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Old 11-14-2024, 07:00 AM   #57
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Originally Posted by BiggBeniii View Post
I have 4-100amp AGM lead batteries (200amps of true usable power)
Why is the other 200Ah untrue, and unusable power?

Mark B.
Albuquerque, NM
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Old 11-14-2024, 02:28 PM   #58
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If you replace the PWM charge controller with an MPPT controller and wire the panels in series you will gain up to about 30% more from the solar system, particularly in marginal conditions.

Ok, so I can swap in a relatively cheap MPPT. Is something like this viable? https://www.amazon.com/Controller-In...1615514&sr=8-5


But help me out, how do panels get wired in series, like batteries? Does this change the voltage and create the need for the different charger? I'm lost here, I know zippity about solar panels. I like to keep it simple but an extra 240 watts a day seems worth it. I'm getting pretty close to the short strokes here, I need to get everything installed and buttoned up early next week to get ready for the vintage races.
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Old 11-14-2024, 04:11 PM   #59
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A buddy just added a couple of arrays, 6 and 8 commercial panels in series, so 240 and 320V output. This is going to a 48V inverter charger, which is capable of that input voltage. The advantage is 50 some feet of 10g wire instead of 2g wire. Plus the higher battery voltage allows the inverter to handle four times the power at the same amps as 12v. The same thing would work with 12v, you could put two commercial panels in series and have 80v and a suitable MPPT controller would convert that to higher amperage at 12V. You'd need a 100v 30A for that. The MPPT controller listed was rated for 18V panels so would not work with panels in series, and is suspiciously cheap, but it might work fine for your use. Putting them in series is not a huge advantage for most RVs as the length of wire is not that long for a couple panels. If you get up into KWs then there's some serious savings, but then you should be going to 24 or 48v at some point, at least if you're going all new, instead of replacing existing components with existing wiring. If you get that MPPT controller, keep the other one in case you need it, and carry a multimeter to keep things running.


Can't remember if this has been covered, but the generator strategy with lead is different than with Li. Li can take a charge fast whether 20% or 90%, lead is slower, but especially slow above 80%. If you're trying to maximize the charge out of short run times, then Li is best, charging lead earlier in the day is better as the solar will then do the slow part. If you're running the generator for a couple hours a day for AC, it might not matter, you'll run it when it's hot, not when you need power.
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Old 11-15-2024, 12:45 AM   #60
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Ok, so I can swap in a relatively cheap MPPT. Is something like this viable? https://www.amazon.com/Controller-In...1615514&sr=8-5


But help me out, how do panels get wired in series, like batteries? Does this change the voltage and create the need for the different charger? I'm lost here, I know zippity about solar panels. I like to keep it simple but an extra 240 watts a day seems worth it. I'm getting pretty close to the short strokes here, I need to get everything installed and buttoned up early next week to get ready for the vintage races.
Yes, the panels get wired in series much like batteries. The MPPT controller needs to have voltage from the panels that is at least five to ten volts higher than the battery voltage to work well. Higher yet is better. Most any two panels in series will provide that or more.

The MPPT controller will pull voltage down on the panels until the voltage times current (power in watts) is maximized. This is especially helpful in the morning and afternoon when the sun is less intense and the controller can eke out more watts than a PWM controller would. Same on cloudy or overcast days.

I'm not sure I would go as cheap as the controller you referenced. Also this controller may be limited to 23 volts total from the two series panels according the the first question near the bottom of the listing. Though I think they are listing the MPPT range, not the maximum panel voltage. If I'm correct, then when the voltage from two series panels is above 23 volts, you will not have MPPT action. Instead you will have MPPT action when the voltage is lower (mornings and afternoons and cloudy or overcast days). If the two panels provide up to 48 volts, there's quite a bit of time that the MPPT action will not be available.

The answer to the question also indicates up to 46 Volts when charging 24V batteries so I'd guess the panel voltage can be up to 46V or maybe higher. It's strange they don't list the maximum panel voltage.

I dubious of this controller. I'd want one with a max panel voltage specified and one that can use more of that voltage in MPPT mode.
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Old 11-15-2024, 05:20 AM   #61
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Originally Posted by medarwin View Post
Ok, so I can swap in a relatively cheap MPPT. Is something like this viable? https://www.amazon.com/Controller-In...1615514&sr=8-5


But help me out, how do panels get wired in series, like batteries? Does this change the voltage and create the need for the different charger? I'm lost here, I know zippity about solar panels. I like to keep it simple but an extra 240 watts a day seems worth it. I'm getting pretty close to the short strokes here, I need to get everything installed and buttoned up early next week to get ready for the vintage races.
I would steer well clear of that el cheapo one. Buying the cheapest of anything just makes the decent/good stuff cost more later. And it's usually junk quality and may ruin batteries.

