse to inverter + terminal?

2. The red cable running straight to the shore power converter box? I'm guessing no,

3. Or the thin red wire running from my charge controller?

The point of that step is to make wire your (2) parallel strings in a way such that only one of the positive or negative wires connect to each string. Yes they are both connected at the ends but if the positive and negative connections are diagonally opposed you'll have more even charging/discharging. It doesn't matter whether you decide to move the negative or the positive wires. Ideally you should move all three 1, 2, and 3 of your itemized list as each of those is either charging or discharging. Maybe I didnt look close enough but I only saw 2 wires on the positive and 2 on the negative leaving your battery bank. Either way. It's pretty hard to diagnose your system without an accurate wiring diagram. You should draw one and post a picture. Otherwise we're all shooting blind.

[Booyah45828]

Originally Posted by djdalfaro

Not what you want to hear I'm sure, but as we now KNOW your batteries are not of equal wear. I would pull them all off, have them all trickle charged and load tested and try to sell the good ones. I think what you'll find is vastly varying capacities. They aren't the type of batteries you should be using in this situation anyways, so If you want to keep this setup you can buy (4) matching 6v deep cycle batteries in the highest ah capacity you can afford and install them in a single series configuration (these are common batteries). This is preferable to (4) 12v 2S2P. If you don't want to keep this weird separated setup you need to make a list of what you have, preferably with clear pictures and tell us what you're trying to accomplish and we can help design your system. Do not just replace a single battery. You'll end up in the same place.

Quoting this, as it's your next step.

With one battery hot, and you smelling sulfuric acid, shut down the system and disconnect all of the batteries. You need to check the electrolyte levels, charge them fully individually, and then test them all for capacity. Any under-perfomers should be swapped out, and being your batteries are all from 2021, they should still have some sort of warranty left on them.

Your most recent picture will operate fine. Yes it leaves the near bank unequal, but your charge/discharge rates shouldn't be high enough that it matters.

And if all of your batteries are junk, follow alf's recommendation and use 6v golf cart batteries. They're better deep cycling and will simplify your setup by being a 4s vs the 2s2p setup you have now.

[Rucker]

Originally Posted by Rwnielsen

This is a handy little voltage drop calculator, switches from AC to DC and covers a wide range of voltages. It's an eye opener, especially ir you're building a full size bus.

https://jcalc.net/voltage-drop-calculator-nec

Nice link.

[kidharris]

Originally Posted by Kwest364

I bought a converted skoolie with solar. I'm trying to understand it more to make it work.

1. The previous owner set up a 24V system.

2. There are 6 x 185 W panels on the top of bus, running the AC system. MPPT charge controller is inside bus, attached to (2x) 12v batteries in SERIES connected in PARALLEL to (2x) 12v batteries in SERIES. So that means I have a 24V battery connected in parallel to another 24V battery, correct?

3. There is a single panel on top that runs a separate DC system. I don't know it's wattage, probably 100W. It's connected to a single battery under the bus, in a compartment and powers the interior overhead led lights, the water pump I'm guessing, and maybe water heater? (at least, I'm pretty sure that's all it powers, don't know what else it could be powering). Have not had a single issue with this system, yet. I limit nightly use till I have this handled.

4. The AC system: I've been having my inverter beeping and mppt controller reading "fault prompt: over discharge protection". Batteries are not holding charge at night. As soon as sun is gone, batteries don't hold any juice, and inverter shuts all 120V outlets and appliances down (my fridge is the only thing it's powering, sometimes charging phone/laptop. So, only getting juice while sun is up and powering panels. How to fix this?

5. Replace batteries? They are deep cycle marine/TV batteries. (Pic attached). When he had bus in storage he said he disconnected batteries. My guess: they discharged and killed em.

6. If replacing them is the ticket, what size batteries do I get? What capacity? How do I build this battery? One guy I met in the Nevada desert recently (@sunnytheskoolie) told me he built his battery bank batteries from blue cell 3.2V batteries by Eve brand, direct from China. This seems the best and cheapest way to go. Thoughts?

I am not as knowlegeable as the people trying to help you but I do have a question. Is the bottom left battery the same as the other three batteries? I am as lost as you and am trying to understand as well. Thanks

[Kwest364]

Yes it is same battery. Not sure why it's the only one with cap on top like that.

[kidharris]

Originally Posted by Kwest364

Yes it is same battery. Not sure why it's the only one with cap on top like that.

