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diy solar

Charging from multiple sources

I still miss Snoobler. I liked him.
I don't like this "Happy, Everything is Sunshine!" guy.
He ought to be living under a cloud all the time, like the rest of us.

I guess not. I knew your secret identity, but I didn't know it wasn't a secret. ;)

I'm not sure why, but I did have the impression we were dealing with Dr. Jekyll and Mr. Hyde.
Maybe because people can be recognized by their writing?
I guess leaving a forwarding and return address seals it. (be careful what you write on envelopes for anonymous letters, and where they are postmarked.)
 
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.):
  1. Solar PV via MPPT
  2. Solar PV via PWM
  3. 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)
  4. Wind with suitable controller
  5. Grid/Generator AC via inverter/charger
  6. Grid/Generator AC via RV AC-DC converter
  7. Hydro with suitable controller
  8. Anything else someone might use to charge an off-grid energy storage system.
This is true for any battery chemistry.

Again, important that all chargers are appropriately configured to handle the battery bank with suitable absorption and float voltages.

Also very important that the sum of all charge currents do not exceed the recommended max charge current of the battery bank.


Note:
Multiple chargers only offer benefit when the battery is below the absorption voltage. Once the absorption voltage is hit, it is now a voltage limited charge and thus current will be lower than the sum of all sources. The battery bank will only accept as much current as it needs to maintain the absorption voltage. As the battery bank fills, current is reduced and chargers can no longer deliver current at the absorption voltage. They will drop out and go to float. Typically, the highest current charging source will always be the last source charging while all others are at 0A and likely in float mode.

Comments and corrections are welcome.
I agree, but am still hesitant to connect a separate charge controller to the battery packs bus bars as they are connected to two other inverter/charge controllers. See pic. below. I would connect a charge controller from separate panels, which would be ok right?!?IMG_0671.jpeg
 
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.):
  1. Solar PV via MPPT
  2. Solar PV via PWM
  3. 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)
  4. Wind with suitable controller
  5. Grid/Generator AC via inverter/charger
  6. Grid/Generator AC via RV AC-DC converter
  7. Hydro with suitable controller
  8. Anything else someone might use to charge an off-grid energy storage system.
This is true for any battery chemistry.

Again, important that all chargers are appropriately configured to handle the battery bank with suitable absorption and float voltages.

Also very important that the sum of all charge currents do not exceed the recommended max charge current of the battery bank.


Note:
Multiple chargers only offer benefit when the battery is below the absorption voltage. Once the absorption voltage is hit, it is now a voltage limited charge and thus current will be lower than the sum of all sources. The battery bank will only accept as much current as it needs to maintain the absorption voltage. As the battery bank fills, current is reduced and chargers can no longer deliver current at the absorption voltage. They will drop out and go to float. Typically, the highest current charging source will always be the last source charging while all others are at 0A and likely in float mode.

Comments and corrections are welcome.

Yes, you would connect the controllers output to the bus bars. The whole job of a bus bar is to give you an easy spot to bring your wires together without needing a wire nut the size of your head.

The charge controllers won't care about anything else connected other than "I have a battery, I will charge it.
Great thanks, I appreciate it!
 
How can I charge my Lithium battery using the cigarette charger in my vehicle?
PL. Pp


I have an MPP Solar all in one unit with 600 watts of solar panels and a 24v lithium battery....but often when traveling on cloudy days my battery is not fully charged when I arrive at my destination 10 hours later and the sun is already down for the night.
Not your best option. Because your cigarette charger is probably 12v, your only option is a plug in boost converter capable of dealing with your battery's needs. Keep in mind whatever you get, you're still limited by the lighter's fuse rating, and the engine will need to burn a lot of gas for a little power.
 
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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.):
  1. Solar PV via MPPT
  2. Solar PV via PWM
  3. 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)
  4. Wind with suitable controller
  5. Grid/Generator AC via inverter/charger
  6. Grid/Generator AC via RV AC-DC converter
  7. Hydro with suitable controller
  8. Anything else someone might use to charge an off-grid energy storage system.
This is true for any battery chemistry.

