Best choice to increase run time ?

[12VoltInstalls]

As 740 is getting at... FLA battery pack is a weekly maintenance "nightmare". water levels, SG number, Equalization cycles.... its a real mess IMHO to keep a FLA pack running long term with

Well I’m sad to learn this. Taking care of my fla bank hasn’t been much of a big deal and both the old P30L pwm and the epever mppt equalize on a cycle.
I guess I need to start sweating over it and suffer since they’re so so bad. That’s it! I’m not going to sleep tonight!! No way, man, not doin’ it- no sleep tonight.

suggestions on what an accurate value would be for this setup ?

My cheap lead acid walmartha deep batteries I estimate at 50% (100% useable) discharged at 12.1. Good batteries should have a published spec for that. I’ve never seen one for these but haven’t looked.
My goal is never below 12.3/12.4 but I was 12.0 this morning after 5 cloudy rainy days.

Hope that helps

 

[GoldenNoodle]

I would suggest you run a capacity test on those batteries.

Do you have an AC charger you can use to top them off?

I’d suggest to disconnect the SCC after the sun has gone down and top off the batteries with an AN AC charger overnight (any half-decent AC charger should have no problem keeping up with a 35W draw).

Then, with the battery ‘full’, disconnect the AC charger and see how long the battery is able to supply your 35W drain before they reach ~50% SOC.

New batteries ought to give you over 7 days (with no charging at all) to 50% SOC, but if your able to get anything over 2 days (48 hours), the batteries are not the issue.

Long story but I've discovered that these are not sealed lead acid like I was lead to believe, but wet cells.... and there's been no maintenance for about 2 years. Argh.

So I went to the location and found that most of the cells were near dry. I topped them to just above the plates and I'm running a 15/40A "smart charger" across the bank (from + on one end to - on the opposite end) for the past few days - the SG is still "poor" but it is getting a bit better each day across the cells.

This seems to be working but I may need to take them right out of the bank and charge them all individually ?

In the meantime the boss is panicking because winter will be here very soon and this location is not easily serviceable after there's snow on the ground, so he bought 6 x Renogy 200Watt panels. https://www.renogy.com/200-watt-12-volt-monocrystalline-solar-panel/ and wants them installed in place of the old PV array ASAP. Because "that should fix it".... (sigh) "No problem bossman".

So now I'm also looking for advice on a new MPPT controller suitable for a 1200 watt 12v array. Preferably (but not an absolute must have) something that allows Internet connectivity via Ethernet. The Victron 150/70 or the 250/100 VE.Can ? Or Midnight solar has a couple of Classic controllers that have good reviews... opinions ?

Thanks.

 

[schmism]

Long story but I've discovered that these are not sealed lead acid like I was lead to believe, but wet cells.... and there's been no maintenance for about 2 years. Argh.

Its almost like I've heard this story countless times before. Despite what others want you to believe, a FLA bank is 100% a weekly maintenance item that 99% of people get tired of very quickly.

As for a plan to salvage what you have <shrug>.... Read up on FLA maintance, Recconfigure to as many in parallel as you can, watch the water and SG levels. Hope for the best.

 

[12VoltInstalls]

As for a plan to salvage what you have <shrug>....

When I first connected up my original 200W windynation kit I hadn’t bought batteries yet. I had a pair of ten-year-old deep cycles from my boat that wouldn’t hold a charge just sitting. But I had them, needed to run lights and an RV water pump. I hooked them up, connected the panels. Needed another pay period to buy batteries…
Short version: in less than two weeks on the SCC the batteries fixed themselves and I used them almost a year. Not as good as new, but usable (until I stopped monitoring water levels and killed them).
But no loss: they were a surprise when they started holding 12.6 lol

 

[Texas-Mark]

So I went to the location and found that most of the cells were near dry. I topped them to just above the plates.....

If the plates were exposed, they probably will not recover.

 

[Texas-Mark]

Despite what others want you to believe, a FLA bank is 100% a weekly maintenance item that 99% of people get tired of very quickly.

Mehh... It does not 'have' to be a weekly thing. I live in TX where my FLAs get pretty toasty. Checking them once a month has been more than sufficient (for years). IMO, if one is needing to top up water levels weekly, there is probably something else wrong.

 

[eXodus]

There's a constant 35 watt draw.

what are you drawing?

Its almost like I've heard this story countless times before. Despite what others want you to believe, a FLA bank is 100% a weekly maintenance item that 99% of people get tired of very quickly.

I'm checking my FLA once a Month usually they don't start needing a lot of water until they are in there 4-6 year.

