Inverter setup not performing :(

[iamgigglz]

I have 2 x Royal 1150K 105ah 12v lead acid batteries in parallel hooked up to a Mecer 1200VA inverter.
On that I'm running a mini PC and monitor that draw an average of 70W

If I do the math:
105ah * 2 @12v = 2520Wh
Assume 80% conversion efficiency = 2016Wh
50% depth of discharge = ~1000Wh
1000Wh / 70W draw = 14 hours

Is that right? I'm getting less than 2 hours before the inverter tells me the batteries are at 50%.
What am I missing? Are the batteries just fubar?

 

[Qui_Illustrati]

I have 2 x Royal 1150K 105ah 12v lead acid batteries in parallel hooked up to a Mecer 1200VA inverter.
On that I'm running a mini PC and monitor that draw an average of 70W

If I do the math:
105ah * 2 @12v = 2520Wh
Assume 80% conversion efficiency = 2016Wh
50% depth of discharge = ~1000Wh
1000Wh / 70W draw = 14 hours

Is that right? I'm getting less than 2 hours before the inverter tells me the batteries are at 50%.
What am I missing? Are the batteries just fubar?

Sounds like your batteries are sulphated and, yeah, farked. That's a tiny load. Also, something to note your load + the inverter power load needs to be considered. So your actual load is a tad higher. A load test on each battery would help you confirm that they are indeed problematic. I will say this though, having had those exact Royal batteries in the past, they are absolutely horrible and prone to failure.

Out of interest, how long have they been in service?

 

[iamgigglz]

Out of interest, how long have they been in service?

Bought them in March here.
I've never let them go below 50%, but that's according to the inverter's readout. I'm wondering how accurate that is...

 

[Qui_Illustrati]

Bought them in March here.
I've never let them go below 50%, but that's according to the inverter's readout. I'm wondering how accurate that is...

Likely caused by overcharge or undercharge. Considering how 'new' they are in age, might be an idea to get them tested.

 

[mradovan]

Thing is, lead acid batteries are not made for load-shedding SA style.
Afaik, not only that they shouldn't be discharged more than 40-50%, they should be kept at 90%+ charge when not in use. Most shops have no idea, and they keep them on the shelves/store for a long time without any maintenance charging. Means they probably have decreased capacity even before you buy.

If I were to get a battery today, I'd bite the bullet and save up for a lithium equivalent (R 8 to 10K for a good 100Ah 12V).
I could flatten it to near-zero and not to worry about recharging as soon as possible. Similar to cellphone batteries, they are expected to survive 1500 to 2000 full cycles without degradation.

 

[iamgigglz]

Means they probably have decreased capacity even before you buy.

Probably the case. I wouldn't even hold it against the seller. This is knowledge that most people (including myself) don't have until they learn the hard way.

If I were to get a battery today, I'd bite the bullet and save up for a lithium equivalent (R 8 to 10K for a good 100Ah 12V).

Yeah, "Goedkoop is duurkoop" right? Definitely going lithium next.

So next question: Is my maths right?
If I got a single 100ah 12v Lithium battery:
1200Wh
Say 120w with inverter draw and conversion losses.
10 hours??

 

[mradovan]

Sounds right - but make that 8-9 hours, as the invertor will tax you some 10-15%, and the batteries never really let you discharge to 0%.
Just make sure you get a "drop-in" certified - it means they emulate the lead acid charge/discharge process, so they would work on any existing inverter.

 

[pikolec]

I've heard good things about the Hubble S120 batteries. I've seen them online at around R6.5k. There was a national stick shortage a few months ago, I hope that it is corrected :/

The other nice thing about the lithium batteries is that they have a battery management system (BMS) the helps condition the battery, balance cells and protect the cells against over discharge, over charge, etc. Lead Acid (SLA) batteries are completely 'dumb' and can be abused.

@iamgigglz , that load is quite low, so you may even be able to get away with a smaller battery if the budget doesn't allow. Since you'll be replacing 2x100Ah SLA with a single +- 120aH Lithium battery space isn't a problem

 

[yourang]

Next batch Hubble is September, the Aug batch sold out i hear.

I got last 2 in cpt, last week.

 

[∀Z‾soʇɐuɐɥ┴]

What program are you using to check capacity?
Coz what I have noticed is that my capacity would show 17% while gaming and basically sit there till power comes back on (sometimes going back up again by 1-2%), but if I close my game then it shoots right back up to like 90% cap.
This is on Watchpower btw, where the capacity seems to calculate based on load which is stupid.

