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54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

4 edits

54067323 (banned) to lutful

Member

to lutful

Re: [Equipment] More power battery talk

said by lutful:

You will need to purchase a separate 28V/175VA rated AC transformer for the 24V/4A DC output. That is also quite bulky and heavy.

Only if the OP needs 4 amps, which at 30 watts from 24 vdc is considerably lower than 4 amps, therefore that oversized transformer is not needed in this application, nor applicable...

You need to remember when sizing up power supplies to match the input to the load and as such in this case, a much smaller plug-in will do the job just fine.

Finally, it only trickle charges at 300mA which means it will take more than 60 hours to recharge your 18000mAh battery bank after each 6 hour outage.

Not sure how you came up with 18000mAh, the OP mentioned using two 12 volt 9 amp hour batteries in series which is still 9 amp hours, not 18 amp hours, in order to achieve 18 amp hours the batteries would need to be wired in parallel.

Wiring in series increases voltage while wiring in parallel increases capacity.
Expand your moderator at work
expohl
join:2002-03-26
Turlock, CA

expohl to 54067323

Member

to 54067323

Re: [Equipment] More power battery talk

your amount of radios (5a will power about 30-40 ubnt radios) and batteries to your desire, I recomend walmart deep cycle boat batteries, they are much better than sealed agm batteries because you can service them to extend the life
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

54067323 (banned)

Member

said by expohl:

your amount of radios (5a will power about 30-40 ubnt radios) and batteries to your desire,

The OP only needs a hair over one amp and a 1.5 amp power supply may do the job and be less expensive, hence the reason I recommended the OP browse the Altronix catalog and decide for him/herself the best choice for the application.

The OP also posted about having a limited amount of space in the cabinet and considered using 9 amp hours of standby which is a very small battery and probably not to be found at Wall Mart.

Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak

Premium Member

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Here the the standard box we use at any sites that are needing an outdoor enclosure. With ups 350 as example for size scaling.
We usually use a 550 ups.

Is there a device like the above anyone know of one that is sorta plug and go? With the transformer already in it and can do at least 2 amps ? Maybe 3?
I don't really care how long batteries take to charge so charge current is not incredibly important.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful

Premium Member

I make my own but you can buy one of these UPS modules from Powerstream. They have the transformer built-in and are quite small.

»www.powerstream.com/12V- ··· ckup.htm

They have 12V/3A and 12V/6A models and also 24V models. DC voltage is adjustable. There are mounting screws for backplates.

Unfortunately, trickle charge current is only 200mA but you don't care.

Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak

Premium Member

THanks, looks like exactly what Im looking for. Only thing that concerned me is that the output voltage was not regulated, and ubiquiti radios to the best of my googling are not tolerable above 24 volts, BUT Im running at this one site 200+ feet of cat5 at least, and pretty sure Im losing 4 or more volts once it gets to the top.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful

Premium Member

said by Inssomniak:

Only thing that concerned me is that the output voltage was not regulated, and ubiquiti radios to the best of my googling are not tolerable above 24 volts ...

The output voltage is indeed regulated and it is also adjustable. However, for nominal "24V" UPS function, the output needs to be adjusted to 26-27V range to allow trickle charging the battery bank. That should be OK with 24V PoE.

Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak

Premium Member

Sorry I actually meant to say the output voltage was the same as the charge voltage. Im thinking it will also be OK for 24v devices