In short, a hard no.
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Old 11-15-2024, 01:05 PM   #62
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Some info for the OP....
Many solar installers offer a "consulting" package to advise diy types. Some of the people offer a wire diagram as a product of the 'consulting.

Your existing converter may have a "lithium" switch(some companies can also modify your existing converter to produce the required lithium charge profile)....in any event you need to check the charge profile provided by the charger to see it is suitable for the lithium batteries you purchase. Typically the battery supplier will tell you what you need and the converter company can tell you what the converter supplies.

Exploristlife.com has much info, as well as pre-packaged wire diagrams for $10 for various solar /camper arrangements. It is a site worth a visit. They also sell equipment.

I have 370 w panel...2 -100ah Battleborns and a 12v Furrion 16cf refrigerator. I don't boondock...but when I drive the batteries run the fridge and the only charge is from the panels (controlled by a victron MPPT) I am always at 100% charge when I arrive at my destination(I drive during the day of course).

The Victron equipment is considered top notch.... look into that.

As far as the JC Dutchaire 17cf 12v fridge.... I am considering that as well when my 1.5yr old Furrion dies (as it seems many do)----so a follow-up post from you regarding your thoughts(likes/dislkes quality etc) on that unit would be helpful for me.
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Old 11-16-2024, 05:50 PM   #63
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Why is the other 200Ah untrue, and unusable power?

Mark B.
Albuquerque, NM
UPDATE: Referator ran for 4.75-days on 4-AGM 100-amp hrs batteries (200-amps workload 50%)
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Old 11-17-2024, 08:43 AM   #64
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I'd say that's excellent. Feel free to use more than 50% of the power, as Mark K5LXP says, you're not going to shorten their usable life in a typical RV by going down to 20%, and if you do then go with Li next time.



Now you know about what you need for solar to keep up with the fridge, double that wattage because they're flat, and double again to account for clouds and shading.
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Old 11-18-2024, 01:44 PM   #65
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[QUOTE=BiggBeniii;6902048]UPDATE: New Norcold 10 CuFt 12V DC Compressor Refrigerator, Right Hand, Black•N10DCBKR

Battery test have 4-AGM Lead Asis batteries 100-amp hr each (only 200-amps of ture usable power).


Started Battery Test:

Victron Energy SmartShunt Battery Monitor (Bluetooth) 6.5V-70V, 500 amp.


Batteries were at 100% charge and 13.75v, refrigator ran for 4.75-days. Victron Energy Smart BatteryProtect shut the batteries down at 43% 11.81v.


I think this refrigerator pasted my test. I am pleased with the new 12v Norcold refrigerator.
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Old 11-23-2024, 06:02 AM   #66
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Darwin.... what is the latest on your refrigerator project? Did you get the Dutchaire? If yes how do you like it?
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Old 11-24-2024, 12:43 AM   #67
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. . . . . . And I don't want a 120 volt AC refrigerator because of the inherent loss of converting DC power to AC via the inverter, no matter how negligible the loss it's still there. . . . . .
Darwin
Fun fact ....... your 12V compressor fridge has an inverter in it. I.e., the motor is actually AC and in most cases it's three-phase AC. You will see a small box about 3" x 2" x 5" near the motor. That is the inverter.

However, it is a very efficient inverter with adjustable frequency AC output that drives the AC motor at an optimum voltage and speed. The inverter and motor combination is considerably more efficient than a 120V inverter and 120V compressor motor.
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Old 11-24-2024, 09:16 AM   #68
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Darwin.... what is the latest on your refrigerator project? Did you get the Dutchaire? If yes how do you like it?
Fridge ready to slide onto new platform. Had to leave home for a week but will be connected and running by Wed. Installed the 200 watts of solar so will be running tests to see what consumption is. The fridge is HUGE compared to the NoCold 1201.

Updates will follow.
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Old 11-24-2024, 11:06 AM   #69
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Fridge ready to slide onto new platform. Had to leave home for a week but will be connected and running by Wed. Installed the 200 watts of solar so will be running tests to see what consumption is. The fridge is HUGE compared to the NoCold 1201.

Updates will follow.
Great....post some pics.....


Patchy
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Old 11-26-2024, 08:52 AM   #70
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Fun fact ....... your 12V comp.ressor fridge has an inverter in it. I.e., the motor is actually AC and in most cases it's three-phase AC. You will see a small box about 3" x 2" x 5" near the motor. That is the inverter.

However, it is a very efficient inverter with adjustable frequency AC output that drives the AC motor at an optimum voltage and speed. The inverter and motor combination is considerably more efficient than a 120V inverter and 120V compressor motor.

Not true. This is a brushless 12v DC motor that powers the compressor. Fun Fact: Typical RV inverters "lose" 10-15% of the energy during conversion from 12v DC to 120 AC. In fact, converting any form of energy results in loss. Which is why it's stupid to generate electricity from natural gas/coal to power electric cars.
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