jossey
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| posted on 31/7/12 at 08:16 AM |
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Electric battery backup calculations confusing me......
So I am having electricity drop outs everyday which kicks my interest off when I turns back on mst of the tie my router does not connect to the net
which is annoying...... It doesn't work with reboot on idle so I'm looking at battery backup systems but I want to calculate how long it
will last with electric off.
So the system I want to buy is 400va
My router is 12v 1 amp which I think is 12va and 12watt does that mean it would last 33 hours?
Just want to get an idea on how long it will last but I don't get
Va
I thought it would be amp hours :-(
Thanks
David
[Edited on 31/7/12 by jossey]
Thanks
David Johnson
Building my tiger avon slowly but surely.
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Paul_C
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| posted on 31/7/12 at 08:31 AM |
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I agree it is confusing.
Typically an Uninterruptible Power Supply output is specified in VA which is the same as Watts when driving a resistive load but not a typical
load.
Batteries are usually specified in Amp Hours at some specific discharge rate.
Can you supply more information about the battery back up system you are looking at?
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MikeRJ
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| posted on 31/7/12 at 09:13 AM |
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VA is a power rating, not a capacity rating. A 400 VA UPS would be more than adequate to power your router, but that rating gives no information
about how long it would operate your router for. The UPS datasheet/technical information should have some information on reserve capacity at
different discharge rates (capacity reduces as the load is increased).
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jossey
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| posted on 31/7/12 at 09:46 AM |
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sorry for the delay.
Ive been trying to get the model number but i have now.
The tech spec is
Battery Type 6V4Ah x 2
capacity 400VA/240W
http://cache-www.belkin.com/support/dl/p75312uk_bu30x000ukdb.pdf
so would that give me about 4 hours backup given 12 watts is about 1 ah?
We lose electric at least 6 or 7 times a week for seconds and this drops my internet connection and then the router needs a power cycle.
My old router used to reboot if not connection was found but the new one doesnt which is annoying as it cost my £50....
So this seemed the best solution and gives me some sort of DR when the electric goes off and saves me bringing in my inverter plugging into the kitcar
and running an extension lead to the router.
Shame they dont do a router which is powered by the 5v feed your phone line
gets.. grrrrr
thanks in advance peeeps.
David
[Edited on 31/7/12 by jossey]
Thanks
David Johnson
Building my tiger avon slowly but surely.
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gremlin1234
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| posted on 31/7/12 at 10:07 AM |
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quote:
when I turns back on most of the time my router does not connect to the net which is annoying
what router is it? most do reconnect on power on,
there are also programs that detect if the router is online, and can issue a reboot.
quote:
My router is 12v 1 amp
that is 1 amp max, should be lower
also could you not use a 12v backup system (rather than convert to mains and back)
ps, a backup battery system would help if you have a laptop with its own battery, keeping you online continuously.
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snakebelly
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| posted on 31/7/12 at 10:14 AM |
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http://www.apc.com/tools/ups_selector/index.cfm
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jossey
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| posted on 31/7/12 at 10:20 AM |
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quote:
Originally posted by gremlin1234
quote:
when I turns back on most of the time my router does not connect to the net which is annoying
what router is it? most do reconnect on power on,
there are also programs that detect if the router is online, and can issue a reboot.
I wont have a PC online to issue the reboot command to the router due to power off and the TP link w 8961ND.
its the first time ive used a non main line company router and I found it is a pain in the arse. But it was by far the strongest signal router I have
seen for the money.
It was about £35.00 and dual aerial and with too 12DB aerials it will work all through the house (which has kingspan wall insulation) and works in the
garage through the foil insulation which my BT router wouldnt and the net gear 3 aerial one wouldnt either.
Thanks
David Johnson
Building my tiger avon slowly but surely.
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MikeR
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| posted on 31/7/12 at 11:07 AM |
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Does the router take 240v in or does it have a plug that converts the power down to 6 / 9 / 12v?