I was thinking that they looked like 3 sealed no maintenance lead acid marine batteries and 1 regular maintenance vented lead acid marine battery by the same manufacturer. Was wondering if that made a difference. Thanks for the reply.

[Kwest364]

Anybody have other ideas on how to make THIS system work? If salvageable. So I should:

1. Pull batteries
2. Trickle charge them until all charged. ANY trickle charger? Specific type of trickle charger for deep cycle or rv/marine batteries?
3. Have them load tested
4. Then....what? How would I wire these up for my current set up. Not lookin to spend a lot/any $, I'm limited on tools, only have a motorcycle for transport, and live in it in the Santa Barbara mountains.
5. Logistics with a motorcycle bike, and not having tools and not having easy/constant access to a house and electricity is wearing me down.
6. I fear I bit off more than I can chew.

System still isn't working overnight or holding charge. WHY? I'm guessing at one point it did for the previous guy who built it. How to modify this current set up to work?

Also, someone recommended taking the center 2 wires off, WHY? In my original configuration, I had 2 x 12v (1x24v) batteries in parallel, connected in series, to 2 x 12v (1x24v). So a 24v series to a 24v. With taking out center cables (taking out a set that parallel-d the bank), is the system still 24v? What did taking out the center cables do?

Why was the top left battery (from my previous pics, circled in red) boiling? What in the way it was wired, made it do that?

Any help appreciated.

[Booyah45828]

Originally Posted by Kwest364

Anybody have other ideas on how to make THIS system work? If salvageable. So I should:

1. Pull batteries
2. Trickle charge them until all charged. ANY trickle charger? Specific type of trickle charger for deep cycle or rv/marine batteries?
3. Have them load tested
4. Then....what? How would I wire these up for my current set up. Not lookin to spend a lot/any $, I'm limited on tools, only have a motorcycle for transport, and live in it in the Santa Barbara mountains.
5. Logistics with a motorcycle bike, and not having tools and not having easy/constant access to a house and electricity is wearing me down.
6. I fear I bit off more than I can chew.

System still isn't working overnight or holding charge. WHY? I'm guessing at one point it did for the previous guy who built it. How to modify this current set up to work?

Also, someone recommended taking the center 2 wires off, WHY? In my original configuration, I had 2 x 12v (1x24v) batteries in parallel, connected in series, to 2 x 12v (1x24v). So a 24v series to a 24v. With taking out center cables (taking out a set that parallel-d the bank), is the system still 24v? What did taking out the center cables do?

Why was the top left battery (from my previous pics, circled in red) boiling? What in the way it was wired, made it do that?

Any help appreciated.

1)Yes, you can leave them in the bus, but remove the cabling and individualize them. Charge and test them individually.
2)Yes, any one that works with 12v lead acid batteries. I recently got this onehere from a sale at my local napa store. A nearby hardware store might sell something similar. Or you could bring the batteries and all to an auto parts store that you trust, and they might charge and load test them for you.
3) Yes, although if you have a dead cell, it will be obvious with a voltmeter.
4) The test results determine your next steps. If they all take a charge, and test fine, then you wire them back up how you have them currently, and look for faults in the charging/inverter system.

If they don't test fine, we'll come up with alternatives and other options for you.
5)Does the bus start and run? Drive that. Balancing a battery on a bike isn't impossible, but it's not entirely easy. It'd also take 4 trips if you do one at a time.
6) You probably did. Most first timers do, because they don't have the understanding and skill set in order to tackle everything they're trying to do. Don't give up, as that's a sure way to defeat.

I recommended that, among others, because it's wasn't necessary, and provided only complications with no benefit. Your original setup was an odd paralleled but in series setup. The goal of any battery system is to group enough of them in series to get to your target voltage, and then parallel strings of those groups together to get your desired wattage.

IMO the top left battery was boiling because it was being overcharged. Might have been caused by how they were wired, might have been caused by overuse creating a dead cell in the battery, could have been a defective battery from the get go. Nobody really knows. I suspect the battery was damaged through use, and that it now has a dead cell in it, testing will confirm if I'm right or not.

[rossvtaylor]

Originally Posted by Kwest364

System still isn't working overnight or holding charge. WHY? I'm guessing at one point it did for the previous guy who built it. How to modify this current set up to work?

