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Post by Deleted on Feb 25, 2021 13:19:20 GMT
Do you doubt the manual?
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Post by Deleted on Feb 25, 2021 13:21:36 GMT
I doubt myself - Grade E at Physics... |
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Post by Deleted on Feb 25, 2021 13:23:20 GMT
Trust what the Chinese tell you..
What's the worst that can happen.
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Post by Deleted on Feb 25, 2021 13:26:46 GMT
Trust what the Chinese tell you.. What's the worst that can happen. I once 'blew up' a hotel room in Mendoza, Argentina whilst trying to rig up a temp arrangement to charge a laptop. Not an experience I'd like to repeat! |
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Post by Deleted on Feb 25, 2021 13:30:40 GMT
Don't know what make of MPPT you have but some (Tracer for example) have a current limiting system. This means you can connect up to twice their rated power of panels.
Obviously you don't get any more charge in bright sunlight but you improve greatly your solar collection in poorer conditions Hopefully a simple question for anyone in the know.
If I did decide to upgrade my solar panals (one damaged and all about 6 years old), could I go up to a total of 780w for solar panals without needing to change the 40A MPPT controller? Page 9 on the manual seems to indicate I can, but I'm a bit of a numpty at times...
Yes you can do that, as Andrew explained earlier. You will benefit during the winter months, though undercut during summer. The tracers are actually very good, but not quite as good during winter and low light compared to the victron. I’ve compared both side by side to reach that conclusion. |
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Post by Deleted on Feb 25, 2021 13:38:20 GMT
Hopefully a simple question for anyone in the know.
If I did decide to upgrade my solar panals (one damaged and all about 6 years old), could I go up to a total of 780w for solar panals without needing to change the 40A MPPT controller? Page 9 on the manual seems to indicate I can, but I'm a bit of a numpty at times...
Yes you can do that, as Andrew explained earlier. You will benefit during the winter months, though undercut during summer. The tracers are actually very good, but not quite as good during winter and low light compared to the victron. I’ve compared both side by side to reach that conclusion. Thanks.
I understood JohnV and Andrew's posts. Just looking at the MPPT manual there seemed to be a limit to how much you could overspec the PV array before risking damage - wanted to check I've understood this ok.
If I do upgrade the panels then I may upgrade the MPPT at a later stage.
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Post by Deleted on Feb 25, 2021 13:42:44 GMT
Yes you can do that, as Andrew explained earlier. You will benefit during the winter months, though undercut during summer. The tracers are actually very good, but not quite as good during winter and low light compared to the victron. I’ve compared both side by side to reach that conclusion. Thanks.
I understood JohnV and Andrew's posts. Just looking at the MPPT manual there seemed to be a limit to how much you could overspec the PV array before risking damage - wanted to check I've understood this ok.
If I do upgrade the panels then I may upgrade the MPPT at a later stage.
It’s the voltage ceiling you need to be wary of. I believe the voltage on that unit is 100. Running your panels in parallel will probably not even be half of that. |
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Post by Telemachus on Feb 25, 2021 13:48:02 GMT
Yes you can do that, as Andrew explained earlier. You will benefit during the winter months, though undercut during summer. The tracers are actually very good, but not quite as good during winter and low light compared to the victron. I’ve compared both side by side to reach that conclusion. Thanks.
I understood JohnV and Andrew's posts. Just looking at the MPPT manual there seemed to be a limit to how much you could overspec the PV array before risking damage - wanted to check I've understood this ok.
If I do upgrade the panels then I may upgrade the MPPT at a later stage.
You can overspec the panels in terms of current, as much as you like. What you can't do is exceed the maximum panel voltage. That will damage the controller. So it is less about how many watts the panels are, more about the open circuit voltage of the panels (allowing for the fact that panel OC voltage increases at low temperatures). Because panels are quoted in watts, the devil is in the detail to ensure that those extra watts are not developed as a result of high voltage, only as a result of high current (Power of course being current x voltage).
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Post by Deleted on Feb 25, 2021 13:50:21 GMT
Thanks.
I understood JohnV and Andrew's posts. Just looking at the MPPT manual there seemed to be a limit to how much you could overspec the PV array before risking damage - wanted to check I've understood this ok.
If I do upgrade the panels then I may upgrade the MPPT at a later stage.
