APC UPS float voltage limit

Earlonics

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Jan 1, 2019
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Folks new to the Forum so be gentle with me


I have three APC UPS inverters 2 3000kva and 1 5000kvawhich I was planning to use tocharge my 14s100p battery packs.

My problem
is adjustment of the float voltage on the unit I am trying to adjust I can only get to 54.5volts I believe I would need to adjust to 57.4 volts anyone advise me what I might be doing wrong?

I can get to the cli no issue and the SM PROG are all taking, what I noticed with ACPFIX program the dashboard is showing my 3000 smart inverter as a smart ups 500 could this be my problem? hopefully someone can point me in the right direction.

Thanks in advance

Paul
 

Korishan

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Perhaps screen shots of your settings and a run down of what you are actually doing. Otherwise, we can't tell you what you might be doing wrong, if anything.

You may need to get the server grade PowerChute software.
 

Earlonics

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Korishan said:
Perhaps screen shots of your settings and a run down of what you are actually doing. Otherwise, we can't tell you what you might be doing wrong, if anything.

You may need to get the server grade PowerChute software.
Thanks for your reply, like I say new to this Forum stuff, and heave read many many articles, I will structure a better request with more relevant information.

but thanks again in replying so quickly.

Cheers

Paul
 

Earlonics

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Ok At home now been at work all day,

This year I had fully installed Solar Panels mad up of 14 320W panels. I have been on a green crusade since I had the panels installed and started to enquire about a commercial offering power-wall. I've also been investigating the possibility of building my own using recycled 18650's, Youtube has inspired me especially the antics of Pete and Average Joe.

My idea was to a 14s100p setup and I have harvested 1400 the batteries and acquired two working secondhand APC UPS units SU3000 and I have just acquired a SU5000 unit. I intend to use one of these units to charge my batteries and also power a number of items in the house.
I was in the process of trying to adjust the float voltage on one of these units but I seem to have managed to inadvertently screwed a setting up in the Smart constants settings which I had to manually reset and recover the unit.

The unit is only connected to Pb 48v batteries at the moment as I'm trying to adjust the float to 56 volts which is 14 x 4.0 for the 18650's I intend to charge, I believe I have this correct, so correct me if I'm wrong.
The APC appears to only allow me to change the float voltage to 54.5 so I'm wondering if these units are viable to achieve my objective of charging 18650's. I see a number of folk on youTube have used them so I believe they should work or am I missing something.

Excuse the ramblings hopefully some of this will make sense.
 

OffGridInTheCity

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Dec 15, 2018
Messages
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Earlonics said:
The APC appears to only allow me to change the float voltage to 54.5 so I'm wondering if these units are viable to achieve my objective of charging 18650's. I see a number of folk on youTube have used them so I believe they should work or am I missing something.
54.5v (3.89v/cell) on yours, 55.5 (3.96v/cell) on my APCs - e.g. close to 4.0v. 4.0v is a good max for extended life. This is 10-13% less that if charge up to 4.1v. I havemoved on to charge controller / large inverter but I still top out at 4.0v for long life and made my battery 15% larger- so its not wrong but rather what works for you. I say this to encourage you :)

I read that certain advanced server APCs are settable but mine of not of that variety so I can't help from experience with this.
 

Earlonics

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OffGridInTheCity said:
Earlonics said:
The APC appears to only allow me to change the float voltage to 54.5 so I'm wondering if these units are viable to achieve my objective of charging 18650's. I see a number of folk on youTube have used them so I believe they should work or am I missing something.
54.5v (3.89v/cell) on yours, 55.5 (3.96v/cell) on my APCs - e.g. close to 4.0v. 4.0v is a good max for extended life. This is 10-13% less that if charge up to 4.1v. I havemoved on to charge controller / large inverter but I still top out at 4.0v for long life and made my battery 15% larger- so its not wrong but rather what works for you. I say this to encourage you :)

I read that certain advanced server APCs are settable but mine of not of that variety so I can't help from experience with this.
Thanks for your reply ;) and your encouragement, sinceI have owned theseAPC UPS I have learnt a lotand its workings.

Ican tweak these devices just so far, like everyone going through thisjourney any advice and knowledge shared is so helpful.I will be posting my findings on the APC UPS's .

I want to ultimately stop wasting the power my solar makes bysending surplus to the grid and maximise my usagethrough the use of batteries. I've been disappointedby theutility companies charging you 3 times more thanwhat they pay you,for what you put back into the grid.Can I ask,what is the Charge Controller/Large inverter that you use?
 

not2bme

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Messages
479
Ahh now we're getting somewhere.... you have a grid tie system but don't want to waste selling back to the grid. Next time start with that. So what you need is an AC coupled system that will work together with your grid tie inverter. A UPS is just terrible because it's not meant to be one. Until someone figures it out, avoid UPS other than to use it as it was intended. As for AC coupled systems, you might want to start with the brand of your grid-tie inverter. For example, if you already have a sunnyboy inverter, then a sunny island may suit you better since it will work well together . A 6000kw sunny island can be had for around $1500 now. You want to load shift so you charge during the day when the inverter is on. You also might want to look at your electric rates, so if you have multi-tiered rates it might benefit to go on battery during peak and charging during off-peak.
 

