Power sources and Lithiums

[MountainBiker]

Hi folk! First thread. I have a custom conversion Sprinter Van with a 200 watts of solar! Love the Van and mountain biking it enables me to do!

I read a thread that was started by "Snoobler" where he described that you can have many powers source powering your battery bank. One of the "rules" was that for AC->DC you would need an AC-DC power supply (i get this) and the DC power output would need to go through a MPPT solar controller with voltage/current consistent with a solar panel. My current setup has 2 lead acid 6v batteries that I want to switch to 2*12v Lithiums with BMS. My sources are....

1. an MPPT charge controller from Renogy for Solar that has a lithium setting. Its a 30amp charger.
2. an NOCO Genius Smart battery charger for AC -> DC. Currently, this doesn't go through the MPPT charge controller from Renogy. Does it need to go through the Renogy Charge controller or is this NOCO genius "good" enough? It has a lithium battery setting too.
3. Vehicle battery charge (source 3) when the vehicle is running using a Renogy DC-DC Battery charger (40amp) with MPPT. Lithium setting here too.

Second question! Another rule was that the sum of all "charge currents do not exceed the recommended max charge current of the battery bank". What does this mean in my case? Ill have two 100ah battteries in parralel so the "bank" is a total of 200ah. Im am also aware that the "best" charge current for battery longevity (sum of all charge currents) is not necessarily the maximum is it?

 

[sunshine_eggo]

Hi folk! First thread. I have a custom conversion Sprinter Van with a 200 watts of solar! Love the Van and mountain biking it enables me to do!

I read a thread that was started by "Snoobler" where he described that you can have many powers source powering your battery bank. One of the "rules" was that for AC->DC you would need an AC-DC power supply (i get this) and the DC power output would need to go through a MPPT solar controller with voltage/current consistent with a solar panel. My current setup has 2 lead acid 6v batteries that I want to switch to 2*12v Lithiums with BMS. My sources are....

1. an MPPT charge controller from Renogy for Solar that has a lithium setting. Its a 30amp charger.
2. an NOCO Genius Smart battery charger for AC -> DC. Currently, this doesn't go through the MPPT charge controller from Renogy. Does it need to go through the Renogy Charge controller or is this NOCO genius "good" enough? It has a lithium battery setting too.
3. Vehicle battery charge (source 3) when the vehicle is running using a Renogy DC-DC Battery charger (40amp) with MPPT. Lithium setting here too.

Second question! Another rule was that the sum of all "charge currents do not exceed the recommended max charge current of the battery bank". What does this mean in my case? Ill have two 100ah battteries in parralel so the "bank" is a total of 200ah. Im am also aware that the "best" charge current for battery longevity (sum of all charge currents) is not necessarily the maximum is it?

@snoobler is a dick.

This one?

Charging from multiple sources

One can have as many independent charging sources running concurrently as they like provided they are programmed properly for the voltage of one's battery bank. Examples (some or all at once, even multiples of a single type, different brands, etc.): Solar PV via MPPT Solar PV via PWM AC-DC...

diysolarforum.com

Not sure what you mean about going through an MPPT. Powering an MPPT with a DC source is an option, but it's not mandatory. There are dedicated AC-DC chargers.

Q1) You CAN'T put the Noco through a MPPT. It must be connected to the battery. The Noco needs to see a battery voltage to work, and the MPPT does not supply a voltage to the PV input terminals.

Q2) Your batteries have a maximum rate of charge. The sum of all applied chargers should not exceed this amount. If you exceed this value, they can still be connected, you just don't want to have them all energized at the same time.

Lead acid is typically 0.1-0.3C or 10-30A for a 100Ah battery.

LFP is typically 0.5C or 50A for a 100Ah battery. However, many LFP batteries recommend a lower charge rate of 0.2C for longevity.

In the case of your 200Ah of LPF, you would not want to exceed 100A of "fast" charging (using a generator or on a time budget) or 40A for a more mellow charge rate.

Placement of charge leads is important. If you have a shunt, all chargers should be attached to the system side of the shunt. If you attach directly to the battery, the shunt won't see that input, and the state of charge will be wrong. If you don't have a shunt, whatever makes sense.

 

[MountainBiker]

This was his comment in relationship to power sources... "AC-DC input via MPPT (using a AC to DC power supply feeding an MPPT solar controller with voltage/current consistent with a solar panel)".

I read this to mean that the AC-DC "output" needs to feed into the MPPT solar controller...presumably along with the power from the panels. My interpretation was that the MPPT charge controller was going to provide control that would be required. But I understand you have addressed this in your point 1 above. Thank you.

Can I consider my battery bank to be 200ah for setting my max charge rather than 100ah because they are in parallel or is max charge set to the ah of a single battery regardless?

Thank you!

 

[timselectric]

Does it need to go through the Renogy Charge controller

Nope

 

[MountainBiker]

Awesome, ty. I don't have a shunt but can add one in. Below you can see the NOCO and negative terminal...the positive one is a bit to the left under the solar charge controller (second pic)

 

[sunshine_eggo]

This was his comment in relationship to power sources... "AC-DC input via MPPT (using a AC to DC power supply feeding an MPPT solar controller with voltage/current consistent with a solar panel)".

I read this to mean that the AC-DC "output" needs to feed into the MPPT solar controller...presumably along with the power from the panels. My interpretation was that the MPPT charge controller was going to provide control that would be required. But I understand you have addressed this in your point 1 above. Thank you.

That was just an example option as it's been discussed as a possibility on this forum, i.e., if you have a benchtop power supply, you could feed a MPPT PV circuit with it.

Can I consider my battery bank to be 200ah for setting my max charge rather than 100ah because they are in parallel or is max charge set to the ah of a single battery regardless?

Yes. I hope you gleaned that from the example currents I gave you based on a 200Ah battery.

Awesome, ty. I don't have a shunt but can add one in. Below you can see the NOCO and negative terminal...the positive one is a bit to the left under the solar charge controller (second pic)

The shunt would be the ONLY thing directly attached to the battery negative. All other (-) wires would be connected somewhere on the other side of the shunt.

 

[MountainBiker]

Yes. I hope you gleaned that from the example currents I gave you based on a 200Ah battery.

Indeed I saw that. Just wanted to be sure that I can think of my battery bank as 200ah..Thx for this.

The shunt would be the ONLY thing directly attached to the battery negative. All other (-) wires would be connected somewhere on the other side of the shunt.

Thank you. I did understand from your post and a quick scan of the internet to figure out what a shunt does.