I'm trying to replace the encoder batteries on my SV3X arm. The batteries don't look like the factory batteries. Something the previous owner put together, maybe. Basically each battery "pack" consists of two Toshiba ER6V cells wired in parallel. On one of the packs, there are two components soldered to each of positive leads from the battery: a resistor and Schottky barrier diode. What purpose do they serve? Current limiting? Should I build a replacement "pack" that exactly matches? The OEM batteries don't appear to be widely available these days. I have included a photo. Thanks for any info.
Mystery components on SV3X encoder battery
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RoboDad -
June 1, 2018 at 9:17 PM -
Thread is Resolved
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Yup, those are home made battery packs. I would call Yaskawa to get the correct batteries for this arm.
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Thanks Robodoc. I will try that.
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Hi , when two batteries are parallel paired a Blocking Diode is put in the circuit to stop discharge between batteries, when batteries have a small output ie. 3volts , putting a silicone Diode with a Fwd VDrop of .5volt , starts to defeat the purpose , especially when Battery alarms are set approx. 2.5volts. By using a Germanium Diode the VDrop is only .2volts , unfortunately this type of Diode has a very small amp loading/rate. To protect it a resistor is put in series , this protects the Diode by limiting battery discharge.
For 30 years all We did was buy the batteries from any source ( Hongkong) and reuse the resistor & Diode circuit.
Hope this helps. -
Ok, yeah, that makes sense. Thanks!
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Ok, I made progress! I replaced the encoder batteries, set the home position, and now I can jog the arm around! Woohoo!
I would also like to replace the battery inside the XRC controller (I haven't gotten an alarm on it, but it's been sitting in my garage for years, so I figure I'm tempting fate). Question is: is it better to replace the battery with the XRC powered on, or off? The manual doesn't say which. It does suggest that there's a super capacitor that will keep the memory going for some period of time. So that would suggest that I change the battery with the power off? What's the best practice here? Thanks!
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Important!!!!!!!!
Only change systems Battery with the POWER ON ! If you change “any Batteries” it pays to leave the power On.
it’s also a good idea to drive the robot to it’s mechanical/ encoder Home position before changing any Batteries this way if you loss recorded Origin position you can re-record without losing positional Data for existing taught programs. one of the weakest components in any electronic circuit is Electrolytic Capacitors and the Super Cap. Is one such device , don’t trust them. They age faster with the power off , it’s a crap game.
I have the manual for the XRC -SV3LX if you send me a PM with your email address i will fwd it. -
Thanks Pcarbines... I will swap the battery with the power on.
I think I found the trove of manuals on the Motoman site, including the SV3X manual. Thanks for the info!