Lets try this again...walmart replaced my dc batteries.

[73powerstroke]

I purchased these 2 group 24 never start batteries in June of last year one of them started to show signs of failing last week I brought them both into Walmart and they load chest item with their battery analyzer and he both failed and I was able to get 2 new replacements kudos to Walmart for making it somewhat easy.

 

[RoadTurtle]

Are you allowing the SOC to drop below 50% (12.2v). If so, the discharge is damaging the batteries.

 

[73powerstroke]

Are you allowing the SOC to drop below 50% (12.2v). If so, the discharge is damaging the batteries.

I'm sure I probably have. It's difficult to say when I'm running 24v system and have my inverter set to cut off at 21v.
A battery under load will quickly rebound once the load is removed.

 

[sunshine_eggo]

Are you allowing the SOC to drop below 50% (12.2v). If so, the discharge is damaging the batteries.

12.2V represents 50% only on batteries that have been completely inactive for 24 hours, and that depends on brands and types. My Rolls Surrette FLA are at 50% @ 12.00V after 20 hours of rest and 11.55V after 1 hour of rest, so 50% on these batteries under load is notably under 11.55V.

12.2V in an active system does not represent anything remotely around 50%. Under load, systems cutting off at 12.1-12.2V to try and prevent discharge below 50% are likely not dropping below 70-80%.

Sorry to be a pedantic dick, but I've lost count of the hundreds of times someone throws a "50% voltage" out there as though it has meaning to a system under active use.

 

[RoadTurtle]

Sorry to be a pedantic dick, but I've lost count of the hundreds of times someone throws a "50% voltage" out there as though it has meaning to a system under active use.

Of course the bigger the draw the in use voltage drop, but where do you draw the line? Light loads on wet batteries won't drop the voltage. Heavy loads definitely do, and if you're running heavy loads you'll burn those electrons pretty quickly.

 

[73powerstroke]

12.2V represents 50% only on batteries that have been completely inactive for 24 hours, and that depends on brands and types. My Rolls Surrette FLA are at 50% @ 12.00V after 20 hours of rest and 11.55V after 1 hour of rest, so 50% on these batteries under load is notably under 11.55V.

12.2V in an active system does not represent anything remotely around 50%. Under load, systems cutting off at 12.1-12.2V to try and prevent discharge below 50% are likely not dropping below 70-80%.

Sorry to be a pedantic dick, but I've lost count of the hundreds of times someone throws a "50% voltage" out there as though it has meaning to a system under active use.

Yep. So my mpp solar hv lv2424 is set to cut off at 21v . I've just been using the 2 walmart group 24dc batteries. I had them in a 12v system for a short while in parallel. With no cut off set.
Any suggestions to make these new ones last longer ? I have 26 panels in this system. 18 are 240w santan solar trinas and 8 are 230w golria panels . They are all 2 in a series. I have a group on the hvlv2424 and smaller groups on two epever 40amp tracer 4210an cc. I don't think I'm doing anything wrong here but maybe I can improve it

 

[sunshine_eggo]

Of course the bigger the draw the in use voltage drop, but where do you draw the line? Light loads on wet batteries won't drop the voltage.

"light" = what C rate?

Heavy loads definitely do,

Yep.

and if you're running heavy loads you'll burn those electrons pretty quickly.

"Heavy loads" = what C rate?

The answer is, "you don't."

You get a battery monitor, OR you be methodical about establishing a voltage to SoC relationship for your system and loads. 11.55, 12.0, 12.1, 12.2V does the average Joe ZERO good. It's a myth that shouldn't be perpetuated.

Pretty easy for FLA... Note voltage and current, cut system off for two hours, note bounced voltage and specific gravity - pretty accurate SoC there. At this point you've established, under X Amps at Y Volts, I'm at Z %.

Battery monitor is SO much easier - especially a quality one that can calculate SoC factoring in Peukert and temperature efficiency factors.

Can't figure out why folks are unwilling to spend $130 to truly know their lead-acid state of charge when they've spent many hundreds $ more on batteries. Sure, not a big deal on an Everstart bank...

