Almost burned my cart and garage down last night

[Pat911]

36v, or even 48v cannot produce the amps through the human body to kill you. The voltage is not high enough. Yes, you can be burnt by those amps flowing through a conductor that is burning up, but you cannot be electrocuted.

You can touch the positive terminal with one hand and the negative terminal with the other on a 36v or 48v battery and you will be fine, now try doing that with 110vac, or heaven forbid, 220vac! (No, please don’t do it, take my word for it.)

Cheers
Pat.

[DaveTM]

Originally Posted by Pat911

36v, or even 48v cannot produce the amps through the human body to kill you. The voltage is not high enough. Yes, you can be burnt by those amps flowing through a conductor that is burning up, but you cannot be electrocuted.

You can touch the positive terminal with one hand and the negative terminal with the other on a 36v or 48v battery and you will be fine, now try doing that with 110vac, or heaven forbid, 220vac! (No, please don’t do it, take my word for it.)

Cheers
Pat.

Welp, I will agree to disagree with your comments on the battery pack amps. A flow of 36V or 48V battery pack through your heart will tell you....or your surviving family, a much different outcome.

Respect the power of that pack.

[bronsonj]

Originally Posted by crash12888

People need to understand it's not the volts that will ruin underwear, it's the amps!
A normal household wall circuit will be 110volts at either 15amp or 20amp, that's like touching your tongue to a new 9V battery,
While a basic electric cart is 36volts but able to produce on average 300 to 400 AMPS!, that's where the pain comes from.....

I like to think of it in terms of watts.
110V*15A = 1650 watts.
400A * 36V = 14,400 watts.
400A * 48V = 19,200 watts...

I have no idea what voltage or amperage it'd take to kill someone, but I can tell you I don't want to "be the conductor" for anything over 1650 watts!

[ThreeCW]

Here is an interesting video that discusses how electricity (either AC or DC) can affect the human body.

Under the right conditions (which can be something as simple as wet skin), either AC or DC can kill you.

https://www.youtube.com/watch?v=9iKD7vuq-rY

[Pat911]

Originally Posted by DaveTM

Welp, I will agree to disagree with your comments on the battery pack amps. A flow of 36V or 48V battery pack through your heart will tell you....or your surviving family, a much different outcome.

Respect the power of that pack.

WARNING, do not try what I’ve done below at home. I KNOW WHAT I AM DOING, both in theory and in practice. It is only for DC as AC current behaves differently in the human body.

Voltage doesn’t flow, current flows. The current that a battery back can deliver is absolutely irrelevant, as are watts or stored energy in electrocution as you can be electrocuted and killed by as little as 10mA, or 0.01A. That can be delivered by an AA battery under the correct conditions.

A 48v pack can deliver 300A, but that is into an almost short circuit. Ohms law states that voltage=current x resistance, or V=IR, so R=V/I. For 300A to flow from a 48v pack, R=48/300 = 0.16ohm. The human body is nowhere near that.

The resistance of the human body is affected by many factors and cannot be predicted accurately for any single person, so I measured mine With dry hands, squeezing tightly I got 3.5Mohm (3.5 million ohms) from one hand to the other. With wet hands it dropped to 1.5Mohm. At 48v, this equates to 0.013mA dry and 0.032mA wet. Well under the electrocution current. Me, being the adventurous type, and having a 72v Lithium pack that I’m in the middle of building thought “let’s get real world numbers”

My 72V pack is currently at 70V, so we’ll use that figure. With dry hands, I MEASURED 0.001mA flowing through my body and with wet hands I MEASURED 0.004mA. The measure to was taken with one hand on the negative terminal, the positive probe of my multimeter on the positive terminal of the battery and my other hand touching the negative probe of the multimeter. The multimeter can resolve down to 0.001mA. I only felt the slightest of tingle when letting go with the wet hands and that would have been the current flow transitioning from directly through my skin to across my wet skin. I felt nothing the rest of the time.

Using the above figures would indicate a dry resistance of 70Mohm and a wet resistance of 17.5Mohm.

Anyhow, I’m still here, typing away and I stand by my previous post that you cannot be electrocuted by a 48v, or even a 72v battery pack, regardless of how much current it can supply as it cannot supply a current through your body that is able to electrocute you. You can however be severely burnt by touching something that is heating up due to a short circuit. My brother in law severely burned his wrist once when working on his car and his metal watch strap shorted 12v to ground. The band heated up and burnt him. That’s why you should remove all Jewelery when working around high current batteries.

Cheers
Pat.