MPPT VS PWM

[johnp10]

OK.

Are 13 PWM volts inferior to 13 MPPT volts?

I guess the simple answer is YES if you get more amps with one of them.

Surely usage is coming from the batteries, not the solar controller itself?
Once batteries are topped, they are topped?

Batteries are reading +13v by mid morning next day.

You need to tread your voltage when the solar is still in bed to get an accurate idea of real voltage.

Don't see that.
I check the batteries, they are reading XX, real voltage?
How can it not be?


That said, what's the point of being able to charge the starter battery?

It allows you to start the van when you need to.

Well you did ask

A decent starter battery will start the vehicle without constant top up?

Martin

Thanks for that, Martin, but I still don't get it.

 

[Ivory55]

OK.


Thanks for that, Martin, but I still don't get it.

It must be a lorry driver thing. Ha ha I never understand it all either

 

[Lenny HB]

Are 13 PWM volts inferior to 13 MPPT volts?

Yes, you won't get a PWM charger that does proper 3 stage charging to ensure your batteries are fully charged and you won't get many volts in low light/low sun angles.

​

Batteries are reading +13v by mid morning next day.
As far as I'm concerned, that's it.

13v volts doesn't mean they are charged that is just the solar voltage you are seeing.
To fully charge a battery you need to give it a bulk charge followed by an absorption phase before it drops to a float charge.

My Votronic regulator will charge my Gell batteries to 14.3v, then the absorption phase will hold at 14.3v with reduced current for 4 hours before dropping to a 13.8v float charge.

 

[johnp10]

Yes, you won't get a PWM charger that does proper 3 stage charging to ensure your batteries are fully charged and you won't get many volts in low light/low sun angles.

​

13v volts doesn't mean they are charged that is just the solar voltage you are seeing.

Don't think so, Lenny.
That's the batteries measured from a 12v outlet using a multi meter.

To fully charge a battery you need to give it a bulk charge followed by an absorption phase before it drops to a float charge.

Isn't that how chargers work...or is it?

My Votronic regulator will charge my Gell batteries to 14.3v, then the absorption phase will hold at 14.3v with reduced current for 4 hours before dropping to a 13.8v float charge.

Thanks for your input folks.
Still don't get it, everything works ok, so I'll just carry on in happy, non disadvantaged ignorance.

 

[Lenny HB]

Don't think so, Lenny.
That's the batteries measured from a 12v outlet using a multi meter.

Unless it was dark or you disconnected your solar panels you will be reading the solar voltage as the output of the regulator will be permantly connected to the batteries.

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[johnp10]

Unless it was dark or you disconnected your solar panels you will be reading the solar voltage as the output of the regulator will be permantly connected to the batteries.

Good point.
I'll try the same exercise after dark and /or with panel switched off for curiosity's sake.

I get what I need from the system, so I'm ok with it.

 

[Jim]

I'll try the same exercise after dark and /or with panel switched off for curiosity's sake.

That won't work for me, as soon as the sun goes down my lunar panels kick in

 

[Rob Hammond]

That won't work for me, as soon as the sun goes down my lunar panels kick in

Don’t brag Jim

 

[Reallyretired]

I replaced my pwm controller with mppt so that I could keep everything charged up in the winter. It makes no difference in the summer as the batteries are fully charged pretty much all the time with either controller.

 

[Dazzlin]

Easy, just sit in the dark.

Who said that?

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[Minxy]

That won't work for me, as soon as the sun goes down my lunar panels kick in

... not as good as 'star' solar panels ...

 

[CazPaul]

I replaced my pwm controller with mppt so that I could keep everything charged up in the winter. It makes no difference in the summer as the batteries are fully charged pretty much all the time with either controller.

Winter is when you need solar the most so a wise move that

 

[chaser]

Yes, you won't get a PWM charger that does proper 3 stage charging to ensure your batteries are fully charged and you won't get many volts in low light/low sun angles.

​

13v volts doesn't mean they are charged that is just the solar voltage you are seeing.
To fully charge a battery you need to give it a bulk charge followed by an absorption phase before it drops to a float charge.

My Votronic regulator will charge my Gell batteries to 14.3v, then the absorption phase will hold at 14.3v with reduced current for 4 hours before dropping to a 13.8v float charge.

My Votronic regulator will charge my Gell batteries to 14.3v, then the absorption phase will hold at 14.3v with reduced current for 4 hours before dropping to a 13.8v float charge.[/QUOTE]

funny, thats exactly what my pwm does

 

[Techno]

Maybe but your PWM will switch on and off constantly by the nature of its regulation while the MPPT is on constantly. Up to 30% off hence MPPT delivering more power

 

[raysalaugh]

That won't work for me, as soon as the sun goes down my lunar panels kick in

Wow, I'd be over the moon with them

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[Jim]

... not as good as 'star' solar panels ...

