[c-nsp] DC powering for 3845 router

Justin Shore justin at justinshore.com
Wed Sep 12 09:35:55 EDT 2007


Our 3845s are pulling under 2.5a per chassis.  On all 3 of our chassis 
one PSU pulled approximately 1a and the other was around 1.5a @ -48VDC 
(54.36VDC is what our chargers are tuned to).  One is loaded (full BGP 
feeds, ACLs, 30Mbps of traffic); the other 2 are essentially idle. 
We've added an NM-1GE and a 4-port non-PoE HWIC to the loaded 3845.  We 
are not doing any PoE which would obviously skew our figures.

Our 7613s are only pulling 17.5a per PSU as compared to the 120a max 
they could be pulling down.

Justin


Frank Bulk - iNAME wrote:
> Thanks.
> 
> The manual also says to power them with 30 A circuits.  Of course, that's
> not actual draw.  
> 
> I was hoping someone was going to say that Cisco has this bit of hidden
> documentation that it's just 13 A per 3845 for 48 VDC fed DC power supplies,
> whether you have one or two of them.  But no one has said so, so we need to
> budget 26 A.  =(



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