Charging a AGM 12v battery

[dato1]

Which is a better panel for charging the battery quicker my regulator takes both panels

Specifications
Maximum Power(Pmax) 200W
Working Voltage 12V
Max Power Current 18V
Open-Circuit Voltage 22.3V
Short-Circuit Current 11.89A
Or
SPECIFICATIONS
Model PANEL200W24V
Maximum power (W) 200w
Optimum power voltage (Vmp) 37.42
Optimum operating current (Imp) 5.34
Open circuit voltage (Voc) 45.45
Short circuit current (Isc) 5.62A

[Wy_White_Wolf]

Depends on controller type.

If PWM then your only option is the first one unless you wish to throw 2/3 of the energy away.

If MPPT then either should work equally.

WWW

[dato1]

Depends on controller type.

If PWM then your only option is the first one unless you wish to throw 2/3 of the energy away.

If MPPT then either should work equally.

WWW

I use a coast to coast 30 amp regulator from Jayco
Is it true the higher amp panel will charge quicker.
Still confused with amps and volts and charging. .
But I know the mppt will re direct extra voltage.

[Sunking]

I use a coast to coast 30 amp regulator from Jayco
Is it true the higher amp panel will charge quicker.
Still confused with amps and volts and charging. .
But I know the mppt will re direct extra voltage.

You have a PWM Controller which is antiquated. Here is what you want and need to know

PWM Output Current = Input Current

1. That means if you use panel 1. you did not list Imp but it should be around 11 amps and 11 amps x 12 volts = 132 watts from a 200 watt panel
2. If you use panel 2 you get 5.34 amps of charge current and 5.34 amps x 12 volts is 64 watts from a 200 watt panel. (Use This Set Up)

MPPT Output Current = Panel Wattage / Battery Voltage

Makes no difference which panel you use, but #2 is the best choice for MPPT because of the higher voltage you get 200 watts / 12 volts = 16.67 amps of charge current and 16.67 amps x 12 volts is 200 watts. Not what you want.

What you want to do is use Panel #2 with a your PWM controller so you only get 64 watts from a 200 watt panel. Getting the full 200 watts is such a waste. You would have to use much larger wire with 200 watts. Just buy a 2 more panels to make up for it. That wilkl be two less panels for the world to have making power. We cannot allow that to happen.

[dato1]

You have a PWM Controller which is antiquated. Here is what you want and need to know

PWM Output Current = Input Current

1. That means if you use panel 1. you did not list Imp but it should be around 11 amps and 11 amps x 12 volts = 132 watts from a 200 watt panel
2. If you use panel 2 you get 5.34 amps of charge current and 5.34 amps x 12 volts is 64 watts from a 200 watt panel. (Use This Set Up)

MPPT Output Current = Panel Wattage / Battery Voltage

Makes no difference which panel you use, but #2 is the best choice for MPPT because of the higher voltage you get 200 watts / 12 volts = 16.67 amps of charge current and 16.67 amps x 12 volts is 200 watts. Not what you want.

What you want to do is use Panel #2 with a your PWM controller so you only get 64 watts from a 200 watt panel. Getting the full 200 watts is such a waste. You would have to use much larger wire with 200 watts. Just buy a 2 more panels to make up for it. That wilkl be two less panels for the world to have making power. We cannot allow that to happen.

That's where the problem lies my regulator controller only allowed Max input vote voltage of 28 volts dc so what I had to do on my panel was disconnect one row of cells so I only use and 2 rows of cells putting out 28 volts dc not 45v.
but 1/3 of the panel is disconnected can someone recommend a controller to use with panel 2.

[jony101]

I recommend the ecoworthy 20 amp mppt controller to use with the 2nd panel. I have a 240 watt 36 volt sharp solar panel connected to the ecoworthy, its been connected 24/7 for about 2 years, its proven very reliable for a 102 dollar controller.

I seen up to 15 amps of charging current and thats with the panel lying flat on my roof. With a PWM controller and the same panel I only got 7 amps max.

There are more expensive name brand mppt controllers in the 200/300 dollar range but you don't need that for 1 panel.