You can overspec the panels in terms of current, as much as you like. What you can't do is exceed the maximum panel voltage. That will damage the controller. So it is less about how many watts the panels are, more about the open circuit voltage of the panels (allowing for the fact that panel OC voltage increases at low temperatures). Because panels are quoted in watts, the devil is in the detail to ensure that those extra watts are not developed as a result of high voltage, only as a result of high current (Power of course being current x voltage).
Posh git. |
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Post by Deleted on Feb 25, 2021 13:54:10 GMT
Thanks.
I understood JohnV and Andrew's posts. Just looking at the MPPT manual there seemed to be a limit to how much you could overspec the PV array before risking damage - wanted to check I've understood this ok.
If I do upgrade the panels then I may upgrade the MPPT at a later stage.
You can overspec the panels in terms of current, as much as you like. What you can't do is exceed the maximum panel voltage. That will damage the controller. So it is less about how many watts the panels are, more about the open circuit voltage of the panels (allowing for the fact that panel OC voltage increases at low temperatures). Because panels are quoted in watts, the devil is in the detail to ensure that those extra watts are not developed as a result of high voltage, only as a result of high current (Power of course being current x voltage).
I'm lost. Back to thinking get a man in...! |
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Post by Telemachus on Feb 25, 2021 13:58:45 GMT
You can overspec the panels in terms of current, as much as you like. What you can't do is exceed the maximum panel voltage. That will damage the controller. So it is less about how many watts the panels are, more about the open circuit voltage of the panels (allowing for the fact that panel OC voltage increases at low temperatures). Because panels are quoted in watts, the devil is in the detail to ensure that those extra watts are not developed as a result of high voltage, only as a result of high current (Power of course being current x voltage).
Posh git. Yes I realised I just said the same as you, (only more eloquently) but when I started typing you hadn't replied and by the time I'd read the manual to see the max OC voltage (and Jeff had bought my post-lunch tea and choccie bar) you had replied some time ago. |
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Post by Telemachus on Feb 25, 2021 14:01:28 GMT
You can overspec the panels in terms of current, as much as you like. What you can't do is exceed the maximum panel voltage. That will damage the controller. So it is less about how many watts the panels are, more about the open circuit voltage of the panels (allowing for the fact that panel OC voltage increases at low temperatures). Because panels are quoted in watts, the devil is in the detail to ensure that those extra watts are not developed as a result of high voltage, only as a result of high current (Power of course being current x voltage).
I'm lost. Back to thinking get a man in...! Not really, just check the panel open circuit voltage. If you are putting panels in series, add the open circuit voltages up and make sure the total doesn't exceed about 90v.
Or just tell us exactly which panels you are proposing to get and we can tell you.
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Post by Deleted on Feb 25, 2021 14:12:51 GMT
I'm lost. Back to thinking get a man in...! Not really, just check the panel open circuit voltage. If you are putting panels in series, add the open circuit voltages up and make sure the total doesn't exceed about 90v.
Or just tell us exactly which panels you are proposing to get and we can tell you.
I stopped and had a thought about it...
Unlikely to do anything before Oct but as this thread came up thought I'd ask.
Max OC of controller is 100v (I think or should I use the lower number?)
Is this what I should be looking/working out?
Edit to add - the mentioned panels are just an example.
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Post by Deleted on Feb 25, 2021 14:26:36 GMT
Not really, just check the panel open circuit voltage. If you are putting panels in series, add the open circuit voltages up and make sure the total doesn't exceed about 90v.
Or just tell us exactly which panels you are proposing to get and we can tell you.
I stopped and had a thought about it...
Unlikely to do anything before Oct but as this thread came up thought I'd ask.
Max OC of controller is 100v (I think or should I use the lower number?)
Is this what I should be looking/working out?
Edit to add - the mentioned panels are just an example.
That suggests you are running the panels in series. In parallel, it would be 36.7 volts. |
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Post by Deleted on Feb 25, 2021 14:32:06 GMT
I stopped and had a thought about it...
Unlikely to do anything before Oct but as this thread came up thought I'd ask.
Max OC of controller is 100v (I think or should I use the lower number?)
Is this what I should be looking/working out?
Edit to add - the mentioned panels are just an example.
That suggests you are running the panels in series. In parallel, it would be 36.7 volts. Thanks to both you and Nick.
One last question just so I'm sure - is what I suggested correct for panels in series. (it might seem a bit pedantic but I can do the calculations knowing that is right). And the OCv important thing to consider.
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