100w Panel output and battery capacity issues

[MurphyGuy]

Unfortunately lithium is not in the budget at the moment. The only reason I bought those is because no one else even had that many matching batteries in stock. I don’t even have a hydrometer haha. I’m getting close to the point where everything is going to go in the garbage and I’ll hook up to the grid. 8k in garbage. Should have just paid the 1k to hook to the grid lol

You don't have to go with lithium, but a quality golf cart deep cycle lead acid battery would work. Probably last a good 5 years if you check water regularly.
Those cheap walmart batteries are garbage, but even so, they should last you a couple years regardless. My money is still on a bad cell, you should figure out which one and get it warrantied.

 

[sunshine_eggo]

Unfortunately lithium is not in the budget at the moment. The only reason I bought those is because no one else even had that many matching batteries in stock.

This is almost always the case. A large battery purchase requires planning. Expecting to find them locally in stock is unrealistic. I'm in Phoenix, and I can guarantee you the batteries I would choose to purchase are not in stock anywhere in this vast metropolis.

I don’t even have a hydrometer haha. I’m getting close to the point where everything is going to go in the garbage and I’ll hook up to the grid. 8k in garbage. Should have just paid the 1k to hook to the grid lol

It kinda sounds like a lack of planning at the outset ensured an unfavorable outcome. Rather than just shitcanning everything, you can still hook to the grid, but do it with the system between the grid and your house, that way you can eventually pay for the $1K hook-up with savings from energy you provide yourself. The batteries can simply be for backup or offsetting any times that result in high fees during peak demand.

 

[TimG303]

This is almost always the case. A large battery purchase requires planning. Expecting to find them locally in stock is unrealistic. I'm in Phoenix, and I can guarantee you the batteries I would choose to purchase are not in stock anywhere in this vast metropolis.



It kinda sounds like a lack of planning at the outset ensured an unfavorable outcome. Rather than just shitcanning everything, you can still hook to the grid, but do it with the system between the grid and your house, that way you can eventually pay for the $1K hook-up with savings from energy your provide yourself. The batteries can simply be for backup or offsetting any times that result in high fees during peak demand.

Local power company will not connect power until all solar is permanently removed. Even if everything is rated and listed. Unfortunately small utility companies suck around here hence why I went off grid.

 

[TimG303]

You don't have to go with lithium, but a quality golf cart deep cycle lead acid battery would work. Probably last a good 5 years if you check water regularly.
Those cheap walmart batteries are garbage, but even so, they should last you a couple years regardless. My money is still on a bad cell, you should figure out which one and get it warrantied.

Just checked the battery voltage. The 8 batteries in the back are 12.55v, the bank in front is a little weird. The battery on the left is 12.22, both middle ones are 12.98 and the right one is 12.39. Does that mean the outer ones are both bad and dragging the system down. Why would the ones in between them be so much higher?

 

[MurphyGuy]

Just checked the battery voltage. The 8 batteries in the back are 12.55v, the bank in front is a little weird. The battery on the left is 12.22, both middle ones are 12.98 and the right one is 12.39. Does that mean the outer ones are both bad and dragging the system down. Why would the ones in between them be so much higher?

You need to charge them all up, then apply an equalization to them.. When that's done, measure voltage.

Go to your local auto store and buy a $9 hydometer and check water.

It is entirely possible for a lead acid battery to show good voltage but still be bad. Frequently, but not always, they need to be charged all the way up, then put under load to test.

Every battery in each string should be within around 0.1 volts of each other.. 12.22 sounds low if you have some at 12.98.. that's a significant difference.

It is the equalization charge that brings up all cells to the same voltage. An equalization charge will overcharge some cells that don't need a charge, but it will not charge them with enough juice do damage the cells.. but as the equalization charge is applied, those cells lagging behind will come up in voltage to meet the higher ones.

So to start a diagnosis, you need to start with a fully charged system.. and if your voltage variance is that wide, you should apply an equalization charge. Equalization charges should be applied regularly.. frequency varies, but generally its every three to four weeks or so. It kind of depends on the characteristics of how the batteries are cycled.. How deep, how often, etc.

Those batteries you have will die fast if you drop them below 70% SOC.. True deep cycle flooded batteries can go to 50%, but even then its not healthy for them. The bats you have are a sort of bastardized starting battery.. Not a true start battery, not a true deep cycle.

On top of this SOC limitation, are some conditions.. The lower you drop, the faster you must get them charged back up to prevent excess damage. "Faster" refers to both speed of charge, and how much time you have before applying that charge.

 

[Mattb4]

... I’m getting close to the point where everything is going to go in the garbage and I’ll hook up to the grid. 8k in garbage. Should have just paid the 1k to hook to the grid lol

It is an option however I would think you can recoup some of your money by selling the solar stuff. If I was not a State away I would make you an offer on them 22-100w panels.

 

[sunshine_eggo]

Just checked the battery voltage. The 8 batteries in the back are 12.55v, the bank in front is a little weird. The battery on the left is 12.22, both middle ones are 12.98 and the right one is 12.39. Does that mean the outer ones are both bad and dragging the system down. Why would the ones in between them be so much higher?

This is because you likely didn't fully charge each 12V to full and then each string's worth of batteries in parallel to full either.

Once you're at a higher voltage (> 56V), measure all 12V and then pair them in strings according to their voltage, i.e., the highest 4 in one string, the lowest four in another string and the middle four in another string. A string is four batteries in series to make 48V.

The issue is that all 12V need to be at 100% SoC at the same time. If you just hooked these up and started using them, they're all likely at different states of charge.

Another option is to do your best to match up two string's worth, take the third string, wire them in parallel for 12V and then charge them all to full. That should get THAT string to be fairly well balanced. Repeat that process for all 3 strings.

@MurphyGuy has several good suggestions as well.

 

[JRH]

Unfortunately lithium is not in the budget at the moment. The only reason I bought those is because no one else even had that many matching batteries in stock. I don’t even have a hydrometer haha. I’m getting close to the point where everything is going to go in the garbage and I’ll hook up to the grid. 8k in garbage. Should have just paid the 1k to hook to the grid lol

Don’t trash them …. There are people who can’t afford even Wally World batts… help em out and donate them or sell em for 20 bucks each or somthing…you will remember the smiles on their face a long time…… they can be used in many ways for many things…?

 

[pollenface]

I recommend getting a HA02/PowMr 48v balancer. They work surprisingly well. Do a search on ebay/amazon.

I would put 2 panels aside and connect the remaining 20 in 4s5p to give you around 80-90voc (assuming they are 36cell panels).