solarnewb123
New Member
- Joined
- Oct 25, 2019
- Messages
- 18
I am totally new to electrical engineering of any kind, aside from fixing phones and small electronics in the past...so be patient with me here. I have a few things I need to clarify, because I am basing my solar set up for my van build solely off of what I've learned by watching Will's tutorials.
Overview:
(#) signifies how many of each item I plan on purchasing...
- Understood means that I understand the function and set up for each item
- Questions following listed items are in the same format
First, my set up will be as follows:
200 ah 12v LiFePo4 battery, 400 watts 12v solar (4x 100w panels)
I (high-end) estimated that I will be using 2,079 watt hours/day.
Now, the components...
(1) 200ah 12vLifePo4 DIY battery (4 x 3.2v cells) - I've already got this, but still need to bottom balance. My question on bottom balancing is this: I bought used cells from someone in my hometown. He was unfamiliar with the capacity but I know they are what I mentioned above. I bought them because I got them at an extraordinary price ($400 total), and I used a volt meter and discovered that the individual voltages are as follows: (S1=4.0v) (S2=3.2v) (S3=3.2v) (S4=2.5v) I am under the impression that S4 could be problematic. What is the best way to balance these, initially, with such a huge range of voltages (before I move on to bottom balance)? I need to buy the tools to do this but I am waiting on clarification. What I was going to do was use resistors to bring down the 4v cell, charge them all in series, and use the resistors again to lower the greater charged cells to match the S1 once it is charged to a stable voltage. I assume there is a way to just charge the S1 alone, but I can't find many clear videos on youtube or elsewhere about how to do that and when I do, they don't explain thoroughly how to make the tools to charge 1 cell at a time. There's limited information about this anywhere on the internet. Also, I am aware that the 2.5v cell may be damaged, but I don't really know until I try to charge and discharge it, and again, I don't currently have the tools to do that until I get clarification. Also, you have mentioned a resistor "pack" that you made to make it go more quickly on the discharge, but there is no tutorial on how to make this. So I am stumped there as well.
The rest on this list I am also waiting on clarification to purchase:
(1) Victron 12v MPPT 100/50 Charge controller - Understood
(1) GoWISE Power PS1005 Pure Sine Wave Inverter 1500W - Understood
(1) ESupport 12v 40a Relay - Understood
(1) VIctron Battery Protect 12v-220A - Could I go with 100A? I don't know how to size this.
(1) Victron Smart Battery Sense Temp/Voltage Sensor for MPPT Solar Charge Controllers - Understood
(1) Waterproof Common Port BMS 4s 12v (???amps) - I have no idea how to size the amperage on this either, how many amps should I get for this? Also, I saw a (Will) video tutorial where this was used and but at the end of the video you said I would need one with different ports, so that the charge controller is protected when it disconnects. You also have a different BMS link on your site than you have in the video tutorial where this particular BMS is used, assuming for the reason above, but I am confused what to get. The common port seems a lot more affordable than the Separate Port BMS. How necessary is this? Is there a cheaper way to bypass the regular BMS disconnecting the charge controller?
I think that's it for now. Thank you so much for what you are doing! I am learning a LOT and I'm now more excited about building and understanding my electrical system than I am to use it. Thank you!!!
Overview:
(#) signifies how many of each item I plan on purchasing...
- Understood means that I understand the function and set up for each item
- Questions following listed items are in the same format
First, my set up will be as follows:
200 ah 12v LiFePo4 battery, 400 watts 12v solar (4x 100w panels)
I (high-end) estimated that I will be using 2,079 watt hours/day.
Now, the components...
(1) 200ah 12vLifePo4 DIY battery (4 x 3.2v cells) - I've already got this, but still need to bottom balance. My question on bottom balancing is this: I bought used cells from someone in my hometown. He was unfamiliar with the capacity but I know they are what I mentioned above. I bought them because I got them at an extraordinary price ($400 total), and I used a volt meter and discovered that the individual voltages are as follows: (S1=4.0v) (S2=3.2v) (S3=3.2v) (S4=2.5v) I am under the impression that S4 could be problematic. What is the best way to balance these, initially, with such a huge range of voltages (before I move on to bottom balance)? I need to buy the tools to do this but I am waiting on clarification. What I was going to do was use resistors to bring down the 4v cell, charge them all in series, and use the resistors again to lower the greater charged cells to match the S1 once it is charged to a stable voltage. I assume there is a way to just charge the S1 alone, but I can't find many clear videos on youtube or elsewhere about how to do that and when I do, they don't explain thoroughly how to make the tools to charge 1 cell at a time. There's limited information about this anywhere on the internet. Also, I am aware that the 2.5v cell may be damaged, but I don't really know until I try to charge and discharge it, and again, I don't currently have the tools to do that until I get clarification. Also, you have mentioned a resistor "pack" that you made to make it go more quickly on the discharge, but there is no tutorial on how to make this. So I am stumped there as well.
The rest on this list I am also waiting on clarification to purchase:
(1) Victron 12v MPPT 100/50 Charge controller - Understood
(1) GoWISE Power PS1005 Pure Sine Wave Inverter 1500W - Understood
(1) ESupport 12v 40a Relay - Understood
(1) VIctron Battery Protect 12v-220A - Could I go with 100A? I don't know how to size this.
(1) Victron Smart Battery Sense Temp/Voltage Sensor for MPPT Solar Charge Controllers - Understood
(1) Waterproof Common Port BMS 4s 12v (???amps) - I have no idea how to size the amperage on this either, how many amps should I get for this? Also, I saw a (Will) video tutorial where this was used and but at the end of the video you said I would need one with different ports, so that the charge controller is protected when it disconnects. You also have a different BMS link on your site than you have in the video tutorial where this particular BMS is used, assuming for the reason above, but I am confused what to get. The common port seems a lot more affordable than the Separate Port BMS. How necessary is this? Is there a cheaper way to bypass the regular BMS disconnecting the charge controller?
I think that's it for now. Thank you so much for what you are doing! I am learning a LOT and I'm now more excited about building and understanding my electrical system than I am to use it. Thank you!!!
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