OffGridInTheCity

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Messages
1,470
Earlonics said:
OffGridInTheCity said:
Earlonics said:
The APC appears to only allow me to change the float voltage to 54.5 so I'm wondering if these units are viable to achieve my objective of charging 18650's. I see a number of folk on youTube have used them so I believe they should work or am I missing something.
54.5v (3.89v/cell) on yours, 55.5 (3.96v/cell) on my APCs - e.g. close to 4.0v. 4.0v is a good max for extended life. This is 10-13% less that if charge up to 4.1v. I havemoved on to charge controller / large inverter but I still top out at 4.0v for long life and made my battery 15% larger- so its not wrong but rather what works for you. I say this to encourage you :)

I read that certain advanced server APCs are settable but mine of not of that variety so I can't help from experience with this.
Thanks for your reply ;) and your encouragement, sinceI have owned theseAPC UPS I have learnt a lotand its workings.

Ican tweak these devices just so far, like everyone going through thisjourney any advice and knowledge shared is so helpful.I will be posting my findings on the APC UPS's .

I want to ultimately stop wasting the power my solar makes bysending surplus to the grid and maximise my usagethrough the use of batteries. I've been disappointedby theutility companies charging you 3 times more thanwhat they pay you,for what you put back into the grid.Can I ask,what is the Charge Controller/Large inverter that you use?
My system is off-grid and I use Midnite Classic 150s as my charge controllers, 14s 18650 DIY battery bank,and an AIMS 12,000w inverter. I use the APCs to smooth the twice daily ATS switch over to inverter power and back to grid.
 

Earlonics

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Jan 1, 2019
Messages
23
OffGridInTheCity said:
Earlonics said:
OffGridInTheCity said:
Earlonics said:
The APC appears to only allow me to change the float voltage to 54.5 so I'm wondering if these units are viable to achieve my objective of charging 18650's. I see a number of folk on youTube have used them so I believe they should work or am I missing something.
54.5v (3.89v/cell) on yours, 55.5 (3.96v/cell) on my APCs - e.g. close to 4.0v. 4.0v is a good max for extended life. This is 10-13% less that if charge up to 4.1v. I havemoved on to charge controller / large inverter but I still top out at 4.0v for long life and made my battery 15% larger- so its not wrong but rather what works for you. I say this to encourage you :)

I read that certain advanced server APCs are settable but mine of not of that variety so I can't help from experience with this.
Thanks for your reply ;) and your encouragement, sinceI have owned theseAPC UPS I have learnt a lotand its workings.

Ican tweak these devices just so far, like everyone going through thisjourney any advice and knowledge shared is so helpful.I will be posting my findings on the APC UPS's .

I want to ultimately stop wasting the power my solar makes bysending surplus to the grid and maximise my usagethrough the use of batteries. I've been disappointedby theutility companies charging you 3 times more thanwhat they pay you,for what you put back into the grid.Can I ask,what is the Charge Controller/Large inverter that you use?
My system is off-grid and I use Midnite Classic 150s as my charge controllers, 14s 18650 DIY battery bank,and an AIMS 12,000w inverter. I use the APCs to smooth the twice daily ATS switch over to inverter power and back to grid.

Thanks for the update everyone and the useful information, I'll go and ponder my next actions, but it seems i might have made the wrong choice of using these APC ups units, although in the back of my head I'm sure they can be utilised
 

kc8adu

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May 22, 2019
Messages
104
there are some precision resistors you can tweak if apcfix wont adjust to your desired setpoint.
without seeing your unit it would be hard to say which.
but the big units with expandable batteries,metal case,and internal fan make nice inverters.
 

Overmind

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Jan 16, 2019
Messages
416
14S means you need voltage superior to 58.8 to fully charge them.
If you want to keep them at around 4.0V for good life-time, you still need over 56V of in-circuit voltage.
Therefore, a FV of 54.5 will be a little below your target.

Best thing is to practically test how well they charge - if this works fine enough you're in luck as APC UPSes have high quality components and high durability over time.
 

OffGridInTheCity

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Dec 15, 2018
Messages
1,470
Overmind said:
14S means you need voltage superior to 58.8 to fully charge them.
If you want to keep them at around 4.0V for good life-time, you still need over 56V of in-circuit voltage.
Therefore, a FV of 54.5 will be a little below your target.

Best thing is to practically test how well they charge - if this works fine enough you're in luck as APC UPSes have high quality components and high durability over time.
I have 4 APCs with 7s7p 18650 batteries. 2 are the 3000va towers (with 2 x 7s7p batteries) and the others are the1500 APC with a single 7s7p. There's room to make a 7s14p that's within the size of original sealed batteries but that's overkill for my needs.

The APCs charge to 27.6v (+/- .1)which is 3.94v/cell. This is great for me because I use them as UPSs.... so the cells are at 3.94 99% of the time and only deliver power briefly during ATS switch-overs. At this voltage/use they should last a very long time ... hopefully much longer than the original sealed batteries.

The low (to cut-off) is about 20v which is 2.85v/cell... so even if something goes completely wrong and you have a total drain situation its still within safe operating parameters for 18650.
 

Earlonics

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Jan 1, 2019
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kc8adu said:
there are some precision resistors you can tweak if apcfix wont adjust to your desired setpoint.
without seeing your unit it would be hard to say which.
but the big units with expandable batteries,metal case,and internal fan make nice inverters.
Hi now back on track with my project, too many distractions both work and Home life, anyway Kc8adu you seem to imply with the above statement that there are components on the main board which could get me the voltage I need if you know the unit, the unit I'm using is a SUA3000RMI does this help or would you need a photo of the board?

Thanks in advance
 
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