Mehh... It does not 'have' to be a weekly thing. I live in TX where my FLAs get pretty toasty. Checking them once a month has been more than sufficient (for years). IMO, if one is needing to top up water levels weekly, there is probably something else wrong.

same here in Florida. FLA is a monthly item, have to add water maybe quarterly.

If you set your charger for daily equalization - that evaporates a lot of water. But when you do like a monthly equalization - no issue. Most large lead cells don't drift that much anymore. So equalization is not really necessary. Usually getting 6-10 years out of bank.

In 2020, we hit the point that LFP is cheaper over a 20 year span (since LFP is also aging out) Still when you got an old good working FLA system, it might be still cheaper till 2022 buy new FLA cells.

When you buy everything new (charger, inverter) sure - LFP is better today.

 

[12VoltInstalls]

If the plates were exposed, they probably will not recover.

Good chance they won’t. But I’m dumb and I’d still try lol

Your solar charging may hit the batteries better/harder than a ‘battery charger’ btw. Most chargers aren’t going to show them 16V like solar charge controllers can.

 

[eXodus]

Good chance they won’t. But I’m dumb and I’d still try lol

you got potentially reduced capacity of the part which got exposed - the submerged part still works fine.
So it very much depends how much got out to air. If you got a tall deep cycle battery and you got 1/2 inch expose - that's only a few percent.

 

[GoldenNoodle]

you got potentially reduced capacity of the part which got exposed - the submerged part still works fine.
So it very much depends how much got out to air. If you got a tall deep cycle battery and you got 1/2 inch expose - that's only a few percent.

I put about 1 liter in each battery. They are group 31. I don't think they would hold a lot more than 1 liter so they may have been almost empty. So they may be toast - but the SG keeps getting a bit better each day so I'm hopeful lol

 

[740GLE]

If only fixing damaged LiFePo cells would be this simple.

 

[GoldenNoodle]

Recconfigure to as many in parallel as you can, watch the water and SG levels. Hope for the best.

The whole battery bank is wired in parallel - is that what you're referring to ? Is series bad ?

I was thinking about changing this from 12vdc to 24 so I'd have 2 parallel strings in series - is that worse for FLAs ?

 

[Texas-Mark]

The whole battery bank is wired in parallel - is that what you're referring to ? Is series bad ?

Having them in parallel is better when trying to recover them as they will all get the same voltage. ,

 

[GoldenNoodle]

Having them in parallel is better when trying to recover them as they will all get the same voltage. ,

Ahh that makes sense. Thank you.

On the PV side can I put a 24 v panel in with 12 v panels ? Would it need to be in series ?

 

[Texas-Mark]

On the PV side can I put a 24 v panel in with 12 v panels ? Would it need to be in series ?

It all depends on your charge controller, but it should not be an issue provided the charge controller knows it's a 12v battery bank. Most will auto detect the bank voltage, but some need to be told.

 

[MichaelK]

As 740 is getting at... FLA battery pack is a weekly maintenance "nightmare". water levels, SG number, Equalization cycles.... its a real mess IMHO to keep a FLA pack running long term with normal use. (you are doing all those things right)

This is total BS. I find I need to add water to my batteries every two or three months, not weekly. And that takes about 10 minutes for a bank of twelve 4V batteries. Call it 50 minutes of maintainance per year. I have my controller programed for automatic equilization once a month. I don't even pay attention to it.

 

[740GLE]

Wouldn’t maintenance depend on daily cycling and charging rates? If your hardly pulling/charge more that 10% nameplate daily, maintenance would be zero.

If they routinely see +1c discharge for a few hours a day, that’s a different story.

 

[Texas-Mark]

Wouldn’t maintenance depend on daily cycling and charging rates?

Sure. But IMO if one is needing to water weekly, their bank in undersized. Hence my earlier comment of "probably something else wrong"

 

[GoldenNoodle]

It all depends on your charge controller, but it should not be an issue provided the charge controller knows it's a 12v battery bank. Most will auto detect the bank voltage, but some need

 

[GoldenNoodle]

It all depends on your charge controller, but it should not be an issue provided the charge controller knows it's a 12v battery bank. Most will auto detect the bank voltage, but some need to be told.

I now have 6 new 200w x 12v panels and a bunch of old 12v panels so I was thinking about having a bank of the new panels and a bank of the old panels with each bank on their own charge controller. From the little that I've learned so far that configuration should prevent any cross contamination between dissimilar panels in the same bank ?

I was looking at the Victron VE.Can controllers as I understand that they can work together so maybe the bank doesn't take such a beating.

Is there value in that idea?