Your Charge Controller "Charges" the line between your Battery.

Michael77 said:

Have you used a Non-Programable PWM Charger designed for Lithium Iron Phosphate like the Renogy Wanderer - that has been recommended several times by WIll? With this Solar Charge Controller, you can not program it, and the only way it stops charging is when the battery BMS turns off the charging current and stops accepting charge into the battery.

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No but a quick check indicates that the Wanderer has a voltage setting for several chemistries, which suggests that it is there for a reason, perhaps to prevent overcharging,. The one I looked at had different settings for Gel, Flooded, AGM and Lithium. If those were not voltage settings why would they give you those options?

"or what about a simple wall charger that charges the battery until the batteries BMS kicks in?"
If it is the correct wall charger it outputs the correct voltage for th

"Or, what about the concept of a "Drop In Replacement LIFEP04 Battery?"
What about the concept of a Drop in Replacement Battery?. Most of the ones I have seen suggest a target voltage for charging. I am sure given that they are marketed as drop ins that they are designed to withstand abuse by people who follow any YouTube video.

Michael77 said:

I hate to tell you this, but you are not correct.

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Is that all you know how to say?

Michael77 said:

There are literally dozens, if not hundreds of wall chargers that do not stop charging until the BMS kicks in.

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And IMO they are crap if they are doing that.

Michael77 said:

At this point; if this is not clear to you, I don't know what to tell you.

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Yep, my thoughts exactly,

Michael77 said:

As I already said, the Renogy Wanderer 30 Amp charger designed for LIFEP04 does not cut off the charge current to the battery until the BMS on the battery kicks in.

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No but it has a voltage setting and as that voltage is reached the current will taper until it goes to zero.

Browneye said:

It is generally accepted that your charging termination parameters are set at the charger level so that the BMS does not need to get involved. Using the BMS to do this is considered bad practice. The BMS shut down of current in or out of a lifepo4 bank is considered emergency use or application.

The battery voltage displayed on the SCC is with the charge current added on top of the system or battery voltage level. It is common for it to read a little higher at the SCC. Again, the only way to get a true volts reading on a battery is after resting with no load or charge current. At that point, your SCC and battery should pretty well read the same. With charging current it is going to read higher at both the SCC as well as the actual battery, and any meters you employ. At least that has been my experience.

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The voltage at a battery terminal changes due to battery chemistry during charging and dis charging, all these voltages are “ battery voltages “ , what you are describing is merely the resting or nominal voltage
The terminal voltage is higher during charge due to a combination of load ( battery) equivalent resistance and charger equivalent output resistance , if the battery had zero or little resistance compared to the charger , then the battery is the sole determinant of terminal voltage , if the charger has very low output resistance, compared to the battery ( very unusual , as the charger would have to be enormously powerful ) then the charger is the sole determinant of the battery voltage. , ie the charger , massively powerful can generate any current necessary to achieve any voltage at the battery terminals

Browneye said:

Same for loading a system - an inverter will show a slightly lower battery voltage that the actual battery - but the battery also reads lower than at rest, called load sag.

Once your system is built and you are monitoring loads and charging, and what everything displays, you'll have a lot better feel for how your system is performing.

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Voltage along a wire is the same everywhere except for small changes due to wire resistance, load sag is merely a function that a battery is not a perfect voltage source , ie it has non zero output resistance , some as load current increases that finite battery output resistance causes the voltage to drop slightly.

Again this is still the “ battery voltage “ , it’s just a voltage at that point on the battery response curve.

Ampster said:

No but a quick check indicates that the Wanderer has a voltage setting for several chemistries, which suggests that it is there for a reason, perhaps to prevent overcharging,. The one I looked at had different settings for Gel, Flooded, AGM and Lithium. If those were not voltage settings why would they give you those options?

"or what about a simple wall charger that charges the battery until the batteries BMS kicks in?"
If it is the correct wall charger it outputs the correct voltage for th

"Or, what about the concept of a "Drop In Replacement LIFEP04 Battery?"
What about the concept of a Drop in Replacement Battery?. Most of the ones I have seen suggest a target voltage for charging. I am sure given that they are marketed as drop ins that they are designed to withstand abuse by people who follow any YouTube video.

