24v PV/12v LiPo4

[BoonieBasher]

New to me pickup camper with PO installed solar.
60x30" PV.
190w 24v (I just discovered)
3 12v wet 100ah LA 5yr old and DOA
Intend to replace with 2 100ah LiPo
Renogy Rover 40a MPPT. 100vdc max in.

Any compatibility issues between the SCC and lithium with 24v?
I'm guessing the batteries don't care after the MPPT has massaged the voltage. The online Renogy manual shows how to switch to Li mode.

Guess I'm just looking for confirmation.

Great resource here; I'll continue perusing.

 

[sunshine_eggo]

Are you asking if you can use a 24V panel on a MPPT for 12V batteries? Yes. That's their point. They allow the panels to operate at their Vmp value rather than forcing them down to battery voltage like a PWM. They're a fancy DC-DC converter with an algorithm to find the max power (best combo of voltage * current).

Now... you said you have a 24V panel...

A "24V" panel has a Voc of about 45V and a Vmp of about 37V.

Does your panel have a Voc of about 24V? If so, that's a "12V" panel.

"12V" and "24" are in quotes because they are the panels you need to use with a given system voltage to properly charge them on a PWM controller.

 

[BoonieBasher]

Are you asking if you can use a 24V panel on a MPPT for 12V batteries? Yes. That's their point. They allow the panels to operate at their Vmp value rather than forcing them down to battery voltage like a PWM. They're a fancy DC-DC converter with an algorithm to find the max power (best combo of voltage * current).

Now... you said you have a 24V panel...

A "24V" panel has a Voc of about 45V and a Vmp of about 37V.

Does your panel have a Voc of about 24V? If so, that's a "12V" panel.

"12V" and "24" are in quotes because they are the panels you need to use with a given system voltage to properly charge them on a PWM controller.

I should have included the data. It is indeed a 24v panel. I also looked it up via manufacturer.

Ameresco Solar
Model: 190J
p/n: 5213.8103

Voc 45.3
Vmp 37.6
Imp 5.06
Isc 5.56


I can run the single 190w panel to see how I do with my 200ah lithium and my minimal requirements (not even an inverter), LED lights, water pump, furnace fan and enough 12v for LP fridge ignition. Camper jacks of course.
Have found this 24v panel that I'd consider if I needed to double my solar but not 100% sure it's compatible. I'm assuming a parallel connection would be appropriate.

Renogy 200W ShadowFlux Anti-shading N-Type Solar Panel

The Renogy 200W ShadowFlux Solar Panel is a revolutionary off-grid power solution. It is 7% smaller and 10% lighter than traditional rigid solar panels. Featuring N-Type solar cells and 16BB technology.

www.renogy.com

Thanks.

 

[sunshine_eggo]

I should have included the data. It is indeed a 24v panel. I also looked it up via manufacturer.

Ameresco Solar
Model: 190J
p/n: 5213.8103

Voc 45.3
Vmp 37.6
Imp 5.06
Isc 5.56

Yep!

I can run the single 190w panel to see how I do with my 200ah lithium and my minimal requirements (not even an inverter), LED lights, water pump, furnace fan and enough 12v for LP fridge ignition. Camper jacks of course.

190W flat on a roof will perform poorly in winter due to the sun angle, but during Summer, you'll likely get close to 1kWh out of it. Probably .3-.4kWh in winter.

Have found this 24v panel that I'd consider if I needed to double my solar but not 100% sure it's compatible. I'm assuming a parallel connection would be appropriate.

Renogy 200W ShadowFlux Anti-shading N-Type Solar Panel

The Renogy 200W ShadowFlux Solar Panel is a revolutionary off-grid power solution. It is 7% smaller and 10% lighter than traditional rigid solar panels. Featuring N-Type solar cells and 16BB technology.

www.renogy.com

That's not a 24V panel. That's a 52 cell panel ("24V" are 72 cells). They're fairly new to the market, and their results do seem fairly impressive especially for partial shading. If you do not have significant shading issues, they're definitely not worth the premium.

