macdad22
New Member
- Joined
- Apr 11, 2021
- Messages
- 13
First of all I would like to thank Will Prowse for the forum and all the great YouTube videos as I've learned so much from him and others over the past few months.
About a month I turned up a Growatt 12k inverter with a 48V 4s4s configured EVE 280AH battery bank. Each 4S battery has a Daly 250A 4s BMS w/ bluetooth and its so interesting to watch all the voltage and amp draws. The system has been working great and under typical scenarios it provides between 3 and 4 hours of AC power to my critical loads panel if I where to lose utility grid power. Almost every day I've been tested a power out scenario and letting a large portion of my house run off of batteries in a test scenario of power out.
My entire plan was to grow the system over time a system that has a little over 40kwh of battery backup as currently there ~ 14kwh. The plan is to add 2 additional 48V battery banks in parallel over the remainder of the year. I'm almost ready to add the 2nd bank which will raise the system to ~28kwh in total.
I've now completed building a new16s battery with CATL 271ah cells I got on Alibaba, however one of the things I'm most concerned with is the energy transfer from one battery to the other when they are first connected. I'm going to do my best to have them at the same ( no load ) voltage prior to connecting them. The 2 battery banks will be connecting via busbars with 1/0 sized cables on. They will have identical cable lengths and bluesea 300A fuses from the busbars to them and on the other includes Anderson PP185 connectors to each battery bank so that it is easy to disconnect/connect a battery bank.
What has been other people's experiences when first connecting 48V batteries in parallel? I've done this quit a bit at lower voltages and have always been very careful in terms of planning and safety.
I think a lower voltage like exactly 48V for each battery might be best with each battery and then let the Growatt charge them back up vs have them top balanced ~56-58V and connecting them together?
I think the 1/0 cables due to short length can handle the current inrush between the batteries in almost any scenario ie.. 1C is still less than what the cable and fuses are rated at but would rather not risk blowing a fuse or worse.
Let me know if I'm overthinking this.
Cheers,
Chris
About a month I turned up a Growatt 12k inverter with a 48V 4s4s configured EVE 280AH battery bank. Each 4S battery has a Daly 250A 4s BMS w/ bluetooth and its so interesting to watch all the voltage and amp draws. The system has been working great and under typical scenarios it provides between 3 and 4 hours of AC power to my critical loads panel if I where to lose utility grid power. Almost every day I've been tested a power out scenario and letting a large portion of my house run off of batteries in a test scenario of power out.
My entire plan was to grow the system over time a system that has a little over 40kwh of battery backup as currently there ~ 14kwh. The plan is to add 2 additional 48V battery banks in parallel over the remainder of the year. I'm almost ready to add the 2nd bank which will raise the system to ~28kwh in total.
I've now completed building a new16s battery with CATL 271ah cells I got on Alibaba, however one of the things I'm most concerned with is the energy transfer from one battery to the other when they are first connected. I'm going to do my best to have them at the same ( no load ) voltage prior to connecting them. The 2 battery banks will be connecting via busbars with 1/0 sized cables on. They will have identical cable lengths and bluesea 300A fuses from the busbars to them and on the other includes Anderson PP185 connectors to each battery bank so that it is easy to disconnect/connect a battery bank.
What has been other people's experiences when first connecting 48V batteries in parallel? I've done this quit a bit at lower voltages and have always been very careful in terms of planning and safety.
I think a lower voltage like exactly 48V for each battery might be best with each battery and then let the Growatt charge them back up vs have them top balanced ~56-58V and connecting them together?
I think the 1/0 cables due to short length can handle the current inrush between the batteries in almost any scenario ie.. 1C is still less than what the cable and fuses are rated at but would rather not risk blowing a fuse or worse.
Let me know if I'm overthinking this.
Cheers,
Chris