The "4800mAh 2-Cell/2S 7.4V Reaper 120C LiPo, Shorty" sounds really promising, they state 1152A max burst discharge. But can someone tell them that Deans/EC3/EC5/Traxxas/XT60 connectors are all hopelessly underrated for a battery that is rated for 576A continuous?The Lightning Stalker wrote: ↑Jan 27, 2018 9:34 amI don't know if these are new or if I just didn't notice them, but Thunder Power has some 120C stuff right now.
The specs on these are getting pretty insane now.
Are there any plans for pulse arc capabilities on the kWeld? Of course it would need the proper solenoid tungsten holder. I'm thinking it could be useful for welding ultracaps etc.
I want to make pulse arc welding experiments with kWeld, as I think that this is well in reach. Maybe it just needs a higher battery voltage.
I actually sell them: www.keenlab.de
Shipping is planned in week 9, but I am not sure if I can keep that because I have trouble with foreign customs at my board assembly service location. I will keep you updated.
What a monster!
That'll probably depends most on your battery, I forgot what type you plan to use? The welder itself accounts for 0.33mOhm (switch path) + 0.78mOhm (fuse path) from terminal to terminal (actual measurement data).
Keep in mind that this also adds inductance, and to dial the total round trip length into the unit if you exceed EDIT: 1 meter.
I will be using a 3S5P lipo made with very old zippy lipo 5000mAh 40C cells; this onetatus1969 wrote: ↑Feb 21, 2018 7:37 amThat'll probably depends most on your battery, I forgot what type you plan to use? The welder itself accounts for 0.33mOhm (switch path) + 0.78mOhm (fuse path) from terminal to terminal (actual measurement data).
That looks like it has very low ESR, together with your thick wires you may exceed the 2kA limit. You'll see during calibration, maybe you need to reduce to 2S. Just guessing, anyway.
No, calibration only measures between the two output terminals of the module, that is Rc3+Rc4. But as Rc1/Rc2 should be extremely low in your case, you can estimate the battery ESR from the current that is displayed, and the other known values.
It is 0.4m each for both electrode wires, and 0.1m each for the battery wires. The total is 1.0m, not including the lengths through the module, those of the electrode holders and electrodes, and of the wires on the Lipo itself. I wasn't too accurate here, but there is quite some safety margin.
While 12v LA batts are bulky, but I can pick them up for the core charge from battery sellers. When done return for money back. Married to a battery charger tender they last through a lot of welding, cheap.bigbore wrote: ↑Feb 22, 2018 9:58 amAs a LiPo alternative I would like to try a 4S4P made of LifePo4 A123 26650 like these:
http://www.batteryspace.com/A123-System ... 0-mAh.aspx
It's not about the inductive kickback, that only depends on flowing current and conductor inductance (inductance is a pure geometrical/material relation). The reasons why I try to keep the battery (or ultracapacitor) voltage as low as possible are this:
Big and heavy, but with a battery tender they re an effective and very inexpensive alternative. I've found a couple of battery resellers. Crown Auto and such, that take batteries in and payout a core charge. I can buy a 12V LA for under $20. T9opping off with distilled water and sometime a bit of battery acid can make for a power source for hundreds of welds. And when they drop off, you can take back and either get the refund or another battery. Not all shops will do that but making good relationships. maybe offering your battery welding skills, can make for an effective barter. I've got a deep cycle marine sealed (troller) battery. It just rocks on and on 640CCAspinningmagnets wrote: ↑Feb 23, 2018 10:23 amIt's starting to look like the 12V car starter lead-acid battery truly is the best option for someone who does not want to use LiPo.
The 12V style is everywhere, but I recall there are 6V lead-acid starter batteries for older cars and golf carts (perhaps rare, and hard to find though...)