 

[el3venth]

Lead acid batteries are notoriously bad with calculating state of charge.
If you want to know actually state of charge, then you need to use Peukerts Law.

Peukert's law - Wikipedia

en.wikipedia.org

So I am guessing they are just using the voltage as a thumbsuck.
So the only real way is to put a constant load on them and see when they hit empty.
Where empty is 1.85VPC typically.

 

[WarHeaD]

Probably the case. I wouldn't even hold it against the seller. This is knowledge that most people (including myself) don't have until they learn the hard way.


Yeah, "Goedkoop is duurkoop" right? Definitely going lithium next.

I also learnt the hard way man, the supplier thankfully gave me a set of replacement Lead Acid batteries which are still working fine, but I totally fried my original batteries over the course of about 6 months. I discharged them too deeply, I'm actually surprised I got 6 months out of them.

I was pushing around 500W to 600W during stage 3 earlier this year on my 24V 100AH setup (2x 12V LA in Series). Lasted well actually, only once went into the 25% range, but they then just suddenly died (couldn't even do 50W for 2 hours). so your batteries are definitely not healthy.

Now that I'm wiser (and poorer - lol), the replacement batteries are only being used for essentials (150W Max) and I don't take them below 50%, but even so I get like 4+ hours, so definitely something not right with your batteries.

That said, after this expensive lesson, I did get myself an entry level 100AH 12V 600W LiFePO4 (Lithium) setup now, very happy thus far. I'm not even seeing the battery dip below 100% after 2 hours of loadshedding when I run around 170W load (TV, media PC, routers, etc).

And as for the "Goedkoop is duurkoop", my LA setup was around the same price as my Lithium setup. So not really a "goedkoop" lesson learnt either, thankfully the supplier was really cool to give me replacement batteries.

All the best for the future man.

 

[ThatGuy_ZA]

I had a similar situation - a Mecer 1200va inverter + 1 x Royal battery powering a +-60w load.

The battery died after approximately 130 x 2 hour loadshedding cycles (120wh is approx 10% DoD per cycle).

 

[Off-The-Chart]

went to get a quote or 2 for basic battery backup setup for our (roughly) 2kw usage, for let's say about 4hrs battery to 50%, in mind

got a quote for 1x 4.8kwh lithium

was very suspect about it and phoned the person... he said that we should be able to run our needs for 24hrs

I was like, um........

not to mention 1 of the quotes was even for 6x 12v batteries, for the 48v setup (rejuvenated SLA/Gel)

 

[eyesuc]

Likely caused by overcharge or undercharge. Considering how 'new' they are in age, might be an idea to get them tested.

I've got a tired deep cycle battery. Where would you recommend I take it to be tested?

I've got one of those Optimate trickle chargers and it states battery is wonky

 

[Qui_Illustrati]

I've got a tired deep cycle battery. Where would you recommend I take it to be tested?

I've got one of those Optimate trickle chargers and it states battery is wonky

Those Optimates are marketed as the bees knees for reviving lead acids. Even claims desulphation capabilities. I also went down the Optimate 6 route a while back in an effort to restore/desuplhate and walked away with spending too much on the Optimate and still sitting with 'dead' batteries.
A proper waste of money, time and effort.

If the Optimate shows the battery as wonky though, then taking it anywhere else will likely show the same test results.

Recycle it and get Lithiums

 

[eyesuc]

Those Optimates are marketed as the bees knees for reviving lead acids. Even claims desulphation capabilities. I also went down the Optimate 6 route a while back in an effort to restore/desuplhate and walked away with spending too much on the Optimate and still sitting with 'dead' batteries.
A proper waste of money, time and effort.

If the Optimate shows the battery as wonky though, then taking it anywhere else will likely show the same test results.

Recycle it and get Lithiums

Damn, not good news. Luckily my house already has LiFePO4, this battery was purely used to power the telescopes when we are remote. Will look at replacing it with a lithium one now.

 

[Qui_Illustrati]

Damn, not good news. Luckily my house already has LiFePO4, this battery was purely used to power the telescopes when we are remote. Will look at replacing it with a lithium one now.

There is one more thing you could try if you happen to have a regulated PSU laying about and some time

I went down the rabbit hole in my quest to revive my lead acids a while back and came upon this

I didn't try it. After wasting money and time (a week on 4 lead Acids) with the Optimates I just couldn't stomach the potential time wasted in giving the regulated PSU thing a go.

The video does seem convincing though. Once you get past the waffling the guy in the vid seems to do.