UPS (APC 3000) Beeping/Saying low battery but lots of volts from Charge controller.

[posplayr]

For Lithium batteries, the ladder type interconnection (make parallel groups and then put them in series) is common, but for lead acid it is much more common to build series strings first and then put them in parallel. Given the resistance and voltage versus SOC curves of lead acid, the latter arrangement works out better in terms of balanced charging without thermal runaway.

I was looking at a utube video of battery pack replacement . The apc smart ups 3000 have two strings of 4 series 12v batts . Either 7 or 9 amp hour.

I have not looked at all the documentation but it looks like you connect yet another 3u cabinet as additional battery capacity which probably parallels with those inside using the same type of battery enclosure. It is apparently arranged to keep everything real balanced.

That being said there must be a way to tell the ups there are additional batteries.

I just posted about using something similar with the SB TL SPS in this other thread.

http://www.solarpaneltalk.com/showthread.php?22001-Grid-tied-solar-system&p=163369&viewfull=1#post163369

[SunEagle]

I was looking at a utube video of battery pack replacement . The apc smart ups 3000 have two strings of 4 series 12v batts . Either 7 or 9 amp hour.

I have not looked at all the documentation but it looks like you connect yet another 3u cabinet as additional battery capacity which probably parallels with those inside using the same type of battery enclosure. It is apparently arranged to keep everything real balanced.

That being said there must be a way to tell the ups there are additional batteries.

I just posted about using something similar with the SB TL SPS in this other thread.

http://www.solarpaneltalk.com/showth...l=1#post163369

The biggest issue you will run into is that most if not all UPS systems were designed for fast discharge to power critical loads in the event of a power outage. They were not designed for daily or even weekly deep cycles.

So they can handle being discharged and then recharged but after a few times the batteries start to suffer and will need to be replaced.

Under best conditions those type batteries last 5 years but they are usually in "float" or standby mode so they see minimal number of cycles in their lifetime.

[posplayr]

The biggest issue you will run into is that most if not all UPS systems were designed for fast discharge to power critical loads in the event of a power outage. They were not designed for daily or even weekly deep cycles.

So they can handle being discharged and then recharged but after a few times the batteries start to suffer and will need to be replaced.

Under best conditions those type batteries last 5 years but they are usually in "float" or standby mode so they see minimal number of cycles in their lifetime.

My interest is grid tied contingency; I'm not looking to cycle batteries and become a battery marm.

[SunEagle]

My interest is grid tied contingency; I'm not looking to cycle batteries and become a battery marm.

I understand what you are looking to do. Althoug I am not sure about if it being cost justified.

If you are only looking for an emergency backup with a grid tie pv system then IMO batteries would not be something I would invest in. I would be spending a lot less money getting a LPG generator that will not only be my standby power source but will provide much more than a medium sized battery bank. But those are my feelings.

[posplayr]

I understand what you are looking to do. Althoug I am not sure about if it being cost justified.

If you are only looking for an emergency backup with a grid tie pv system then IMO batteries would not be something I would invest in. I would be spending a lot less money getting a LPG generator that will not only be my standby power source but will provide much more than a medium sized battery bank. But those are my feelings.

I understand that, but the math is not in your favor given the parameters I have outlined. The battery investment could be as little as $300 and be worth $10 per day of propane operation and more so substantially enhanced endurance of whatever propane storage is installed. I think you are using a rote off-grid financial analysis and trying to apply it to an grid-tied contingency, but then "that is just my feeling".

[SunEagle]

I understand that, but the math is not in your favor given the parameters I have outlined. The battery investment could be as little as $300 and be worth $10 per day of propane operation and more so substantially enhanced endurance of whatever propane storage is installed. I think you are using a rote off-grid financial analysis and trying to apply it to an grid-tied contingency, but then "that is just my feeling".

I am talking about emergency backup power using a 10kw generator with a hundred gallon LPG tank that would be used for short term power outages. Even if you have a half dozen outages a year lasting 8 hours each I still believe the gen set would be much cheaper to run as well as provide much more power then a battery bank. The gen set would also have auto start/stop and provide power for the house even if I am not there so I would not have to worry about the loss of food.

If you are using the parameters of many lengthy power outages where fuel costs will add up as compared to a set of cheap batteries then the math may work in your favor.

[Sunking]

I understand that, but the math is not in your favor given the parameters I have outlined. The battery investment could be as little as $300 and be worth $10 per day of propane operation and more so substantially enhanced endurance of whatever propane storage is installed. I think you are using a rote off-grid financial analysis and trying to apply it to an grid-tied contingency, but then "that is just my feeling".

