APC Smart-UPS 48V or 192 V external Battery cables too short !!!

[Anonymous user]

Do any of the APC folks who contribute to this forum know why APC's external battery packs have overly short cables ? IE, if you want to install the packs above the rack in the case of a Smart UPS XL or RT rack mount model you are out of luck - the cables are too short.

Later on, if you need to add capacity don't have space below the UPS for more packs you are forced to either relocate the UPS upwards or purchase expensive extender cables. OUCH !

Why can't APC would make a simple change and eliminate this headache...

Thanks , ....Dave

[EZ_Button_apc]

Good question Battman! While I'm certainly not someone that designed the units, I'm sure some of my comments were things that were taken into account.

Due to the pure weight of the UPS and battery packs, they are simply meant to be installed in the bottom of a rack. This certainly may mean that if you add packs for more runtime, then yes, you will need to move some equipment up in the rack. However, it seems that in most cases I've seen moving equipment is pretty common in an IT enviroment, unfortunately, ours just weighs more. The external packs are meant to be installed directly beneath the units, which seems pretty standard. Like you said, extensions can often be purchased if there are reasons otherwise.

A good reason for short cables is so there isn't a lot of excessive cable hanging around the bottom of the rack. We've all seen our fair share of cabling nightmares and birdsnests. Having short cables simply keeps the battery pack cables out of the way.

Message was edited by: EZ Button

[Anonymous user]

Battman wrote:
Do any of the APC folks who contribute to this forum know why APC's external battery packs have overly short cables ? IE, if you want to install the packs above the rack in the case of a Smart UPS XL or RT rack mount model you are out of luck - the cables are too short.

Later on, if you need to add capacity don't have space below the UPS for more packs you are forced to either relocate the UPS upwards or purchase expensive extender cables. OUCH !

Why can't APC would make a simple change and eliminate this headache...

Thanks , ....Dave

I^2R loss, especially with 48v.

Same amount of voltage is dropped per amp, regardless of system voltage, but at half the voltage you need twice the amp.
Twice the amp means twice the voltage drop. Twice the voltage drop at half the voltage means 4 times the percentage drop.

This is why.

Not sure why not with 192v.

[Anonymous user]

With all due respect KVar, I don't believe it is because of resistive losses...firstly, it is only a matter of adding a couple of extra inches of wire to the connecting cables that come out of the battery module and they would reach - taking into consideration there is already upwards of 2-plus feet of interconnection wiring between the jars, fuses, etc inside the battery modules. Secondly, if resistive losses were so critical to avoid then APC wouldn't be able to sell battery extension cables !

Dave

[Anonymous user · Accepted solution]

Battman wrote:
With all due respect KVar, I don't believe it is because of resistive losses...firstly, it is only a matter of adding a couple of extra inches of wire to the connecting cables that come out of the battery module and they would reach - taking into consideration there is already upwards of 2-plus feet of interconnection wiring between the jars, fuses, etc inside the battery modules. Secondly, if resistive losses were so critical to avoid then APC wouldn't be able to sell battery extension cables !

Dave

Perhaps it is to ensure the sale of high margin extension cable, which probably offers resellers with great overhead too.