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I'm begging to like you. I mean, come on, are you trying to find fault and argue with every last thing it say? I'm sure by the end of the day I will have a good handle on your thought process and I will actually be able to communicate with you. lol

This is my old Wanderer I used for 2 years and it worked great. The "Battery Management System" in my battery that can be programmed to disconnect charging at many voltages; from 14.2, 14.6, or even 14v or less, worked great with this non-programmable LIFEP04 rated Solar Charge Controller set to "Blue Li" setting. When the BMS saw the battery was full, it simply stopped accepting charge. Exactly like it is designed to.

Goboatingnow said:

Voltage along a wire is the same everywhere except for small changes due to wire resistance, ....

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He does not seem to be able to grasp this concept. He is claiming a 1V voltage drop, and thinks he does not have a problem. However, as far as I have seen he has not actually measured the voltage with the same meter at both ends, and is going by what the charge controller is reporting. Who knows how well it is calibrated.

Texas-Mark said:

He does not seem to be able to grasp this concept. He is claiming a 1V voltage drop, and thinks he does not have a problem. However, as far as I have seen he has not actually measured the voltage with the same meter at both ends, and is going by what the charge controller is reporting. Who knows how well it is calibrated.

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He’s mixing up panel voltage with charger ouput voltage ,remember this is a cheap and nasty PWM controller , PWM controllers aren’t optimised for lithium anyway. personally , I would only use mppt controllers as they have internal dc dc convertor allowing much better control of ouput settings.

This guy has either discovered he can break the laws of physics , or he’s simply misinformed , I know where my money is.

Texas-Mark said:

However, as far as I have seen he has not actually measured the voltage with a meter at both ends and is going by what the charge controller is reporting.

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Maybe it was on on the other thread that he posted the voltage readings from a multimeter and he reported an almost one volt difference. In other words the charge controller and battery voltages initially reported were corrrect. He also reported that one of the wires was warm which supports the hypothesis that there may be resistance somewhere on that current path which is causing the voltage drop. He has his own theory.

Goboatingnow said:

He’s mixing up panel voltage with charger ouput voltage ,remember this is a cheap and nasty PWM controller

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I looked at the pictures and he is reporting battery voltage of 14.7 but i did notice that the panel voltage was only 15.1 volts. It did say on the screen that it was MPPT but I thought even MPPT need more of a delta between panel voltage and output voltage? I still think there is resistance along the path between the charge controller that is causing the voltage drop.

Ampster said:

No but it has a voltage setting and as that voltage is reached the current will taper until it goes to zero.

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You are so correct. I wasn't using it correctly for 2 years, and that is why I keep using my system and continually getting more and more power out of it, while incrementally upgrading each and every component, because it's all broken and doesn't work, and I have no idea what I am doing and I should just give up and go count grains of sand. I am so happy I found you, you have been the absolute most helpful person on these forums, thank you for pointing out to me how everything I do is wrong and every idea I have is wrong. How would the world get by without you! Thank you so much for your amazing help! All the extra energy and power I am getting free from the sun is an abomination to all the decent and respectable people on this planet. And the hardware I use is working so opposite to how its supposed to, there really should be a war over it. I mean, how can we let it stand that a person can buy and build a DIY Solar System; use it completely incorrectly, and still gain more and more power out of it, we should start taking no only peoples private well water, we should tax their well water, the air, and any power they make from the sun, especially when they are completely inaccurate in everything they do, and still manage to make more and more energy! We should double tax them - hey lets put them in lockdown so they don't spread their craziness... Hell, lets throw them in jail! How dare they use their hardware completely incorrectly and still successfully manage to gain more and more free energy, they could blow up the world with their unsafe practices and contaminate everyone who ever was who every thought about trying to use solar. So, thank you man, thank you - I'm so happy you were so helpful in pointing out to me everything I do is wrong - thanks man! I will make sure to recommend you to all my friends and tell everyone how amazing, smart and brilliant you actually are - heck, you may even qualify to be the president of the USA! Thanks again!

Ampster said:

Maybe it was on on the other thread that he posted the voltage readings from a multimeter and he reported an almost one volt difference. In other words the charge controller and battery voltages initially reported were corrrect. He also reported that one of the wires was warm which supports the hypothesis that there may be resistance somewhere on that current path which is causing the voltage drop. He has his own theory.

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I must have missed that. I wanted to see actual pictures of the readings. And yes, if there actually is a 1V drop (with a warm cable as validation) that is proof he has a resistance issue either due to undersized cables, or poor connections somewhere. It really is that simple.

