Voltage drop and Triplite rackmounts

[CortexConstruction]

First question,

I have a 200AH lithium with 3000W inverter on my van and it recharges quickly. When put a heavy load for more than a short time (10 min) the voltage drops (11v) rapidly. If I let it rest with no power input to system the battery/voltage recovers quickly. How rapidly or in what increments to you think you can drain battery without serious voltage drop that would trip other devices.

2nd question I have some newer rack mount battery back ups with dead lead batteries. Could I use these for other things with new lithium batteries? They have a lot of copper and technology.

https://www.amazon.com/Tripp-Lite-Line-Interactive-Rackmount-SMART2200RM2U/dp/B002S2KUZS?th=1

 

[sunshine_eggo]

First question,

I have a 200AH lithium with 3000W inverter on my van and it recharges quickly.

Does it reach 14.4V AT the battery terminals for at least 15 minutes?

When put a heavy load for more than a short time (10 min) the voltage drops (11v) rapidly. If I let it rest with no power input to system the battery/voltage recovers quickly. How rapidly or in what increments to you think you can drain battery without serious voltage drop that would trip other devices.

Click spoiler in my sig and consult line #2.

 

[CortexConstruction]

Thank you I think I have a low voltage short but I can turn all that off to isolate. I do have good/ heavy guage connections from battery to inverter. How fast do you think can you discharge Lipo4 battery without voltage drop? I was experimenting/using portable room AC and a medium sized concrete core drill but not at the same time.

 

[sunshine_eggo]

You can't discharge any battery without voltage drop.

Most LFP are rated for 0.5 to 1.0C, so I would expect your battery can handle 100-200A. At 200A, I would expect a drop into the low to mid 12s, but it would stay there for a long time.

 

[CortexConstruction]

Sorry what is .5 to 1 C?

 

[SunDave]

2nd question I have some newer rack mount battery back ups with dead lead batteries. Could I use these for other things with new lithium batteries? They have a lot of copper and technology.

We have a lot of rack mount battery backups at work and we just keep on putting the sealed lead acid batteries in them. They are meant to charge them, and the battery swaps are dirt cheap compared to a whole new unit.

Cheap insurance to swap them every 2-3 years. If you let them go too long, they will either not work when you need them, or swell up and get difficult to remove.

 

[sunshine_eggo]

Sorry what is .5 to 1 C?

C is the rated capacity.

C-rate is the rate at which you are charging or discharging relative to the capacity.

For a 200Ah battery, 0.5C = 100Ah. 1.0C = 200A.