Should do. Have you got a suitable reg connected between the Panels and the batteryas you will cook the batterys otherwise. I have an mppt(multi point power tracking) reg which works well.I use a terminal block which turns 2 into 1 and then onto the batterys. I hope this helps. Bill
-- Edited by bill12 on Tuesday 17th of September 2013 07:15:56 PM
ken thomas said
12:31 AM Sep 18, 2013
For all you nomads out there with some electrical knowledge ??
If I have 1x 80 watt panel putting out approx 4-5 amps and I join another 80 watt panel via a 2 to 1 anderson plug will this put 8-9 amps into a deep cycle battery ??
Ken
oldboar said
02:10 AM Sep 18, 2013
In theory, yes provided both were the same output voltage rating. In practice, it would probably be a tad less
Darrell & Sandra
justcruisin01 said
02:11 AM Sep 18, 2013
Ken , are your panel's fixed to the roof?
I run 120 watt portables & they will do 8-9 amps.Being able to track the sun will always give you more input.
If you can store a portable & connect it to you existing reg, given that the reg is capabile of the extra amps you will gain more.
If not, then add another & the figures should be correct, remember the state of battery charge will always control the amount of ingoing charge reguardless of how many panels you have.
JC.
ken thomas said
05:21 PM Sep 18, 2013
Thanks for your replies
Both panels are portable and have regulators on them
Ken
oldtrack123 said
08:25 PM Sep 18, 2013
ken thomas wrote:
Thanks for your replies Both panels are portable and have regulators on them Ken
HI
That can present problems[not serious]
But it is quite likely the actual control points will not be identical
That could cause the panels to cycle on & off once the battery gets near to fully charged.
It simply means that at that time both panels may not be fully utilised.
BUt I would just see how it goes
The panels or the reg cannot be damaged
ken thomas said
12:29 AM Sep 19, 2013
thanks oldtrack
son is getting hold of gadget to test amps so will hook up one panel then the other and see what is happening
Ken
justcruisin01 said
02:54 AM Sep 19, 2013
Ken, two panels; one reg/controler.
As stated there will be a conflict of interest between the two if they both have a reg attached to each.
When you connect the first panel it will read the voltage & charge accordingly.
Connect the second panel, its reg will get a false voltage reading because the first panel is already read the voltage & is charging according to this reading, meaning the second unit is reading a voltage of the first panel & will not charge as high as needed.
Sounds a bit complicated but realy, so go two panels into one reg of ample capacity.
JC.
countryroad said
12:08 PM Sep 19, 2013
Would it be easier if you had 2 new panels at the same time and had them connected, OR is the problem with adding another panel later ?
OR just the fact of having 2 panels ?
Robyn
-- Edited by countryroad on Thursday 19th of September 2013 12:09:21 PM
oldtrack123 said
02:09 PM Sep 19, 2013
countryroad wrote:
Would it be easier if you had 2 new panels at the same time and had them connected, OR is the problem with adding another panel later ?
OR just the fact of having 2 panels ?
Robyn
-- Edited by countryroad on Thursday 19th of September 2013 12:09:21 PM
HI Robin
The potential problem is not with the panels [provided they have the same operating voltages]
What can happen with different controllers connecting to the batteries[it does not matter what the source is ,solar alternator or a mains charger is that ALL will not all have exactly the same operating points for fully charged, float,etc [in fact it would be very unlikely for even two]
That can lead to one source being turned "OFF : before the other/s when a set point is reached.