Michael77 said:

You are so correct. I wasn't using it correctly for 2 years, and that is why I keep using my system and continually getting more and more power out of it, while incrementally upgrading each and every component, because it's all broken and doesn't work, and I have no idea what I am doing and I should just give up and go count grains of sand. I am so happy I found you, you have been the absolute most helpful person on these forums, thank you for pointing out to me how everything I do is wrong and every idea I have is wrong. How would the world get by without you! Thank you so much for your amazing help! All the extra energy and power I am getting free from the sun is an abomination to all the decent and respectable people on this planet.

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Famously “ you canna change the laws of physics

Michael77 said:

And the hardware I use is working so opposite to how its supposed to,

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You have not demonstrated that , either you have a wiring fault , or mis understanding the whole thing

Michael77 said:

there really should be a war over it. I mean, how can we let it stand that a person can buy and build a DIY Solar System; use it completely incorrectly, and still gain more and more power out of it,

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Your not getting more power , it can only give you what’s it’s rated for

Michael77 said:

we should start taking no only peoples private well water, we should tax their well water, the air, and any power they make from the sun, especially when they are completely inaccurate in everything they do, and still manage to make more and more energy! We should double tax them - hey lets put them in lockdown so they don't spread their craziness...

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The last line has certain benefits , I’ll give you that.

Michael77 said:

Hell, lets throw them in jail! How dare they use their hardware completely incorrectly and still successfully manage to gain more and more free energy,

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There’s loads of people who believe an election was stolen , belief doesnt make things true however

Michael77 said:

they could blow up the world with their unsafe practices and contaminate everyone who ever was who every thought about trying to use solar. So, thank you man, thank you - I'm so happy you were so helpful in pointing out to me everything I do is wrong - thanks man! I will make sure to recommend you to all my friends and tell everyone how amazing, smart and brilliant you actually are - heck, you may even qualify to be the president of the USA! Thanks again!

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Texas-Mark said:

I must have missed that. I wanted to see actual pictures of the readings. And yes, if there actually is a 1V drop (with a warm cable as validation) that is proof he has a resistance issue either due to undersized cables, or poor connections somewhere. It really is that simple.

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Well, I just ordered 3' 6AWG Silicone Tined High Amp Wire. We will see.. I know for sure there is some resistance form the wire. But as someone (Browneye) stated in the comments above;

"The battery voltage displayed on the SCC is with the charge current added on top of the system or battery voltage level. It is common for it to read a little higher at the SCC. Again, the only way to get a true volts reading on a battery is after resting with no load or charge current. At that point, your SCC and battery should pretty well read the same. With charging current it is going to read higher at both the SCC as well as the actual battery, and any meters you employ. At least that has been my experience."

Please look at the pick in the the original top post, and these are the pics of the actual hardware - will take more pics once I swap out the 3' 8 AWG with the 3' 6 AWG wires.

Texas-Mark said:

And yes, if there actually is a 1V drop (with a warm cable as validation) that is proof he has a resistance issue either due to undersized cables, or poor connections somewhere. It really is that simple.

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I guess it all depends on where you are standing? He thinks he has found some magic way to get more "juice" out of his system with no data to support that notion except an anonymous YouTube video when in fact some of the energy from the charge controller is probably being dissipated as heat and never making it to the batteries. i suggested a load test to see if the voltage drop is symmetrical. In the meantime he has ordered bigger wires.
To be perfectly clear I am not running for President of the USA and if nominated I will respectfully decline.

None of your pictures confirms anything your saying , if you have excessive voltsage drop along the cable , that’s needs to be fixed , voltage drop shouldn’t exceed 1% , ie at nominal 12v , that’s 0.12V

Again other then wire resistance issues
the voltage is the same everywhere on a wire , that’s just conductor physics.

Goboatingnow said:

None of your pictures confirms anything your saying , if you have excessive voltsage drop along the cable , that’s needs to be fixed , voltage drop shouldn’t exceed 1% , ie at nominal 12v , that’s 0.12V

Again other then wire resistance issues
the voltage is the same everywhere on a wire , that’s just conductor physics.

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Okay. I got what you are saying, and I see the theory you are invoking, and I essentially agree with it. Wires are not "HOT" they are warm. There is no doubt there is some resistance.

What are your thoughts on this statement by Browneye

"The battery voltage displayed on the SCC is with the charge current added on top of the system or battery voltage level. It is common for it to read a little higher at the SCC. Again, the only way to get a true volts reading on a battery is after resting with no load or charge current. At that point, your SCC and battery should pretty well read the same. With charging current it is going to read higher at both the SCC as well as the actual battery, and any meters you employ. At least that has been my experience."

