Running out?

[csp99]

From what I'm reading here, the fact that you can check the water levels means these are NOT AGM, but flooded lead-acid.

Which is perfectly fine. The advantage of flooded is that you can read the specific gravity of each battery cell and determine the battery's true state of charge. You can also use the SG to evaluate the battery's health.

Do you have a battery hydrometer? I use this one, because it has temperature compensation. Basically the gold-standard for flooded battery health/charge.

Deka East Penn 00231 Glass Temperature Correcting Battery Hydrometer | eBay

Deka East Penn 00231. Glass tube.

www.ebay.com

Do this. Get the bank fully charged, and after completing the charge, take a hydrometer reading of each cell. A fully charged battery will have an SG of ~1.165-1.175. Maybe a bit higher for a new battery, and maybe a bit lower for older batteries. The hydrometer is also great for spotting a defective cell. Each cell should not vary by more than ~0.01SG. Maybe 0.005SG for a new, healthy battery.

If you've fully charged the bank and the cells have a significant variation, cell to cell, or if the SG average is significantly less than 1.150, I'd say it's time to replace them.

If it is time to replace the batteries, I'd suggest it's also a good time to pull out that bigger 60A controller, so you can charge the new bank with more amps. Remember, chronic undercharging is the death of lead-acid. Keep them at a respectable charging rate, and they will last a long time.

Not only do I not have a battery hydrometer, I had no idea they existed. I will do that.
Thanks, guys. Learning a lot.

 

[Mattb4]

If you are going to do battery SG readings also pickup heavy rubber gloves, goggles or face shield and many folks like to wear an acid proof apron.

 

[12VoltInstalls]

Setup is...
- 4x 100w panels, south facing
- 40a MPPT controller
- 4x 200ah 6v batteries in series
- 1100w inverter

In my experience you have half of the panels you need for the battery Ah

I agree w/ @MichaelK about huge-ish cheap panels and a second SCC.

 

[csp99]

In my experience you have half of the panels you need for the battery Ah

I agree w/ @MichaelK about huge-ish cheap panels and a second SCC.

Got some new stuff that I'm going to put in this weekend. 5x 210 PV's, Victron 150/70 SCC, Victron 1200 inverter, 8x 6v GC2's.
I was between 6 batteries and 8. If I was around half the panels needed @ 400 W for 4 batteries, I'm probably still going to be light with 1050 W for 8, huh? Maybe I'll return 2.

 

[12VoltInstalls]

Got some new stuff that I'm going to put in this weekend. 5x 210 PV's, Victron 150/70 SCC, Victron 1200 inverter, 8x 6v GC2's.
I was between 6 batteries and 8. If I was around half the panels needed @ 400 W for 4 batteries, I'm probably still going to be light with 1050 W for 8, huh? Maybe I'll return 2.

The issue with lead acid in this kind of circumstance is that they want to be 100% recharged on a daily basis, not languishing at 12.4V or less for days on end. (12.4V is an arbitrary mention, not a specific threshold btw)

200W of panels in good sun generally handles recharging the useable amp hours of one 100Ah 12V lead acid battery. With lithium batteries that can stay at 50% or 35% or 80% for days on end without any practical negatives being ‘over batteried’ aka ‘under-paneled’ is not so much of an issue. That is why when I bought new batteries I picked LiFePo.

 

[MichaelK]

Got some new stuff that I'm going to put in this weekend. 5x 210 PV's, Victron 150/70 SCC, Victron 1200 inverter, 8x 6v GC2's.
I was between 6 batteries and 8. If I was around half the panels needed @ 400 W for 4 batteries, I'm probably still going to be light with 1050 W for 8, huh? Maybe I'll return 2.

I think you are still making design mistakes and are susceptible to impulse buying. Please slow down and make a complete plan before buying anything else.

First off, buying five panels is generally a mistake, because the only ways to wire them are either 5S1P or 1S5P. Five is NOT a good choice. Six is far better. In addition to 1S6P and 6S1P, you also get 2S3P and 3S2P. Is there a chance you can get one more of those panels?

If you want to stick with 12V, then eight 6V batteries would be four parallel strings. Again, that is another mistake. Four strings are much harder to keep balanced, and an early death is likely for at least some of them.