Also, someone recommended taking the center 2 wires off, WHY? In my original configuration, I had 2 x 12v (1x24v) batteries in parallel, connected in series, to 2 x 12v (1x24v). So a 24v series to a 24v. With taking out center cables (taking out a set that parallel-d the bank), is the system still 24v? What did taking out the center cables do?

Actually, 3 of us suggested you remove those center cables (the ones oriented vertically in the pics). They were at the least unnecessary and possibly a problem, depending upon where the cables went out of the photo's field of view...we couldn't be sure. So, we recommended you do that and you now certainly have two 24V strings connected in parallel. I also suggested that you move the black (negative) cable from the inverter to the bottom left post on your battery bank...while djdalfaro suggested that you move the red (positive) cable down to the bottom right. Either would work...they do the same thing. I just thought moving the negative cable would be easier because it's longer and not limited by the fuse screwed to the panel. This suggestion is for balance, though, and won't impact the bank voltage.

So, your battery bank is now wired correctly for 24V.

As to the other questions, this system might work just fine now with good batteries. Test and charge these to see if they can be saved. Keep in mind that these don't appear to be deep cycle batteries, so they won't ever work as well as true deep cycles.

I'd get a clamp-on ammeter with DC capability, so that you can measure the draw from that inverter. I've seen inverters draw signifiant idle current, just sitting there, and that might be 7 amps per hour. Overnight for 12 hours that's 84 amp-hours sucked from your batteries just for being on. A meter will help you check that and will also be useful in lots of other phases of your build.

EDIT: As soon as I hit post, I see Booyah was also posting...and none of our suggestions are in conflict. Kwest...I learn new things all the time and don't pretend to know it all with these things...but there have been several of us here all suggesting the same things, which tells me that we're not off base.

[djdalfaro]

Originally Posted by Kwest364

Anybody have other ideas on how to make THIS system work? If salvageable. So I should:

1. Pull batteries
2. Trickle charge them until all charged. ANY trickle charger? Specific type of trickle charger for deep cycle or rv/marine batteries?
3. Have them load tested
4. Then....what? How would I wire these up for my current set up. Not lookin to spend a lot/any $, I'm limited on tools, only have a motorcycle for transport, and live in it in the Santa Barbara mountains.
5. Logistics with a motorcycle bike, and not having tools and not having easy/constant access to a house and electricity is wearing me down.
6. I fear I bit off more than I can chew.

System still isn't working overnight or holding charge. WHY? I'm guessing at one point it did for the previous guy who built it. How to modify this current set up to work?

Also, someone recommended taking the center 2 wires off, WHY? In my original configuration, I had 2 x 12v (1x24v) batteries in parallel, connected in series, to 2 x 12v (1x24v). So a 24v series to a 24v. With taking out center cables (taking out a set that parallel-d the bank), is the system still 24v? What did taking out the center cables do?

Why was the top left battery (from my previous pics, circled in red) boiling? What in the way it was wired, made it do that?

Any help appreciated.

Yep, pull batteries, trickle charge them. Take them to a shop and have them load tested. This is different than just testing the voltage. There was nothing incorrectly hooked up on your batteries. It was still a 24v battery bank, BUT... it was hooked up unbalanced which means one battery (probably the one that was boiling) was charging/discharging at a higher rate.

Those are not the best type of batteries to use anyways. Those are like a hybrid starting/storing battery, and from what I can dig up they are the costco marketed version of https://www.interstatebatteries.com/...uctline=marine which is an 88ah battery. So your bank with brand new batteries is 12v x 88ah x (4 qty) = 4,224 wh. Yes they are deep cycle batteries, but as these are lead acid batteries they should never have been drained below 50%. Here's why. If these batteries were only discharged 25%, you would have 2200 cycles before the capacity dropped to 50%, if you only cycled once per day, that's 6 years. If you discharge to 50%, that drops to 2.75 yrs. If these have been getting discharged to 100%, they are expected to only last 250 days.

So let's look at the capacity again. Whenever possible we want to convert to Watts and Watt-hours. This is because they are universal. It doesn't matter if you are talking 240AC, 120AC, 12DC, or 24DC. (For electrical nerds, I'm not going to go into the difference between Volt-Amps and Watts, just deal with it.) Let's do some napkin math. Your (6)x185w charging is probably averaging somewhere around 800w, so it would take 5 hours of direct sun to charge 4000wh completely. That's basically 1 full day of sun to charge from completely empty WITH NO USAGE WHILE CHARGING. I have no idea what your usage looks like, but if you're using anything, then you're batteries are not getting a full charge by the end of the day.

