BMS max amps?

[OzSolar]

https://batteryhookup.com/products/new-12-8v-30ah-lifepo4-battery-series-12-24-36-48v

BMS is rated at 65a for 2 seconds.

Any thoughts on what it might rated at for a 1/2 second or an even shorter time?

I'm thinking about using it for my tractor's starter battery which hits 220 amps for a fraction of a second. I'm tired of buy a new one every 3 years.

Crazy? Probably but at this price it's at least worth trying.

Also thinking about using three of them for my golf cart. I can't measure it's surge at the moment because several of it's 6v FLA batteries are bad. I don't need much range so that not my concern.

One challenge is that I will regularly trying to use them in below freezing temps so that may be the bigger challenge. Suppose I could get battery heater.

 

[Skypower]

For this application I’d stick with the FLA because of current draw at cranking. There are high cranking current lithiums but they are expensive, unproven and require changes to your charging system. Your FLA is probably dying from long term low state of charge till next season. I’d suggest using a “Battery Tender” brand charger on it 24/7 when not in use. It charges, shuts off and monitors then charges as needed and shuts off, repeat….They won’t slowly cook your battery like a trickle charger will. We use one for the starting battery on a bass boat and just now replaced the starting battery after 8 years.

 

[hwy17]

Not exactly the question, but my PowerSonic 12v 35Ah SLA battery has been going since 2017 in my riding mower. OEM car batteries often go 10 years too.

 

[OzSolar]

For this application I’d stick with the FLA because of current draw at cranking. There are high cranking current lithiums but they are expensive, unproven and require changes to your charging system. Your FLA is probably dying from long term low state of charge till next season. I’d suggest using a “Battery Tender” brand charger on it 24/7 when not in use. It charges, shuts off and monitors then charges as needed and shuts off, repeat….They won’t slowly cook your battery like a trickle charger will. We use one for the starting battery on a bass boat and just now replaced the starting battery after 8 years.

I agree! My challenge is that between the lawnmowers, four wheelers, farm truck, motorcycles and tractor I've got more pieces of equipment than I have Battery Tender's. Inevitably, while playing musical chairs with the BT's, something gets left alone for too long. Even when I do remember to clip them on it's not uncommon for something to knock one of the spring loaded alligator clamps loose. I've handled that by using the ring terminals to SAE adapted when possible.

Also I have to remember to plug it in as soon as I'm done using it. I often intend to use something the next day then don't get around to for another month or two..... I suffer with CRS.

Now I have culled some pieces of equipment and purchased a few more BT's, (Harbor's Freight's version seems to do pretty good).

Mostly I'm just curious how that amp curve on a BMS looks. You frequently see them published for inverters.