What improvement will a MPPT charger provide in my system

Discussion about OutBack Inverters in Marine Applications

Moderators: OutBack, OutBack Moderator Team

What improvement will a MPPT charger provide in my system

Postby guymadison on Wed Apr 19, 2017 12:01 pm

Currently I have a 240 Watt solar panel with a PWM charge controller and a 800 ah 12v battery bank, I see charge rates of about 6 amps on the sunniest of days will I get better performance with a SCCM10-100? Ideally if it's not connected to the 12v battery rail it should benefit but I am not sure I understand if the SCCM10-100 isolates the battery from the solar panels which produce most of their power at 30 V.
guymadison
Member
 
Posts: 5
Joined: Tue Apr 18, 2017 4:43 pm
My RE system: Solar World 235 Watt panel / PWM controller / 12v 800 ah battery bank

Re: What improvement will a MPPT charger provide in my syste

Postby hendrik krijt on Mon Apr 24, 2017 2:57 am

mppt.jpg
Hi

Currently you have 6A coming to your battery at 12 volts, that gives you about 70Watts, A mppt charge controller will draw power from your panel at its max powerpoint of 30volts. Depending on the amount of sunshine and the temperature and the angle of incidence of the sun onto the panels and atmospheric conditions, you may see upto the 240watts going to the batteries. you might see upto 20 Amps into your batteries. I will try to post a photo of what my mppt charger is currently doing. 70v at 6.3A coming from panels, 29.5v at 14A. that 441watts coming from panels, 413watts going to batteries. thecharge controller uses some power, but you will win big time.

Lots of South African Southern sunshine to you all!
Hendrik Krijt
hendrik krijt
Member
 
Posts: 20
Joined: Sat Dec 31, 2016 6:33 am
Location: South Africa, KZN province
My RE system: pv=4.9Kw, 2xflexmax 80, 2x 24v-240v 50Hz outback inverters, fla's 12x Willard rt25 tubular 2v cells. rsa, kzn prov. (may change to aquion batteries)

Re: What improvement will a MPPT charger provide in my syste

Postby billi on Mon Apr 24, 2017 7:36 am

Please provide the specs of your PV panel , hard to believe for me that a 240 watt panel is ideal for 12 volt charging without an Mppt charger
billi
OutBack Guru
 
Posts: 139
Joined: Tue Oct 23, 2007 12:25 pm
Location: ireland
My RE system: 4000 watt PV array , Outback MX 60 and FM80 charge controller ,24 volt 1600 AH Battery @ C5 ,6 Kw Victron inverter charger, 1000 watt windturbine AC-coupled , 1.1 kw high head hydro turbine as a back up generator

Re: What improvement will a MPPT charger provide in my syste

Postby guymadison on Mon Apr 24, 2017 11:42 am

Oh I knew it wasn't ideal, but based on the sun we get here in Seattle it's been quite impressive. On a bright sunny day I did some experiments under load with an adjustable switching power supply and I found I was able to get about 8-10 amps as I drove the max current / voltage up to the peak output of 30V for the panel.. since I already had a PWM controller it just didn't seem worth the extra cost to install a MPPT controller which is pretty much a switching power supply on using the inductance of a toroidal coil to isolate the voltage between the batter and the panel.

It's a big panel at 240 Watts with a peak output of 8 amps at 30 volts, the curve is pretty static until it hits that point and drops off like most panels.

But Hendrik is getting good results, I ordered a OB MPPT controller just to see if there is a noticeable difference.

I will probably add another 240 Watt panel on the back of my sailboat which will give me plenty of power for long anchorages.
guymadison
Member
 
Posts: 5
Joined: Tue Apr 18, 2017 4:43 pm
My RE system: Solar World 235 Watt panel / PWM controller / 12v 800 ah battery bank

Re: What improvement will a MPPT charger provide in my syste

Postby billi on Sun Apr 30, 2017 5:24 am

...... so your battery is 12 volt or when charging around 14V and a 8 A panel then gives you 14Vx8 A= 112 watt only so you waste half of the panel without an Mppt controller
billi
OutBack Guru
 
Posts: 139
Joined: Tue Oct 23, 2007 12:25 pm
Location: ireland
My RE system: 4000 watt PV array , Outback MX 60 and FM80 charge controller ,24 volt 1600 AH Battery @ C5 ,6 Kw Victron inverter charger, 1000 watt windturbine AC-coupled , 1.1 kw high head hydro turbine as a back up generator

Re: What improvement will a MPPT charger provide in my syste

Postby guymadison on Mon May 01, 2017 12:22 pm

In Seattle we don't see the same amount of sun as say South Africa, so that was one of the considerations when purchasing a solar panel and the fact that most all panels are the same size. If you think of a solar panel as a large capacitor powered by light knocking electrons free the bigger the better. My expected use was from May - Oct for solar and even at the lower wattage it keeps up with my daily use. The average radiation in kW/m^2 is around 3 for Seattle.

