I don't need deep cycle. No space, and I would need two, since it's a 24v system. They are very expensive. I get over an hour runtime with the standard pair of 7.2ah batteries it came with.If your UPS won't complain about a different capacity (like that it takes longer to charge), I'd consider a deep cycle battery from Costco, Sam's Club or Walmart. I mean something with higher capacity, and if not in an area you can monitor and that has good ventilation, then sealed, not vented wet acid type.
Otherwise, I have let my UPS go, haven't replaced their batteries recently. I got a sealed one for my old vehicle jump starter here, seemed to have about the same lifespan as the original:
Chrome Battery
HIGH PERFORMANCE REPLACEMENT BATTERIES · Maintenance Free Power Sports Batteries · Reliable Sealed Lead Acid Batteries · 12-24 Month Warranty · Money Back Guarantee · Free Shippingchromebattery.com
RBC48 looks like just a pair of standard ~7Ah, 12V batteries in series so I would consider taking off the original wiring/connectors if needing to reuse them, and getting a couple of those from a local supplier to avoid the shipping cost. IDK how inflation has affected pricing on those but not too long ago they were about $20 locally, from hardware stores, maybe the three stores mentioned previously too.
Otherwise, Yuasa is considered a top brand and although they tend to cost more, you might find some of those locally too, at Walmart ( size?) or a motorcycle shop? They have a dealer locator tool on their site:
Find a Yuasa Battery | Yuasa Batteries Inc
Find a Yuasa battery dealer near you. Whether you need a powersports or industrial battery, Yuasa provides the best batteries on the market.www.yuasabatteries.com
I bought SigmasTek from Battery Sharks, after reading this thread:Looking at Sigmatek if anyone has tried them?
Weird, after reading that thread I decided against Sigmastek. Battery Sharks was where I saw them, decided not to chance it. His didn't last either. There was also many poor online reviews.I bought SigmasTek from Battery Sharks, after reading this thread:
Question - UPS replacement battery only lasted 2.5 yrs?
APC RS800 Uses dual 12 Volts 7.5 AH (F2 terminal) batteries. It's beeping intermittently and 'replace battery' is lit. Don't know what brand i used last time but this time the same online store (Battery shark) says: 2 SigmasTek SP12-7.5HR batteries $20 total + $10 shipping I think the UPS...forums.anandtech.com
They seem fine, but I'm only using it in an ancient APC BK500MC.
Not sure if you mis-read that thread's content? That poster said he didn't know the brand of his old batteries that died.Weird, after reading that thread I decided against Sigmastek. Battery Sharks was where I saw them, decided not to chance it. His didn't last either. There was also many poor online reviews.
Went with CSB, the originals were CSB 7.2ah, these are 9ah:
Sigasmstek is their own store brand, so I assumed that's what he bought that only lasted 2.5 years. Batterysharks online is where the BBB link takes you to:Don't know what brand i used last time but this time the same online store (Battery shark) says:
2 SigmasTek SP12-7.5HR batteries
$20 total + $10 shipping
They are based in New York:The Battery Sharks in NYC is a different outfit.
If your UPS won't complain about a different capacity (like that it takes longer to charge), I'd consider a deep cycle battery from Costco, Sam's Club or Walmart. I mean something with higher capacity, and if not in an area you can monitor and that has good ventilation, then sealed, not vented wet acid type.
Many UPS now let you adjust how long they'll run, so you can do one of two things:do not get them from amazon... most of the batteries there have been sitting.
Problem with boosting the aH is that the inverter was not designed to be run that long.
So even with the higher battery capacity, chances are depending on the load, the inverter will overheat and melt into a ball fire as UPS's have very poor cooling.
Edit:
Lastly... do not replace it with a Lifepo4 battery.
Lithiums do not like to be put on Float, which 99% of the UPS's do.
do not get them from amazon... most of the batteries there have been sitting.