This is probably way to complex of an issue to attempt to correct all in one post, and I'm sure it's overwhelming. So just take it one step at a time. First thing, charge and test your batteries. While that's going on, make a spreadsheet of EVERY electrical load on your bus, divide it by system, so in your case all your AC loads will be in one list. You really need the power usage (in watts), and the amount of time you use it every day (in hours). Be as accurate as you can. For the fridge because it cycles, unless you are actively monitoring this with a meter, we'll take our best guess, look up your model online for yearly consumption and divide by 365. (233KWh = 233,000Wh. 233,000Wh/365days = 638wh per day.

   Item   | Volts   | Amps | Watts |per day use|per day elec 
Microwave | 120VAC  | 8.3A | 1000W |  .5hr     |  500Whr
Fridge    | 120VAC  | unk  | unk   |  unk      |  638Whr

Lights    | 12VDC   | 1A   | 12W   |  8hr      |  96Whr

[djdalfaro]

Originally Posted by rossvtaylor

Actually, 3 of us suggested you remove those center cables (the ones oriented vertically in the pics). They were at the least unnecessary and possibly a problem, depending upon where the cables went out of the photo's field of view...we couldn't be sure. So, we recommended you do that and you now certainly have two 24V strings connected in parallel. I also suggested that you move the black (negative) cable from the inverter to the bottom left post on your battery bank...while djdalfaro suggested that you move the red (positive) cable down to the bottom right. Either would work...they do the same thing. I just thought moving the negative cable would be easier because it's longer and not limited by the fuse screwed to the panel. This suggestion is for balance, though, and won't impact the bank voltage.

So, your battery bank is now wired correctly for 24V.

As to the other questions, this system might work just fine now with good batteries. Test and charge these to see if they can be saved. Keep in mind that these don't appear to be deep cycle batteries, so they won't ever work as well as true deep cycles.

I'd get a clamp-on ammeter with DC capability, so that you can measure the draw from that inverter. I've seen inverters draw signifiant idle current, just sitting there, and that might be 7 amps per hour. Overnight for 12 hours that's 84 amp-hours sucked from your batteries just for being on. A meter will help you check that and will also be useful in lots of other phases of your build.

EDIT: As soon as I hit post, I see Booyah was also posting...and none of our suggestions are in conflict. Kwest...I learn new things all the time and don't pretend to know it all with these things...but there have been several of us here all suggesting the same things, which tells me that we're not off base.

Looks like this is correct regarding cable length and ease of movement.

    12v 88ah   12v 88ah
    ┌─────┐     ┌─────┐ ┌──
   ┌┤-   +├─────┤-   +├┬┼──
   │└─────┘     └─────┘│└──
   │                   │      Total: 24v 176ah = 4224wh
──┐│┌─────┐     ┌─────┐│
──┼┴┤-   +├─────┤-   +├┘
──┘ └─────┘     └─────┘
    12v 88ah   12v 88ah

[rossvtaylor]

Posted in error... sorry

[Kwest364]

Originally Posted by Booyah45828

1)Yes, you can leave them in the bus, but remove the cabling and individualize them. Charge and test them individually.
2)Yes, any one that works with 12v lead acid batteries. I recently got this onehere from a sale at my local napa store. A nearby hardware store might sell something similar. Or you could bring the batteries and all to an auto parts store that you trust, and they might charge and load test them for you.
3) Yes, although if you have a dead cell, it will be obvious with a voltmeter.
4) The test results determine your next steps. If they all take a charge, and test fine, then you wire them back up how you have them currently, and look for faults in the charging/inverter system.

If they don't test fine, we'll come up with alternatives and other options for you.
5)Does the bus start and run? Drive that. Balancing a battery on a bike isn't impossible, but it's not entirely easy. It'd also take 4 trips if you do one at a time.
6) You probably did. Most first timers do, because they don't have the understanding and skill set in order to tackle everything they're trying to do. Don't give up, as that's a sure way to defeat.

I recommended that, among others, because it's wasn't necessary, and provided only complications with no benefit. Your original setup was an odd paralleled but in series setup. The goal of any battery system is to group enough of them in series to get to your target voltage, and then parallel strings of those groups together to get your desired wattage.

IMO the top left battery was boiling because it was being overcharged. Might have been caused by how they were wired, might have been caused by overuse creating a dead cell in the battery, could have been a defective battery from the get go. Nobody really knows. I suspect the battery was damaged through use, and that it now has a dead cell in it, testing will confirm if I'm right or not.