May be better to run the router directly off a car battery with a small regulator and have a trickle charger on the battery. This will reduce the
losses in converting from 12v to 240v to router voltage and may be a simpler / cheaper solution / more reliable solution.
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britishtrident
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| posted on 31/7/12 at 11:09 AM |
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Normally router should come back up without needing human intervention, change the router.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Paul_C
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| posted on 31/7/12 at 11:55 AM |
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Thanks for the link.
Yes the Belkin Specification is confusing.
The Capacity is the rated load it can supply, 400 VA (400W resistive load) or 240 W real load. It is missing detail but I am quibbling.
The back up time is quoted as 10 minutes with a PC load with 15" monitor. It's devious not to quote the load power. The back up time could
be less when supplying it's rated load of 240 W.
It should be much longer just powering the router.
The battery could supply 12 V for 4 hours assuming no losses. So I guess it should run the router for 3 to 4 hours.
I don't like the Transfer Time specification of 2 - 6 ms typical. I would hope that it's instantaneous. It implies that in normal
operation the output is connected to the input. When the input mains drops is switches over to running off the battery but isn't instantaneous.
Also it might not cope with voltage dips (brown outs) very well.
The output waveform is stated to be a modified sine wave which is rather crude.
Another router sounds like a good option.
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gremlin1234
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| posted on 31/7/12 at 01:45 PM |
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you could use your old bt router for the routing, and the tp-link one as a wireless access point.
and I think the tp-link only fails because its off for < 1 second.
edit tplink not dlink
[Edited on 31/7/12 by gremlin1234]
[Edited on 31/7/12 by gremlin1234]
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jossey
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| posted on 31/7/12 at 01:45 PM |
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paul thanks and thanks everyone else.
Ill send the router back then :O(
OK see my next forum post on which router.....
Thanks
David Johnson
Building my tiger avon slowly but surely.
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ChrisW
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| posted on 31/7/12 at 01:55 PM |
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You'd be better off buying a 12v gel 'alarm' battery (probably ~£10) and a diode (20p) and wiring that up as a backup system.
The PSU might be rated for 1A, but I'd doubt the router uses anything like that except perhaps on boot up. I'd be suprised if a 7Ah
battery didn't give you 24 hours running.
Chris
My gaff my rules
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loggyboy
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| posted on 31/7/12 at 01:58 PM |
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Surely if the power drops are only for seconds even the most basic UPS should be able to cope with the load of a pc and router.
Mistral Motorsport
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jossey
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| posted on 31/7/12 at 02:00 PM |
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ill see if I can return the item first then look at my options but thanks all for the help.
have a nice day :O)
DJ
Thanks
David Johnson
Building my tiger avon slowly but surely.
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ChrisW
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| posted on 31/7/12 at 02:02 PM |
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quote:
Originally posted by loggyboy
Surely if the power drops are only for seconds even the most basic UPS should be able to cope with the load of a pc and router.
I don't think the PC itself has been mentioned? It's just the router. I'd assumed the OP was using a laptop with it's own
"battery backup".
Seems to me like a huge overkill to use a 'real' UPS. Mains to 12v to mains to 12v conversion has to take more power than the router
itself, surely?
Chris
My gaff my rules
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jossey
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| posted on 31/7/12 at 02:10 PM |
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ye its just the router. I can use my laptop or Ipad when the electric dies and this lasts a long long while.
Thanks
David Johnson
Building my tiger avon slowly but surely.
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loggyboy
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| posted on 31/7/12 at 02:31 PM |
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Surely your elec provider should be looking at the main problem, rather than you looking at a smaller problem/soluition?
Mistral Motorsport
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jossey
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| posted on 31/7/12 at 03:23 PM |
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quote:
Originally posted by loggyboy
Surely your elec provider should be looking at the main problem, rather than you looking at a smaller problem/soluition?
Your telling me. Ps stop following me
Thanks
David Johnson
Building my tiger avon slowly but surely.
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