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home ups, no pv; suggestions?


Gabriël
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hi! i'd like to tap some brains :)

with the odd power failure a ups for my wife's practice is a must. the batteries can trickle charge from the grid, so no pvs are necessary but an inverter which can in future take pvs as well is a plus. an alarm, preferably pulsing light, must indicate when grid is off in order to remind the girls not to use the kettle/snack-which/toaster/heater. so doing the 4 pcs/printers/lights/switch-board will draw a max of 3kw.

OR

would it be more cost effective to get a self starting generator?

any suggestions?

thanks and God bless

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Hi Gabriel

Since you already have an Axpert Might I suggest that you again go with an Axpert. I will lay my thoughts down in  bullet form.

  • You already have an Axpert which is a UPS that can accept PV. Why not get another. I think the 3kVA 24V Axperts are less robust than the 5kVA units.
  • The Axpert already has a flashing light to indicate whether it is on grid or on battery power.
  • Wire you DB so that toaster/kettle etc. draw directly from the grid - then there can be no issue with draining the batteries unnecessarily.
  • Batteries maintenance free LAs or Lithium (more expensive) together with Coulomb's firmware, so that you can raise the battery low cut-off to a meaningful value, will give you hassle-free install. I say Lithium is more expensive but Lithium (Pylontech) prices are plummeting. I don't want to get folks hopes up but prices for Pylontechs are dropping. It is pointless trying to order as there are none in the country. I am trying to find alternative suppliers.

The one draw back with a 48V system is increased cost. 

The above scenario is due to you already having  your eye on going solar in the future.

If the Axpert lack of hybrid capability is going to be a hindrance in the future then I would spend a little more tom for a hybrid inverter.

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Like the idea of wiring high power equipment to grid . No mistakes possible . I have a 40 Amp plug witch is used for welding , I dont want to overload the inverter . My wife have a remote Axpert display in the kitchen . She nou knows when what is avialable . Now she also likes solar .

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20 minutes ago, plonkster said:

On the other hand, this might be the perfect chance to buy a decent smaller inverter :-P

My Axpert has lasted 3 years and counting......... At the time my Axpert needed to last 2 years before I could buy a second unit on the interest saved on the more expensive unit I was considering. No it was not a Victron but some (other :P) disreputable brand

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Yeah the smallest Multiplus is 430 Euro. About R6500. If you're looking this way, I would rather steer you towards a 1200VA or 1600VA model that is a true hybrid and could in future help offset consumption, but for what you want to do... dare I suggest you use a proper UPS with nice fast change-over? TTT is the man to ask about that.

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Option one is as per Chris suggestion.

Option two as per Plonkster, is even cheaper than a Axpert.

See, I have "new" old second hand units, 2400VA each, for a R1000 each. They are brand new, but out of manufacturer warranty, never used. Can offer 2 month exchange or refund on inverter if there is a problem.

Then get 2 x 100ah batteries (24v) per inverter, sealed maintenance ones as it is inside a office, connect all and plug said computers direct into inverters, and forget about it.

How long will UPS run? Work it out based on the load per 24v 100ah bank. 

Option3: Online UPS'es ... too costly and they run about 5-15min. :-) 

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On 2018/05/02 at 7:35 AM, gabriel said:

hi! i'd like to tap some brains :)

with the odd power failure a ups for my wife's practice is a must. the batteries can trickle charge from the grid, so no pvs are necessary but an inverter which can in future take pvs as well is a plus. an alarm, preferably pulsing light, must indicate when grid is off in order to remind the girls not to use the kettle/snack-which/toaster/heater. so doing the 4 pcs/printers/lights/switch-board will draw a max of 3kw.

OR

would it be more cost effective to get a self starting generator?

any suggestions?

thanks and God bless

Before you buy a UPS, lemme ask you this: Why you do ^need^ a UPS? What equipment does she have? That will determine a lot in terms of which UPS to get. Cheaper offline UPS' is fine for the odd PC, to make sure the OS saves all data and safely shuts down in the 15 minutes the battery lasts. 

Online, and more expensive, UPS can run longer, but cost a lot more. 

 

As suggested, if you use something like an Axpert (cheaper pure sinewave inverters are available, like the IR Series / Devel inverters) would work well, but you won't have the option to monitor it from the OS. i.e. with most UPS's, the PC connected to the USB port and an application monitors the load and shutdown when necessary. 

 

But, if it will be used in conjunction with your existing solar setup, then changning program 3 on your Axpert inverter to UPS, will give you the same benefit as using a UPS - thought it would mean you need enough PV & battery storage to cater for the business' needs. 

 

I work with UPS systems a lot, and in some cases, like servers and networking equipment, you might want to spend the extra bucks on the good stuff that was built for that purpose. 

For home-use, small office use, a Powercom UPS works fairly well. 

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5 hours ago, SilverNodashi said:

lemme ask you this: Why you do ^need^ a UPS?

there are a couple of things which must run during office hours, they include inside lights, two fridges [with heat sensitive medicine like inoculations], 3 pcs, router, switchboard and two outlets for stuff like ear/nose/throat gadget and two printers

i think a cost effective solution will be to get two batteries [size?] and an inverter of between 2-3kw in order to carry the load for about 3-4 hours and follow chris's advice below in as far as the old house [>50years] makes it possible

On 5/2/2018 at 9:45 AM, Chris Hobson said:

Wire you DB so that toaster/kettle etc. draw directly from the grid - then there can be no issue with draining the batteries unnecessarily.

 

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20 hours ago, gabriel said:

 

there are a couple of things which must run during office hours, they include inside lights, two fridges [with heat sensitive medicine like inoculations], 3 pcs, router, switchboard and two outlets for stuff like ear/nose/throat gadget and two printers

i think a cost effective solution will be to get two batteries [size?] and an inverter of between 2-3kw in order to carry the load for about 3-4 hours and follow chris's advice below in as far as the old house [>50years] makes it possible

 

This helps a lot ;)

Lights and fridges don't need expensive UPS to run a long time. Light can run off a cheap modifified sinewave inverter + battery. And modern fridges as well. Or if you want to go pure sinewave, don't bother with stuff like online UPS's or any fancy expensive names. BUT, a fridge can draw a lot more current that what UPS's are designed for, especially if the door is opened / closed a lot. 

The PC's on the other hand could benefit from a separate UPS, if the battery bank you already have is insufficient. Routers / switches / etc als don't need expensive UPS, in fact, I would run them off their own battery if / where possible, and charge the battery from solar / eskom as needed. 

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On 2018/05/06 at 5:16 PM, gabriel said:

thanks @SilverNodashi, i believe i failed to mention that the practice is housed on its own, totally separate from our home were the existing pv system is; so it will have to be a de novo setup

now that changes things a bit ;) But I think you have enough info to make a decision. IF you decide to go the Axpert (or other cheap inverter) route, you have the added bonus of running it off solar during the day. 

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22 hours ago, SilverNodashi said:

... (or other cheap inverter) route, you have the added bonus of running it off solar during the day. 

Do not run a UPS 24/7 unless it is online.

Most UPS'es are not designed for 10 hours per day everyday. 

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