It simply means that ALL sources may not be fully utilized to do that last bit to get the batterries fully charged,
Likewise they may bot all turn on again at the same pont
NO HARM wil be done to ANY component if this occurs
Such arrangements are in common use every day in the RV area
If you have a mains charger plus solar it WILL occur when on mains power'
If you have Solar & Have some model DC <DC chargers from the alternator to the house batteries ,IIT WILL OCCUR
If you have solar & directcable charging from the alyternator to the house batteries,IT WILL OCCUR
But yes, IF you are concerned you could remove BOTH the existing regs from the back of the panels & wire them both into a higher rated regulator, which is best located as CLOSE AS PRACTICAL to the HOUSE batteries
BUT that wiill only stop the panel's regulators interacting
Those other interactions will still occur between each other & the ONE SOLAR reg
PeterQ
-- Edited by oldtrack123 on Thursday 19th of September 2013 02:12:32 PM
ken thomas said
06:41 PM Sep 19, 2013
JC
What you are saying is take the individual controllers off the 2 panels and put a bigger one for both of them??
seems like a problem if only one is being used
Ken
oldtrack123 said
08:51 PM Sep 19, 2013
justcruisin01 wrote:
Cruising Cruze wrote:
@ JC
Jim can someone use say an 80 watt and a 120 watt panel at the same time before it come into one 30 amp regulator
want to get a portable fridge that's why, got a 80 W so need most likely another 120 I think
cheers John
It doesn'y matter how many or what size the panels are, they all need to go through one reg of a suitable size to be able to handle the max charge of all panels at peak performance. This is when you are charging one battery bank.
120+80=200 watts Divided by 12volts =16.6 amps minus 10%loss =15amps of charge max.
Run a 20amp reg & all is good.
JC.
HI JC
Since when did one divide the PANEL watts by 12V to get the Amperage output
ThAT will only be NEAR correct with a MPPT reg & high light
The Max Peak powerpoint WATTS [the one they are sold] is USUALY at 17V
The MAX current @ rated WATTS is WATTS divided MPP VOLTS
!00W /17v =5.88A
only get that when panels are running at the STANDARD test conditions, USUALLY LESS
Provided the panels are the SAME nominal voltage any combination of WATTs can be used in parallell use
Each panel having it's own regulator is NO DIFFERENT to the panels charging the battery at the same time as a mains charger or from the alternator.
That's being done all over every day!
But I agree IF the OP is concened at getting the last possible drop of energy from the panelsAS THE BATTERY APPROACHES FULL CHARGE he should remove the current regulators a fit a larger suitable one AS CLOSE AS PRACTICAL TO THE BATTERY
In FACT I recommend that for ALL solar panels:
The REG should ALWAYS be as near as practical to the battery, to allow the reg to sense true voltage of the battery ,not the batery voltage plus cable voltage drop , which resuts in the reg believing the battet is more charged than it actually is
That will remove any interreaction between the panel regs but NOT from other charging sources connected.
AND I repeat NO HARM can be done to any source or regulators due to the possible interreaction>
PeterQ
-- Edited by oldtrack123 on Thursday 19th of September 2013 08:52:37 PM
ken thomas said
10:19 PM Sep 19, 2013
At the moment I connect to the cars dual battery via an anderson which I use to charge the vans battery while travelling, and when parked I put the 2 panels onto the cars anderson plug and so charge up only the dual battery.
What I do not know at this stage is whether double or slightly less amps is going into this dual battery by having 2 solar panels
Ken
Cruising Cruze said
12:14 AM Sep 20, 2013
@ JC
Jim can someone use say an 80 watt and a 120 watt panel at the same time before it come into one 30 amp regulator
want to get a portable fridge that's why, got a 80 W so need most likely another 120 I think
cheers John
justcruisin01 said
03:12 AM Sep 20, 2013
Cruising Cruze wrote:
@ JC
Jim can someone use say an 80 watt and a 120 watt panel at the same time before it come into one 30 amp regulator
want to get a portable fridge that's why, got a 80 W so need most likely another 120 I think
cheers John
It doesn'y matter how many or what size the panels are, they all need to go through one reg of a suitable size to be able to handle the max charge of all panels at peak performance. This is when you are charging one battery bank.
120+80=200 watts Divided by 12volts =16.6 amps minus 10%loss =15amps of charge max.
Run a 20amp reg & all is good.
JC.
justcruisin01 said
03:24 AM Sep 20, 2013
ken thomas wrote:
JC What you are saying is take the individual controllers off the 2 panels and put a bigger one for both of them?? seems like a problem if only one is being used Ken
Ken; if the regs are glued to the back of the panels as some are then I wouldn't try to remove them as you may break the glass.