Michael77 said:

I know for sure there is some resistance form the wire.

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Yes, enough resistance to create a 1V drop. And it may not be just because of the cable. It could easily be the connectors (bad crimps or corrosion in the lug barrel).

Michael77 said:

Okay. I got what you are saying, and I see the theory you are invoking,

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It is not a theory, it is Ohm's Law (R=E/I)

Michael77 said:

What are your thoughts on this statement by Browneye

"The battery voltage displayed on the SCC is with the charge current added on top of the system or battery voltage level. It is common for it to read a little higher at the SCC.

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A "little,", as in the 0.12V mentioned above.

Goboatingnow said:

None of your pictures confirms anything your saying , if you have excessive voltsage drop along the cable , that’s needs to be fixed , voltage drop shouldn’t exceed 1% , ie at nominal 12v , that’s 0.12V

Again other then wire resistance issues
the voltage is the same everywhere on a wire , that’s just conductor physics.

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One quick voltage drop test I learned when I was an automotive technician is to put the positive wire of your multimeter on one end of a cable run (closer to positive source), and put the negative multimeter lead on the other end of the cable run (closer to the negative source) and say you read some voltage like .712v there (just example), then that is voltage drop (because it shows the cable is acting like a resistor, a load, a light bulb, whatever metaphor). Also if you increase the amperage running across the wire, the voltage drop can increase... And even notice the cable get hot.

When both of my Victron chargers are running at 100a each (peaked), both sets of wires get hot. I'm using the largest cable that will fit into the Victron SCC battery bank lugs...

Samsonite801 said:

...put the positive wire of your multimeter on one end of a cable run (closer to positive source), and put the negative multimeter lead on the other end of the cable run...

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Yep, that is the easiest way if the two ends are not farther apart than the length of the meter leads.

Samsonite801 said:

One quick voltage drop test I learned when I was an automotive technician is to put the positive wire of your multimeter on one end of a cable run (closer to positive source), and put the negative multimeter lead on the other end of the cable run (closer to the negative source) and say you read some voltage like .712v there (just example), then that is voltage drop (because it shows the cable is acting like a resistor, a load, a light bulb, whatever metaphor). Also if you increase the amperage running across the wire, the voltage drop can increase... And even notice the cable get hot.

When both of my Victron chargers are running at 100a each (peaked), both sets wires get hot. I'm using the largest cable that will fit into the Victron SCC battery bank lugs...

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Nothing should get hot ! , 5 degree rise over ambient is typically acceptable, voltage drops should not exceed 1% in proper speced systems.

If the OP is seeing 1v or more drops at 30 A , that’s 30 watts is being wasted as a space heater

Samsonite801 said:

One quick voltage drop test I learned when I was an automotive technician is to put the positive wire of your multimeter on one end of a cable run (closer to positive source), and put the negative multimeter lead on the other end of the cable run (closer to the negative source)

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That would be an easy test for @Michael77 to do.

Goboatingnow said:

Nothing should get hot ! , 5 degree rise over ambient is typically acceptable, voltage drops should not exceed 1% in proper speced systems.

If the OP is seeing 1v or more drops at 30 A , that’s 30 watts is being wasted as a space heater

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Well tell Victron to put larger connector lugs on their 250|100 (I think they are 2 AWG), because when I'm running the AC all day, both of those babies are pegged at 100a each, and even the inverter wire with 4/0 gets warm too. Of course the temps are still under what the wire is rated at so I'm not worried.

Not to mention, both of the Victrons get hot enough to almost BBQ off of, so I put a 12v RV dashboard mount type fan down there blowing on them during the Sun harvest so they are not as warm to the touch. Turn the fan off at night hehe..

Goboatingnow said:

Nothing should get hot ! , 5 degree rise over ambient is typically acceptable, voltage drops should not exceed 1% in proper speced systems.

If the OP is seeing 1v or more drops at 30 A , that’s 30 watts is being wasted as a space heater

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While I agree that nothing should get hotter then a couple degrees above ambient, I have a couple questions.

What is the rated capacity of 3 feet of 8 gauge AWG wire. Is it 50 Amps?

And what about cable that is rated to get hot like "Silicone Tinned Copper that is designed to Withstand Temperature 150°C-200°C" is that wire any good?