Paul
Solar Newcomer
Posts: 4
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Post by Paul on Mar 11, 2019 12:37:45 GMT
I am not sure of which figure to work with after considering increasing my solar panels to Panasonic HIT Slim 4 x 245W (980W).
So.. My Rover MPPT 40A, says Max PV Solar input Power in spec 520W@12V. Max Voltage 100V. I have a 12V system. I also assume (possibly incorrectly) that the PV input current can go up to the 40A controller limit?
However although these panels can produce up to 44.3V they only go up to 5.54A so only a total of 22 Amps with all 4 panels at max this is no where near 40 Amps. I would wire in parallel to keep to under 100V for system.
Therefore if my panels did eventually produce the full 980W and were running with say 40V (which may be likely at that power) the current would only be 24.5A. (not 40A)
I feel sure I have misunderstood something..
Please advise.
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Post by tattoo on Mar 11, 2019 12:50:51 GMT
It won't work you need a larger CC............ Plus why would you want to try and wire it under 100v if you could??? Just buy a larger CC or use 2 panels and the 40a CC you have now......
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Paul
Solar Newcomer
Posts: 4
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Post by Paul on Mar 11, 2019 15:28:07 GMT
Thanks for the reply tattoo, I thought that might be the case. It seems I'm greener than I thought and that doesn't refer to my ECO credentials!! I couldn't get my head round the idea the Rover 40A CC could do 40A PV and 40A Batts. It did seem that the power ability was voltage dependent, thus if 980W @ 40V= only 22Amp it would work. However looking at the Rover book it would seem that if I went to a 24V system (24V@1040W in book), it would work but I would need to reconfigure my batts and get a new 24V inverter. Or as you suggest a bigger CC, oh well all my stuff is new so what to discard to upgrade? Theres not enough sun to put the charge back my equipment take out during the day. I just need more power, bet you've heard that before from newbies..
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Post by bupkis on Mar 11, 2019 16:22:32 GMT
hi paul, the 40A limit is on the battery side and generally based on 13v so 13*40 = 520 watts. You can over power the converter and it will clip anything above 40A to the battery, this helps on those not so sunny days when 900w is only making 500w or during times the sun is not at the best angle (that be be all the time!!!). As you can see this gives you extra charging amps almost all the time up to the 40A limit.
Ya might check with support on how much overpower is allowed, I assume different mppt controllers have different limits
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Post by tattoo on Mar 11, 2019 16:42:38 GMT
Yes 24v is a different story.....
Man have things changed a while back to much power would burn up a CC now the new CC will cut back the extra power that's awesome.....
I don't see why you would want to make more power when it can't be used by a smaller CC.... Just buy a larger CC and a couple of more batteries and your all set..... Well closer anyways.....
Paul what are you trying to run off of your system?
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Paul
Solar Newcomer
Posts: 4
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Post by Paul on Mar 11, 2019 17:04:45 GMT
Hi Tattoo, thanks again for your comments, and bupkis. You asked what I had hooked up, well! My wife has a garden pond, it runs 24/7/365 it has some filter stuff with UV and small internal silt pump, plus two external larger pumps shifting the water around. I have calculated approx 125 watts 230V (I'm in the UK) this is born out by the inverter drain on the 12V batts of around 10 amp when connected. (125/12=10.41) I currently have (all new!!) 2 x 160W solar panels (affixed to my fence at the correct angle and adjustable, home made set up like a deck chair), Rover 40A MPPT, 2 x 110 ah batteries, 3000W (I had high hopes!!)Spark 12V pure sine wave inverter, also used for hoovering occasionally. Unfortunately if the pool stuff is left operating 24/7 off the inverter it drains the batteries right out, the PV is unable to put back during the day enough to keep up... So currently I turn on in morning and off at night, she's not happy.
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Post by tattoo on Mar 11, 2019 17:12:12 GMT
So you have a 3000w inverter? That's to big it's using a lot of power just by it's self..... A 1000w would be more than plenty...... I have a 500w running most of my stuff running 24/7....
Do you know how many watts the pump takes at start up?
One more of the same panel and two more of those batteries and I'd bet you would be just fine... But it's gonna be close.....
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Post by bupkis on Mar 11, 2019 17:48:04 GMT
I currently have (all new!!) 2 x 160W solar panels (affixed to my fence at the correct angle and adjustable, home made set up like a deck chair), What kind of amps charging are you getting?
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Paul
Solar Newcomer
Posts: 4
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Post by Paul on Mar 11, 2019 19:51:36 GMT
Hi bupkis, I am getting up to 18+? volts and just over 20 amps on a very very good day, more usually 16-17V and 5-10amps which is why it loses the battle as the battery runs down quicker than it charges up most of the time, it just needs that extra bit and of course more sun.. It does appear from using the helpful calculator I would need around 650W and yes another battery or two and I may just get enough juice. But I don't want to have to buy a bigger CC right now or battery as I'm already a bit overspent. So I'll hold off for now and may try the suggested extra panel 160W to match existing (total 480W) and see how it goes, but the spend goes up and although it was never going to be a money saver over mains power it is getting more costly than I had expected.