Fit a suitable reg near you battery pack, capable of running the two panels, remove the wireing from the fixed regs & bypass them , wire the two panels into the new reg. Make up a short lead with two plugs to go into the reg's solar input, like a doubble adaptor & easy with anderson plugs.
If you wish to only use one panel at some time then no problem.
JC.
countryroad said
04:55 AM Sep 20, 2013
Thanks PeterQ...a few considerations whichever way you go.
This is what they should be teaching in school....in preparation for the next generations of GN's !!!
Robyn
Cruising Cruze said
08:53 AM Sep 20, 2013
Thanks Jim and Ralf
I'm still learning every day who told us life is boring
Waiting for Battery World to come back with new or fixed panel " regulator gone " ( wont happen that often he told me ) we know better will bypass when I've got back and get a bigger Regulator
cheers John
justcruisin01 said
01:53 AM Sep 21, 2013
oldtrack123 wrote:
justcruisin01 wrote:
Cruising Cruze wrote:
@ JC
Jim can someone use say an 80 watt and a 120 watt panel at the same time before it come into one 30 amp regulator
want to get a portable fridge that's why, got a 80 W so need most likely another 120 I think
cheers John
It doesn'y matter how many or what size the panels are, they all need to go through one reg of a suitable size to be able to handle the max charge of all panels at peak performance. This is when you are charging one battery bank.
120+80=200 watts Divided by 12volts =16.6 amps minus 10%loss =15amps of charge max.
Run a 20amp reg & all is good.
JC.
HI JC
Since when did one divide the PANEL watts by 12V to get the Amperage output
ThAT will only be NEAR correct with a MPPT reg & high light
The Max Peak powerpoint WATTS [the one they are sold] is USUALY at 17V
The MAX current @ rated WATTS is WATTS divided MPP VOLTS
!00W /17v =5.88A
only get that when panels are running at the STANDARD test conditions, USUALLY LESS
Provided the panels are the SAME nominal voltage any combination of WATTs can be used in parallell use
Each panel having it's own regulator is NO DIFFERENT to the panels charging the battery at the same time as a mains charger or from the alternator.
That's being done all over every day!
But I agree IF the OP is concened at getting the last possible drop of energy from the panelsAS THE BATTERY APPROACHES FULL CHARGE he should remove the current regulators a fit a larger suitable one AS CLOSE AS PRACTICAL TO THE BATTERY
In FACT I recommend that for ALL solar panels:
The REG should ALWAYS be as near as practical to the battery, to allow the reg to sense true voltage of the battery ,not the batery voltage plus cable voltage drop , which resuts in the reg believing the battet is more charged than it actually is
That will remove any interreaction between the panel regs but NOT from other charging sources connected.
AND I repeat NO HARM can be done to any source or regulators due to the possible interreaction>
PeterQ
-- Edited by oldtrack123 on Thursday 19th of September 2013 08:52:37 PM
K I S
Keep it simple, a simple question with a simple answer that he can understand.
oldtrack123 said
03:59 AM Sep 21, 2013
Hi
Right
:
THE SIMPLE equation for the current output of paralled panels is: divide the combined Wattage of the panels by THEIR rated voltage for Peak power[USUALY around 17<18V for a nominal 12V panel]
for 200W of panel :200W/ 17V=11.76A
It is unlikely you will ever achive that from the panels except in very bright sun,or highly reflective clouds &COLD weather.
Typical sunny days would be more like 9<10A MAX,especially if the panels are flat mounted.
PeterQ
wasn_me said
02:02 PM Sep 21, 2013
justcruisin01 wrote:
Ken, two panels; one reg/controler.
As stated there will be a conflict of interest between the two if they both have a reg attached to each.
When you connect the first panel it will read the voltage & charge accordingly.
Connect the second panel, its reg will get a false voltage reading because the first panel is already read the voltage & is charging according to this reading, meaning the second unit is reading a voltage of the first panel & will not charge as high as needed.
Sounds a bit complicated but realy, so go two panels into one reg of ample capacity.
