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Author Topic: ups battery recommendations please...  (Read 1342 times)
knighty
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« on: March 06, 2019, 10:50:06 PM »

I have a ups for my cctv/server at work (bought an apc one after recommended here ages ago)

I'd really like to add some extra/eternal batteries to it so it lasts a bit longer in a power cut (mostly so I can intentionally turn the power off while doing electrical work)... and I was planning to run the light next to the fuse box from it

any recommendations?

I've always liked https://www.tayna.co.uk/ for car/van batteries... but the ups batteries are a small fortune?  I didn't expect them to be so expensive

it runs with 48v batteries... I thought I'd buy 4 x 12v 100ah batteries till I saw the price :-o
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Scruff
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« Reply #1 on: March 06, 2019, 11:46:58 PM »

Car batteries are the cheapest per Wh...for light use...especially when you combine them with Halfrauds no quibble warranty.

If you want good ones get golf carts.
If you want cheap ones that's it.

If you want efficiency use an inverter not a UPS. What happened yer yellar Xantrex?
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biff
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« Reply #2 on: March 07, 2019, 12:34:00 PM »

The aps are good quality sine wave which do well with pcs and the long florescent factory tubes.
The modified sine is excelenT for drills abd grinders. Small stuff around 1kw. When you buy a pure si e we inverter you will find that it eats the juice as well.
It's horses for courses.. there are external bank fittings for the rack mounted smart 3000va. A neat little 50 amp Anderson can slip in the rear left hand side  edgeways up. I would not hesitate to connect it to a 48v forklift pack. The 3.000va will never charge an external pack and will always give you a false reading. Just dump the internal bats and use the 3xternal only. Golf cart bats are fine. But the real power is in the forklift cells..
           Biff
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biff
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« Reply #3 on: March 07, 2019, 01:34:54 PM »

If you had a 48v battery forklift you could make a lead with a big Anderson connector on it to match the one on the forklift. Then if you had a power cut you could plug your APC into it and Bobs your aunt.
I used the exact same method in 120vdc for years and it word perfect.
          Biff
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Westie
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« Reply #4 on: March 07, 2019, 06:20:30 PM »

The issue with 'bodgeneering' a large battery to a small UPS is that the charging circuit OP will be the same for 100A/hr battery pack as it is for (guessing...) a 7A/hr battery pack, so typically, a small APC UPS, will charge at 4A so the recovery time for the 100A/hr batts is 25 hrs.... It may not be an issue in your application but needs to be borne in mind.


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biff
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« Reply #5 on: March 07, 2019, 09:35:49 PM »

And the condition and state of charge don't register properlly.
  I fitted several different types of APCS to large external banks and discounted any charge coming  from the UPS. Even my large RM APC just does not bother to make the effort. It must be because of the other charging  sources. I have one particular 24v 850watt ups non APC which can charge a pair og 100 amp Yousa without a problem but for some reason I have found that APC have on board tricks that do not allow them to even make the effort to charge large external packs.
There are tremendous variations in UPSs  but APC seem to exert very strict control on how they are used.     
          Biff
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knighty
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« Reply #6 on: March 07, 2019, 09:38:26 PM »

If you want efficiency use an inverter not a UPS. What happened yer yellar Xantrex?

I won it on ebay... it wasn't delivered :-(
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knighty
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« Reply #7 on: March 07, 2019, 09:41:44 PM »

I'll keep hunting, see if I can see any cheap golf cart batteries... I don't need massive capacity, a few hours at a few hundred watts would do
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Scruff
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« Reply #8 on: March 07, 2019, 10:03:23 PM »

Smallest golf cart set = 1.3kWh

I've had a few inverter/solar controller wins like that...promise to paypal them loadsa dosh when it arrives then don't after it magically shows up... Wink

Here's a cheaper wan...she'll pollish up grand. UPS are fit to task but too much self-consumption and two decade old charger design... Roll Eyes
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regen
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« Reply #9 on: March 08, 2019, 04:44:54 PM »

Our tramper off road mobility scooter has 2 off 73 Amp hr jel batteries. We had to change them after 5 years use but they still hold a good charge and are very heavy.
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knighty
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« Reply #10 on: March 08, 2019, 08:07:32 PM »

Smallest golf cart set = 1.3kWh

I've had a few inverter/solar controller wins like that...promise to paypal them loadsa dosh when it arrives then don't after it magically shows up... Wink

Here's a cheaper wan...she'll pollish up grand. UPS are fit to task but too much self-consumption and two decade old charger design... Roll Eyes

I bought a 'line interactive' UPS (I think that's whats it's called anyway) which always filters the incoming/outgoing power (or something like that)... we can dim the lights here a bit with big machines so figured that would be a bit nicer for the computers/server

there's less efficient which bugs me, I tell myself the improvements I've made in other areas vastly outweigh the loss, in kwh terms it does... but it still feels a little... immoral :-o
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Scruff
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« Reply #11 on: March 08, 2019, 08:47:57 PM »


Line interactive is a pass-thru I think.
Double conversion is the clean filtered type.


there's less efficient which bugs me, I tell myself the improvements I've made in other areas vastly outweigh the loss, in kwh terms it does... but it still feels a little... immoral :-o

I do stuff like that all the time....then a few months later I haveta fix it becoze it'll bug me til I do. Have I mentioned the base load of my avater is <1W?  whistlie  stir
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knighty
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« Reply #12 on: March 08, 2019, 09:01:58 PM »

must be a double conversion one I bought then, I know it does the constant filtering thing anyway!
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Westie
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« Reply #13 on: March 08, 2019, 09:21:55 PM »

must be a double conversion one I bought then, I know it does the constant filtering thing anyway!

Line Interactive UPS are the cheap and nasty ones, the inverter kicks in when the mains fail and are supposed fire up quickly enough to limit the drop out time to the load to around 1 cycle (1/50 sec).

Double conversion UPS are the dogs, the inverter feeds the load all the time so there's no interuption.  Named double conversion as it continually converts AC -> DC -> AC. The batteries on float charge on  the DC link.

If your just trying to keep stuff like  lights on etc.. line interactive is fine, if you need clean power for PC's/Servers you buy double conversion.



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knighty
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« Reply #14 on: March 15, 2019, 08:13:05 PM »

you know when you fall on your head fracture your skull and forget some stuff...

I forgot about the time I bought some UPS batteries from a UPS repair guy... so I could use them on my camper van... but never did

just found them, there's 4 of them, 90ah each.... doh


got them on charge now, they were all only just over 12v, after sitting for about 4 years, parallel'd them all up... bit of a bodge but I figure it'll be good enough to charge and balance them all



charger pulled them all up to 13.6ish then slowly lowered down to 13.2ish... it's apparently in constant current mode... I have no idea if it's a good charger... I bought it for the camper van because it can charge 3 seperate batteries at the same time... or you can parallel them up and it'll charge at a higher rate... 10 amps each channel   (thought I'd charge main battery at 10 amps and house batteries at 20 amps)



printed on the side of the battery is says "constant voltage charge for standby use use 13.6 to 13.8v... I'll check the ups, I assume it'll be set right



depending on finale charge voltage, I guess I'll have to unplug the current ups batteries and plug these in instead to start with... to let the ups float them to whatever voltage it likes... then after a few days I'll plug them all in together :-)
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