No, you can discharge lead crystal completely. If you've got the money for it, go for itWish I was in your shoes though.
It still last longer if not 100% discharged
See pic attached
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Axpert invertors
- Thread starter Draganchor
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It still last longer if not 100% discharged
See pic attached
MrGray
Honorary Master
Have an Axpert 3Kva installed with 4x100ah lead/acid deep cycle batteries, wired into the DB board - most overhead (LED) light circuits are on it and some key plugpoints (TV, wifi router, etc - nothing in the kitchen apart from fridge). Needed a bit of re-wiring but complete solution came in under R20k.
Average sustained draw is about ~1KW so it lasts easily for as long as the load shedding.
Works like a dream and life is now mostly completely normal during load shedding, although obviously you can't make toast, boil a kettle or use the oven and you have to watch out for things like people plugging hair dryers, irons or electric heaters while Eskom does it's thing. The psychological difference of just having normal overhead lights instead of huddling around a candle is enormous.
The Axpert unit is very impressive. Had one of those unconfigurable no-name jobs before - couldn't see what was going on. The Axpert shows you exactly what's what and is quite configurable and flexible.
Next step - adding PV to the setup. The Axpert has all the functionality for this, and can dynamically work out what to do with the mains, battery and PV inputs depending on demand and settings.
I'm hoping that by the time the lead acids pack up lithium's (or other alternatives) will be more reasonable.
Average sustained draw is about ~1KW so it lasts easily for as long as the load shedding.
Works like a dream and life is now mostly completely normal during load shedding, although obviously you can't make toast, boil a kettle or use the oven and you have to watch out for things like people plugging hair dryers, irons or electric heaters while Eskom does it's thing. The psychological difference of just having normal overhead lights instead of huddling around a candle is enormous.
The Axpert unit is very impressive. Had one of those unconfigurable no-name jobs before - couldn't see what was going on. The Axpert shows you exactly what's what and is quite configurable and flexible.
Next step - adding PV to the setup. The Axpert has all the functionality for this, and can dynamically work out what to do with the mains, battery and PV inputs depending on demand and settings.
I'm hoping that by the time the lead acids pack up lithium's (or other alternatives) will be more reasonable.
savage
Expert Member
It's definitely do-able. Could more than likely even have been cheaper. I wouldn't personally recommend 100Ah (presuming a series setup here), on a 3KVA Inverter though.
Whilst you may only have 1KW on the inverter right now, and your batteries will last during load shedding right now... What do you do when your load goes up to 2KW (for whatever reason), two years from now? You can't add new batteries with old ones. Do you now throw out your 2 year old batteries, because you need 200Ah? Not saying there's anything wrong with it - just food for thought, for you, and others on myBB
Other that that, yes, I fully agree with your post. My wife, my child, and I don't even know when Eskom does load shedding anymore. I have to turn on something like the tumble dryer to find out whether we have load shedding - or go outside and look for street lights (I can even make coffee / tea too
). There is indeed, a HUGE burden that is taken off your shoulders, and it does indeed psychologically change your mind set completely.PS...
48v * 100ah = 4800 vah
(4800/1000 ) * 60 / 2 = 144 mins - So you're just above a 50% discharge on your batteries (presuming Eskom does 2 hours, and not 2 and a half hours). If you add any more load on that 3KVA inverter, you're discharging your batteries too much. Personally, I would have rather installed a 2KVA (1500W) inverter to ensure I can't put more load on the batteries.
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MrGray
Honorary Master
The Axpert will cut off at 50% so not too concerned about discharging too much provided it's reasonably accurate at estimating 50%. Yip, we have to be careful about what we use during load shedding, but the more important thing for me was to get it all running reasonably well, have the wiring in place and it's ready for PV. As soon as these batteries start showing signs of deterioration will replace the lot and hopefully prices on the newer tech will be better then.
This unit is actually 24V input (the Axpert's are available in 24/48V) so it's wired 2 sets in parallel. Also, presumably means it can be scaled in units of 2 batteries i/o 4, but not keen on mixing batteries of different ages.
The nice thing about the Axpert is that you can see exactly what the load is on the display without guessing so you can easily moderate your usage.
my setup is the 2400va Mecer with 2x 105Ah Energizer Deep cycles (haven't received it yet.. still being delivered from Geewiz)
How long should i get on a 300watt load (my TV, DSTV , Media player and CCTV system uses about 260watts to 280watt. to round it off to 300watt)
How long should i get on a 300watt load (my TV, DSTV , Media player and CCTV system uses about 260watts to 280watt. to round it off to 300watt)
savage
Expert Member
+-2Hrs, borderline. If you increase your load at all, and over time as your batteries age, your runtime will become less and less. I don't think the above will get you through load shedding within a year's time due to your batteries discharging frequently (due to load shedding)...
