I had to do an emergency replacement last weekend. The bad battery was:
12vdc, 4 amp hour gell cellAll I could find locally was:
12vdc, 5 amp hour gell cellThe batteries are identical except for the amp hour ratings.
I don't *think* moving up an amp hour should be a problem with this type of battery. Am I right?
Thanks for your time.
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Very probably. It is *possible* that the new battery may have slightly different charging requirements than the old one, if you want to get the maximum service life out of it, but that's by no means certain. Aside from that, the two should be compatible.
--
Dave Platt AE6EO
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Watch out for gel cells that aren't rated for SMPS service. Those suckers get drawn down _fast_, and lots of the cheaper ones won't survive. (Ask me how I know.)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
An increase like that won't hurt, except to need 25% more time to fully cha rge the battery, and notice that older backup supplies fully charge in 8-12 hours, while newer ones need up to twice that time (seems to make batterie s last longer). IOW even a much lower charging current won't hurt, and it' s only when you switch to a far larger battery that current can become too low (car batteries are rated for 60 amp hours).
It they are the same size, the rating is just a marketing ploy!
Paul
I've had that same question. I get that cheapo batteries are typically lower quality. But how do you tell that an expensive battery isn't just a cheapo battery with a higher price tag? They all seem to have the same specs. Any advice on brands?
Not a problem as such, but you need to ensure that the replacement(s) are suitable for UPS duty and not just GP types.
I've bought lead-acid batteries for several products (lantern, audio analyzer, alarm system), and have been happy with CS3 batteries. My alarm system uses Power Sonic, but I don't know what that proves.
I've found that the quality and survivability of gel cells can be estimated by their weight. Light weight batteries don't have enough lead and will die an early death. The differences are fairly subtle for small 50A-hr gel cells, but become obvious with the bigger batteries.
I don't know what constitutes a SMPS (UPS) rated gel cell. Most of the batteries I buy claim that the battery can be used in everything from electric toy cars to USP's with little distinction as to type of service. What I've found is that many UPS's over charge their batteries. Measure the charge current at various discharge levels and I suspect you'll find that many UPS's are trying to squeeze the last bit of power out of their batteries in order to give longer runtime. They also tend to recharge rather quickly, in order to deal with repetitive power failures.
I had a running battle with APC over this issue on some of their products. Note the pile of rack mounted (forgot the model number) APC UPS's piled up on my deck: There were many many more that were ummm... recycled because the batteries got hot, bulged, and eventually leaked electrolyte all over the equipment. This UPS used four 12V 7A gel cells in a 24V series/parallel combination.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Weight. Heavier is better. See my previous rant in this thread. Also, the length of the battery warranty is an important clue.
PowerSonic, Yuasa are what I like and use. The local Batteries Plus store sells Werker, with which I've seen a few short lifetime problems. I've been experimenting with random AGM battery replacements, with good results so far.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
I've had good luck with the on-shore and European brands, e.g. Varta. IME usually there's a sticker inside the unit or a table in the manual that gives recommended battery types.
I tend to buy used IBM e-server UPSes, which are rebranded APC SmartUPS units, and seem to go much cheaper than the APC-branded ones. I've got three 750 VA ones for $50 each, so even with a $60 battery it's still pretty affordable. (The supplies themselves seem pretty bulletproof.)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
I buy my UPSes at garage sales. They're the cheapo consumer toys that went dead and were left in the garage a few more years. Batteries are always toast. Power around here rarely goes out for more than a second. If it's out longer than that, it's probably gonna be out for longer than an affordable UPS could handle. Current system is down to about a minute run time. Should replace the battery.