Parallel wouldn't be great due to the Vmp of the 190W being above the Voc of the 200W, but series would work okay. Unfortunately, it would force the 200W panel to operate at 5.05A instead of 6.38A turning it into a 160W panel.

 

[BoonieBasher]

Yep!



190W flat on a roof will perform poorly in winter due to the sun angle, but during Summer, you'll likely get close to 1kWh out of it. Probably .3-.4kWh in winter.

Don't camp in Winter so unless I wander off to AZ or such the LiPo will likely be stored in the house. Also, planning on adjustable mounting brackets to optimize in Montana or during hunting season in NENV.

That's not a 24V panel. That's a 52 cell panel ("24V" are 72 cells).

Aha. Just shows I don't know what I don't know.

They're fairly new to the market, and their results do seem fairly impressive especially for partial shading. If you do not have significant shading issues, they're definitely not worth the premium.

Maybe if I was starting from scratch. Shading is an issue since I camp in the trees most often. Work around is the generator.

Parallel wouldn't be great due to the Vmp of the 190W being above the Voc of the 200W, but series would work okay. Unfortunately, it would force the 200W panel to operate at 5.05A instead of 6.38A turning it into a 160W panel.

So, if I want to double up on panels, I'll need to find one much closer in specs to the existing.
I'm guessing I'll be fine with the 190J that's on there.

Just got an email reply from Ameresco. (I'm not willing to pay that kind of coin for my limited use.). If price is an indicator (right!?) the panel on the camper is a good one.

"I received your quote request for x1 190J-V, I’m happy to assist.
We no longer have 190J-V, but we do have the following, both are 24V:
180J-V- $355.00/ea.
200J-V- $377.00/ea."

Thanks a bunch for the feedback/education.

 

[sunshine_eggo]

Don't camp in Winter so unless I wander off to AZ or such the LiPo will likely be stored in the house. Also, planning on adjustable mounting brackets to optimize in Montana or during hunting season in NENV.

AZ is a great place for winter.

Aha. Just shows I don't know what I don't know.

Every day for me.

Maybe if I was starting from scratch. Shading is an issue since I camp in the trees most often. Work around is the generator.

Maybe so. They behave as though they have bypass diodes on every cell, so if 15% of the cells get shaded, you lose about 15% of the power. With traditional 2-3 bypass diode panels, you can cut the power from a panel to 0 by shading the bottom row of cells when standing in portrait orientation.

So, if I want to double up on panels, I'll need to find one much closer in specs to the existing.
I'm guessing I'll be fine with the 190J that's on there.

Those voltage numbers are very common for 24V panels and should be pretty easy to match.

Just got an email reply from Ameresco. (I'm not willing to pay that kind of coin for my limited use.). If price is an indicator (right!?) the panel on the camper is a good one.

"I received your quote request for x1 190J-V, I’m happy to assist.
We no longer have 190J-V, but we do have the following, both are 24V:
180J-V- $355.00/ea.
200J-V- $377.00/ea."

Victron generator auto-start

Thanks a bunch for the feedback/education.

 

[BoonieBasher]

By my count on Rich Solar website photo, this panel is 64 cells (16 x 4) but listed at 24v? Am I overthinking or overlooking?
Wondering if the specs on this are 'close enough' to my existing? I'll put 190J specs in (parenthesis) adjacent to Rich's.
I do appreciate your patience.

MEGA 200 MAX​

200W 24V SOLAR PANEL​

• Maximum Power (Pmax)
  200W (190W)
• Maximum Power Voltage (Vmp)
  36.3V (37.6V)
• Maximum Power Current (Imp)
  5.51A (5.06A)
• Open Circuit Voltage (Voc)
  43.5V (45.3V)
• Short Circuit Current (Isc)
  5.93A (5.56A)

 

[sunshine_eggo]

By my count on Rich Solar website photo, this panel is 64 cells (16 x 4) but listed at 24v? Am I overthinking or overlooking?
Wondering if the specs on this are 'close enough' to my existing? I'll put 190J specs in (parenthesis) adjacent to Rich's.
I do appreciate your patience.

