diy solar

diy solar

Prevent the damage on the solar charge Controller

I keep on hearing this. I have multiple charge controls, mppt, pwm, stecca, zantrex, outback, morningstar.

I have left them with pv input on and no battery for a year at a time without damage....... who has had a failure from this.?

Show me the smoking circuit board!
 
kernel said:
I keep on hearing this. I have multiple charge controls, mppt, pwm, stecca, zantrex, outback, morningstar.

I have left them with pv input on and no battery for a year at a time without damage....... who has had a failure from this.?

Show me the smoking circuit board!
Click to expand...
Many manufacturers build their SCC's with battery disconnect in mind & provide the circuitry to accommodate the situation. Alas others do not & state not to connect the solar panels till after a battery connect.
I suspect the battery auto sensing variety is victim due to its strategy. Without a battery to tell it a voltage range it is clueless. I'd suspect SCC's with battery profile settings may well handle a no battery condition because a target voltage is set.
 
SCClockDr said:
Many manufacturers build their SCC's with battery disconnect in mind & provide the circuitry to accommodate the situation. Alas others do not & state not to connect the solar panels till after a battery connect.
I suspect the battery auto sensing variety is victim due to its strategy. Without a battery to tell it a voltage range it is clueless. I'd suspect SCC's with battery profile settings may well handle a no battery condition because a target voltage is set.
Click to expand...
Absolute. And some controllers i have also say to avoid it.

A good example. Morningstar ssmppt15 charger. 12/24v, auto sensing. Never an issue. Added panels to fm60 on 50a breaker (one i had) every once in a while it would open, rare. Never have seen one of mine or one im servicing fail from having the cc breaker tripped accidently or otherwise.
 
kernel said:
Absolute. And some controllers i have also say to avoid it.

A good example. Morningstar ssmppt15 charger. 12/24v, auto sensing. Never an issue. Added panels to fm60 on 50a breaker (one i had) every once in a while it would open, rare. Never have seen one of mine or one im servicing fail from having the cc breaker tripped accidently or otherwise.
Click to expand...
Newbie question here. Are you saying you have a 50a circuit breaker in-line between solar panels & SCC?
 
Time to dump all this rubbish about damaging the MPPT charge controller if, you disconnect the battery before the solar panels, well, in the case of a Victron controller at least.

I couldn't go along with all this DESTRUCTION tosh being banded about so signed up with Victron's Q&A board, and to cut a long story short; I finally got this reply:

"I have got a few more comments back from the Victron MPPT hardware engineering dept:
  • The MPPT should NEVER break due to a battery disconnection. Even if that happens often.
  • If no other load is applied to the DC bus when the battery disconnects, a short voltage overshoot may occur.
  • The overshoot should only last a second or two, if it occurs, then the voltage will stabilise at the voltage set point of the current charge state (eg float, absorption), including temperature compensation.
  • Be careful if also using a remote battery sense option, if the MPPT sees a variation between the battery sense and the voltage at the terminals, it will adjust output to compensate (up to + - 2V)
  • The MPPT is not designed to be a power supply, it is a battery charge controller. So fast load variations may lead to voltage dips and spikes when the battery is disconnected and loads turn on and off. The MPPT output voltage will stabilise when loads are stable though.
  • Using the MPPT with a BMS like this that disconnects the battery is allowed by Victron, from our equipments perspective. In fact our own
  • SuperPack lithium batteries operate on this same principle, where the battery disconnects itself internally to protect itself".
  • So, it would appear that it is perfectly fine to use a common port BMS with a Victron charge controller, that will, in effect, be disconnecting the batteries whilst the panels are still connected.
    People should try a lot harder to get their info from the horses mouth, there's far too much tripe being banded about as fact when it is just a belief or, to put it another way; crap.
  • A link to my Q&A with the Victron community manager:

    Using a SmartSolar MPPT 100|30 with a Common Port BMS and LiFePo4 batteries. - Victron Community

    community.victronenergy.com community.victronenergy.com

Hope this information from Victron engineers (the horses mouth) gets rid of all this panel/controller/battery connection fretting.
 
