Howdy; I've been in energy industry since early 2000s, and I believe energy storage has the potential to radically transform power markets.I have been wanting to build an energy storage system for the past few years to teach myself about the technology. It was through this process that I found Jehu's YouTube videos, which sped things up a bit for me. So I finally pulled the trigger on 2 cases of Panasonic NCR18650BD cells (qty 380, typical capacity 3.18 A, Nominal Voltage 3.6 V,Max Charging Voltage 4.2 V) and then (60)of Jehu's PCBs and (4) of his BMS PCBs.
My goal is to build a nominal 24 V 7s16p system with (3) banks, each with its own BMS PCB--so I suppose this technically would be a 7s48p battery. Nominal Voltage will be 25.2 V and typical Amp-Hrs should be 152.6 Ah, which then translates out to 3,847 Wh. Charging voltage will be 29.4 V. This equates to a 12V-equivalent 320.5 Ah, which is basically (3) lead acid camper batteries (ish).
Each of the three banks of (16) PCBs will have a Jehu BMS to keep the cells balanced within each bank.
I know people are going to light me up on this, but I am going to install this system in our camper, which I'm basically going to treat as my little test lab. The Camper is 12V. I am going to install a large 24V-12V buck converter, which I fully understand sucks and is imperfect andi is going to be a failure point and is going to cut down on round trip efficiency. But my goal is not roundtrip efficiency. My goal is learning how batteries work, and this application will be just fine for my purposes. My ultimate goal will be to install this system in a new office ran exclusively by solar and this battery, but that won't be for a couple years. So for now, I learn.
I'm only going to charge the unit via 110V shore power at this point.
I am going to install an inverter that I can use to power the AC side of my camper's breaker to power AC outlets in the unit (microwave, coffee pot, laptops, etc). Max AC load can be assumed to be <2000W (and probably only 1350 W, which is size of my microwave--but I'd like some buffer room).
The system will be installed within the unit, which can be assumed to be dry.
Next summer, I may opt to add roof mounted solar panels, so that I can charge the system when we're out and about. But for now, only assume shore power charging.
I'm posting this here because I feel like I have a pretty good idea on how to build up each of the (3) 7s16p banks--along with their BMS units--from Jehu's videos. I need help with:
Thanks a ton for your comments, questions and feedback. I REALLY appreciate them.
My goal is to build a nominal 24 V 7s16p system with (3) banks, each with its own BMS PCB--so I suppose this technically would be a 7s48p battery. Nominal Voltage will be 25.2 V and typical Amp-Hrs should be 152.6 Ah, which then translates out to 3,847 Wh. Charging voltage will be 29.4 V. This equates to a 12V-equivalent 320.5 Ah, which is basically (3) lead acid camper batteries (ish).
Each of the three banks of (16) PCBs will have a Jehu BMS to keep the cells balanced within each bank.
I know people are going to light me up on this, but I am going to install this system in our camper, which I'm basically going to treat as my little test lab. The Camper is 12V. I am going to install a large 24V-12V buck converter, which I fully understand sucks and is imperfect andi is going to be a failure point and is going to cut down on round trip efficiency. But my goal is not roundtrip efficiency. My goal is learning how batteries work, and this application will be just fine for my purposes. My ultimate goal will be to install this system in a new office ran exclusively by solar and this battery, but that won't be for a couple years. So for now, I learn.
I'm only going to charge the unit via 110V shore power at this point.
I am going to install an inverter that I can use to power the AC side of my camper's breaker to power AC outlets in the unit (microwave, coffee pot, laptops, etc). Max AC load can be assumed to be <2000W (and probably only 1350 W, which is size of my microwave--but I'd like some buffer room).
The system will be installed within the unit, which can be assumed to be dry.
Next summer, I may opt to add roof mounted solar panels, so that I can charge the system when we're out and about. But for now, only assume shore power charging.
I'm posting this here because I feel like I have a pretty good idea on how to build up each of the (3) 7s16p banks--along with their BMS units--from Jehu's videos. I need help with:
- Selecting a DC-DC buck converter, which I will just home run right into the DC side of camper's DC panel.
- Selecting a 110V charger that can deliver 29.2 V and enough Amps to safely charge my system, as well as accommodate future solar panels (although I am fine running solar panels right into a MPPT and then right into the batteries if that is better).
- Selecting an inverter somewhere in the range of 2000-3000W.
Thanks a ton for your comments, questions and feedback. I REALLY appreciate them.