Replacement battery for UPS

lightseeker2009

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Hi guys, I've got a APC UPS of which the battery is not fine anymore. I suppose I can open the device without electrocuting myself using common sense?

Secondly, while I am replacing the battery, why can't I replace it with a bigger capacity lead acid that can stand next to the UPS? Can it be done without a problem? I am thinking of getting a huge capacity 102A connected to it.
 

Timothybil

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All of the APC UPSs are designed for the user to be able to change the battery. Directions usually come with the replacement battery. AFAIK, it shouldn't be a problem to parallel another battery externally. Just determine what voltage is required before you purchase. I say this because some of the larger UPSs have two batteries in series, some in parallel, and you will want to echo whichever setup yours has. I would strongly recommend a battery case of some sort for the external battery(s), to protect against dirt, moisture, and shorts. Be sure to use heavy enough cables between the two as well. I would go up at least one size larger than the cables on the internal battery, due to the greater distance involved.
Let us know what you do and how well it turns out. Pictures would be nice.
 

lightseeker2009

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All of the APC UPSs are designed for the user to be able to change the battery. Directions usually come with the replacement battery. AFAIK, it shouldn't be a problem to parallel another battery externally. Just determine what voltage is required before you purchase. I say this because some of the larger UPSs have two batteries in series, some in parallel, and you will want to echo whichever setup yours has. I would strongly recommend a battery case of some sort for the external battery(s), to protect against dirt, moisture, and shorts. Be sure to use heavy enough cables between the two as well. I would go up at least one size larger than the cables on the internal battery, due to the greater distance involved.
Let us know what you do and how well it turns out. Pictures would be nice.

Thanks.
If I connect the bigger battery, I will couple it directly to the terminals of the UPS and will not buy the smaller original batteries as well.
 

NoNotAgain

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Hi guys, I've got a APC UPS of which the battery is not fine anymore. I suppose I can open the device without electrocuting myself using common sense?

Secondly, while I am replacing the battery, why can't I replace it with a bigger capacity lead acid that can stand next to the UPS? Can it be done without a problem? I am thinking of getting a huge capacity 102A connected to it.


Before opening the UPS, unplug the unit and remove the battery isolation plug. This will keep you from getting hit with 120 volts.

You didn't mention the model number of the unit, it does matter.

The most common battery for UPS units larger than 1000 vA is the RBC7 pack. The pack is made up of two sealed lead acid 6 volt batteries wired in series with a 40-60 amp fuse or circuit breaker. Provided that your unit uses the standard plug in connection, you can splice the wires to extend them for using another type of battery. A deep cycle automotive/marine battery in a case is going to give you the longest run time. I'd suggest not using a sealed battery, but one that you can check the electrolyte level in. Being on a constant charge, the sealed batteries usually fail by being over charged and splitting the case.
 

Lynx_Arc

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Before opening the UPS, unplug the unit and remove the battery isolation plug. This will keep you from getting hit with 120 volts.

You didn't mention the model number of the unit, it does matter.

The most common battery for UPS units larger than 1000 vA is the RBC7 pack. The pack is made up of two sealed lead acid 6 volt batteries wired in series with a 40-60 amp fuse or circuit breaker. Provided that your unit uses the standard plug in connection, you can splice the wires to extend them for using another type of battery. A deep cycle automotive/marine battery in a case is going to give you the longest run time. I'd suggest not using a sealed battery, but one that you can check the electrolyte level in. Being on a constant charge, the sealed batteries usually fail by being over charged and splitting the case.

I think you got this wrong... I don't think the RBC7 pack uses 6v batteries but rather 2 x 12v battery in series for 24v as I've taken apart quite a few APC UPSes. In other words the larger UPSes won't run off 1 12v battery at all they require 24v. The UPSes that require only 12v are smaller 600VA or less I believe once you get up to the 1000VA range they go to 24v systems.
 
