Car Battery UPS

[Cobalt2112]

Hey gang question... I have an APC 1000W and a 650W that the on-board batteries have failed. I've seen on the net where folks use car batteries and inverters as UPS. However, I dont know if anyone actually plugs the car battery to an actual failed UPS and it works w/o short or long term problems (specially to the PC)

I know other have talked about this on the net, but most of them DYI all of the hardware, I was thinking of using the APC units with the car battery. Has anyone heard/tried/seen this ?

 

[apt403]

I've seen it done. Just get a good, sealed battery, and try not to run it down too far. The UPS won't be able to bring that big a battery back from the dead, you'll need an actually recharger for a car battery.

 

[BillParrish]

Best damn thing you can do to it, I have been doing it for years. I always look for ups that have external battery connectors. A deep cycle marine trolling motor battery is best but anything has so much more power reserve than the dinky batterys they put in the consumer UPS. Get a battery box (basicly a plastic box) from the auto parts store to keep it in or kiss a big square of carpet or flooring good bye.

Every time I buy a battery for my car ( I dont wait till they die, about every 2 years) I use the old one on one of the UPSs, it runs the machine at least 3 times as long as the new UPS battery. So even a used car battery works well. A used 12v golf cart battery would be great.

Its harder to find UPS with the external battery connectors. I have a small UPS I just went into the battery compartment and connected longer leads to the existing battery leads and ran them to the battery box. Just use same size/guage wire or larger.

I have 3 of these "big battery" UPS scattered around the house and have had for years. Never a problem. Just be carefull battey acid will eat up your clothes and if you get any on you wash it off immedately.

During hurricane Fran (I think) in 1998 we were without power for over a week. I would play computer games for 4 hours straight, put the battery in the car and run to the store or just let it idle for 1/2 hour and was good for the next day The UPS will charge it back but it will take a lot longer, but hopefully you will not be running the thing down every day, who cares if it takes a week to come all the way back up. Ideally your UPS is mainly to prevent a crash and let you gracefully shut down. The Hurricane deal was an emergency, I would have died of boredom otherwise.

 

[dandragonrage]

That 1000W is probably 24V, so would take 2 car batteries in series. My Liebert is 48V and would take 4... But that just means better uptime.

 

[[Spectre]]

Hey gang question... I have an APC 1000W and a 650W that the on-board batteries have failed. I've seen on the net where folks use car batteries and inverters as UPS. However, I dont know if anyone actually plugs the car battery to an actual failed UPS and it works w/o short or long term problems (specially to the PC)

I know other have talked about this on the net, but most of them DYI all of the hardware, I was thinking of using the APC units with the car battery. Has anyone heard/tried/seen this ?

In the UPS sticky there is a link to building your own UPS using car batteries.

 

[Cobalt2112]

I was thinking the same thing, using my old car battery (8 years old!) and use it to power the UPS. I think the 1000W is not a 24V battery. If I remember correct (I have the old batteries around) they are two 6V in series. I'll find them and report... also, I'll read the sticky on the UPS forum (gee, must have missed it, that's why I posted here)

Best damn thing you can do to it, I have been doing it for years. I always look for ups that have external battery connectors. A deep cycle marine trolling motor battery is best but anything has so much more power reserve than the dinky batterys they put in the consumer UPS. Get a battery box (basicly a plastic box) from the auto parts store to keep it in or kiss a big square of carpet or flooring good bye.

Every time I buy a battery for my car ( I dont wait till they die, about every 2 years) I use the old one on one of the UPSs, it runs the machine at least 3 times as long as the new UPS battery. So even a used car battery works well. A used 12v golf cart battery would be great.

Its harder to find UPS with the external battery connectors. I have a small UPS I just went into the battery compartment and connected longer leads to the existing battery leads and ran them to the battery box. Just use same size/guage wire or larger.

I have 3 of these "big battery" UPS scattered around the house and have had for years. Never a problem. Just be carefull battey acid will eat up your clothes and if you get any on you wash it off immedately.

During hurricane Fran (I think) in 1998 we were without power for over a week. I would play computer games for 4 hours straight, put the battery in the car and run to the store or just let it idle for 1/2 hour and was good for the next day The UPS will charge it back but it will take a lot longer, but hopefully you will not be running the thing down every day, who cares if it takes a week to come all the way back up. Ideally your UPS is mainly to prevent a crash and let you gracefully shut down. The Hurricane deal was an emergency, I would have died of boredom otherwise.

 

[Michael Daly]

I was thinking the same thing, using my old car battery

Car batteries are a poor choice - they are made for short bursts at very high amps. They also can't stand many cycles of deep discharge - if you draw them down a lot, they have a short life.

The best choice is a battery that does the opposite - lower amps for a long time. Called deep-discharge batteries, they can be cycled deeply much more often than a car battery without a significant reduction in lifespan.

