This is freaking amazing. I'm a cheap ass but I'm really starting to think your prices are actually a damn good deal for someone that wants to know FOR SURE they are getting a Grade A cell that doesn't break a sweat at 0.5C and still holds steady at 1C
This is great! Love the larger terminals! The smaller terminals work when new but how do the smaller terminal handle loads after years of aluminum oxide has built up on the terminals?
With the lid closed (and if sealed with removable silicone) this will be very minimal affect at all, however Antioxidant paste can be used to further reduce this affect. This is one of the potential downsides of a serviceable terminal vs laser welding permanent terminals, but we feel is a fair compromise all things considered.
@@sfkenergy For more info on the difficulties with aluminum connections. I'd suggest looking into the number of NEC certified aluminum wire connection that haven't stood the test of time.
@@JohnLKeating Yes these are valid points, but we must comes to the realization is that 90% of our customers are average DIYers... most will use commonly available items so its important we focus what is readily available to most. That being said we will look into this. Thank You.
If you're only pulling 0.25C. you'll be ok. The big difference is the internal resistance. SFK cells actually meet or exceed the datasheet when it comes to typical mΩ. Try pulling 1C on a Amazon/Aliexpress cell and you're probably going to be dropping close to LVC, so you're voltage would be very low if you had to sustain that kind of load, meaning less Wh pulled. Most of the manufacturers have discharge graphs on their datasheets so you don't even need a YR-1035+ or other meter to measure IR. Just find a way to put a big load on the cell and compare the voltage (you need to measure the cell voltage at the terminals and not on the same wire carrying the current). If the datasheet shows a cell at 1C holding 3.2V and you're holding 2.60V then you know what you got. You can even work backwards to determine DC IR. Rough numbers would be 3.45-2.60=0.85 voltage drop ÷ current (304 amps)=0.00279605 ohms or 2.79 milliohms....no bueno It should be ~3.2V so 0.25÷304=0.00082237 or 0.8mΩ. Remember thats DC IR not AC impedance. In the case of this cell we saw 3.35 holding 3.26 at 245A which is mind boggling. Just remember the top end of the voltage range is fluff so starting your DC IR test after the voltage has settled gives you a more realistic number. That extra 0.20V on the top just disappears under a load so don't include it. Let your cells rest for at least an hour or two off the charger when doing these tests
We are having a 10% off sale on these + free shipping (Mainland US): 304DEAL coupon code! Limited to on hand stock & ends March 3rd 2023!
Very cool! I love how you 3d printed the parts in the kit.
This is freaking amazing. I'm a cheap ass but I'm really starting to think your prices are actually a damn good deal for someone that wants to know FOR SURE they are getting a Grade A cell that doesn't break a sweat at 0.5C and still holds steady at 1C
This is great! Love the larger terminals! The smaller terminals work when new but how do the smaller terminal handle loads after years of aluminum oxide has built up on the terminals?
With the lid closed (and if sealed with removable silicone) this will be very minimal affect at all, however Antioxidant paste can be used to further reduce this affect.
This is one of the potential downsides of a serviceable terminal vs laser welding permanent terminals, but we feel is a fair compromise all things considered.
@@sfkenergy For more info on the difficulties with aluminum connections. I'd suggest looking into the number of NEC certified aluminum wire connection that haven't stood the test of time.
@@JohnLKeating Yes these are valid points, but we must comes to the realization is that 90% of our customers are average DIYers... most will use commonly available items so its important we focus what is readily available to most. That being said we will look into this. Thank You.
I'm about to buy one or two 300ah cheapos from Amazon. I wish I could afford these high-end batteries.
Keep your amps low and you'll be fine, 9/10 of our customers buy our kits and use grade B cells it works majority of the time.
If you're only pulling 0.25C. you'll be ok. The big difference is the internal resistance. SFK cells actually meet or exceed the datasheet when it comes to typical mΩ. Try pulling 1C on a Amazon/Aliexpress cell and you're probably going to be dropping close to LVC, so you're voltage would be very low if you had to sustain that kind of load, meaning less Wh pulled. Most of the manufacturers have discharge graphs on their datasheets so you don't even need a YR-1035+ or other meter to measure IR. Just find a way to put a big load on the cell and compare the voltage (you need to measure the cell voltage at the terminals and not on the same wire carrying the current). If the datasheet shows a cell at 1C holding 3.2V and you're holding 2.60V then you know what you got. You can even work backwards to determine DC IR. Rough numbers would be 3.45-2.60=0.85 voltage drop ÷ current (304 amps)=0.00279605 ohms or 2.79 milliohms....no bueno
It should be ~3.2V so 0.25÷304=0.00082237 or 0.8mΩ. Remember thats DC IR not AC impedance. In the case of this cell we saw 3.35 holding 3.26 at 245A which is mind boggling. Just remember the top end of the voltage range is fluff so starting your DC IR test after the voltage has settled gives you a more realistic number. That extra 0.20V on the top just disappears under a load so don't include it. Let your cells rest for at least an hour or two off the charger when doing these tests
Yes akb👍🔋 LiFePO 4⚡🔌🔋🇺🇦