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NoNotAgain

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I think you got this wrong... I don't think the RBC7 pack uses 6v batteries but rather 2 x 12v battery in series for 24v as I've taken apart quite a few APC UPSes. In other words the larger UPSes won't run off 1 12v battery at all they require 24v. The UPSes that require only 12v are smaller 600VA or less I believe once you get up to the 1000VA range they go to 24v systems.

Lynx Arc, you're correct on the 12 batteries being used. UPS units under 2200VA (the 1000 and 1500VA units) use a single battery pack that is made up of two 12 volt packs wired in series with a slow blow fuse link between them. The larger units use two battery packs of the same configuration.
 

Timothybil

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How will two larger batteries in series like being recharged that way? I know my 1000vA APC has a reasonably slow recharge rate since it takes 10-12 hours to recharge. Will larger batteries have any problems recharging in series with a low recharge rate? I have been toying with the idea, but just planned on getting two replacement packs and wiring one externally to keep things even.
 

lightseeker2009

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How will two larger batteries in series like being recharged that way? I know my 1000vA APC has a reasonably slow recharge rate since it takes 10-12 hours to recharge. Will larger batteries have any problems recharging in series with a low recharge rate? I have been toying with the idea, but just planned on getting two replacement packs and wiring one externally to keep things even.

From what I could gather what Lynx said. The system might overheat as it was not designed to charge so long at any one time. It was designed to be only working for 5 minutes, now I want to run it 2 hours. Quite a big difference. But then again, I could always supplement the UPS by charging the external battery with another charger.
 

WalkIntoTheLight

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From what I could gather what Lynx said. The system might overheat as it was not designed to charge so long at any one time. It was designed to be only working for 5 minutes, now I want to run it 2 hours. Quite a big difference. But then again, I could always supplement the UPS by charging the external battery with another charger.

My APC UPS has a fan that kicks in as soon as it takes over. So, I doubt it will overheat from constant use. Perhaps smaller units (without fan) might. I think all the larger APC units have fans (I'm guessing those over 1000VA).

As for charging a large external battery, I don't think there's a risk of overheating, because the charge rate is so slow. The issue may be that it takes several days to recharge it.
 

NoNotAgain

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If you get to the point when you have had to use the unit as back up power, I'd unplug the batteries and charge them with another charger before reconnection. Your advantage will be that the batteries will be readily accessible.
 

lightseeker2009

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Other thing is, I can't think the 102A will even come down to 50% charge after two hours, so it is not as if the battery will have zero charge left. That should help a bit.
 

Lynx_Arc

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Other thing is, I can't think the 102A will even come down to 50% charge after two hours, so it is not as if the battery will have zero charge left. That should help a bit.
Without a good idea what load you will have on it I wouldn't know for sure. Inverters aren't 100% efficient perhaps 85% efficient and a 102Ah battery won't deliver that total when the current load starts rising beyond a certain point. If the battery is deep cycle the rating is for about 5A draw per hour exceeding that amount drops your 102Ah number down considerably with increasing current draw. At a 20A draw on the battery the capacity can drop down about 20 to 50% from rated and the inverter would only be delivering around 2A at 120v to your stuff.
 
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lightseeker2009

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Without a good idea what load you will have on it I wouldn't know for sure. Inverters aren't 100% efficient perhaps 85% efficient and a 102Ah battery won't deliver that total when the current load starts rising beyond a certain point. If the battery is deep cycle the rating is for about 5A draw per hour exceeding that amount drops your 102Ah number down considerably with increasing current draw. At a 20A draw on the battery the capacity can drop down about 20 to 50% from rated and the inverter would only be delivering around 2A at 120v to your stuff.

I will power only my 40'' LED tv and my decoder. We are on 220V. For lights, I don't need them, I have tons of flashlights:thumbsup:
 

broadgage

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Yes you can connect a large external battery to a UPS in place of the small internal battery, I have done this several times.
Since the larger battery will permit of a much longer run time, I would be concerned that the inverter might overheat. For this reason I would limit the load to about 50 % of the rating.
The built in battery charger will indeed take longer to charge the much larger battery, I would simply accept this. I doubt that the battery charger will overheat since it is designed to run for some hours. I doubt that the charging circuit will get any hotter after 24 hours than after the say 6 hours to charge the internal battery.