FrankH said:
Time to dump all this rubbish about damaging the MPPT charge controller if, you disconnect the battery before the solar panels, well, in the case of a Victron controller at least.

I couldn't go along with all this DESTRUCTION tosh being banded about so signed up with Victron's Q&A board, and to cut a long story short; I finally got this reply:

"I have got a few more comments back from the Victron MPPT hardware engineering dept:
  • The MPPT should NEVER break due to a battery disconnection. Even if that happens often.
  • If no other load is applied to the DC bus when the battery disconnects, a short voltage overshoot may occur.
  • The overshoot should only last a second or two, if it occurs, then the voltage will stabilise at the voltage set point of the current charge state (eg float, absorption), including temperature compensation.
  • Be careful if also using a remote battery sense option, if the MPPT sees a variation between the battery sense and the voltage at the terminals, it will adjust output to compensate (up to + - 2V)
  • The MPPT is not designed to be a power supply, it is a battery charge controller. So fast load variations may lead to voltage dips and spikes when the battery is disconnected and loads turn on and off. The MPPT output voltage will stabilise when loads are stable though.
  • Using the MPPT with a BMS like this that disconnects the battery is allowed by Victron, from our equipments perspective. In fact our own
  • SuperPack lithium batteries operate on this same principle, where the battery disconnects itself internally to protect itself".
  • So, it would appear that it is perfectly fine to use a common port BMS with a Victron charge controller, that will, in effect, be disconnecting the batteries whilst the panels are still connected.
    People should try a lot harder to get their info from the horses mouth, there's far too much tripe being banded about as fact when it is just a belief or, to put it another way; crap.
  • A link to my Q&A with the Victron community manager:

    Using a SmartSolar MPPT 100|30 with a Common Port BMS and LiFePo4 batteries. - Victron Community

    community.victronenergy.com community.victronenergy.com

Hope this information from Victron engineers (the horses mouth) gets rid of all this panel/controller/battery connection fretting.
Click to expand...
This most certainly applies to quality brand products which have safeties built in to deal with such but unfortunately, the older PWM SCC's and several of the "value" ones lack such features and could fail. But then that is part of the difference between a $1000 Solar Charge Controller and a $200 one.
 
Steve_S said:
This most certainly applies to quality brand products which have safeties built in to deal with such but unfortunately, the older PWM SCC's and several of the "value" ones lack such features and could fail. But then that is part of the difference between a $1000 Solar Charge Controller and a $200 one.
Click to expand...

My Victron SmartSolar 100|30 was just £185 new, I suppose it would be considered small but, It'll do me. What size controller does a $1000 get you over there?
 
FrankH said:
Hope this information from Victron engineers (the horses mouth) gets rid of all this panel/controller/battery connection fretting.
Click to expand...
I'd love to see @Will Prowse put a variety of SCC units to the test for this cause! This would certainly be a huge advancement to the solar community if this "fail point" could be dispelled.
 
MisterSandals said:
I'd love to see @Will Prowse put a variety of SCC units to the test for this cause! This would certainly be a huge advancement to the solar community if this "fail point" could be dispelled.
Click to expand...

Forget the testing, Will needs to contact the engineers that design these things, no hearsay, no what I feel, what I think mumbo jumbo; It's the people that design this stuff that know the limitations.

Will is on a learning curve here, he was wacking sparks all over the place not so long ago, no thought as to what the EMF could do to semiconductors, and the same sort of thing with relays; just slapping them in with no diode to kill the EMF.

It is his videos that has got me interested in this stuff again but, having worked in the electronics industry for some 40 years as a prototype wireman for engineers; he does make me cringe sometimes.
 
FrankH said:
My Victron SmartSolar 100|30 was just £185 new, I suppose it would be considered small but, It'll do me. What size controller does a $1000 get you over there?
Click to expand...
Thanks. Always best to ask the design engineers for answers to deep esoteric mysteries!

For 1000$ and standard RE solar charge controls flexmax 100. 100A/300v
If someone had 2k$ you could get a morningsrar 600v control with all the whistles.

Ive had a sunsaver 6 more or less operating since 2004. I couldnt tell you the amount of weeks or months it has been connected to a module without a battery....