For agm you need to charge at minimum 14.4 volts to get a good charge. you can keep it at that voltage all day long, when the battery gets full it accepts less current on its on. You wont overcharge it from the solar panel/mppt. I have my mppt float voltage set to 14.3 volts (the highest it well go). The recommended float voltage for my agm is 13.7 but it wont give the battery a good charge if i leave it at that voltage. So far I had it this way way for about 6 months and very happy with the results.

The bigger the panel (high voltage 30+ volts panel) and mppt controller means more amps to charge your battery quicker. Your talking at least 10+ amps for a 200 watt panel. Also you won't see max amps unless the battery is almost completely drained at about 12.1 volts. Though my panel can put out 12 amps , my battery is usually at 12.5 volts in the morning and I rarely see more than 6 amps of charge power. When its all the way full I see only about 1 amp of charge power.

[PNjunction]

For agm you need to charge at minimum 14.4 volts to get a good charge. you can keep it at that voltage all day long, when the battery gets full it accepts less current on its on. You wont overcharge it from the solar panel/mppt.

That is generally a good idea with an agm since they really require a good amount of float after absorb. But we don't have that luxury of time in solar, so we set the bulk / absorb / float values ALL to 14.4-14.7v depending on manufacturer. This prevents falling back to float too soon scenarios. Nature's own light-switch and daily cycling take care of what would normally be an endless absorb scenario, which would be very bad from an ac-charge standpoint.

BUT, it is critical for the op to determine his own usage pattern to see if it falls between daily cyclic, moderate cycling, and float / standby. If you fall into a moderate cycling pattern, that is reaching full charge, but not cycling it for a few days on end, with the CC set like the above, you WILL spend too much time in endless absorb every day.

Some controllers have time-limits that may or not be adjustable on the user's end to help prevent this from happening. I just wanted to put this out there for those that may have less expensive controllers, and who also don't do daily cycles or total standby. When you are in the middle ground, you just want to be aware of what is ok for extended absorb, and what may fall into overcharge with moderate use.

[dato1]

That is generally a good idea with an agm since they really require a good amount of float after absorb. But we don't have that luxury of time in solar, so we set the bulk / absorb / float values ALL to 14.4-14.7v depending on manufacturer. This prevents falling back to float too soon scenarios. Nature's own light-switch and daily cycling take care of what would normally be an endless absorb scenario, which would be very bad from an ac-charge standpoint.

BUT, it is critical for the op to determine his own usage pattern to see if it falls between daily cyclic, moderate cycling, and float / standby. If you fall into a moderate cycling pattern, that is reaching full charge, but not cycling it for a few days on end, with the CC set like the above, you WILL spend too much time in endless absorb every day.

Some controllers have time-limits that may or not be adjustable on the user's end to help prevent this from happening. I just wanted to put this out there for those that may have less expensive controllers, and who also don't do daily cycles or total standby. When you are in the middle ground, you just want to be aware of what is ok for extended absorb, and what may fall into overcharge with moderate use.

I connected the panel as normal panel 200 watt output 45v DC.
Then by the MPPT controller from eBay
Check out this item I found on eBay: http://pages.ebay.com/link/?nav=item...168735&alt=web

The panel reads 45 volt while disconnected, when I connect it to the controller it only says 12 volt on the panel input terminals shouldn't it say 45v

[inetdog]

I connected the panel as normal panel 200 watt output 45v DC.
Then by the MPPT controller from eBay
Check out this item I found on eBay: http://pages.ebay.com/link/?nav=item...168735&alt=web

The panel reads 45 volt while disconnected, when I connect it to the controller it only says 12 volt on the panel input terminals shouldn't it say 45v

The 12 reading on the input terminals with a separate volt meter is telling you one of two things:
1. The panel is not working correctly (high resistance) and is only putting out 12V at its maximum power point, or
2. The CC is not really MPPT but PWM and you are reading the battery voltage as the CC tries to connect the panel directly to the battery.
The price of $58 for what is supposed to be an MPPT CC tilts the odds in the direction of option 2.