The most important point to be aware of is that the internal battery may NOT BE ISOLATED FROM THE LINE SUPPLY and therefore perhaps fatal line voltage electric shock could be received from the battery terminals. It is therefore MOST IMPORTANT that the battery terminals be treated with the same respect as line voltage connections.
I would place the battery in a strong plastic crate with lid secured.

UL, CE or other safety listing sets strict standards for the isolation between line voltage and connections that can be touched by the user. These standards DO NOT apply to UPS units as the batteries are intended to be internal and not able to be touched.
 

lightseeker2009

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@ Broadgage. Can it really be that the battery terminals can go over 12/24V? That would surely fry the batteries? I thought I will never risk a shock by just touching the leads from the lead acid.
 

NoNotAgain

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lightseeker,

If you are using the APC branded UPS, go to APC's website and download the manual for your unit. You'll need the model number and possibly the serial number.

Ensure that the unit isn't plugged into supply voltage, which you stated earlier was 220 volts. Wire the external batteries in series, and use the APC blade connector to connect the batteries to the UPS. Once the batteries are connected, turn the unit on and let it perform the self check. Then apply a load to the unit and verify that the load indicator lights work. A hand held hair dryer should supply enough current draw to show if the unit is working correctly.
 

lightseeker2009

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Guys, I was wrong about the brand. Its not a APC. My friend who gave it to me said its a APC.
The model number of the UPS I have is: BNT-1000AP. I am so sorry for this, I never used it before as it is a gift after the battery died.
It is a 600W, 1000VA UPS . My TV and decoder will use less than 50% of the current this UPS can deliver.
There is not much I can find on the internet about this UPS, mostly in languages I don't understand. Sorry for not making sure before I posted. I am going to take it apart now, that is when I realized it is not a APC.
 

Timothybil

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When I googled the part number, I found a page of illustrations that included the batteries. It appears it uses four 12v, 8or9Ah batteries in a series parallel arrangement, for a total of 24v & 16/18Ahs, or around 400WH. The UB 1280 battery shown is an AGM SLA with nut and bolt terminals. The next step up to the size you are talking about would be the 35/55 AH batteries, at about $120 + shipping each.
 

broadgage

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@ Broadgage. Can it really be that the battery terminals can go over 12/24V? That would surely fry the batteries? I thought I will never risk a shock by just touching the leads from the lead acid.

I am not suggesting that the battery is directly connected across the line voltage input, that would indeed fry the battery as the line supply is both AC and the wrong voltage.
What is entirely possible though is for one side of the battery to be connected to one side of the line supply, the battery would still receive the correct DC charging voltage, but would ALSO be live at line voltage and therefore dangerous to touch.

Battery chargers sold for charging vehicle batteries etc have the output carefully isolated from the line voltage input to avoid danger if the battery or connecting clips be touched in use. This is a legal requirement in all developed countries.
Battery chargers built into UPS units do not have to comply with this requirement because the battery is intended to be enclosed within the equipment and not accessible to touch.
 

NoNotAgain

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Guys, I was wrong about the brand. Its not a APC. My friend who gave it to me said its a APC.
The model number of the UPS I have is: BNT-1000AP. I am so sorry for this, I never used it before as it is a gift after the battery died.
It is a 600W, 1000VA UPS . My TV and decoder will use less than 50% of the current this UPS can deliver.
There is not much I can find on the internet about this UPS, mostly in languages I don't understand. Sorry for not making sure before I posted. I am going to take it apart now, that is when I realized it is not a APC.

A Google search of the part number supplied led me to this http://www.powercom-usa.com/ProductDetail.asp?ID=8974 If it were me, I'd send them an email for any technical info (user manuals) as well as a schematic for the unit.
 
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