Inverter and Battery Charging Question

Lucas61

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Jun 13, 2014
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retired English teacher (30 years)
Hello All,

This post is directed to those who have a lot of experience with AC/DC inverters (inversores). I know you're out there.
We have power outages every week, often more more than a day. We've run the battery to zero charge many times. It is a PowerTek with a digital readout and one sealed battery.
Sometimes I plan to shut it down when the battery is at, say, 20%, but that's often when we're sleeping with one fan going, and the inverter shuts down when we're asleep with a only a red system light remaining.

Suffice it to say that, after about a year, the battery only holds a charge for about one hour, and that's with everything in the house shut off except for maybe one light and a fan.
So, basically, we have no inverter at this moment.

I'm thinking that the battery has lost its charge capacity even though the readout says 100% charged. Is this what is happening? Is it normal? Where do I go from here? What's the solution?

Many thanks.

P.S. The failure of the electric grid is my biggest gripe about living in this country and probably my biggest complaint. We have gone as long as five days without electricity and many times, two or three days. And that's in Zona Colonial on a main business street. Last weekend we were off for two days. Today we were going into our second day and we were told 48 more hours to repair. That's intolerable. A family member paid someone nearby, who works for CDE, RD$1,500 to do a repair "under the table."

This post is in "living in." If you are planning to move to this country, I would say that a prime consideration in choosing a place is the reliability of the electricity. It can change house by house or block by block. . .
 
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reilleyp

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Dec 12, 2006
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Without know exactly which PowerTek battery you own, it is difficult to comment. In general it is very hard on your battery to discharge it down to zero, or even 20% unless it is a LiFePo4 battery. You should get some kind of charge controller that will regulate how it is charged, and you can also regulate how far down it is discharged. Some batteries should not even fall below 50% on a regular basis. Sounds like will also need more batteries and some solar panels.
 
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beeza

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Nov 2, 2006
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Unfortunately it sounds like your battery has had it. Multiple discharges to zero and full recharges will eventually decrease its capacity. Very few inverters have the sophisticated battery management systems to prolong battery life. Total discharging is not good neither is rapid full charging. If you can change any settings of your inverter, set a higher trip off voltage for low voltage cutout and try to slow down the charging process. The main culprit that harms the battery is rapid charging which can cause it to overheat. This increases battery resistance, resulting in higher charge current, resulting in higher temperatures. This phenomenon is called thermal runaway and is a battery killer.
 

cavok

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There are plenty of people in the barrios with inverters that let their batteries discharge to zero and they aren't buying new batteries every year. Sounds like you got a defective battery(?).
 

Seamonkey

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There are plenty of people in the barrios with inverters that let their batteries discharge to zero and they aren't buying new batteries every year. Sounds like you got a defective battery(?).
Any lead deep cycle battery should never be discharged below 50%. When it reaches below 50% the acid boils and thins the plates. A regular deep cycle battery has a lifespan of roughly 500 discharges at 50%.
 

johne

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Jun 28, 2003
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Two opinions above ,#3 & #4, voice 100% different facts. How do we get down to 100% FACTS? This is very important information that needs qualified substantiation.
 

chico bill

Dogs Better than People
May 6, 2016
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I believe PowrrTek is the brand of inverter?
The battery is 'sealed'? Is that a lithium battery? Most lead acid batteries for inverters are made to have distilled water added.
Seems odd for a Deep Cycle battery ?
But with just one battery - yeah it works harder and is probably is kapoot. 3 years is the effective life.
Get four when you replace.
 
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Seamonkey

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Two opinions above ,#3 & #4, voice 100% different facts. How do we get down to 100% FACTS? This is very important information that needs qualified substantiation.
#4 is wrong. Those batteries that are being discharged to zero are not holding a full charge anymore. It's common knowledge to not let your lead battery drop below 50%.
 

chico bill

Dogs Better than People
May 6, 2016
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#4 is wrong. Those batteries that are being discharged to zero are not holding a full charge anymore. It's common knowledge to not let your lead battery drop below 50%.
Which inverter do you have that shuts off when it senses 50% battery use ?
 

reilleyp

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Dec 12, 2006
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This guy explains it well.

A BMS will make sure it does not drop below 50% or whatever your manufacturer recommends. It will also monitor the temperature of the cells to make sure it does not overheat or overcharge.
 