Marine batteries are somewhere in between - they are used for starting engines, but also for providing onboard power.

If you don't want to buy a new deep-discharge battery, you can get a second-hand battery used for golf carts or some industrial equipment.

 

[Cobalt2112]

Hmm... I would have to buy new... No marinas in my area (even though I'm in NJ) and no real good way of getting golf cart batteries. I may be able to buy one at Sears or some automotive store (PEPBoys, AutoZone etc?)

Car batteries are a poor choice - they are made for short bursts at very high amps. They also can't stand many cycles of deep discharge - if you draw them down a lot, they have a short life.

The best choice is a battery that does the opposite - lower amps for a long time. Called deep-discharge batteries, they can be cycled deeply much more often than a car battery without a significant reduction in lifespan.

Marine batteries are somewhere in between - they are used for starting engines, but also for providing onboard power.

If you don't want to buy a new deep-discharge battery, you can get a second-hand battery used for golf carts or some industrial equipment.

 

[dandragonrage]

Golf cart batteries are a good choice and can sometimes be found cheap on Ebay, though I dunno what kind of shipping cost you're looking at

 

[Michael Daly]

If you're loaded ($$$), you can get the AGM (absorbed glass mat) sealed deep discharge batteries sold for solar photovoltaic and/or wind generator power systems. The ultimate in reliability compared to things like car batteries for this sort of use.

When you choose a deep discharge battery, for maximum life, you should plan for a maximum discharge of no more than 50% in normal use and not more than 80% on very rare occasions. Under those conditions, they can easily last over ten years of regular use and possibly as much as 15-20. So if you need a regular use of, say, 20 AH, buy 40AH. 20AH for my computer (C2D E6600 3SATA, mid-range graphics etc) would run for an hour (that's about 240W).

 

[Cobalt2112]

My mom lives in the Caribbean and she's got an 8 battery 3500 watt inline inverter for the house. I wonder what she uses. I may try the local auto stores for the Golf cart batteries or maybe the marine batteries. I'm OK with a 3-5 year life.

If you're loaded ($$$), you can get the AGM (absorbed glass mat) sealed deep discharge batteries sold for solar photovoltaic and/or wind generator power systems. The ultimate in reliability compared to things like car batteries for this sort of use.

When you choose a deep discharge battery, for maximum life, you should plan for a maximum discharge of no more than 50% in normal use and not more than 80% on very rare occasions. Under those conditions, they can easily last over ten years of regular use and possibly as much as 15-20. So if you need a regular use of, say, 20 AH, buy 40AH. 20AH for my computer (C2D E6600 3SATA, mid-range graphics etc) would run for an hour (that's about 240W).

 

[FLECOM]

If you're loaded ($$$), you can get the AGM (absorbed glass mat) sealed deep discharge batteries sold for solar photovoltaic and/or wind generator power systems. The ultimate in reliability compared to things like car batteries for this sort of use.

the Optima batteries are AGM... you can get a deep-cycle version of those and they work well in this situation... and they are not quite as expensive as the solar AGM's...

if you really have money flowing out your... ... ear... then you can get "site" or "telecom" batteries... also AGMs they are designed for things like cell-sites and only have to be replaced every 20 years...

large gel-cells from solar arrays also work well for this...

i have dealt with a few large dc plants for large radio systems and AGM and Gel-cell are probably the most common type of battery i have seen used

also like someone mentioned some UPS' wont like having a huge battery connected... the chargers wont handle it or they will get confused at the large current load and think the battery is dead/shorted...

the best UPS to use for this is like a large APC with a battery connector in the back becuase then you know its designed to have a large battery plant attached (although these are usually 24v!)

 

[jimnms]

Every time I buy a battery for my car ( I dont wait till they die, about every 2 years)

Sorry to go off topic, but this is a complete waste of money and batteries. Are you aware that most car batteries come with a 5 year warranty? Only once have I ever had to replace a car battery before it's warranty ran out. My old truck's battery had a 5 year free replacement warranty, and a 7 year pro-rated warranty. It died a little over 5 years after I bought it, and I only had to pay about $15 to get it replaced.

 

[Cobalt2112]

True that... my Honda CR-V's battery is the original battery from when I bought it new in 1999... and it froze this past winter... I had to bring it in and put it on top of a radiator heater and it defroze. I put it back on the CR-V and gave it a boost! We're in July and it's still going strong!

Sorry to go off topic, but this is a complete waste of money and batteries. Are you aware that most car batteries come with a 5 year warranty? Only once have I ever had to replace a car battery before it's warranty ran out. My old truck's battery had a 5 year free replacement warranty, and a 7 year pro-rated warranty. It died a little over 5 years after I bought it, and I only had to pay about $15 to get it replaced.