JC.
This is the way I have understood to connect more than one panel. I would invest in an MPPT regulator to get the best out of the panels.
I have one 130 watt BP panel roof mounted. The best I've seen out of it is 8 amps, usually around 5-7. Last weekend while raining I was still getting 1.5 amps. I believe good quality solar products pay for themselves.
I am thinking of changing the fridge to 12 volt, in which case I will add a 100 watt folding panel to the system, as above, for low light conditions.
Cheers Pete
oldtrack123 said
03:52 PM Sep 21, 2013
wasn_me wrote:
That the way I have understood to connect more than one panel. I would invest in an MPPT regulator to get the best out of the panels.
I have one 130 watt BP panel roof mounted. The best I've seen out of it is 8 amps, usually around 5-7. Last weekend while raining I was still getting 1.5 amps. I believe good quality solar products pay for themselves.
I am thinking of changing the fridge to 12 volt, in which case I will add a 100 watt folding panel to the system, as above, for low light conditions.
Cheers Pete
Hi Pete
HI pete
It has nothing to do with more panels when" parallel"but can be usefullwith panels in series
When you got 8A you were getting the panel's MAX current
130W /17V =7.64A
Since the lighting conditions & panel temp rarely meet the the figures that the panel is tested& marketed at you did quite good
5<7A would be around the average with a PWM reg .
Now with a MPPT reg ,in theory, you will get different CHARGE CURRENTS into the battery [although the panel output will remain the sam
Takng your average of 6Asolar current
if the battery SOC volt is 12V the max current into the battery would be around 7.8A
you gain a little
if the battery SOC was 14v the max current would be around 6.8A
But these figures do not allow for inefficiency losses so take off 5<10%
PeterQ
-- Edited by oldtrack123 on Saturday 21st of September 2013 03:55:46 PM
oldtrack123 said
10:46 PM Sep 21, 2013
justcruisin01 wrote:
oldtrack123 wrote:
Hi Right : THE SIMPLE equation for the current output of paralled panels is: divide the combined Wattage of the panels by THEIR rated voltage for Peak power[USUALY around 17<18V for a nominal 12V panel] for 200W of panel :200W/ 17V=11.76A It is unlikely you will ever achive that from the panels except in very bright sun,or highly reflective clouds &COLD weather. Typical sunny days would be more like 9<10A MAX,especially if the panels are flat mounted.
PeterQ
Why quote a figure that is unachiveable;your words.
The formula I quoted is achivable with no problems, If I apply it to my own system that is exactly what I get & has been doing it over the last five yrs & thats why I stick with it..
JC.
HI
JC
YOU just DO not get it
You pull a mysterious % loss out of the air
BUT that just happens to suit your set up
To suggest that you could get 8.33A from a 100Wsolar panel is ridiculous
IT would require Extremely HIGH light levels.!!!
& is simply incorrect information.
The WAY I have described is the CORRECT WAY
THE PANEL'S WATTAGE DIVIDE BY THE PANEL'S VOLTAGE [NOT the battery's voltage] woll give you the PANEL's AMPS output under the specified light conditions of ONE sun @a panel temp of 25C
THAT IS THE WAY THE PANEL's WATTAGE IS DETERMINED
Those AMPs are the best you can expect from the PANEL under that light condition
AND you will achieve it IF you have a bright sun that meets that level
If you have ever looked at a panel spec you will see that info!!!
The way those who understand & know how the rating system works can use it to work out the possible advantages of a MPPT controller with different levels of light & temp & battery SOC
Certainly you are totally WRONG by using the panel wattage & dividing by 12V
Where does that figure of 12V come from??? certainly not from the battery since it is not likely to be 12v for most of the charge period.