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JD Jones

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My PowerTek 2.6 inverter has dip switches that allow me to set charge rate and shut off rate.

inverter.jpg
 

cavok

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Jun 16, 2014
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Any lead deep cycle battery should never be discharged below 50%. When it reaches below 50% the acid boils and thins the plates. A regular deep cycle battery has a lifespan of roughly 500 discharges at 50%.
From what I've read, deep cycle lead/acid batteries are designed to be discharged 80%. The thing is, how many people in the barrios have pure sine wave inverters with digital read-outs, adjustable charge rates, and all the other high-tech stuff talked about here? In the barrios, the inverter stays on until either power comes back orthe lights go out and the fan stops working - and they aren't buying new batteries every year. Not that I recommend doing that, just saying.
 
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johne

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Jun 28, 2003
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From what I've read, deep cycle lead/acid batteries are designed to be discharged 80%. The thing is, how many people in the barrios have pure sine wave inverters with digital read-outs, adjustable charge rates, and all the other high-tech stuff talked about here? In the barrios, the inverter stays on until either power comes back orthe lights go out and the fan stops working - and they aren't buying new batteries every year. Not that I recommend doing that, just saying.
They have inverters in barrios??
 

Lucas61

Well-known member
Jun 13, 2014
814
97
48
69
retired English teacher (30 years)
Unfortunately it sounds like your battery has had it. Multiple discharges to zero and full recharges will eventually decrease its capacity. Very few inverters have the sophisticated battery management systems to prolong battery life. Total discharging is not good neither is rapid full charging. If you can change any settings of your inverter, set a higher trip off voltage for low voltage cutout and try to slow down the charging process. The main culprit that harms the battery is rapid charging which can cause it to overheat. This increases battery resistance, resulting in higher charge current, resulting in higher temperatures. This phenomenon is called thermal runaway and is a battery killer.
If you can change any settings of your inverter, set a higher trip off voltage for low voltage cutout and try to slow down the charging process.
 

Lucas61

Well-known member
Jun 13, 2014
814
97
48
69
retired English teacher (30 years)
Thanks for this. I messed up my reply. Anyway, see your quote that I separated. Can you explain this a little more. My inverter is programmable and I will look in the manual. If I can in fact set a higher triip off voltage for low voltage cutout what will change in the functioning of the inverter? I'm on the verge of understanding but not quite.

Charging and discharging of the inverter/battery is what these devices are made to do. I don't understand what the aberration is. As long as my power continues to go out, which it will, I'm going to continue to discharge (and recharge) my battery. I don't understand exactly what happened that's not supposed to happen.

Using the analogy of a car battery. If you run down a battery trying to turn over the starter motor, then you need to re-charge the battery. Is this not the same, that I need to re-charge my inverter's battery? If so, how do I do that?
 

Lucas61

Well-known member
Jun 13, 2014
814
97
48
69
retired English teacher (30 years)
Any lead deep cycle battery should never be discharged below 50%. When it reaches below 50% the acid boils and thins the plates. A regular deep cycle battery has a lifespan of roughly 500 discharges at 50%.
Maybe as a member here suggested here, I need to check my manual, since my inverter is programmable, and see if I can implement a discharge cutooff. Meanwhile, I don't think anyone has suggested a solution. Why cannot I re-charge my battery just as you would a insufficiently charged car battery? But if I can do that, how do I do that?

Further, if charging > 50% is verboten, then, really, what's the point in even bothering with an inverter?? The use of 50% of one battery is almost useless. And that setup costs $1,000.
 

Lucas61

Well-known member
Jun 13, 2014
814
97
48
69
retired English teacher (30 years)
I believe PowrrTek is the brand of inverter?
The battery is 'sealed'? Is that a lithium battery? Most lead acid batteries for inverters are made to have distilled water added.
Seems odd for a Deep Cycle battery ?
But with just one battery - yeah it works harder and is probably is kapoot. 3 years is the effective life.
Get four when you replace.
Four when I replace? Not happening. That would cost $2,400.00. It is sealed lead acid. You don't have to top off because it's sealed, in fact, you can't. What I'm still not understanding are: a. Why can I not re-charge my inverter's battery just like you would an undercharged car battery?, b. It seems like my inverter/battery has been doing exactly what such a system does when the power goes off. What did I do wrong or is this normal functioning?