[Sunking]

I connected the panel as normal panel 200 watt output 45v DC.Then by the MPPT controller from eBay Check out this item I found on eBay: http://pages.ebay.com/link/?nav=item...168735&alt=web The panel reads 45 volt while disconnected, when I connect it to the controller it only says 12 volt on the panel input terminals shouldn't it say 45v

You gotta problem. Your panel has two voltage ratings called Voc which means Voltage Open Circuit or Disconnected from anything. The other is VMP which means Voltage at Maximum Power. So a 200 watt panel with a Voc = 45 volts would have a Vmp of around 35 to 38 volts. So to answer your question 45 Voc is OK. When you connected the panel and the voltage dropped to roughly = battery voltage, should be about .5 to 1 volt higher tells you that you have a PWM controller. With MPPT controllers the voltage assuming bright sun light will be as low as Vmp and as high as Voc. With a PWM controller the voltage can be as low as the Battery voltage, and as high as Voc.So if you had a MPPT controller with bright sun shine you should see something 35 on the low side and 45 on the high side. Just look at your panel specs and nothe Voc and Vmp. That is your range. Otherwise you have a PWM controller and it is turning your 200 watt panel into 70 watts.

[Sunking]

The price of $58 for what is supposed to be an MPPT CC tilts the odds in the direction of option 2.

It is a Dead Give Away it is fake. A decent 15 amp MPPT controller is going to cost a minimum of $160 up to $220 for high end. All he needs now is 2 more 200 watt panels so he actually has 200 watts.

[jimindenver]

I have used the same 20 MPPT controllers Joey has recommended for 3 years and found them to do what they say they will. There is now a newer version with a higher Voc rating, the ability to set and hold absorption voltage and equalization cycles. You can usually find them on ebay, in auctions with free shipping for $85. I sold all but one of mine off when I upgraded. That one is my back up should anything should happen to the big controller.

[dato1]

You gotta problem. Your panel has two voltage ratings called Voc which means Voltage Open Circuit or Disconnected from anything. The other is VMP which means Voltage at Maximum Power. So a 200 watt panel with a Voc = 45 volts would have a Vmp of around 35 to 38 volts. So to answer your question 45 Voc is OK. When you connected the panel and the voltage dropped to roughly = battery voltage, should be about .5 to 1 volt higher tells you that you have a PWM controller. With MPPT controllers the voltage assuming bright sun light will be as low as Vmp and as high as Voc. With a PWM controller the voltage can be as low as the Battery voltage, and as high as Voc.So if you had a MPPT controller with bright sun shine you should see something 35 on the low side and 45 on the high side. Just look at your panel specs and nothe Voc and Vmp. That is your range. Otherwise you have a PWM controller and it is turning your 200 watt panel into 70 watts.

The vmp on the panel is 37.5 volts the MPPT controller says pwm + MPPT regulator in the fine print. In full sun when I put the probes on the input terminals it fluctuate between 14 and 15 Voltz. And the battery is on 12v. You can manually change the panel voltage( overcharge) if I turn the panel voltage down .1 of volt under 12v the solar input terminal voltage jumps back to 45v but it stops a the panel charge.

[dato1]

The vmp on the panel is 37.5 volts the MPPT controller says pwm + MPPT regulator in the fine print. In full sun when I put the probes on the input terminals it fluctuate between 14 and 15 Voltz. And the battery is on 12v. You can manually change the panel voltage( overcharge) if I turn the panel voltage down .1 of volt under 12v the solar input terminal voltage jumps back to 45v but it stops a the panel charge.

[PNjunction]

I have used the same 20 MPPT controllers Joey has recommended for 3 years and found them to do what they say they will.

I'm sure they do function. They do the voltage buck/boost and whatnot to function at all. The question is, how *well* does their mppt algorithm work compared to say a Morningstar or other higher tiered product? That algorithm is usually proprietary.

If you put an inexpensive mppt controller up next to a quality pwm controller, would you see any real benefit (aside from just functioning)? What is really being tested and what I'd like to see is a comparison between an inexpensive mppt vs a higher quality mppt.

In other words, the reason to go mppt is not just for functionality, but for efficiency with the mppt algorithm itself. If that algo is not efficient, then yes, your system works, but the gains usually hyped up may not not compare to the higher tier stuff.