How pass-through charging work?

[pirron]

I'm not sure if I'm not confusing Hybrid Inverter with pass-through charging. I don't quite know how to search for this online.

I would like to know how in an off-grid solar system current from the solar panels is distributed between batteries and appliances in real-time. What I mean by that is, what is the component that is responsible for which percentage of input power will go to the battery and which to the appliances and how does it do it? The power output of the solar panels is variable so is the power draw of the appliances. I'm guessing that most sophisticated systems have the ability to balance these in real-time.

Can someone point me to the literature explaining this? I don't know what combination of search words to use.

 

[BentleyJ]

MPP LV6548 charging

I have 4 lv6548 inverters, and I'm currently trying to learn how to set up the first 2 in a temporary fashion at my current home, before I take them and my 64 CATL lifepo4 cells to my off grid build site with no internet or cell service. I have charged and discharged my cells a couple cycles now...

diysolarforum.com

Link to a recent thread where this was discussed fairly well.

 

[pirron]

MPP LV6548 charging

I have 4 lv6548 inverters, and I'm currently trying to learn how to set up the first 2 in a temporary fashion at my current home, before I take them and my 64 CATL lifepo4 cells to my off grid build site with no internet or cell service. I have charged and discharged my cells a couple cycles now...

diysolarforum.com

Link to a recent thread where this was discussed fairly well.

I just started to learn about solar recently. The technical lvl of that post is above me.

All I got from it is that an additional battery charger between All In One Inverter and the batteries will enable dynamic use of a battery depending on the total Input/Output power balance fluctuations of the whole system.
I will look into that. Thx!

 

[HRTKD]

I can't speak to the all-in-one device as I have separate components in my system.

Let's say the PV and solar charge controller are producing 1000 watts.
1. You have a 12 volt device that is on and draws 300 watts. That leaves 700 watts that can go to charge the battery.
2. You have a 12 volt device that is on and draws 1200 watts. That leaves 0 watts that can go to charge the battery and in fact the battery is supplying the remaining 200 watts that the the solar charge controller isn't.

 

[Ampster]

All I got from it is that an additional battery charger between All In One Inverter and the batteries will enable dynamic use of a battery depending on the total Input/Output power balance fluctuations of the whole system.

I have an All In One and do not have an additional battery charger. As far as I can tell my battery is used dynamically depending on settings and power needs. Mine works like @HRTKD described. Is that what you mean? If not, can you simplify that statement, or give an example?

 

[Steve_S]

It does depend on the hardware.
I use a Samlex Inverter/Charger not an AIO. The EVO's are a pretty advanced & highly programmable type and in my case even has Dual AC Input (Gen & Grid if wanted). I do charge my battery bank occasionally with it usually pushing 75A at the battery bank.

Case scenario:
Charge is going into the battery bank at 75A, no solar input from Midnite Classic SCC.
Minus the slight bit of overhead (Samlex EVO is 92% Efficient) the balance goes to battery.
If all of a sudden I have a 50A Load, the Amperage will divert from the AC Input from Generator while providing the 25A Balance to the bank.
As soon as load ends it reverts to Battey Bank.
*NOTE* Samlex inverter programming allows to set a Max Draw Limit from external sources, so you can use a smaller genny that only outputs 120V/15A or 120V/30A or 240V/50A (pending on model) of the inverter, this is factored for passthrough handling.
Now if the Battery Bank is near full and only taking say 15A and a Load Hits of 50A, the genset will provide that without drawing from the battery at all. But if a 100A Load Hits the genset will deliver what it is limited to and the balance is pulled from the battery bank, after which the genset will step up amps and top off batteries as required.

A few GOTCHAS !
!!! An Inverter/Charger or AIO will NOT CHANGE THE SINE WAVE or FREQUENCY!
If your genset is a Mod-Sine basic construction generator then you will get AC ModSine pushed through your system.
If your genset is an Pure-Sine Inverter Generator then you will get Pure-Sine pushed through the system.
North America the Frequency is 60Hz. Pure Sine inverters will output 60Hz +/- 1Hz variable (normal) While a ModSine construction generator can float from 57-63 Hz (sometimes more) and its voltage will also float 118-122V which is NOT Unusual.

When anything deviates from 60Hz, you will see it affect lights & electronics, digital clocks will either speedup or slow down. If running a ModSine Genset, you will also notice the Fridge Motor / Compressor will be louder, same for Air Con and even your well pump will be adversely affected.

 

[MichaelK]

It does depend on the hardware.

If your genset is a Mod-Sine basic construction generator then you will get AC ModSine pushed through your system.
If your genset is an Pure-Sine Inverter Generator then you will get Pure-Sine pushed through the system.

When anything deviates from 60Hz, you will see it affect lights & electronics, digital clocks will either speedup or slow down. If running a ModSine Genset, you will also notice the Fridge Motor / Compressor will be louder, same for Air Con and even your well pump will be adversely affected.

Steve, a question for you. If a generator works by an engine spinning a shaft that rotates in a stator, and generates the electrical current, how can it be anything but sine-wave. I could understand a poorly tuned motor suttering, and producing distortion, but wouldn't the wave always be more or less sine? Is it downstream electronics trying to modulate the current that's being produced?

 

[Steve_S]

The motor is moot, it's the electronics attached to that motor which outputs the power is where all the Magic Happens.
My own Construction Generators current & previous have all been mod sine, they all float on frequency & voltage relative to load and temperatures --- This is true at -30C or +30C temp. My Inverter Gensets always stay at 60hz and will only deviate 2.0V in either direction pending on load. I have also observed that they do NOT vary much regardless of temp BUT you do have to let them warm up a bit before adding load in extreme cold.

 

[pirron]

I have an All In One and do not have an additional battery charger. As far as I can tell my battery is used dynamically depending on settings and power needs. Mine works like @HRTKD described. Is that what you mean? If not, can you simplify that statement, or give an example?

I've red a bit more on it recently and I think I'm getting it now. For some reason I thought it's a device in the system that allocates current dynamically depending on where it is needed.

If my understanding is correct now, it's just a matter of voltage finding a path of least resistance. So the DC current flowing from a charge controller is connected with the inverter and a battery bank. The "vacuum" so to speak created by either the charge level of the battery or the operation of the inverter (ON/OFF or just the level of power draw in ON state) will determine how the current will find its path. In other words, it's just the physics of how electricity behaves and not some dedicated device that actively manipulates the process as I assumed.

I hope it's clearer what I meant now. I might be completely off with my new understanding of course.
Any comments are very much appreciated.

 

[Bud Martin]

The current will flow easily through the least resistance but it will still flow through the higher resistance connected in parallel with the least resistance but at less current.

 

[Ampster]

If my understanding is correct now, it's just a matter of voltage finding a path of least resistance. So the DC current flowing from a charge controller is connected with the inverter and a battery bank. The "vacuum" so to speak created by either the charge level of the battery or the operation of the inverter (ON/OFF or just the level of power draw in ON state) will determine how the current will find its path. In other words, it's just the physics of how electricity behaves and not some dedicated device that actively manipulates the process as I assumed.

It makes sense when you describe it it terms of physics. The term vacuum describes how the loads from the inverter and battery charger pull current from the source.