Terrapin
New Member
My situatiion is a small travel trailer that will remain all 12v. I have PD converter to install with lithium capable charging at bluk of 45amp. I plan to build the battery system my self. It will be a 4S 240ah single battery
This is the BMS en route:
4s BMS 120a LifePo4 Battery Management System for 12v DIY Batteries, Programmable, Bluetooth Included. - 8 gauge x 12" (wires were upgraded)
this is the one referred by Will's site. It is on back order but I am still snow covered so the build is set for early spring.
The (rare use) largest single intermittent load (maybe for 10 min. max) I want the system to power is a Dometic 800w microwave that is rated at 1300w max usage with the LP gas refrigerator fuel solenoid operating (with no internal frig. fans but a .5a one on a thermostat in the vent stack) and a few led ceiling lights. this will be through the Shore Power hookup and an inverter.
TV and radio will be on a separate closed loop system as "nonessential"*.
I am researching the transfer switch for the inverter loop so those questions will come later.
The inverter I have ordered hoping to do this is:
GoWISE Power 1500W Pure Sine Wave Power Inverter 12V DC to 120 V AC with 3 AC Outlets, 1 5V USB Port, 2 Battery Cables, and Remote Switch (3000W Peak) PS1005 (Brand Name/Packaging May Vary)
Link: https://www.amazon.com/gp/product/B01COA0UTE/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
This is also one referred by Will's site.
#1 Before I ask my questions... am I on track so far? is this math working at all????
#2 what is my weakest link thus far.
#3 What is the calculation needed to determine the C rating of the cells I need to buy for the battery build?
#4 Or, is that a typical 12v 4S prismatic battery build C rate limitation a factor of the BMS used?
#5 If multiple 12V batteries are used in parallel to be able to tune their bandwidth for longer life (say, +/-35-85& charge) and still have decent capacity, then will the effective C rate of the bank system change or there an electrical bottleneck somehow?
#6 If it does rise what is the change calculation, does it simply double assuming adequate wiring?
#7 is it possible to simply charge the *"nonessential" battery at the same time as the rest but not have it's output shared?
# If that's possible must it be manually switched or can it be isolated for output only automatically?
#7 Is there anyone here who draws schematics for this stuff for noobs? Those would include a few peripherals like some external solar hookups to augment charging with suitcase panels (a single 120w folder is on hand so far...but others may come if the trees here don't kill the dream).
Well that's where I am at. ... just catching on enough to be dangerous...
Thanks to everyone who has helped so far. It was suggested I number my questions, I hope that didn't come off as cold. Any help is greatly appreciated.
I wish we had more direct sun so it was worthwhile to go with 100% full time roof top solar but we tend to seek the trees a lot. I hope we see some free juice from this first panel set though.
This is the BMS en route:
4s BMS 120a LifePo4 Battery Management System for 12v DIY Batteries, Programmable, Bluetooth Included. - 8 gauge x 12" (wires were upgraded)
this is the one referred by Will's site. It is on back order but I am still snow covered so the build is set for early spring.
The (rare use) largest single intermittent load (maybe for 10 min. max) I want the system to power is a Dometic 800w microwave that is rated at 1300w max usage with the LP gas refrigerator fuel solenoid operating (with no internal frig. fans but a .5a one on a thermostat in the vent stack) and a few led ceiling lights. this will be through the Shore Power hookup and an inverter.
TV and radio will be on a separate closed loop system as "nonessential"*.
I am researching the transfer switch for the inverter loop so those questions will come later.
The inverter I have ordered hoping to do this is:
GoWISE Power 1500W Pure Sine Wave Power Inverter 12V DC to 120 V AC with 3 AC Outlets, 1 5V USB Port, 2 Battery Cables, and Remote Switch (3000W Peak) PS1005 (Brand Name/Packaging May Vary)
Link: https://www.amazon.com/gp/product/B01COA0UTE/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
This is also one referred by Will's site.
#1 Before I ask my questions... am I on track so far? is this math working at all????
#2 what is my weakest link thus far.
#3 What is the calculation needed to determine the C rating of the cells I need to buy for the battery build?
#4 Or, is that a typical 12v 4S prismatic battery build C rate limitation a factor of the BMS used?
#5 If multiple 12V batteries are used in parallel to be able to tune their bandwidth for longer life (say, +/-35-85& charge) and still have decent capacity, then will the effective C rate of the bank system change or there an electrical bottleneck somehow?
#6 If it does rise what is the change calculation, does it simply double assuming adequate wiring?
#7 is it possible to simply charge the *"nonessential" battery at the same time as the rest but not have it's output shared?
# If that's possible must it be manually switched or can it be isolated for output only automatically?
#7 Is there anyone here who draws schematics for this stuff for noobs? Those would include a few peripherals like some external solar hookups to augment charging with suitcase panels (a single 120w folder is on hand so far...but others may come if the trees here don't kill the dream).
Well that's where I am at. ... just catching on enough to be dangerous...
Thanks to everyone who has helped so far. It was suggested I number my questions, I hope that didn't come off as cold. Any help is greatly appreciated.
I wish we had more direct sun so it was worthwhile to go with 100% full time roof top solar but we tend to seek the trees a lot. I hope we see some free juice from this first panel set though.