Stecca 6a with display, 110w array 2-3 months at a time since 2006. Its on a rolling platform and is the driveway shop charger. If there isnt a battery for it to tend........ it does not have one.

Ssmppt 15 223w module does it quite a bit also.

These controllers range in price from 40$ to 225$
 
Ah ok.
FrankH said:
Forget the testing, Will needs to contact the engineers that design these things, no hearsay, no what I feel, what I think mumbo jumbo; It's the people that design this stuff that know the limitations.

Will is on a learning curve here, he was wacking sparks all over the place not so long ago, no thought as to what the EMF could do to semiconductors, and the same sort of thing with relays; just slapping them in with no diode to kill the EMF.

It is his videos that has got me interested in this stuff again but, having worked in the electronics industry for some 40 years as a prototype wireman for engineers; he does make me cringe sometimes.
Click to expand...
Do your own videos on YouTube. We'll watch & learn. WIll has been a blessing for solar dumbass like myself.
 
my MPP manual specifically list the order of connection and warn there will be possible damage if not followed
 
nosys70 said:
my MPP manual specifically list the order of connection and warn there will be possible damage if not followed
Click to expand...

Order of connection is different than damage occurring if battery is disconnected during use. The battery should always be connected first so the CC can sense the correct battery voltage (when the CC can do 12/24/48v). Once it has that it will be saved in the eprom or ram in case of battery disconnect.
 
FrankH said:
Time to dump all this rubbish about damaging the MPPT charge controller if, you disconnect the battery before the solar panels, well, in the case of a Victron controller at least.
Click to expand...
FrankH said:
Forget the testing <snip>
Click to expand...

I went in a completely different direction than @FrankH and tested out my bottom-end Renogy Wanderer 10A PWM SCC (since nobody seems to ever get a response out of Renogy...)

This afternoon I disconnected the battery while my 50W panel was in full sun. No smoke (so I didn't win the @kernel "smoking circuit board" challenge). The cheap PWM didn't care. I left it disconnected for a few minutes then reconnected the battery. Not a problem for the controller.

It's noteworthy that while the manual has three separate warnings about the order of connection (see pages 1,2, & 7), none of them warn that the controller will be damaged. The warnings are safety notifications. Don't worry about the controller, worry about your safety.

Here's the statement on page 1.

1580417716455.png
The page 2 note is as follows:
1580418317238.png
Where WARNING is defined on page 1 as:
1580418390396.png
 
FrankH said:
Forget the testing, Will needs to contact the engineers that design these things, no hearsay, no what I feel, what I think mumbo jumbo; It's the people that design this stuff that know the limitations.

Will is on a learning curve here, he was wacking sparks all over the place not so long ago, no thought as to what the EMF could do to semiconductors, and the same sort of thing with relays; just slapping them in with no diode to kill the EMF.

It is his videos that has got me interested in this stuff again but, having worked in the electronics industry for some 40 years as a prototype wireman for engineers; he does make me cringe sometimes.
Click to expand...
When did I say something based on emotion? I also understand how mppt circuits work. It's a highly sophisticated buck converter, that's all. Nothing fancy.

Also the 12v system "Sparks" are fine. It won't hurt the fets if it's under a certain size. I have verified this with engineers from multiple companies. And on lead acid I could care less. I have a video covering how to connect large inverters safely with LiFePO4, and I follow that procedure every time. What video did I make that made you cringe?

Oh right, the relay. The difference between the one I had in video and what chargery uses is the integrated diode. The polarity should have told me that, ahh well. I added a diagram for the flyback diode, did you see that? Seemed pretty straight forward.

Now I don't use relays at all. I'll probably take that video down. I really liked that video though, it's a pretty easy little system, and diodes are cheap.

Yes I am on a learning curve as is many electrical engineers I know. 40+ years experience is awesome, and most engineers do not have that. That's why I make the videos and the forum. So we can learn. If a video I post has bad information, let me know. I will take it down immediately. If I say something vaguely wrong, I get 100 electrical engineers correcting me instantly. It doesn't happen often but it does happen.
 
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