With five 210W panels, that's 1050W, and assuming charging starts at 12.5V, that means 1050W/12.5V = 84A. Even with derating to 85%, that is still somewhat over the Amp limit of your controller.

I really think you will be better off with a 24V system instead of 12V. By switching to 24V, you'd only have two parallel strings of batteries, which will be easier to keep balanced. Which battery is that? A 250Ah Trojan T-105 needs ~460W of panels for optimal charging, so that means ~1840W of solar. That's quite a bit more than what you have now. At 24V, your controller would handle that much power just fine. You'd need two of those controllers to handle the extra amps needed at only 12V. At 24V, your controller would easily handle 8-9 panels.

With a smaller capacity CostCo golf-carts, at 210Ah, that would be 1550W.

 

[csp99]

I think you are still making design mistakes and are susceptible to impulse buying. Please slow down and make a complete plan before buying anything else.

100% correct.
Trying to improve upon what the last guy left me and it's become a rabbit hole 10x more complicated than I had intended. I start out upgrading cables and that got me thinking panels, which led to a new controller, then to an inverter, then to more batteries, then to Series vs. Parallel vs. Series-Parallel, then to adding fuses where none existed.
They'll be putting "all he wanted was a small upgrade" on my tombstone when I electrocute myself.

First off, buying five panels is generally a mistake, because the only ways to wire them are either 5S1P or 1S5P. Five is NOT a good choice. Six is far better. In addition to 1S6P and 6S1P, you also get 2S3P and 3S2P. Is there a chance you can get one more of those panels?

I only have room for 5 comfortably, so that's part of it. The other reason; I had been thinking hard about 2S3P or 3S2P but for the life of me- after hours upon hours of videos and reading- could not define what the tangible benefit was in doing that. I thought I was probably over complicating things and it was better to just go with a series install.

If you want to stick with 12V, then eight 6V batteries would be four parallel strings. Again, that is another mistake. Four strings are much harder to keep balanced, and an early death is likely for at least some of them.

This is good to know.
I've held off on the batteries for now, it seems I was way out to lunch there. 12VoltInstalls makes a lot of sense with the lithium suggestion. Do either of you have any thoughts on what might be a good battery and amount of them in this 12v (840W?) system?

With five 210W panels, that's 1050W, and assuming charging starts at 12.5V, that means 1050W/12.5V = 84A. Even with derating to 85%, that is still somewhat over the Amp limit of your controller.

Well...that is concerning that I missed that. And a little confusing. Probably a stupid question here, but the controller says it supports 1000W @ 12v...if the calculation is to divide by 12.5, that = 80A, on a 70A controller...why would they say it's doable, what am I missing?

I really think you will be better off with a 24V system instead of 12V. By switching to 24V, you'd only have two parallel strings of batteries, which will be easier to keep balanced. Which battery is that? A 250Ah Trojan T-105 needs ~460W of panels for optimal charging, so that means ~1840W of solar. That's quite a bit more than what you have now. At 24V, your controller would handle that much power just fine. You'd need two of those controllers to handle the extra amps needed at only 12V. At 24V, your controller would easily handle 8-9 panels.

I would have loved to have done this but what stopped me from abandoning the 12v is the wiring that this previous fella did. He hooked lights up directly to the 12v batteries and trenched to outbuildings. I'm pretty far from an electrician, as you may have guessed, and did not love the idea of monkeying around with that.

I'm sure there's a way to make that work and probably another dozen ways to improve upon what I've got going, but maybe the thing to do here is just remove a panel to get under the 70A, switch batteries to lithium, and call it good? I'm afraid if I don't, I'll spend the next 4 months designing and redesigning. At the end of the day that will have doubled the Watts on what was already an "okay" system, and hopefully made it safer and more efficient with much better cabling and equipment... ?

 

[12VoltInstalls]

only have room for 5 comfortably,

So put 3 or 4 in the comfortable space, and find another spot to put 3 or 2 panels maybe facing SW to extend harvest?
That’s worked great for me (my ‘core’ system is two 400W arrays facing SE and SW, respectively. There’s other panels running, too, on separate controllers) and even with Canadian smoke drifting down or all the cloudy days I have adequate watts.

so that's part of it. The other reason; I had been thinking hard about 2S3P or 3S2P but

See above. Too little always is, too much isn’t inconvenient.