If you look at wasnme 's [pete] post you will see he gets up to 8amps from a 130W panel he could never get 10.84A as by YOUR formula
130/17 =7.65A
I would suggest that on that occasion he was getting a light intensity on the panel close to the figure that the panel is rated at
His normal figure is 5<7A simply because his PANELS are not receiving the RATED light intensity
One of the reasons to position panels so they FACE DIRECTLY INTO THE sun is to try & get the RATE light intensity onto the panels
With any reg ,PWM or MPPT,the PANEL's output current is the same for the same light intensity, but a MPPT reg can convert the panel power efficiently to a higher CHARGE CURRENT FROM THE REG but not by increasing the PANEL current or getting more current from the panel!!
PeterQ
-- Edited by oldtrack123 on Saturday 21st of September 2013 10:49:29 PM
justcruisin01 said
01:51 AM Sep 22, 2013
oldtrack123 wrote:
Hi Right : THE SIMPLE equation for the current output of paralled panels is: divide the combined Wattage of the panels by THEIR rated voltage for Peak power[USUALY around 17<18V for a nominal 12V panel] for 200W of panel :200W/ 17V=11.76A It is unlikely you will ever achive that from the panels except in very bright sun,or highly reflective clouds &COLD weather. Typical sunny days would be more like 9<10A MAX,especially if the panels are flat mounted.
PeterQ
Why quote a figure that is unachiveable;your words.
The formula I quoted is achivable with no problems, If I apply it to my own system that is exactly what I get & has been doing it over the last five yrs & thats why I stick with it..
JC.
ken thomas said
11:35 PM Sep 22, 2013
looks like I opened a can of worms here.
ken
oldtrack123 said
04:48 AM Sep 23, 2013
ken thomas wrote:
looks like I opened a can of worms here.
ken
HI ken
No ,do not worry about that
You just have to sort the wheat from the chaff
OR facts from from misunderstandings of simple BASIC electrics
PeterQ [retired electrician]
ken thomas said
11:13 PM Sep 23, 2013
Many thanks for that and all other postings,we need a cross reference from others as long as we eventually get the right answer
Ken
Should do. Have you got a suitable reg connected between the Panels and the batteryas you will cook the batterys otherwise. I have an mppt(multi point power tracking) reg which works well.I use a terminal block which turns 2 into 1 and then onto the batterys. I hope this helps. Bill
-- Edited by bill12 on Tuesday 17th of September 2013 07:15:56 PM
For all you nomads out there with some electrical knowledge ??
If I have 1x 80 watt panel putting out approx 4-5 amps and I join another 80 watt panel via a 2 to 1 anderson plug will this put 8-9 amps into a deep cycle battery ??
Ken
Darrell & Sandra
Ken , are your panel's fixed to the roof?
I run 120 watt portables & they will do 8-9 amps.Being able to track the sun will always give you more input.
If you can store a portable & connect it to you existing reg, given that the reg is capabile of the extra amps you will gain more.
If not, then add another & the figures should be correct, remember the state of battery charge will always control the amount of ingoing charge reguardless of how many panels you have.
JC.
Both panels are portable and have regulators on them
Ken
HI
That can present problems[not serious]
But it is quite likely the actual control points will not be identical
That could cause the panels to cycle on & off once the battery gets near to fully charged.
It simply means that at that time both panels may not be fully utilised.
BUt I would just see how it goes
The panels or the reg cannot be damaged
son is getting hold of gadget to test amps so will hook up one panel then the other and see what is happening
Ken
Ken, two panels; one reg/controler.
As stated there will be a conflict of interest between the two if they both have a reg attached to each.
When you connect the first panel it will read the voltage & charge accordingly.
Connect the second panel, its reg will get a false voltage reading because the first panel is already read the voltage & is charging according to this reading, meaning the second unit is reading a voltage of the first panel & will not charge as high as needed.
Sounds a bit complicated but realy, so go two panels into one reg of ample capacity.
JC.
Would it be easier if you had 2 new panels at the same time and had them connected, OR is the problem with adding another panel later ?
OR just the fact of having 2 panels ?
Robyn
-- Edited by countryroad on Thursday 19th of September 2013 12:09:21 PM
HI Robin
The potential problem is not with the panels [provided they have the same operating voltages]
What can happen with different controllers connecting to the batteries[it does not matter what the source is ,solar alternator or a mains charger is that ALL will not all have exactly the same operating points for fully charged, float,etc [in fact it would be very unlikely for even two]
That can lead to one source being turned "OFF : before the other/s when a set point is reached.