MEGA 200 MAX​

200W 24V SOLAR PANEL​

• Maximum Power (Pmax)
  200W (190W)
• Maximum Power Voltage (Vmp)
  36.3V (37.6V)
• Maximum Power Current (Imp)
  5.51A (5.06A)
• Open Circuit Voltage (Voc)
  43.5V (45.3V)
• Short Circuit Current (Isc)
  5.93A (5.56A)

Not all solar cells are the same. Historically, a single cell gets you about 0.5-0.6Vmp, with closer to 0.5V being common. Some manufacturers seem to be moving to the higher half of that range.

If the ratings match up, a slight cell count discrepancy isn't an issue.

 

[BoonieBasher]

Are those specs close enough?

 

[sunshine_eggo]

Are those specs close enough?

Very. I use 10% on Vmp as a rule of thumb. You're way closer than that.

 

[BoonieBasher]

Nice. Not only affirmative but information for 'why' going forward. Love me some 'rule of thumb'.

Thanks.

 

[HRTKD]

By my count on Rich Solar website photo, this panel is 64 cells (16 x 4) but listed at 24v? Am I overthinking or overlooking?
Wondering if the specs on this are 'close enough' to my existing? I'll put 190J specs in (parenthesis) adjacent to Rich's.
I do appreciate your patience.

MEGA 200 MAX​

200W 24V SOLAR PANEL​

• Maximum Power (Pmax)
  200W (190W)
• Maximum Power Voltage (Vmp)
  36.3V (37.6V)
• Maximum Power Current (Imp)
  5.51A (5.06A)
• Open Circuit Voltage (Voc)
  43.5V (45.3V)
• Short Circuit Current (Isc)
  5.93A (5.56A)

As @sunshine_eggo has said more than one way, don't worry about 12v/24v panels. That's more of a marketing label. Focus on the Voc to determine what solar charge controller to pair with your panels.

One of the better tools available to help match PV to MPPT is the Victron MPPT Calculator.

While you can match the panel, don't discard the idea of replacing the panel. The smaller size panels can be rather expensive, especially when yo add shipping, which is always a crap-shoot with PV. I bought residential size panels locally. You're not close to a GreenTechRenewables.com office. That's where I bought mine and it was easy and cheaper than buying online.

 

[BoonieBasher]

As @sunshine_eggo has said more than one way, don't worry about 12v/24v panels. That's more of a marketing label. Focus on the Voc to determine what solar charge controller to pair with your panels.

One of the better tools available to help match PV to MPPT is the Victron MPPT Calculator.

While you can match the panel, don't discard the idea of replacing the panel. The smaller size panels can be rather expensive, especially when yo add shipping, which is always a crap-shoot with PV. I bought residential size panels locally.

You're not close to a GreenTechRenewables.com office. That's where I bought mine and it was easy and cheaper than buying online.

GTR is in W. Valley, UT (also, Provo, Pocatello, and Boise) but the best he could do is 400W bi-facial. Killer price at $325 for 2 (pickup). I might call the others. So far nothing compatible from GTR (guess I'll get on the phone).
I had considered those for my 5th Wheel - another thread so trying to stay on topic on each.

Plan for the Lance is to get the panel off the camper and outside to test with my new PowerWerx and take it from there. If it's performing, I'll add the Mega 200, if not I'll reset and look at 'N-type' or even ShadowFlux from Renogy.
With my minimal loads I expect a single 100ah LiPo will work but I'll likely get 2 in case one takes a dump. 400w of solar, and if needed, Honda backup should be fine.