 

[sunshine_eggo]

Yep. So my mpp solar hv lv2424 is set to cut off at 21v . I've just been using the 2 walmart group 24dc batteries. I had them in a 12v system for a short while in parallel. With no cut off set.
Any suggestions to make these new ones last longer ? I have 26 panels in this system. 18 are 240w santan solar trinas and 8 are 230w golria panels . They are all 2 in a series. I have a group on the hvlv2424 and smaller groups on two epever 40amp tracer 4210an cc. I don't think I'm doing anything wrong here but maybe I can improve it

Monitor them in series to make sure they're at the same voltage when at peak 24V absorption voltage. That's usually what kills them - one is being overcharged, while its series mate is being undercharged.

Lead acid should not be charged more than about 0.15C. If you can feed them substantially more than that, you may kill them.

 

[73powerstroke]

Monitor them in series to make sure they're at the same voltage when at peak 24V absorption voltage. That's usually what kills them - one is being overcharged, while its series mate is being undercharged.

Lead acid should not be charged more than about 0.15C. If you can feed them substantially more than that, you may kill them.

That's what happened. One worse than the other. It was at 10.7v and the other at 13.5 usually. I have shunt meters with state of charge on them. Sorta odd to read the Chinese manual for calibration.
Of course I'm monitoring them together.

 

[sunshine_eggo]

Is one shunt for charging and the other for discharging? I'm having a little trouble wrapping my head around that double shunt terminal.

Something like this might help:

https://www.amazon.com/Display-Battery-Equalizer-Voltage-Balancer/dp/B09GLMCNXK

 

[73powerstroke]

Is one shunt for charging and the other for discharging? I'm having a little trouble wrapping my head around that double shunt terminal.

Something like this might help:

https://www.amazon.com/Display-Battery-Equalizer-Voltage-Balancer/dp/B09GLMCNXK

Yes.

 

[MichaelK]

Any suggestions to make these new ones last longer ? I have 26 panels in this system. 18 are 240w santan solar trinas and 8 are 230w golria panels . They are all 2 in a series. I have a group on the hvlv2424 and smaller groups on two epever 40amp tracer 4210an cc. I don't think I'm doing anything wrong here but maybe I can improve it

This is really a grossly imbalanced system, and this is just going to happen over and over again. With just the Trina panels only, they would support a battery in the 1200-1400Ah range. 100Ah is tiny for this application. You would have been far better off spending more money on battery and less on solar.

The 2424 can support how many charging amps, I think without looking it might be 80A? Assuming you can only utilize a max of 80A, then the most solar you can practically apply is 80A X 25Vcharging X 1.175 fudgefactor = 2350W. So 10 of those Trina's would have been fine.

It was poor design on your part to pair such an extremely large solar array to such an extremely small battery.

What I could suggest is switching to a far larger battery bank. Maybe two parallel strings of golf-cart batteries is a better fit for this size inverter. CostCo has a 210Ah golf-cart on sale now for 110$. Eight of those would run you ~900$ plus core-charges. Even then, you really only need about six of those Trina panels to completely charge them. Once you've installed the new batteries, set the low-voltage limit to at least 23V.

 

[Browneye]

Those are not deep cycle batteries and will not tolerate any extended discharge time - they will fail. Engine starting batteries are designed for a quick high-amp burst and then fully recharge - as in a vehicle. Pulling power from them over an extended period, and particularly more than 50% of their amp hours, will guarantee early death. The plates are light and sulfate over easily - those are not suited for a solar bank.

EDIT: BTW, everstart batteries from wallyfart are actually pretty good batteries - I've used them in a lot of vehicles, get five years out of them. They are made by Johnson Controls. A very good value. For deep cycle cheap lead acid batteries, GA-2 'golf cart' batteries in series work pretty well - has been the gold standard for a few decades till LFP came along.

 

[73powerstroke]

Those are not deep cycle batteries and will not tolerate any extended discharge time - they will fail. Engine starting batteries are designed for a quick high-amp burst and then fully recharge - as in a vehicle. Pulling power from them over an extended period, and particularly more than 50% of their amp hours, will guarantee early death. The plates are light and sulfate over easily - those are not suited for a solar bank.