Again, important that all chargers are appropriately configured to handle the battery bank with suitable absorption and float voltages.

Also very important that the sum of all charge currents do not exceed the recommended max charge current of the battery bank.


Note:
Multiple chargers only offer benefit when the battery is below the absorption voltage. Once the absorption voltage is hit, it is now a voltage limited charge and thus current will be lower than the sum of all sources. The battery bank will only accept as much current as it needs to maintain the absorption voltage. As the battery bank fills, current is reduced and chargers can no longer deliver current at the absorption voltage. They will drop out and go to float. Typically, the highest current charging source will always be the last source charging while all others are at 0A and likely in float mode.

Comments and corrections are welcome.
Thank you snoobler, I totally understand. Yeh the charger that I have now (shown in the link I provided) does automatically drop the charge amperage the closer I get to the absorption stage being complete. The battery I have is a 300ah Lifepo4 that I use in my RV and sometimes I can run it down to 80ah and I have to leave my generator on for 4.5 hours to get it back up to at least 275ah and I wanted to shorten that time. Thanks again!
 
A better way to do that could be an AC to DC power supply (or 48V battery charger) connected to the input of a charge controller which has suitable profile. Probably not "PV" input, but one that has "turbine" input settings. Outback and Midnight have such SCC.
Just curious, why wouldn't you put the 48v charger directly on the battery bank instead of feeding into a charge controller to send back out to the battery bank? I would think this would only be needed when the the bank is low and needs help on a cloudy day. In other words, it won't be left on all the time. At least that is what I am planning on doing, I am currently in the process of assembling my first solar system so take that for what it is worth. But I came here looking to confirm you can have a, AC charger hooked up to your battery bank at the same time as your inverter charger is running.
 
You can, but if its charge voltage is higher than BMS cutoff it could cycle on and off nearing full charge. I'd rather the battery charger regulated to desired voltage. If you had a way to stop it that could be OK. I figure an electronic charge controller could be programmed and charging would slow as battery neared full.

Yes, you can have multiple charge sources connected.
 
It should be easy enough to check the specs of each one to know for sure but realistically, I wouldn't be leaving the charger on long enough to get into BMS cutoff voltage. I would only be using it when it has been cloudy or covered with snow long enough to drain down to 10-15% and turn it off when it gets above 80%. No need to stress the batteries if I can come back the next day to turn it on again. Or, I could just switch back to grid power until the snow melts. This small system I'm building is more a SHTF scenario for when I don't want to be running the whole house natural gas generator or one of my two other small generators. My usage parameters will be slightly different than those living off grid with fewer options. But I understand now why some would want to run it through the charge controller if possible, to be more fully automated.
 
Sounds like you need a DC-DC charger so your battery is charged up while you drive.
I charge mine directly without a dc-to-dc charger. From the starter battery, thru the boost solenoid to the battery. My Sprinter has the factory 150 amp alternator.
 
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.):
  1. Solar PV via MPPT
  2. Solar PV via PWM
  3. 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)
  4. Wind with suitable controller
  5. Grid/Generator AC via inverter/charger
  6. Grid/Generator AC via RV AC-DC converter
  7. Hydro with suitable controller
  8. Anything else someone might use to charge an off-grid energy storage system.
This is true for any battery chemistry.

Again, important that all chargers are appropriately configured to handle the battery bank with suitable absorption and float voltages.

Also very important that the sum of all charge currents do not exceed the recommended max charge current of the battery bank.


Note:
Multiple chargers only offer benefit when the battery is below the absorption voltage. Once the absorption voltage is hit, it is now a voltage limited charge and thus current will be lower than the sum of all sources. The battery bank will only accept as much current as it needs to maintain the absorption voltage. As the battery bank fills, current is reduced and chargers can no longer deliver current at the absorption voltage. They will drop out and go to float. Typically, the highest current charging source will always be the last source charging while all others are at 0A and likely in float mode.

Comments and corrections are welcome.
Thanks greatly for this post, it was exactly the information I needed!
 

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