Prevent the damage on the solar charge Controller

kenkoh

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When do 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.
I can honestly say your videos are the BEST on YouTube.
 

Dakar Dad

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What I do is to interrupt the two ground connections on the solar controller with one of these switches before doing any battery changes or disconnecting the battery from my trailer before anything requiring service.
 

Dakar Dad

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Seriously? I would think having the entire system grounded would make it much safer.
The instructions were so specific about always never letting the battery become disconnected that I put the switch in line to disconnect the panels and battery at the same time using the ground connections.

One time during the day I bumped the main cutoff switch in my trailer and all my electronics were only being powered by my panels.

Everything was making bad sounds but I didn't have anything burn up from it at least.
 

MisterSandals

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to disconnect the panels and battery at the same time using the ground connections.
Are you calling the negative lines "ground connections"?

I think of "grounding" as connecting to the frame of a vehicle or to an actual ground rod for stationary installations. Your SCC probably has a green ground lug (in addition to the positive and negative leads). Quite different things.
 

Dakar Dad

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My controller has positive and negative from the panels, and a positive and negative from the batteries only. I interrupt the negative wires with the switch. :)
 

Will Prowse

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Will,
What prompted your change on this?
Mainly the selection of higher voltage BMS. You can easily use a 100A lifepo4 bms to power a 4800 watt inverter. 100A is a lot. We should redesign the system to work more efficiently instead of using a massive relay. Relay does work well though. I ordered the chargery one and want to see how well it works.
 

Craigmck

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I run a 45a breaker before the charge controller and a 60 a breaker after the controller. That way you can shut down the solar charging before and after the controller. Works for me no problem.
 

FilterGuy

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Mainly the selection of higher voltage BMS. You can easily use a 100A lifepo4 bms to power a 4800 watt inverter. 100A is a lot. We should redesign the system to work more efficiently instead of using a massive relay. Relay does work well though. I ordered the chargery one and want to see how well it works.

I figured that was the reason.... but I never like to make assumptions.

I am trying to find a source for an affordable magnetic latching relay for use with Chargery. This would allow using the relays but only have a few 10s of mA constant draw. See this post where I talk about the idea.
 

Craigmck

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Here is also another situation where solar charge controller can be damaged by the bms shutting down the battery pack while charging for low temperature disconnect. Whenever the BMS disconnects the battery pack for what ever reason, the solar charger is still trying to charge a battery that is not there. Which in turn could fry the solar charge controller. Smart thing would be to install a normally closed relay on the negative side of the input into the solar charge controller. So when the BMS disconnects from the battery bank it also disconnects the the solar charge controller. Using normally closed relays only uses power to disconnect.
 

FilterGuy

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Here is also another situation where solar charge controller can be damaged by the bms shutting down the battery pack while charging for low temperature disconnect. Whenever the BMS disconnects the battery pack for what ever reason, the solar charger is still trying to charge a battery that is not there. Which in turn could fry the solar charge controller. Smart thing would be to install a normally closed relay on the negative side of the input into the solar charge controller. So when the BMS disconnects from the battery bank it also disconnects the the solar charge controller. Using normally closed relays only uses power to disconnect.
If the soar charge controller can not handle a battery disconnect I will not be using it. There is no excuse for a company putting out a design that can not handle this occurrence. (Victron says they *can* handle it).
 

FilterGuy

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Are you calling the negative lines "ground connections"?

I think of "grounding" as connecting to the frame of a vehicle or to an actual ground rod for stationary installations. Your SCC probably has a green ground lug (in addition to the positive and negative leads). Quite different things.
Yup. the term ground is used and abused so many different ways, it is hard to know what someone is saying when they use the term.
 

Craigmck

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If the soar charge controller can not handle a battery disconnect I will not be using it. There is no excuse for a company putting out a design that can not handle this occurrence. (Victron says they *can* handle it).
Problem is most people don't understand what the full function of what a BMS does. They are only seeing the down steam of the bms not the charging source side. No body has talked about what happens when the bms shuts down the battery pack. What can occur when your charging and the bms suddenly shuts down. There are some serious problems that can occur, but there are simply solutions for these design failures.
 

Craigmck

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I'm just understanding myself. From what i have read about solar charge controllers, mfg say you must have a battery connected to the charge controller before turning on the charge controller or you can damage the charge controller. No warranty if you don't before turning on charge controller could cause damage. Saying that, in my opinion the BMS manufacture engineers are only thinking about the safety of battery pack which i understand. But in the big picture we are also concerned about the safety of the battery pack and not having any damage to our expensive solar charge controller. I have read the wiring schematics and can't understand first of all why they would not use normally closed relays to disconnect the loads. There is no power consumption under normal use. Only need 12v to disconnect for how ever short time to figure why a disconnect happened. My second thing is bms do not disconnect the charge load at the solar controller. But just thinking about this you could put the charge disconnect relay before the solar charger controller (input side into controller) and you could accomplish charge disconnect to the battery pack and the charge controller. Kill to birds with one stone. No damage to your charge controller. i'm going to try and see if i can find some normally closed relays and figure out how i can do that with the Chargery bms. Really like this Chargery bms8t 300a bms. All the loads run through the relays which means no big heat running through the bms. good luck, Cheers
 

MisterSandals

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But just thinking about this you could put the charge disconnect relay before the solar charger controller (input side into controller) and you could
This horse was beaten quite a bit here and earlier:
 

durval

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Thanks. Always best to ask the design engineers for answers to deep esoteric mysteries!

I just sent this in an email to EPEver/EPSolar support regarding my Tracer3210AN solar charge controller:
[...] a question has come up re: the EPEver Tracer3210AN solar charge controller, as per its manual (https://www.epsolarpv.com/upload/cert/file/1811/Tracer-AN-SMS-EL-V1.0.pdf):

(a) On printed page 12 (p.17 of the PDF file), it says:​
Connect the system in the order of (1)battery, (2) load, and (3) PV array
[...] and disconnect the system in the reverse order(3)(2)(1).
(b) And right afterwards, on the same page, it says:​
CAUTION: A fuse which current is 1.25 to 2 times the rated current of the
controller, must be installed on the battery side with a distance from the
battery not greater than 150 mm.

This seems contradictory because, if the fuse mentioned in (b) ever blows, battery will be disconnected *wthout* first disconnecting either load or the PV array, contrary to what is recommended in (a).

Our question is: does disconnecting the battery before disconnecting the PV array incurs any risk of damaging the controller? If not, why the recommendation on (a) above?

If/when I receive a response from them, I will post it here.

Cheers,
-- Durval.
 

durval

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If/when I receive a response from them, I will post it here.
And here's their reply:
It has risk but low. User intentionally not disconnect the battery first can void the warranty, but if the charger is damaged just because of the fuse blows has the warranty.
So, according to EPEver, there's a low risk of damaging their controller (at least the Tracer3210AN model), and they will void the warranty if done on purpose (@Will Prowse , looks like they are on to you! :)) but keep honoring it in case of a blown fuse mishap.
 

sunshine

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So, according to EPEver, there's a low risk of damaging their controller
Play safe & follow the manual. No 12 months warranty from here!
Even earth the panels momentarily before connecting like pc repairers do (me when I remember) the common terminals first, and if you can, do the final connection at night.
 
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