I found a white paper from the Texas Instruments site that states a MPPT controller is about 20-30% better than a PWM, even with that my expected output will be around 10 amps. But I would need more like 16-20 amps to make a significant difference and I am not sure a MPPT controller will provide a 100% increase when loaded down with a 14v charge on a battery.

But I will find out once the sun shows up...
guymadison
Member
 
Posts: 5
Joined: Tue Apr 18, 2017 4:43 pm
My RE system: Solar World 235 Watt panel / PWM controller / 12v 800 ah battery bank

Re: What improvement will a MPPT charger provide in my syste

Postby billi on Tue May 02, 2017 1:23 pm

Hi, it does not matter how much sun u have in Seattle , all i am saying is that a 30 volt PV panel is not ideal to charge a 12 volt battery !!!!!
billi
OutBack Guru
 
Posts: 139
Joined: Tue Oct 23, 2007 12:25 pm
Location: ireland
My RE system: 4000 watt PV array , Outback MX 60 and FM80 charge controller ,24 volt 1600 AH Battery @ C5 ,6 Kw Victron inverter charger, 1000 watt windturbine AC-coupled , 1.1 kw high head hydro turbine as a back up generator

Re: What improvement will a MPPT charger provide in my syste

Postby guymadison on Tue May 02, 2017 1:52 pm

No it should work fine, a MPPT is just a DC-DC converter (some sort of buck converter). The power across the output inductor will remain constant, I(in)V(in) = I(out)V(out).

The max current from a panel is defined by your latitude as this defines your average W/m^2 of solar radiation, which is constant for any panel Voltage (see IV curves in pdf).

https://www.wholesalesolar.com/cms/specs-2801912752.pdf

The efficiency is defined by how well the MPPT can convert from 30V to 14V, that's the question.
guymadison
Member
 
Posts: 5
Joined: Tue Apr 18, 2017 4:43 pm
My RE system: Solar World 235 Watt panel / PWM controller / 12v 800 ah battery bank

Re: What improvement will a MPPT charger provide in my syste

Postby EMCF on Tue May 02, 2017 4:36 pm

Don't underestimate the Washington state sunshine :smile: On a good sunny day, you can get around 15A from your 240W solar panel using an MPPT charge controller. And say, the voltage is the same 14V, you have 210 watts there.
EMCF
OutBack Expert
 
Posts: 55
Joined: Thu Jul 21, 2016 10:22 am
My RE system: FX3048, 4 200a batteries, FM60. 3 kw array

Re: What improvement will a MPPT charger provide in my syste

Postby guymadison on Tue May 02, 2017 4:46 pm

EMCF.. that's good news!

I have spent a lot of days like this on the water, but there are plenty of sunny ones also.

(https://drive.google.com/file/d/0B_BQKz ... sp=sharing)

Hence the big panel.. after my alternator blew on two separate trips I decided to go solar.
guymadison
Member
 
Posts: 5
Joined: Tue Apr 18, 2017 4:43 pm
My RE system: Solar World 235 Watt panel / PWM controller / 12v 800 ah battery bank

Re: What improvement will a MPPT charger provide in my syste

Postby billi on Thu May 04, 2017 9:46 am

.... I sometimes get more as the rated watt of my panels (66 Vmp connected to 24 volt battery via FM 80 ) and Ian in Ireland , with a non mppt controller it would be about half the watts
billi
OutBack Guru
 
Posts: 139
Joined: Tue Oct 23, 2007 12:25 pm
Location: ireland
My RE system: 4000 watt PV array , Outback MX 60 and FM80 charge controller ,24 volt 1600 AH Battery @ C5 ,6 Kw Victron inverter charger, 1000 watt windturbine AC-coupled , 1.1 kw high head hydro turbine as a back up generator

Re: What improvement will a MPPT charger provide in my syste

Postby cyrax on Thu May 04, 2017 10:54 pm

Dear All,

How effective are PV Maximizers? especially the one from solaredge and tigo
read online they use MPPT technology.

Please help
cyrax
Member
 
Posts: 14
Joined: Tue Apr 18, 2017 7:24 pm
My RE system: Outback mate, Charge controller, Hub 4 communication manager ,Outback radian series inverter


Return to Marine Applications

Who is online

Users browsing this forum: No registered users and 2 guests

cron