Renogy 100ah LifePo4 Lithium - Max Surge Current

There are "inductive" loads and "resistive" loads, but also you get "in-rush" like with converters, and "surges" like with motors winding up. I got lost trying to figure out if any of them is the same thing as another.

"They" do advise if your inverter won't run an inductive load at full speed, just add a resistive load like an incandescent lamp to the mix.
That might only apply to MSW inverters, don't know.

I don't know if that trick would help with an Li's BMS.

From the Owners Manual, an Onan QD3200 diesel generator can draw up to 675 CCA under very cold conditions, with a draw of 475A just to get it to turn over at ambients down to 0F. I believe I read somewhere that they can suck up to 300A to start at more comfortable/normal temps.
Once again, any electric (starter) motor or other mechanical device can draw mucho amps when starting/running.

time2roll wrote:
I don't think a microwave has much surge at the start. s/b easy to stay under 100 amps. Only real surge in an RV would be an air conditioner and that is not really a concern if you are limited to one battery.

A "700w" Danby MW we had wanted 1050w input and made the 1000w PSW inverter pull 100 amps as seen on the Trimetric. The inverter showed its overload light but kept running. After a few times doing that, the inverter burnt out some components on its circuit board.

I don't think a microwave has much surge at the start. s/b easy to stay under 100 amps. Only real surge in an RV would be an air conditioner and that is not really a concern if you are limited to one battery.

They also have a slightly more expensive (what's a few hundred bucks to get what you need?) model, the RB100 HP with an 800A peak discharge rating and a 1000A discharge cutoff. More in line with the cranking amps ratings of an FLA chassis/starting battery.

DISCHARGE SPECIFICATIONS

Maximum Continuous Discharge Current 100 A
Peak Discharge Current 800 A (2 s)
BMS Discharge Current Cut-Off 1000 A ±100 A (2.2 ±1 ms)
Recommended Low Voltage Disconnect 11 V
BMS Discharge Voltage Cut-Off 9.2 V (2.3 ±0.08 vpc) (4.2 ±0.5 s)
Reconnect Voltage 10 V (2.5 ±0.1 vpc)
Short Circuit Protection 200-600 µs

Just depends on your needs. They've got something for everyone there.

The RB100 has a little bit of a cushion that might keep the BMS from shutting off the discharge circuit at almost 330A, if I read the + or - thing correctly.

Here is the specs for the Relion RB100

The discharge shows peak 200a. One thing I'll say about Relion battery site it is hard to find info without a lot of fishing.



Incase that is small here is a shot of the discharge specs.

Itinerant1 wrote:
LFP batteries are good, maybe you're expecting more than what 1 100ah battery can perform. What exactly are you using over 100a on a 100ah battery?

We're trying to power some portable test equipment. Only have weight/space available for one group 31 sized LifePo4 battery. FWIW, the same scenario could be applicable to someone with, say, a truck camper (with very limited battery space) who wanted to run a very small microwave.

In any case, just spoke to a LifeBlue distributor who does solar installs. I asked him about the LifeBlue LifePo4 100ah battery's performance when discharged/loaded slightly above its rated continuous capacity. He seemed intriqued with the question, so he's offered to test a fully-charged Lifeblue 100ah (with a 100a continuous rating) at 110-120a sometime this week. It'll be interesting to hear the results.

Edit: Wow, the distributor just emailed me his test results! Apparently the LifeBlue LifePo4 100ah battery's BMS shuts down the battery with a 110a load after 30 seconds. He did the test several times. It would appear the Renogy and LifeBlue BMS's, both, operate similarly.

Disappointing. On to plan B.

LFP batteries are good, maybe you're expecting more than what 1 100ah battery can perform. What exactly are you using over 100a on a 100ah battery?

2oldman wrote:
I'm using 100ah 48v pack and it surges just fine. It's hard to imagine subjecting a single 12v battery to 100a draw.

It also has to be a known fact those other batteries actually *will* do that.

Assuming the Battle Born and LifeBlue 100ah batteries can perform to their own specs, I'd say yes, they will. Both are rated at 100a continuous. The BB can surge to 200a for 30 sec. The LB, 300a for 3 sec. So, the question remains, how long can they produce, say, 110a before the BMS shuts the battery down (due to excessive heat or discharge). How long at 120a? How long at 130a? etc.

For those with space/weight/cost concerns, and high current needs, this would be nice data to have.

Mechanical devices may have short duration high amp draws.
Generator or engine starter motors, are 2 examples that may or may not invoke the excessive discharge/shut down programming of the internal BMS. I have 2 Relion 100Ah low temp 12V batteries in parallel, and they have exhibited intermittent tendencies to shut down during generator starts. Usually, if I depress the gen prep button and hold it for 30 seconds before hitting the start button, it will fire up without issue. Starting the generator with chassis engine running also works/helps. I haven't tried the battery boost switch to start the chassis engine with help from the lithiums yet.
I'm also guessing that SoC of the battery(ies) will affect the decision making process for when the BMS will invoke the high draw shutdown.
It might be the only down side (besides price?) of lithium batteries. I am aware that some of the manufacturers also offer models that are less susceptible to this issue. Relion does, but I wanted the cold weather charging models.