I'm not a big fan of the consumer models, e.g. the APC BackUPS. The SmartUPSes connect to the server, and in Gnome, the battery icon on the desktop automatically tells you what the UPS is doing. I assume Windows does something similar. They're also much better built, so for $50, they're an excellent deal.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
APC would be a step up for me ;-) I have no need to know what the UPS is doing. The lights going out are my clue that something happened. It's always good to match the tool to the job. For me, a free garage sale ups that keeps my system from resetting on a 1-second power glitch gives me all the bang for none of the buck ;-) But it is time to get a new battery for it.
is
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ust
lPS
t sI buy my batteries from the local Batteries Plus store and they sell the "Werker" brand. These are probably not top of the line but they are cost effective batteries for service work. For emergency lighting applications I've noticed that the equipment seems to charge the batteries quite heavily and so they last only about three years. Most alarm systems will go about five. I designed and built the charger for my own alarm system. I use a common 12 volt 7 amp hour battery and I trickle charge it at about a 10ma. rate. This is easily done by putting a small incandescent lamp in series with the charging current. When the battery is low the lamp is lit. As the terminal voltage increases the lamp dims and eventually goes out. The exact lamp employed will depend on the battery type,and the magnitude of the charging voltage applied. It's a bit of trial and error to find the right lamp that will give you the trickle charge you're looking for once the battery is fully charged, but it makes a great deal of difference in the life of the battery. I've got almost 9 years on this one so far and that's pretty remarkable for a Chinese Werker battery. Lenny.
The idea is that the computer can shut itself down before the power goes off, to avoid massive file system corruption. If your computers are usually not doing very much, that's much less of a danger.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
In a particular size/case manufacturers often list a couple of types, aimed at general duty and UPS-type duty. The latter are reputedly optimised for the higher discharge rate found in that role compared to the more urbane alarm system backup role (which only hits decent discharge current if an audible alarm device is exercised).
Claims and reality are often strangers.
Indeed. IMOE the things that kill UPS batteries are:
A bit off-(thread)-topic, but I have a $20k+ communicatios test set that uses Gates cylindrical sealed lead-acid cells in the battery pack. The inbuilt charger design was such that these sets seem to kill packs ina couple of years. Tiring of this recurrent cost, I rejigged the charging circuit some 12 years ago, and haven't had a pack die since. Sample of one isn't generally considered statistically significant, but this is to me.
Just as laptops do ...
Yes, almost universally.
I have been called on to "service" quite a number of failed soho UPS' of varying sizes from 150W to 4kW, mostly APC. The electronics are almost universally fine - except for one with dead FETs in the inverter, the failure mode in every single one was batteries. When I bothered to check the charge regime, it was found to implement the above rules 1 and 3 on how to kill UPS batteries.
This does sound like maybe an IFR communications service monitor. If so, can you give any details on your mod?
Thanks
tm
Sounds familiar. I have an IFR-1500 that uses those Gates cells. They're really made for alarm system use, not for a power hungry
1980's service monitor. It would kill off 6 batteries every 2 years or so. I have up, removed the internal batteries, and run it off a big gel cell when needed.Good idea. Incidentally, IFR power supply design is just plain weird and difficult to repair. Mine have been down for many months because the AC section of the power supply won't play switcher. So far, I've replaced literally everything that could possibly cause a problem without results. I'm running it on the DC section which fortunately still works.
The joy of specmanship. If I'm lucky, and can find a way to reduce charge current or float voltage limit in software, I can usually extend the battery life. However, that's often impossible without inside information or reverse engineering. I see far too many laptops eat batteries due to overheating and overcharging in laptops that have never been run on battery power.
I've often wondered if there's a recharge time spec for UPS's. A few quick Google searches didn't find anything. I can see why the UPS manufacturers would want to recharge quickly, but they should at least give the customer the choice between fast recharge and long battery life.
Yep. I've had similar experiences. I don't see many big UPS's but overcharging is epidemic on small UPS's.
Rhetorical question: Why are there no UPS's that use Li-Ion batteries? Spoiler:
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Yep, 1200S
Well, it was 12 or so years back. I may have documented the change somewhere, and I'll look through my mountain of "design notes" for it, but I wouldn't go without food and drink waiting if I were you. I certainly didn't put the note in the Service Manual.
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