You are day dreaming making up numbers. A $300 dollar battery can only supply at best 1.2 Kwh per day to 50% DOD. That is roughly 15 cents worth of electricity and even if using a cheap LPG genny is about 30 to 40-cents worth of Propane.

To protect your battery investment dollar, perform monthly EQ charge, and carry you through cloudy spells requires a Generator period. No off-grid system should be without a genny, as they are required.

[posplayr]

I am talking about emergency backup power using a 10kw generator with a hundred gallon LPG tank that would be used for short term power outages. Even if you have a half dozen outages a year lasting 8 hours each I still believe the gen set would be much cheaper to run as well as provide much more power then a battery bank. The gen set would also have auto start/stop and provide power for the house even if I am not there so I would not have to worry about the loss of food.

If you are using the parameters of many lengthy power outages where fuel costs will add up as compared to a set of cheap batteries then the math may work in your favor.

I think we are in agreement with the math. I think the difference is in the assumed periods of generator outage. I'm looking at an extended period of no need for a generator (2-5 years) and then where there might be a sudden outage that could be 2-6 weeks (who knows). Or after the power comes back on for a few weeks it is off for a similar or longer periods. We are not concerned about the Haagen Dazs melting; people die in the heat of the desert;

I have already bought into the GT Solar thing and realize that the generator is the lowest cost per KW solution for a Grid replacement; it is included in the mix. The day time solar backup basically doubles the propane endurance and is renewable even if the propane runs out.

[posplayr]

You are day dreaming making up numbers. A $300 dollar battery can only supply at best 1.2 Kwh per day to 50% DOD. That is roughly 15 cents worth of electricity and even if using a cheap LPG genny is about 30 to 40-cents worth of Propane.

To protect your battery investment dollar, perform monthly EQ charge, and carry you through cloudy spells requires a Generator period. No off-grid system should be without a genny, as they are required.

I think you are in a different conversation. The batteries are in a double conversion UPS to provide surge capacity to utilize a solar supply for normal household loads other than heavy AC; they are not being cycled.

[SunEagle]

I think we are in agreement with the math. I think the difference is in the assumed periods of generator outage. I'm looking at an extended period of no need for a generator (2-5 years) and then where there might be a sudden outage that could be 2-6 weeks (who knows). Or after the power comes back on for a few weeks it is off for a similar or longer periods. We are not concerned about the Haagen Dazs melting; people die in the heat of the desert;

I have already bought into the GT Solar thing and realize that the generator is the lowest cost per KW solution for a Grid replacement; it is included in the mix. The day time solar backup basically doubles the propane endurance and is renewable even if the propane runs out.

Well if you working on a system that provides power for an extended grid outage that lasts for weeks then I agree having multiple sources of power generation (gen, battery, solar, etc) is a good idea.

If you are worried about a SHTF problem with a very long power outage then I would say that the lack of electricity should not be even close to the top of your concern list because without any form of broadcast entertainment (tv, cable, internet, cell phone, etc) there really will not be as much of a need to have electrical power (cold storage food will be gone and light can be achieved through other more rudiment sources).

And for that matter anyone that does have a power source still working after months of no grid will become a target for those people that will do anything to acquire it.

[Will-UK]

please do just chat amongst yourselves on my thread about recalibrating my battery beeper.

[lkruper]

please do just chat amongst yourselves on my thread about recalibrating my battery beeper.

That's what you get for sleeping in the UK while we are awake in the US!

[posplayr]

Sorry, I lost track of what thread this was in.











P.S. SunEagle you are making my argument for me: solar is stealth generator is not so much.

[Topcat36]

please do just chat amongst yourselves on my thread about recalibrating my battery beeper.

Sorry for the late reply. The beeper can be disabled from the UPS config, using an APC COM cable and a terminal software. Or get hold of a network management card and you could even monitor your UPS from internet.

I have a question for you in return: how is the UPS coping with charging that HUGE battery ? No blown up components yet ?
I have a 2200VA APC ups and I am trying to make an automatic system that, when the battery is low, connects the UPS to mains and inserts a diode between the battery and UPS, to block charging while still supplying power to the battery input. Unfortunately I get a Battery not connected error led on when the diode is in line.
I am worried the ups charger might get blown up from charging my 100Ah battery. And if it works, using power from mains to charge the battery is a waste of power I want to avoid. Battery should most of the time be charged from the solar panels.