General DIY maintenance and safety for EVs

[Theo]

In the video tutorials of the Varg, in the owner's manual and in their technical pdf files they write that high voltage components should be handled only by qualified personnel.
Yet it seems to me that some people change power units or batteris on their own and some buy Talarias and upgrade them on their own, without mentioning safety.
I've been wondering how safe it really is and whether people protect theirselves when doing those things. I'm starting to gather some information about it on the internet but I haven't found anything very specific yet, like a video about safety guidelines for EV maintenance with technichains showing how they do certain things, just something for general concepts like electrical grounding.
Just as an example, if I wanted to disconnect the battery, would it be a wise idea to clean its plug -probably dirty- pouring water on it before disconnecting it and then waiting until it dries? Should I wear things like insulating rubber gloves or electric static shoes?
I hope that someone can contribute to this thread, hopefully someone who has professional experience in EV maintenance and/or manufacturing.

 

[happyinmotion]

The Stark is a different level of quality and safety to a Talaria or similar. For example, the 400V battery in the Stark has an internal contactor that doesn't turn on until the battery receives the right commands over the CAN Bus. That should make sure the external terminals aren't powered up until everything is connected. Whereas the batteries on the cheaper bikes are much dumber - my Sur-Ron has a 60V battery with that Voltage exposed at the terminals.

As for cleaning connectors - just a wipe with a dry cloth. No reason to put water near electrics even if those electrics are powered down.

 

[ProperHooligan]

There are two things to consider, voltage and current. It’s reported to only take around 100 milliamps to stop your heart. Human skin will start to conduct electricity over 48v. So yes there is a real danger working on these systems without taking precautions. At a minimum gloves rated for the voltage you’re working with when the circuit is energized is a good idea.

 

[datadog]

EV batteries are generally safe until there is loss of isolation, or things like welded contactors or cell imbalance. If you are looking for info on the internet, Google isolation loss and HVIL.

 

[Theo]

There are two things to consider, voltage and current. It’s reported to only take around 100 milliamps to stop your heart. Human skin will start to conduct electricity over 48v. So yes there is a real danger working on these systems without taking precautions. At a minimum gloves rated for the voltage you’re working with when the circuit is energized is a good idea.

Research done: apparently there are different classes for those gloves according to the ASTM D120 standard, that is used even here in Italy: the 00 class should be suitable for the Varg, since it's approved for 500 V AC or 750 DC. They seem affordable.
A piece of advice I've liked is to test those gloves for air leaks before use to make sure they are not pierced.
Considering that they look so thick, though, especially when protected against cuts and abrasions by other gloves over them, I suspect that they would make it difficult to use tools etc., so I also like the idea of using one unportected hand only when possible so that it's unlikely that voltage would pass from one hand to the other through the chest; I guess that using some insulator under the feet should prevent the current from passing from that hand to the ground.

If you are looking for info on the internet, Google isolation loss and HVIL.

Done it, thanks; from the videos I've seen, it looks to me like the battery of the Varg has an HVIL connector, with a pair of low voltage pins and a pair of high voltage pins.

 

[datadog]

If busbars are not exposed, Cat zero gloves are not a requirement, but are recommended f you are not certain of battery health. Test them every time you use them and replace them yearly.

 

[Theo]

The Stark is a different level of quality and safety to a Talaria or similar. For example, the 400V battery in the Stark has an internal contactor that doesn't turn on until the battery receives the right commands over the CAN Bus. That should make sure the external terminals aren't powered up until everything is connected.

Does this work when the bike is shut down, meaning with no light at all from the LED in the control switch? In their video and pdf tutorials they say that the bike should be turned off before disassembling electrics or electronics, but in their videos and documents sometimes they consider it "off" if it's in standby mode with a flashing red LED and sometimes when the LED is completely off...

 

[happyinmotion]

It should do. The whole point of an EV contactor is to make sure that high voltages are not exposed under everything else is connected and powered up and working correctly.