It simply means that ALL sources may not be fully utilized to do that last bit to get the batterries fully charged,
Likewise they may bot all turn on again at the same pont
NO HARM wil be done to ANY component if this occurs
Such arrangements are in common use every day in the RV area
If you have a mains charger plus solar it WILL occur when on mains power'
If you have Solar & Have some model DC <DC chargers from the alternator to the house batteries ,IIT WILL OCCUR
If you have solar & directcable charging from the alyternator to the house batteries,IT WILL OCCUR
But yes, IF you are concerned you could remove BOTH the existing regs from the back of the panels & wire them both into a higher rated regulator, which is best located as CLOSE AS PRACTICAL to the HOUSE batteries
BUT that wiill only stop the panel's regulators interacting
Those other interactions will still occur between each other & the ONE SOLAR reg
PeterQ
-- Edited by oldtrack123 on Thursday 19th of September 2013 02:12:32 PM
What you are saying is take the individual controllers off the 2 panels and put a bigger one for both of them??
seems like a problem if only one is being used
Ken
HI JC
Since when did one divide the PANEL watts by 12V to get the Amperage output
ThAT will only be NEAR correct with a MPPT reg & high light
The Max Peak powerpoint WATTS [the one they are sold] is USUALY at 17V
The MAX current @ rated WATTS is WATTS divided MPP VOLTS
!00W /17v =5.88A
only get that when panels are running at the STANDARD test conditions, USUALLY LESS
Provided the panels are the SAME nominal voltage any combination of WATTs can be used in parallell use
Each panel having it's own regulator is NO DIFFERENT to the panels charging the battery at the same time as a mains charger or from the alternator.
That's being done all over every day!
But I agree IF the OP is concened at getting the last possible drop of energy from the panelsAS THE BATTERY APPROACHES FULL CHARGE he should remove the current regulators a fit a larger suitable one AS CLOSE AS PRACTICAL TO THE BATTERY
In FACT I recommend that for ALL solar panels:
The REG should ALWAYS be as near as practical to the battery, to allow the reg to sense true voltage of the battery ,not the batery voltage plus cable voltage drop , which resuts in the reg believing the battet is more charged than it actually is
That will remove any interreaction between the panel regs but NOT from other charging sources connected.
AND I repeat NO HARM can be done to any source or regulators due to the possible interreaction>
PeterQ
-- Edited by oldtrack123 on Thursday 19th of September 2013 08:52:37 PM
What I do not know at this stage is whether double or slightly less amps is going into this dual battery by having 2 solar panels
Ken
Jim can someone use say an 80 watt and a 120 watt panel at the same time before it come into one 30 amp regulator
want to get a portable fridge that's why, got a 80 W so need most likely another 120 I think
cheers John
It doesn'y matter how many or what size the panels are, they all need to go through one reg of a suitable size to be able to handle the max charge of all panels at peak performance. This is when you are charging one battery bank.
120+80=200 watts Divided by 12volts =16.6 amps minus 10%loss =15amps of charge max.
Run a 20amp reg & all is good.
JC.
Ken; if the regs are glued to the back of the panels as some are then I wouldn't try to remove them as you may break the glass.
Fit a suitable reg near you battery pack, capable of running the two panels, remove the wireing from the fixed regs & bypass them , wire the two panels into the new reg. Make up a short lead with two plugs to go into the reg's solar input, like a doubble adaptor & easy with anderson plugs.
If you wish to only use one panel at some time then no problem.
JC.
This is what they should be teaching in school....in preparation for the next generations of GN's !!!
Robyn
Thanks Jim and Ralf
we know better
I'm still learning every day
who told us life is boring
Waiting for Battery World to come back with new or fixed panel " regulator gone "
( wont happen that often he told me )
will bypass when I've got back and get a bigger Regulator
cheers John
K I S
Keep it simple, a simple question with a simple answer that he can understand.
