nick9

Is it bad that I now *want* load shedding to kick in, at least a little, so I can use my lovely UPS kit??!! 😀

Classic, Eskom got it wrong about load shedding! However, I feel that if by Sod's law I averted load shedding by stocking up on batteries, then it's money well spent. https://mybroadband.co.za/news/energy/294672-where-is-the-load-shedding.html?source=newsletter

Indeed @The Terrible Triplett has sorted me out. Thanks to all of you for the advice. Any news on load shedding schedules? I used to use an app that was pretty reliable and it would tell me when it was happening in my area (which was Fish Hoek back then).

With regard to battery types, and sealed vs non-sealed, do I need to worry much about that, especially as I work in a small room with limited ventilation. i.e. are the sealed battery types keeping any off gassing inside the box and the non-sealed letting off gases into the room?

This is fantastic info, thank you. Looks like it's definitely not worth it for me. Is there an Axpert model you'd recommend I look at to go with 2 x 100Ah's and charging from mains, rather than solar? At this point I don't have a solar panel.

Thanks for all this great info. My goal is to run my desktop PC (not my laptop) and one monitor and two powered external drive enclosures for 2 hours during load shedding & nothing else in the house. My alternative plan to that is to switch to my laptop when the power goes down, having saved my work during the 5 minutes I have on the UPS. And do without the drives, which is not ideal in my workflow. I am travelling in the UK at the moment so I can't test the power use of my set up, but I am estimating it at 500W. Not sure how accurate that is. Please can you point me in this direction! If I am right at 500W, let me see if I can calculate the battery capacity I need correctly. 500W for 2hrs = 1000Whr at 12V 1000/12V = 83 Ah at C/20, But at C/4, say 120Ah And if I want to discharge battery to only 50%, it would be 240Ah Is that right or do I also need to allow for power factor to get between VA and W?

Just saw this as well. I take your point - I don't know much about all this, and though I think I could learn sufficiently, I don't think I have the time to experiment. Plus it is quite a cheap UPS, so more likely to have the issues you talk of. And it's only saving me the cost of an inverter, it may not be worth it. Aside from getting a new system (e.g. was quoted around R20,000 from ExSolar for a full Victron system with very posh pure sine wave inverter) - is there an option of going second hand, perhaps via this forum? I don't have a device to load test a battery which means I wouldn't really know much, but I may not need this system for more than a few months so I don't want to spend too much.

Aha, I thought the powerforum might be the place to come! Got some good info at mybb, but not this level. OK so let me see if I have it right. With a 100Ah battery, they need to be charged at around 10 amps - and the little UPS charger will only be able to charge at 1 amp max. So the UPS charger gets hot because it's running at max the whole time AND the battery is being treated badly with a charging current much lower than it wants, plus anyway it would charge v slowly and would not be ready for the next round of load shedding. So really I'd only be saving on the cost of an invertor, which is something though. I am presuming the invertor doesn't mind having a bigger capacity battery feeding it? Also, I have read mixed thoughts on the use of a modified sine wave invertor (as my UPS has) with a PC - some say the PC's PSU will handle it fine and others say you need a pure sine wave. There is also the PC monitor. Like the idea of the connectors yes. Any recommendations on a decent battery charger for the job? And I was thinking of a Victron AGM or Gel (https://www.victronenergy.com/batteries/gel-and-agm-batteries) - is that a good idea?

I have read a bit about people wiring a large 12V deep cycle battery into their UPS to make it last longer (say a 100Ah or 2x100Ah if it is a 24V UPS). In theory the UPS already has a battery charger, small battery and inverter and so replacing the battery is a cheaper alternative to buying a whole new system to keep my PC going for the 2 hours of load shedding. The main reported problem seems to be overheating and therefore safety - how hot is too hot. I'd love to hear from people who've done this. My UPS: The 800VA AP series from PSS (http://pss.co.za/wp-content/uploads/2017/06/PSS-Distributors-AP-Series-Brochure.pdf http://pss.co.za/product/ap-series) which has 1 x 12V battery (9AH) in it.