(105/2×24) =1260/300= 4 hours
savage
Expert Member
Right, 24V system. Sorry, I stand corrected.
4hours is good enaugh for me (my setup's Wattage won't really increase... it's a simple setup. Just 47inch LCD TV, DSTV Decoder, Multimedia Player and CCTV Camera system).
I have a Kill a Watt (watt meter). This unit says i'm using about 260-280watt maximum. So lets round it off to 300watt.
300watt giving me 4hours is very good. That should last 2 loadsheddings..
Is that 4hours taking into account (that i don't want to use the battery's above the 50% capacity) ?
I have a Kill a Watt (watt meter). This unit says i'm using about 260-280watt maximum. So lets round it off to 300watt.
300watt giving me 4hours is very good. That should last 2 loadsheddings..
Is that 4hours taking into account (that i don't want to use the battery's above the 50% capacity) ?
greg_SA
Expert Member
Yes - he divided the 105Ah by 2.
savage
Expert Member
It does come with (relatively crappy) software that can be used to monitor it via PC. It uses Serial communications however, so you'd need a USB to Serial device.
The software itself isn't 100% accurate, and quite a few features doesn't work. I'm not too impressed by it, and I don't rely on it a lot either.
Johnny_Q
Well-Known Member
thanks so can someone recommend how many batteries i would need to last 2.5hours ?
Ja indeed. Software doesn't look to bad on Youtube but will see.
Is there anything such as a bolt on product available then to publish results to web portal for solar production, state of charge, power usage and so on?
savage
Expert Member
About 225Ah.
You can work with +- 110Ah per 1KW of power for a 2.5hour period.
48V * 225Ah = 10800VAh
(10800/2060)*60 = 314 Minutes (100% drain)
50% Drain will give you 157 Minutes (2.6 Hours) with a 2KW load.
greg_SA
Expert Member
2060W x 2.5 hours = 5*150 Wh
I recommend a maximum discharge of 50% for the lead crystals that you mentioned. This means that a 12 V 100 Ah battery will give you 12 x 100 x 50% = 600 Wh.
So you'll need 5150 / 600 = 8.5 batteries.
By your inverter is 48V... so you have to work in series strings of 4 batteries.
So 8 batteries is an option... But this will actually take you a bit below 50% DOD. So that's about R28 000 in batteries
Or 12 batteries is better - then the DOD will only be about 36% - much better for the batteries.
You load is pretty hectic - what do you want to power during load shedding?
MrGray
Honorary Master
To get a general idea of battery requirement:
1. Divide expected load in watts by input voltage of batteries to get AMPS:
2000W/48V = 41.67 Amps
This tells you that to run that load for 1 hr you will need 41.67 Amp Hours (AH)
2. But there is up to a 30% loss factor due to various factors so to be safe add 30%:
41.67 AH * 1.3 = ~54 AH
3. And with lead acid/crystal batteries you shouldn't go below 50% charge so you'll need twice the amp hours:
54 * 2 = ~ 108AH
4. So for each hour you plan to run 2000W you need about 108AH of battery:
108AH * 2.5 hrs = 270AH
Remember that battery AH is additive in parallel but not in series, so if you're using 12V batteries and need a 48V input you need one or more series of 4x12V batteries arranged in parallel. To get above 270AH you'd need 3 sets of 4 batteries to give you a total of 300AH.
1. Divide expected load in watts by input voltage of batteries to get AMPS:
2000W/48V = 41.67 Amps
This tells you that to run that load for 1 hr you will need 41.67 Amp Hours (AH)
2. But there is up to a 30% loss factor due to various factors so to be safe add 30%:
41.67 AH * 1.3 = ~54 AH
3. And with lead acid/crystal batteries you shouldn't go below 50% charge so you'll need twice the amp hours:
54 * 2 = ~ 108AH
4. So for each hour you plan to run 2000W you need about 108AH of battery:
108AH * 2.5 hrs = 270AH
Remember that battery AH is additive in parallel but not in series, so if you're using 12V batteries and need a 48V input you need one or more series of 4x12V batteries arranged in parallel. To get above 270AH you'd need 3 sets of 4 batteries to give you a total of 300AH.
Johnny_Q
Well-Known Member
Ok thanks
This is my load calculation please correct me and advise on the battery setup I need
House lights 100W
Garden Lights 300W
Alarm 20W
DStv 75W
Home Enter 200W
LCD TV 200W
Total Watts 895 X 2.5 Hours = 2237.5
All above lights are LED
Thanks again all for your help
This is my load calculation please correct me and advise on the battery setup I need
House lights 100W
Garden Lights 300W
Alarm 20W
DStv 75W
Home Enter 200W
LCD TV 200W
Total Watts 895 X 2.5 Hours = 2237.5
All above lights are LED
Thanks again all for your help