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Dialysis Discussion => Dialysis: Home Dialysis - NxStage Users => Topic started by: rcjordan on October 14, 2018, 06:33:25 AM

Title: Battery backup for Nxstage cycler & pureflow
Post by: rcjordan on October 14, 2018, 06:33:25 AM
We live in the coastal 'lightning belt' and possible power disruptions during sessions was a real problem this summer.  I have generators available but do not have -nor want- an automatic transfer switch. What we DID want was the ability to do an emergency rinseback with power.  I checked with support and they recommended a minimum of 1200va battery backup. I found a namebrand 1500va model on Amazon that did NOT require software/computer monitoring but simply shows "time remaining" while in use.  https://www.amazon.com/gp/product/B06VY6FXMM

If you kill the heat on the pureflow, which is very quick & easy to do during session, it gives you approximately 30 minutes of runtime for the system. (With heat on, the time available drops to 9 minutes.)

System power requirements (@ 123v incoming):
Pureflow heat off: 82 VA
Pureflow heat on: 442 VA
Cycler: 108 VA

Related - Network for Lightning and Thunderstorms in Real Time
http://en.blitzortung.org/live_lightning_maps.php?map=30



Title: Re: Battery backup for Nxstage cycler & pureflow
Post by: Simon Dog on October 14, 2018, 07:01:18 AM
Are the 30 minutes determined by working the specs or experimentally verified?

Be cautious about relying on specs, especially since batteries can lose their ability to hold a charge as they age.

Any word on how the poor approximation of a sine wave works with the NxState equipment?
Title: Re: Battery backup for Nxstage cycler & pureflow
Post by: rcjordan on October 14, 2018, 08:17:20 AM
>Sine

Research by others online indicated that good quality hardware negated this problem.  Since Nxstage Support quickly & readily had a recommendation as to capacity, I figured it was OK to try.  If I fried the circuitry, I could tell them I'd checked with Nxstage before proceeding.

>verified

I checked it out experimentally. The estimated times remaining (9, 30) were read on-the-fly from the screen of the backup unit.  That said, I'm fully expecting the specs to be hyped/over-stated (companies lie) but I'm not too concerned since we need only an estimated 10 minutes to gracefully power down, even with waiting the 2 minutes to see if the power comes back on.

Yeah, SLA batteries degrade.  I'd expect to replace them every summer --every other summer, for sure.  That's another reason I went with a name brand, replacement batteries easily available.