Endless Sphere

I'm pretty sure they are 18650 LiFePo4's.

Thats super useful thanks alot btw, for how long did you "stay" on each current for the test? I did the test a couple years ago. It was either 5 or 10 minutes. Certainly long enough to heat soak the material. Keep in mind that real world results will vary a little. This testing was done w...

rg12 wrote: ↑

May 04 2019 9:01am

I will be using a 6.75mm wide 0.2mm thick nickel for constant current of about 6.5A
Will it not go hot enough while it's sitting on the cell holder plastic?

You will be just fine. Likely your nickel will be <10C above ambient temperatures at that current.

Yes, I've done testing:

Is this the same company that was selling Leaf modules that only had ~50% of original capacity? In general the industry deems anything in the 70-80% of original capacity range to be end of life (EOL). So you shouldn't buy anything like that. What capacity were the cells originally and what is their ...

When I have to glue cells together I use Quick Grip. It works great, highly recommended! Been using it for years. Part number 873388

The best way to soldier 18650's is not to solder them at all. Spot weld.

Black and Decker 36v/40v and Die Hard 40v packs are the same thing. At least the versions that look the same are the same.

Ryobi and craftsman 4v packs (the 1x18650 ones) are the same.

~3.6v is very typical for new cells. They made SOC for shipping even more strict in the past couple of years I think its <30% SOC now.

VTC6 clones? Why are you buying clones?

Completely incorrect just as I originally guessed. Just took a clamp meter and tested the car under various load conditions. It draws 25A upon startup (when some pump is running, presumably some hydraulic pump for breaks/power steering). Then settles down to around 20A with headlights on. This is c...

Sorry, you are not making sense, and I believe you are incorrect. DC/DC converter literally dumps power to the 12V + and - terminals of the battery. These same 12v battery + and - connections have cables to the cars chassis which then powers accessories. Right. So if you measure power to/from the b...

That doesn't make sense to me, unless there is a bypass that allows power to flow from the DC/DC directly to the accessories and not through the battery. The battery is not an energy source, and no power flows "through" it. In a hybrid it only provides power to start the car (and power fo...

I might try connecting my DC clamp meter to the 12V battery cable so I can see what kind of power that puppy is supplying with the AC and heat on etc. You have to put the clamp on the output of the DC/DC not the battery. Why? The fans, lights, radio are all drawing power through the battery which i...

Regarding low voltage protection, that would only work on batteries where the power flows through mofets. What I'm seeing in many newer batteries is they don't send the power through mosfets (this increases resistance and voltage loss) but instead rely on the tool to sense when the battery is low an...

70Kmph max speed. Couldn't take it on the highway. If it was highway legal and was $7500 it would be a free car for those in the US, because there is a $7500 federal rebate on Electric cars lol

The 12V is used to power 12V items. Not major power loads. So it powers fans and electronics. The biggest load is probably headlights. For example on the A/C the compressor motor runs on the mail traction battery at 400V or whatever, but the controls and air-moving fans will power on 12V. The best ...

I might try connecting my DC clamp meter to the 12V battery cable so I can see what kind of power that puppy is supplying with the AC and heat on etc. You have to put the clamp on the output of the DC/DC not the battery. Why? The fans, lights, radio are all drawing power through the battery which i...

5Kw could be ~500x 18650's which would be sub 25KG just for the cells or around 55lbs. I might try connecting my DC clamp meter to the 12V battery cable so I can see what kind of power that puppy is supplying with the AC and heat on etc. I believe the real killer of the battery is the liquid chilled...

So all production EV's I'm aware of use a 12V flooded lead acid battery which is charged by a DC to DC converter off the main Li-ion pack. This 12v battery powers lights, fans, accessories, and other car electronics. Some articles I read suggested that it may even be powering the heating and cooling...

Need more information. What is the BMS cutoff voltage? What temperature? What is your average current consumption?

I'd say make sure the cell continuous amp rating is at least double your actual continuous amp draw, or your pack will have a very short cycle life of maybe only 100-150 cycles if pushed to their limit. Also consider the Sanyo NSX. I prefer it over the 25R, its a bit more expensive, but has lower re...

LG M36 is the highest capacity readily available 18650 on the market. 3600mAh, 10A rated.

Sanyo GA, Samsung 35W, LG MJ1 are all 3500mAh and are close.

Any battery will prefer to spend its life at 25'C. Charging at 2C is no different to discharging at 2C - the heat is mainly coming from I^2R losses in the current collectors. The degradation is quicker at high states of charge too - more reactive species present. I agree, the heat dissipated will b...

I agree, it depends on your needs. The military often charges their long life Li-ion batteries to 3.92v per cell, which is around a 70% SOC providing much longer cycle life, and basically eliminating the CV stage of charging. NASA in some applications in space has used 20-30% DOD and achieved 10's o...