EDIT: BTW, everstart batteries from wallyfart are actually pretty good batteries - I've used them in a lot of vehicles, get five years out of them. They are made by Johnson Controls. A very good value. For deep cycle cheap lead acid batteries, GA-2 'golf cart' batteries in series work pretty well - has been the gold standard for a few decades till LFP came along.

These are the deep cycle everstarts

 

[Browneye]

Ah...couldn't see that.
They still won't last - the lead plates are nearly the same as their starting batteries. I think they'll only replace them once. Figure you might get six to nine months out of them.

 

[sunshine_eggo]

They are middle-of-the-road at best. If you take diligent care of them with occasional equalization charges, yes. They can last awhile. I have one of the big 29DC "deep cycle" beasts (122Ah @ 1A rating) from 2014 that's still working at about 70% rated. It underwent massive abuse during times in its life with excessive charge and discharge for a custom application, but with good maintenance, it's still going.

 

[73powerstroke]

This is really a grossly imbalanced system, and this is just going to happen over and over again. With just the Trina panels only, they would support a battery in the 1200-1400Ah range. 100Ah is tiny for this application. You would have been far better off spending more money on battery and less on solar.

The 2424 can support how many charging amps, I think without looking it might be 80A? Assuming you can only utilize a max of 80A, then the most solar you can practically apply is 80A X 25Vcharging X 1.175 fudgefactor = 2350W. So 10 of those Trina's would have been fine.

It was poor design on your part to pair such an extremely large solar array to such an extremely small battery.

What I could suggest is switching to a far larger battery bank. Maybe two parallel strings of golf-cart batteries is a better fit for this size inverter. CostCo has a 210Ah golf-cart on sale now for 110$. Eight of those would run you ~900$ plus core-charges. Even then, you really only need about six of those Trina panels to completely charge them. Once you've installed the new batteries, set the low-voltage limit to at least 23V.

It happened a little at a time. I used to have more batteries also. In order to get full power from either of my charge controllers in poor conditions I needed alot more panels so I just kept buying more till I had it where I was able to power the window ac units last summer.
I actually have 2 other 40amp cc hooked up here.
I can certainly break things up into different systems till I can figure/afford big batteries.
The epevers seem to go kinda high on charge even set to fla.
I have 3x epever 40amp tracer 4210an cc 2 are in play here.
So I cant really find a answer on how many ah these group 24 deep cycle batteries are. I know that it's usually a misleading number anyway. Because of how they test. I've always been under the impression that solar only produces under load. I mean If the batteries are full theres no load on the system.
Typically I run 2 or 3 window ac units (smaller ones) and in winter a electric heater .

 

[Browneye]

FAQ from AZ wind and sun says 70-85Ah: https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/

Now it makes a little more sense - you're running high load air conditioners with solar.
Your two are in series for 24V? If so you have about 45Ah usable.

You might get some more efficiency at 48 volts - maybe two more of them. But your SCC's are already 24's?

How has this system been working out for you? Someone else here was just asking about running a mini-split for their sun room. It does seem like there needs to be a battery in the system somehow, and an inverter to make AC power.

 

[73powerstroke]

FAQ from AZ wind and sun says 70-85Ah: https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/

Now it makes a little more sense - you're running high load air conditioners with solar.
Your two are in series for 24V? If so you have about 45Ah usable.

You might get some more efficiency at 48 volts - maybe two more of them. But your SCC's are already 24's?

How has this system been working out for you? Someone else here was just asking about running a mini-split for their sun room. It does seem like there needs to be a battery in the system somehow, and an inverter to make AC power.

I had originally thought of getting a mpp 6548 since it will do battery less operation but it would be pretty difficult I think. So I started out 12v with a few hf 100w panels and a hf 2kw 12v inverter and some epever 40amp tracers. And these batteries. 12v proved difficult. So I got the 48v and a the hvlv2424.
It actually works well in the summer. I have arrays of panels that face different directions . I'm able to run ac from 10am till 6pm in the summer.
4 panels face the setting sun. 6 more are on a wall that loses sun half the day.

 

[73powerstroke]

So I guess for now I will disconnect everything.