Do either of you have any thoughts on what might be a good battery and amount of them in this 12v (840W?) system

I have two Btrpower 140Ah lithiums and one Chins 200Ah lithium because I couldn’t buy more 140’s as they went out of stock.
A pair or three of the Chins 200Ah is what I would suggest to keep cabling manageable. I use USA-made Class T 125A fuses right on the batteries.

controller says it supports 1000W @ 12v...if the calculation is to divide by 12.5, that = 80A, on a 70A controller...why would they say it's doable, what am I missing?

The bit of inherent inefficiency wipes a bit of power.
I’d be more than inclined to NOT use one charge controller but rather do two strings to two 40A-60A controllers for redundancy and to keep from pounding them with max power. I have four SCCs on the wall and currently using two of them (presently only about 1350W of solar input). I could activate up to 2500W or install the unused panels for 5000W but I’d do that with multiple controllers. I keep the 4S2P 800W of ‘main’ panels on the turned-off 1012LV-MK because it’s a dead dependable SCC and the other stuff is on a cheapo powerMR 60A SCC.

Everything works ?

stopped me from abandoning the 12v is the wiring that this previous fella did. He hooked lights up directly to the 12v batteries and trenched to outbuildings. I'm pretty far from an electrician, as you may have guessed, and did not love the idea of monkeying around with that.

should have a fuse box

But for a small power system with less than around a 2500W pure sine inverter, the convenience and dependable service of 12V lighting is hard for me to abandon. 24V almost makes no sense to me; if you need that much more power 48V and straight up 120V service seems logical.

In my shop 12V is of limited use; if I create a second system with a split-phase AIO I’ll likely use 12V batteries in 48V configuration. But my household system will always be 12V. It makes too much sense. The only thing that limits me currently is the 2000W inverter- occasionally it would be nice to have 3000W for a couple tools.
I did recently acquire a 6500W inverter generator for 240V welders and 120V 15A table saw, but a 3000W inverter would cover everything else needing more startup headroom without any fuss and still be 12V functional.

 

[csp99]

So put 3 or 4 in the comfortable space, and find another spot to put 3 or 2 panels maybe facing SW to extend harvest?
That’s worked great for me (my ‘core’ system is two 400W arrays facing SE and SW, respectively. There’s other panels running, too, on separate controllers) and even with Canadian smoke drifting down or all the cloudy days I have adequate watts.

See above. Too little always is, too much isn’t inconvenient.

Now that I'm out here in the bush today looking at it, I can see 6 just won't work with the size of these new panels. Even 5 is going to be a tight squeeze.
Good thought on the second array. I'd have to set a new set of posts in the ground and it'd be a bit of a thing, probably more than I ought to bite off at the moment, but something I think I'll add to the project list.

I have two Btrpower 140Ah lithiums and one Chins 200Ah lithium because I couldn’t buy more 140’s as they went out of stock.
A pair or three of the Chins 200Ah is what I would suggest to keep cabling manageable.

I use USA-made Class T 125A fuses right on the batteries.

When you say right on the batteries, do you mean the cable from batteries to SCC? Or is there some other fusing needed with these?

The bit of inherent inefficiency wipes a bit of power.
I’d be more than inclined to NOT use one charge controller but rather do two strings to two 40A-60A controllers for redundancy and to keep from pounding them with max power. I have four SCCs on the wall and currently using two of them (presently only about 1350W of solar input). I could activate up to 2500W or install the unused panels for 5000W but I’d do that with multiple controllers. I keep the 4S2P 800W of ‘main’ panels on the turned-off 1012LV-MK because it’s a dead dependable SCC and the other stuff is on a cheapo powerMR 60A SCC.

Everything works ?

My head is spinning. I would not know where to start with multiple charge controllers and that just seems like one more area for me to make several bad decisions on.

In the short term to get something up and running now with what I have, would you be comfortable putting 1050W on that Victron 150/70? Would the "risk" there simply be that it may not be able to utilize the full 1050, or is there a possibility of damage?

should have a fuse box

But for a small power system with less than around a 2500W pure sine inverter, the convenience and dependable service of 12V lighting is hard for me to abandon. 24V almost makes no sense to me; if you need that much more power 48V and straight up 120V service seems logical.