Hi
Right
:
THE SIMPLE equation for the current output of paralled panels is: divide the combined Wattage of the panels by THEIR rated voltage for Peak power[USUALY around 17<18V for a nominal 12V panel]
for 200W of panel :200W/ 17V=11.76A
It is unlikely you will ever achive that from the panels except in very bright sun,or highly reflective clouds &COLD weather.
Typical sunny days would be more like 9<10A MAX,especially if the panels are flat mounted.
PeterQ
This is the way I have understood to connect more than one panel. I would invest in an MPPT regulator to get the best out of the panels.
I have one 130 watt BP panel roof mounted. The best I've seen out of it is 8 amps, usually around 5-7. Last weekend while raining I was still getting 1.5 amps. I believe good quality solar products pay for themselves.
I am thinking of changing the fridge to 12 volt, in which case I will add a 100 watt folding panel to the system, as above, for low light conditions.
Cheers Pete
Hi Pete
HI pete
It has nothing to do with more panels when" parallel"but can be usefullwith panels in series
When you got 8A you were getting the panel's MAX current
130W /17V =7.64A
Since the lighting conditions & panel temp rarely meet the the figures that the panel is tested& marketed at you did quite good
5<7A would be around the average with a PWM reg .
Now with a MPPT reg ,in theory, you will get different CHARGE CURRENTS into the battery [although the panel output will remain the sam
Takng your average of 6Asolar current
if the battery SOC volt is 12V the max current into the battery would be around 7.8A
you gain a little
if the battery SOC was 14v the max current would be around 6.8A
But these figures do not allow for inefficiency losses so take off 5<10%
PeterQ
-- Edited by oldtrack123 on Saturday 21st of September 2013 03:55:46 PM
HI
JC
YOU just DO not get it
You pull a mysterious % loss out of the air
BUT that just happens to suit your set up
To suggest that you could get 8.33A from a 100Wsolar panel is ridiculous
IT would require Extremely HIGH light levels.!!!
& is simply incorrect information.
The WAY I have described is the CORRECT WAY
THE PANEL'S WATTAGE DIVIDE BY THE PANEL'S VOLTAGE [NOT the battery's voltage] woll give you the PANEL's AMPS output under the specified light conditions of ONE sun @a panel temp of 25C
THAT IS THE WAY THE PANEL's WATTAGE IS DETERMINED
Those AMPs are the best you can expect from the PANEL under that light condition
AND you will achieve it IF you have a bright sun that meets that level
If you have ever looked at a panel spec you will see that info!!!
The way those who understand & know how the rating system works can use it to work out the possible advantages of a MPPT controller with different levels of light & temp & battery SOC
Certainly you are totally WRONG by using the panel wattage & dividing by 12V
Where does that figure of 12V come from??? certainly not from the battery since it is not likely to be 12v for most of the charge period.
If you look at wasnme 's [pete] post you will see he gets up to 8amps from a 130W panel he could never get 10.84A as by YOUR formula
130/17 =7.65A
I would suggest that on that occasion he was getting a light intensity on the panel close to the figure that the panel is rated at
His normal figure is 5<7A simply because his PANELS are not receiving the RATED light intensity
One of the reasons to position panels so they FACE DIRECTLY INTO THE sun is to try & get the RATE light intensity onto the panels
With any reg ,PWM or MPPT,the PANEL's output current is the same for the same light intensity, but a MPPT reg can convert the panel power efficiently to a higher CHARGE CURRENT FROM THE REG but not by increasing the PANEL current or getting more current from the panel!!
PeterQ
-- Edited by oldtrack123 on Saturday 21st of September 2013 10:49:29 PM
Why quote a figure that is unachiveable;your words.
The formula I quoted is achivable with no problems, If I apply it to my own system that is exactly what I get & has been doing it over the last five yrs & thats why I stick with it..
JC.
looks like I opened a can of worms here.
ken
HI ken
No ,do not worry about that
You just have to sort the wheat from the chaff
OR facts from from misunderstandings of simple BASIC electrics
PeterQ [retired electrician]
Ken