Thank you so much!

[Kwest364]

Originally Posted by djdalfaro

Yep, pull batteries, trickle charge them. Take them to a shop and have them load tested. This is different than just testing the voltage. There was nothing incorrectly hooked up on your batteries. It was still a 24v battery bank, BUT... it was hooked up unbalanced which means one battery (probably the one that was boiling) was charging/discharging at a higher rate.

Those are not the best type of batteries to use anyways. Those are like a hybrid starting/storing battery, and from what I can dig up they are the costco marketed version of https://www.interstatebatteries.com/...uctline=marine which is an 88ah battery. So your bank with brand new batteries is 12v x 88ah x (4 qty) = 4,224 wh. Yes they are deep cycle batteries, but as these are lead acid batteries they should never have been drained below 50%. Here's why. If these batteries were only discharged 25%, you would have 2200 cycles before the capacity dropped to 50%, if you only cycled once per day, that's 6 years. If you discharge to 50%, that drops to 2.75 yrs. If these have been getting discharged to 100%, they are expected to only last 250 days.

So let's look at the capacity again. Whenever possible we want to convert to Watts and Watt-hours. This is because they are universal. It doesn't matter if you are talking 240AC, 120AC, 12DC, or 24DC. (For electrical nerds, I'm not going to go into the difference between Volt-Amps and Watts, just deal with it.) Let's do some napkin math. Your (6)x185w charging is probably averaging somewhere around 800w, so it would take 5 hours of direct sun to charge 4000wh completely. That's basically 1 full day of sun to charge from completely empty WITH NO USAGE WHILE CHARGING. I have no idea what your usage looks like, but if you're using anything, then you're batteries are not getting a full charge by the end of the day.

This is probably way to complex of an issue to attempt to correct all in one post, and I'm sure it's overwhelming. So just take it one step at a time. First thing, charge and test your batteries. While that's going on, make a spreadsheet of EVERY electrical load on your bus, divide it by system, so in your case all your AC loads will be in one list. You really need the power usage (in watts), and the amount of time you use it every day (in hours). Be as accurate as you can. For the fridge because it cycles, unless you are actively monitoring this with a meter, we'll take our best guess, look up your model online for yearly consumption and divide by 365. (233KWh = 233,000Wh. 233,000Wh/365days = 638wh per day.

   Item   | Volts   | Amps | Watts |per day use|per day elec 
Microwave | 120VAC  | 8.3A | 1000W |  .5hr     |  500Whr
Fridge    | 120VAC  | unk  | unk   |  unk      |  638Whr

Lights    | 12VDC   | 1A   | 12W   |  8hr      |  96Whr

Super helpful, thank you!

[Kwest364]

Originally Posted by rossvtaylor

Actually, 3 of us suggested you remove those center cables (the ones oriented vertically in the pics). They were at the least unnecessary and possibly a problem, depending upon where the cables went out of the photo's field of view...we couldn't be sure. So, we recommended you do that and you now certainly have two 24V strings connected in parallel. I also suggested that you move the black (negative) cable from the inverter to the bottom left post on your battery bank...while djdalfaro suggested that you move the red (positive) cable down to the bottom right. Either would work...they do the same thing. I just thought moving the negative cable would be easier because it's longer and not limited by the fuse screwed to the panel. This suggestion is for balance, though, and won't impact the bank voltage.

So, your battery bank is now wired correctly for 24V.

As to the other questions, this system might work just fine now with good batteries. Test and charge these to see if they can be saved. Keep in mind that these don't appear to be deep cycle batteries, so they won't ever work as well as true deep cycles.

I'd get a clamp-on ammeter with DC capability, so that you can measure the draw from that inverter. I've seen inverters draw signifiant idle current, just sitting there, and that might be 7 amps per hour. Overnight for 12 hours that's 84 amp-hours sucked from your batteries just for being on. A meter will help you check that and will also be useful in lots of other phases of your build.

EDIT: As soon as I hit post, I see Booyah was also posting...and none of our suggestions are in conflict. Kwest...I learn new things all the time and don't pretend to know it all with these things...but there have been several of us here all suggesting the same things, which tells me that we're not off base.

Thanks! It's not that I don't think you're right. I just wanted an explanation to help me understand. Massively thankful for these posts and explanations. I'm picking it up