In my shop 12V is of limited use; if I create a second system with a split-phase AIO I’ll likely use 12V batteries in 48V configuration. But my household system will always be 12V. It makes too much sense. The only thing that limits me currently is the 2000W inverter- occasionally it would be nice to have 3000W for a couple tools.
I did recently acquire a 6500W inverter generator for 240V welders and 120V 15A table saw, but a 3000W inverter would cover everything else needing more startup headroom without any fuss and still be 12V functional.

I have a couple of generators out here as well that I'm running for the bigger stuff, so this does not need to be an all-encompassing solution.

One thing he did have that was handy, and I've lost, is some things that were wired to the load of the last charge controller. The new charge controller does not have a spot for load wires; is there an easy solution to that? Could I go straight to the battery? (Probably a scenario where multiple charge controllers would come in handy )

 

[12VoltInstalls]

When you say right on the batteries, do you mean the cable from batteries to SCC? Or is there some other fusing needed with these?

Class T fuse bolted to the pos(+) battery post of each battery (100A bms for each) and the cable from the Class T fuses to pos(+) busbar.
SCC usually has a fuse in it for the output already. The output of the SCC(s) goes to busbars.

150/70? Would the "risk" there simply be that it may not be able to utilize the full 1050, or is there a possibility of damage?

Read the manual but I think you can overpanel it safely. Just don’t exceed max voltage.

would not know where to start with multiple charge controllers and that just seems like one more area for me to make several bad decisions on

Just start with your one; you connect to busbar, not the batteries.
You merely connect array ‘B’ to another SCC and wire output to the busbar

new charge controller does not have a spot for load wires; is there an easy solution to that? Could I go straight to the battery? (Probably a scenario where multiple charge controllers would come in handy )

I do not use the load outputs- I did for a while to try on some Epever SCCs

I prefer to come off the busbar with an 8ga wire fused at 40A to a bluesea fusebox with ‘ground’ terminals. If you have higher current low voltage a six gage can feed 50A; the bluesea fusebox is rated to 100A but you don’t have to provide it 100A - you can just provision what you need and fuse accordingly.

 

[RoadTurtle]

Sorry for the stupid question, but is the converter turned off?

 

[12VoltInstalls]

Sorry for the stupid question, but is the converter turned off?

Are you referring to the 1012LV-MK?
I have no converter.

The 1012LV-MK AIO is turned off, only functioning as a SCC currently. It is there all wired up in case of an emergency where I need the inverter as a backup or need its 60A utility charger. Mostly for the charger but the SCC functions great.

 

[Zwy]

All batteries are marked 2019 so they might be getting due?

Has any capacity test been done on these batteries?

The biggest problem with lead acid batteries in a solar powered system is absorption charge and equalization.

Absorption takes time, it doesn't matter how many panels or how high amperage the charge controller is, the batteries will only accept X number of amps. Usually on a solar system, the sun goes down, the batteries never reach 100% SOC and the sulfation begins. Second, if equalization has not been performed, the plates may have hard sulfation and why you ran out of capacity.

I've written many post about this problem. Here is one. https://diysolarforum.com/threads/flooded-lead-acid-revitalization.61730/post-770590 Please educate yourself first about lead acid used on system if you want to get full life out of the batteries.

I personally would not waste money on additional lead acid batteries unless you need to charge below freezing. That money would be better spent on LFP. However, if it is cold at the cabin and charging will occur below freezing, then you need to either use lead acid or devise a system to keep LFP warm.

Lead acid will require some maintenance by you. This will eat into the time you get to spend enjoying your time at the cabin.

I don't think the battery wires were sufficient when I took the system over, but I've since replaced them with 2/0. Not sure about the others, however. Water levels are good and all connections clean and tight.

Until you capacity test these batteries, you really have no idea what you have. Capacity test, then run an absorption charge and equalization if flooded lead acid, then test capacity again. Repeat the process if the batteries do not have full capacity and see if the capacity recovers. At some point, you will not see an improvement in capacity. This is due to plate material that has been sulfated beyond recovery and most likely sitting at the bottom of the cells. Only then can you decide to add more batteries or just switch to different chemistry. If you do add more lead acid, put them in a separate bank, swap banks so each bank can reach 100% SOC and you can perform equalization once a month if the manufacturer specifies it.

No switches or breakers. There is one surge protector (Starlink not plugged into it, and was off for the week). And 1 fuse from batteries to inverter.

Most likely these batteries are sulfated from sitting with less than 100% SOC.