Making my ups last longer

[shant]

hello, so we get power cuts a lot where i live and im not satisfied with the backup power time of my ups, i have a 1500va one which originally had 2x9amp 12v batteries each, combining into 24 volts, i changed them when they died with 7amps because i couldn't find any 9amps at that time, anyway i keep seeing people modding their ups with car batteries to make it last longer, i also want to do that with mine, however i have a few questions before i mod it, won't my ups fry its circuits trying to charge that big battery? or wont the bigger amp going thru the circuit heat it up and also end up frying it?
can my ups even charge a car battery anyway? if not, lets say i used an external charger, wouldn't connecting an external charger to the battery harm the ups when the ups is connected to the battery at the same time with the external charger? its gonna receive charge from 2 separate places, one from ups and second from external charger, wont that be bad?

 

[notarat]

The best way to make your UPS last as long as possible is to buy an adequate unit for the load you're running.

Too many people (not saying you...just saying too many people) underbuy on the UPS and that causes too much of a load on it causing premature failure of either the battery or the circuitry.

I use an AX-850W PSU and a 30" U3011 so, at the VERY minimum, I need a 1600VA unit.

Concentrate on getting a good battery and get your voltage correct if you use a car battery. The amperage will take care of itself...The thing about using a car battery is; The Amperage of your car battery(ies) can far exceed your Amperage need. Too many Amps is not a problem normally since the system will only pull what amperage it needs. Keep in mind, however, if there is a short-circuit, it can cause major problems, even a fire.

 

[shant]

i don't need a new ups 1500va is enough, i just need it to last longer with a better battery, i need to make sure of my questions before i do anything

 

[larrymoencurly]

The charger can't fry bigger batteries, only smaller ones, but I don't think your 7 A*H are too much at risk, especially if the backup is a newer "eco-friendly" type and requires more than 12-16 hours to fully charge its original 9 A*H batteries. OTOH a car battery is 50-60 A*H and could require almost a week to fully charge. Also a deep-discharge battery is better for backup than a car or marine starting battery

 

[shant]

no no, i meant the charger frying itself trying to charge the big battery, or when you use an external charger, yes ill be getting deep cycles

 

[larrymoencurly]

no no, i meant the charger frying itself trying to charge the big battery, or when you use an external charger, yes ill be getting deep cycles

That can't happen, either, because the charger limits current to no more than about 5% - 10% of the amp number printed on the original battery, and that's why it needs about a week to fully charge a car battery.

 

[shant]

awesome! ill go to a battery store as soon as possible then, what kind/brand battery do you recommend ? i will be using 2 batteries to get 24v out of them

 

[wagex]

any kind of deepycycle type battery should be fine. preferably the optima yellowtop or you can get online and get some XS batteries they are completely sealed you can orient them any way and it will not effect them.

 

[Lady Fitzgerald]

Or you just get the monster UPS I just ordered. I spent part of yesterday installing a dedicated 20A outlet for the beast (and paying for it today with assorted aches and pains; I'm too old for this).

 

[shant]

Or you just get the monster UPS I just ordered. I spent part of yesterday installing a dedicated 20A outlet for the beast (and paying for it today with assorted aches and pains; I'm too old for this).

no way im paying 430$ for a ups this way i can finish with just 100$

 

[Lady Fitzgerald]

no way im paying 430$ for a ups this way i can finish with just 100$

Yeah, the sticker shock was painful. Too many times in the past, though, I've bought something then later wished I had gotten a bigger, better, or faster one so I decided to just go ahead and bite the bullet on Gargantua (never mind that I'll be eating mustard sandwiches—without the bread—for the next few months). The extra capacity will allow me more time to shut down so I might be able to finish a job rather than just save it. Even when the batteries eventually wear down to half capacity, I'll still have plenty of time for a safe shutdown. And there is something to be said for having everything in one, neat package.

$435 is actually a bargain; it was almost $100 more when I first put it on my wish list. Also, the shipping was free (it's in transit now and will be delivered Monday). NewEgg was wanting over $100 more than Amazon, including shipping, but just recently dropped the price, including shipping, to about the same price.

 

[shant]

also, i can't ship a huge ups, batteries not allowed + weight cost is crazy

 

[shant]

i just got a different idea, how about i don't plug in the ups to the ac socket, i leave it unplugged and connect it to the big battery, and use an external 10amp charger on the battery, this way the ups would only be converting and not charging, good idea?

 

[Lady Fitzgerald]

Depends. The UPS inverter may not be rated for continuous operation.

 

[shant]

right,so that wont work either

 

[gangaskan]

just whatever you do get a deep cycle, i think the normal car batteries are not made to be topped off constantly. eventually they will die out and vent all of the juices.

 

[Bobnova]

Normal car batteries are being topped off any time your car's engine is running.
What they aren't designed to do is drop below ~70% charge.

 

[shant]

yes, im getting deep cycle 100%
but what im still worried about is the ups's charger killing itself trying to charge the big battery, 50% of the people i ask keep saying it will die, the other 50% say it wont, im totally confused

 

[wagex]

the charger isnt going to put out anymore than it is designed to do, hook up a car battery charger to a dead car battery does the charger explode because the battery is completely dead and is taking alot of power? no because the circuit inside the charger stops it from giving too much current.

There are two common charge methods, which are voltage limiting (VL) and current limiting (CL). Lead- and lithium-based chargers cap the voltage at a fixed threshold. When reaching the cut-off voltage, the battery begins to saturate and the current drops while receiving the remaining charge on its own timetable. Full charge detection occurs when the current drops to a designated level. Read more about Charging Lead Acid.

http://batteryuniversity.com/learn/article/all_about_chargers there is a TON of information on chargers there.

its like taking a car charger hooking it up to a pickup / semi battery, no difference, might take longer to charge but thats about it.

but once its charged you still only have the same VA rating while there is power, it will just last longer if the power goes out. (more AH)

 

[boucher91]

yep thats the only difference the bigger batteries take lots longer to charge...
we use 2 semi sized batteries on our ups at work..only for phones and server but the power can be off a week lol...