Lunar panels are light years ahead of star panels

 

[chaser]

Maybe but your PWM will switch on and off constantly by the nature of its regulation while the MPPT is on constantly. Up to 30% off hence MPPT delivering more power

if the battery is full, how can anything put anymore into it?

 

[Techno]

If your battery is full that is fine but it has more chance of being full with better charging technology.

This is the insides of a quality Mppt. I dare you to open yours and find more than two bobs worth

 

[Ivory55]

To be fair how many on here would know what they was looking at if they did open it up. Haha

 

[Techno]

Lenny will confirm we have seen high charge amps even in almost foggy conditions. Like I did as pictured in Holland the other year

To be fair how many on here would know what they was looking at if they did open it up. Haha

Fair comment but its not right to claim a PWM can deliver as well as an MPPT it is simply not possible

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[Burgo]

Isn't there another variable in the equation, insofar as to whether the regulator is connected directly to the battery/ies, or connected via an Elektroblock? Just wondering if that could make a difference??

 

[Techno]

Isn't there another variable in the equation, insofar as to whether the regulator is connected directly to the battery/ies, or connected via an Elektroblock? Just wondering if that could make a difference??

No
You have the choice of PWM or MPPT regulators for electro blocs too at very different prices for obvious reasons

 

[Minxy]

If your battery is full that is fine but it has more chance of being full with better charging technology.

This is the insides of a quality Mppt. I dare you to open yours and find more than two bobs worth

OOooooOOOoooOOooooo ... I like the look of that ... powered by 2 doughnuts!!!!

 

[Silver-Fox]

OOooooOOOoooOOooooo ... I like the look of that ... powered by 2 doughnuts!!!!

It’s all the sugar in them

 

[Richard n Ann]

OOooooOOOoooOOooooo ... I like the look of that ... powered by 2 doughnuts!!!!

Toroidal inductor
Sorry

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[chaser]

Toroidal inductor
Sorry

can they do you for that

 

[Minxy]

Nah, definitely doughnuts ...

 

[Guigsy]

My technical understanding of the difference between MPPT vs PWM is (which is probably wrong):

If you don't connect significant load to a solar panel, it's voltage is pretty high (and gets higher as it gets brighter), but as you put load on it and pull more current, the voltage sags down. Voltage x current gives you power.

PWM controllers have a fixed load which they pulse on and off extremely quickly. This is dumped into capacitors to smooth out the power and get it down to the appropriate level to charge your battery. Once light levels get too low, the voltage sag under load gets too much and PWM stops providing juice.

MPPT controllers can actively adjust the load (and still do some PWM and capacitor tricks) on the solar panels. On nice sunny days, they pull the most load they can, just like cheaper PWM controllers. As light levels drop, they reduce the load so the solar panels' voltage doesn't sag as much so there's still a bit of power to be drawn. Basically they have much better efficiency in lower light.

MPPT is a bit like having gears in the van. When it gets steep (lower light), you can change down gears. You don't go as fast, but you still get somewhere. PWM only has a 6th gear.

 

[funflair]

My technical understanding of the difference between MPPT vs PWM is (which is probably wrong):

If you don't connect significant load to a solar panel, it's voltage is pretty high (and gets higher as it gets brighter), but as you put load on it and pull more current, the voltage sags down. Voltage x current gives you power.

PWM controllers have a fixed load which they pulse on and off extremely quickly. This is dumped into capacitors to smooth out the power and get it down to the appropriate level to charge your battery. Once light levels get too low, the voltage sag under load gets too much and PWM stops providing juice. It's a bit light being able to change down gears when it gets steep, you can't go as fast, but it keeps you moving somewhere.

MPPT controllers can actively adjust the load (and still do some PWM and capacitor tricks) on the solar panels. On nice sunny days, they pull the most load they can, just like cheaper PWM controllers. As light levels drop, they reduce the load so the solar panels' voltage doesn't sag as much so there's still a bit of power to be drawn. Basically they have much better efficiency in lower light.

MPPT is a bit like having gears in the van. When it gets steep (lower light), you can change down gears. You don't go as fast, but you still get somewhere. PWM only has a 6th gear.

Well I have not got a clue how accurate that is But I like it all the same

Martin

 

[eddie]

If your battery is full that is fine but it has more chance of being full with better charging technology.

This is the insides of a quality Mppt. I dare you to open yours and find more than two bobs worth

Don’t open the lauded Schaudt

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