Thanks to all for your help and advice, probably we should close off for now, but feel free to continue comments if anyone chooses of course.
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Post by tattoo on Mar 11, 2019 22:28:51 GMT
Your 3000w inverter is using a lot of your power... I couldn't believe how much the difference was in a 2000w and a 500w inverter usage....
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Post by Admin on Mar 12, 2019 11:48:57 GMT
Thanks for the reply tattoo, I thought that might be the case. It seems I'm greener than I thought and that doesn't refer to my ECO credentials!! I couldn't get my head round the idea the Rover 40A CC could do 40A PV and 40A Batts. It did seem that the power ability was voltage dependent, thus if 980W @ 40V= only 22Amp it would work. However looking at the Rover book it would seem that if I went to a 24V system (24V@1040W in book), it would work but I would need to reconfigure my batts and get a new 24V inverter. Or as you suggest a bigger CC, oh well all my stuff is new so what to discard to upgrade? Theres not enough sun to put the charge back my equipment take out during the day. I just need more power, bet you've heard that before from newbies.. You would not need to disregard all of your items. With your current panels and charge controller you would just have to upgrade the inverter and perhaps buy a wire to connect your batteries in a 24V fashion. This would allow you to get more out of your panels since you're clearly oversized for a 12V system. -Renogy Team
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Post by Admin on Mar 12, 2019 11:53:45 GMT
Hi Tattoo, thanks again for your comments, and bupkis. You asked what I had hooked up, well! My wife has a garden pond, it runs 24/7/365 it has some filter stuff with UV and small internal silt pump, plus two external larger pumps shifting the water around. I have calculated approx 125 watts 230V (I'm in the UK) this is born out by the inverter drain on the 12V batts of around 10 amp when connected. (125/12=10.41) I currently have (all new!!) 2 x 160W solar panels (affixed to my fence at the correct angle and adjustable, home made set up like a deck chair), Rover 40A MPPT, 2 x 110 ah batteries, 3000W (I had high hopes!!)Spark 12V pure sine wave inverter, also used for hoovering occasionally. Unfortunately if the pool stuff is left operating 24/7 off the inverter it drains the batteries right out, the PV is unable to put back during the day enough to keep up... So currently I turn on in morning and off at night, she's not happy. We can determine an approximate system size figure out what changes need to be made accordingly. What are the watts of the pumps individually, as in what does it say on the device when it comes to watts? We are also a little confused. You're saying you have 245W panels and 2 x 160W panels? As for the 3000W, Tattoo is correct in that there's a load that's also adding to draining your batteries. if it's about 2.5A draw then you're looking at something close to 30W continuously for 24H which is about 720Wh daily on top of your electronics. -Renogy Team
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terracore
Solar Advocate
Chillin at EZwineKIT.com
Posts: 50
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Post by terracore on Mar 18, 2019 20:43:25 GMT
Not sure I would downgrade the inverter because your power demands may increase in the future. 2.5A draw is a lot for sitting idle, but it's only 0.5A higher than a 2000 watt inverter. These draws are only really relevant when the inverter isn't doing anything. You really shouldn't run an inverter at more than 50% of it's capacity most of the time if you want it last. I would consider a 3,000 watt inverter to be a "1500 watt" inverter that can handle up to 3000 watts occasionally.
The "peak surge" of 6000 watts advertised on most 3000 watt inverters is only available for a few milliseconds. Very few inverters can actually deliver a useful peak surge.
If saving 1 amp or a fraction of an amp is that important in your setup, buy an inverter with a sleep mode.
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Post by tattoo on Mar 18, 2019 21:58:00 GMT
Not sure I would downgrade the inverter because your power demands may increase in the future. 2.5A draw is a lot for sitting idle, but it's only 0.5A higher than a 2000 watt inverter. These draws are only really relevant when the inverter isn't doing anything. You really shouldn't run an inverter at more than 50% of it's capacity most of the time if you want it last. I would consider a 3,000 watt inverter to be a "1500 watt" inverter that can handle up to 3000 watts occasionally.
My power usage dropped dramatically when I went from a 2000w to a 500w inverter with the same draw.....
So what ever you want to believe is fine with me....
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terracore
Solar Advocate
Chillin at EZwineKIT.com
Posts: 50
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Post by terracore on Mar 18, 2019 23:09:39 GMT
I would expect it would probably drop to as low as 0.5 amps, so yes that's about 1/3 less power being used, and that's great if you only need a few hundred watts of power. Frequently less is more. I have a 400 watt inverter I use when I'm only running the chest freezer and solar hot water pump, but honestly I didn't really notice any big difference in energy usage compared to running my 2000 watt inverter. Because I'm over paneled my batteries are usually always full regardless.
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