Deep cycle batteries cost more than LifePO4 at this point, they are not cheap. And most LifePO4's have built in controllers these days, only about $60 each. But I don't trust them not to explode.You can get BMS/charge-controllers for LiFePO4 or other chemistries, but the total expense w/batteries seems overkill for an application taking a pair of ~7Ah batteries, unless power goes out weekly so that many recharge cycles are needed, also considering you can get a high # of cycles cheaper just doing what I had already suggested which was the larger capacity deep cycle batteries, not discharged nearly as deeply, but their greater volume will at least require a separate, bulky battery box. On the other hand, not having a battery in the UPS itself, leaves some extra room to slap a fan in.
High quality LiFePO4 batteries have low risk, are not prone to fire like some other Li chemistries.Deep cycle batteries cost more than LifePO4 at this point, they are not cheap. And most LifePO4's have built in controllers these days, only about $60 each. But I don't trust them not to explode.
The battery compartment of an SUA750 is walled off from the transformer, and the front has no vents, so there would be 0 airflow from a fan there.
Yes the battery compartment is walled off. You mod it, add intake and exhaust area. Not a big deal, use a drill and make several little holes and/or a larger hole saw, but it's a non-starter without the space for the larger batteries. Well, not really, given adequate motivation you could just build a box that sits under that cabinet the UPS is in, but I can appreciate not wanting to put forth that much effort if your power outages are not long and frequent enough to bother.
The reviews have many saying LifePO4's would not work in their UPS. It just shuts down. Probably because the UPS is not designed to work with them.The problem with LiFePO4 batteries is the CCA raiting tho.
Some can not put out enough amps to meet inverter demands even for the smaller UPS's.
And again.. LiFePO4 do not like put on Float charging.
Yes the BMS can handle it up to a certain point, but its a good way to burn though the BMS by applying current on it non stop.
The reviews have many saying LifePO4's would not work in their UPS. It just shuts down. Probably because the UPS is not designed to work with them.
There are batteries that supply enough ah. Problem is that the BMS keeps the output at 13.6 volts, and when power drops below, it just shuts them off. That's what I meant by "just shuts off". Removes the ability of a clean shutdown by software if you are not present.no its the Cranking Amps required.
For example... if you have a 500W load @ 24V that would require the battery to be able to crank about 21A.
Problem is the cheaper lithium BMS's can only do half that.
Then you have a problem.... as the inverter is trying to pull more then what the battery can crank out.
This is why there are special Lithium batteries for cars, because 90% of what you see on Amazon can not be used to start a car due to the lack of cranking amps. (CA)
A fan doesn't have to be directly blowing on something to still move enough air around to keep temperatures in check on something designed to run passively, but when doing a mod like that, it is still the burden of the person doing it, to compare before and after temperatures.The fan is needed to cool the transformer, which is in the back of the UPS. I assumed that's what you meant by mounting a fan in the battery compartment. It's the back portion of the UPS that gets warm when on battery power. It does have ventilation on both sides, but no fan.
There isn't enough space under the cabinet for battery boxes, and even if there were, how would you access them? There is also the concern of Deep Cell batteries off gassing inside my room/home when charging.
Plenty of runtime now with the SUA750, about 80 minutes,. The computer is all that is plugged into it. Probably longer with higher ah rating of the CSB's.
The white UPS is a 600VA. 450 watt unit, that's running the monitors, router, modem, and phone. After the computer monitors are off, it will continue to power the internet/phone for hours and hours. I've never had an outage long enough for it to shutdown. The load is less than 50 watts. 90 with the monitors on.
Space under the cabinet could be made by just building a simple box out of wood, same width as the cabinet, so the cabinet just sits on top of it.
I know, an interesting discussion though. I just don't see the benefit, and I'd be looking at $200+ every time I need new batteries.I'm not trying to talk you into doing it. The extra effort and cost has to be weighed against the benefit or lack thereof.
Sorry, I should have said deep discharge, not fully. My neighbor uses deep cycle batteries (full size) on his trolling motors almost daily, and typically get 8-9 years from them.^ UPS batteries are deep cycle. Apparently they just don't suit your notion of what deep cycle is. You cannot fully drain deep cycle leadj-acid batteries without substantially reducing their lifespan. Not sure where you got the idea that you could.