Shocked Touching my 12v Car Battery

[Hedges]

And to reinforce the concepts here. Pretty sure 12V->120VAC inverters are required to be isolated.

Some cheap ones aren't, put out +/-60V instead of 120V.
Better ones are.

On a listed AIO or hybrid there is supposed to be PV side ground fault detection

That would not shut anything off until after it had fried you.
About 1A ground-fault detection level. Some even used a 1A fuse between PV- and ground, checked for voltage across it.

 

[HarryN]

What might help is an isolated converter from a reputable source.

This will separate both sides of the circuit from each other.

The ecoflow or whatever you use will need to also be isolated from ground during this charging process.

I am trying to figure out why your are getting a shock from the car itself to the garage floor. This would imply that your car has a power leak - like a wire touching the frame of the vehicle ? Not sure.

Is the ground path coming through your house AC panel on the wall - through the house ground system ?

Do you get shocked or measure a DC voltage from car to ground without the DC - DC charger in place ?

Just really curious, because I had planned at some point to do this with a DIY power system.

My approach was going to be to:
- use an inverter to turn the 12 volt EV battery into 120 vac
- and feed it to the DIY power system 120 vac battery charger.

In my case, it is all double insulated through, so not a common ground path.

 

[MtnXfreeride]

Do you get shocked or measure a DC voltage from car to ground without the DC - DC charger in place ?

i dont.. only when the pro ultra solar switch is flipped on does it shock me.

I was wondering if sucking it up and doing the less efficient dc to ac back to dc is safer.
What brand are you looking at for this?

 

[Bluedog225]

Not trying to be an @ss. But going around barefooted and touching electrical stuff is not going to end well for you.

And glad you have a multimeter to test everything relative to everything you touch is a great idea.

 

[Brucey]

Not trying to be an @ss. But going around barefooted and touching electrical stuff is not going to end well for you.

And glad you have a multimeter to test everything relative to everything you touch is a great idea.

Maybe add some water ponding on the floor and seems to be ideal situation for a GFCI to trip?

 

[MtnXfreeride]

Maybe add some water ponding on the floor and seems to be ideal situation for a GFCI to trip?

You guys make me want to re setup this thing and *with shoes on* touch it again and something tells me I will still get a shock.
I can see from my nest camera in the garage 1 foot was on dry carpet and one was on dry concrete.

 

[Bluedog225]

We want new members to stick around. We need the dues.

And welcome!

 

[Hedges]

Touching a car with bare feet is usually OK.
The only shocks you're supposed to get are static.

An EV that is plugged in, or any car with a battery charger, vacuum cleaner, any other AC connection ought to be treated as an AC appliance. (kitchen, we hope things are properly grounded or otherwise safe.

Consider a quality inverter that you would use for other purposes as well, e.g. for tools, camping appliances, portable backup.

 

[MtnXfreeride]

Touching a car with bare feet is usually OK.
The only shocks you're supposed to get are static.

An EV that is plugged in, or any car with a battery charger, vacuum cleaner, any other AC connection ought to be treated as an AC appliance. (kitchen, we hope things are properly grounded or otherwise safe.

Consider a quality inverter that you would use for other purposes as well, e.g. for tools, camping appliances, portable backup.

It was hard to find the aliexpress inverter. I'm not sure a good brand 12v to 48v 20amp dc step up converter exists?

At this point I wont use the thing unless we get a 4 week ice storm and its life or death.

Before I give up on trying to use my ev battery I may give a high quality dc to ac inverter a try and plug the delta pro ultra in with the charge set to 700watts max.

 

[mrzed001]

And to reinforce the concepts here. Pretty sure 12V->120VAC inverters are required to be isolated.

Not even 12Vdc -> 230Vac inverters :D

I dig up the video I was referring previously. It is in hungarian language but the pic speaks for itself (also has English subtitle)

Non isolated inverter -> Null to ground -> 12V battery terminal lethal shock.

DC DC converters in general are probably safer to assume to be non-isolated, unless advertised to be isolated. Since it's more expensive to build an isolated one (need to add an internal transformer [could be LF or HF] big enough to pass the power)

In the offgrid - hybrid inverters the battery side is isolated (12-48Vdc <--> 400Vdc bidirectional DC/DC), but the MPPT side is not (60 - 1000Vdc --> 400Vdc DC/DC)
Both use the highVDC BUS. From there the inverter makes the DC/AC (bidirectional so it makes AC/DC too)

Some old inverters were wired so that low 120-140V MPPT was working to the lowVDC BUS. So battery to Solar not isolated, but both isolated to AC.

 

[zanydroid]

Some cheap ones aren't, put out +/-60V instead of 120V.
Better ones are.

That’s probably not UL compliant.

 

[zanydroid]

That would not shut anything off until after it had fried you.
About 1A ground-fault detection level. Some even used a 1A fuse between PV- and ground, checked for voltage across it.

This is true. But nothing alarmed on the EcoFlow. WTF? (Unless OP missed it)


To be clear, I was throwing yet more shade on the EcoFlow for not having a sensitive enough PV ground fault detector. On top of not isolating a 30V side from 120V, in an appliance intended for noobs.

 

[zanydroid]

Not even 12Vdc -> 230Vac inverters :D

I don’t think it can get a safety listing though?

Double power move/gigachad: skip the isolation and GFCI on output. Puts hairs on your chest

 

[zanydroid]

An EV that is plugged in, or any car with a battery charger, vacuum cleaner, any other AC connection ought to be treated as an AC appliance. (kitchen, we hope things are properly grounded or otherwise safe.

A proper EVSE will have a lot of ground monitoring checks before it closes the contactors and energizes the car. And there is GFCI to boot. But, a lot of people buy non-proper EVSE. Surprised the RealNews outlets haven’t reported on EV charging killing people, maybe it’s not really that bad.

Kitchen appliances — people usually aren’t buying countertop AC appliances off Amazon/Aliexpress. And the fixed appliances are well vetted since they generally come through appliance stores and big box.

 

[efficientPV]

A lot of wild speculation here and perfect fodder for a forum. This wouldn't take 10 minutes to solve with some instrumentation. Jumping to conclusions is the worst way to solve a problem.

 

[Bluedog225]

A lot of wild speculation here and perfect fodder for a forum. This wouldn't take 10 minutes to solve with some instrumentation. Jumping to conclusions is the worst way to solve a problem.

Dunno, touching stuff is a little worse.

 

[zanydroid]

A lot of wild speculation here and perfect fodder for a forum. This wouldn't take 10 minutes to solve with some instrumentation. Jumping to conclusions is the worst way to solve a problem.

WDYM?

FWIW I’m not counting on OP to test the ecoflow to a level of accuracy to see whether it’s isolated or not.

I don’t think it’s fair to call what I and others said wild speculation. People generally are not aware enough about the fact that non isolated is the dominant form of power architecture today (outside of microinverters, which aren’t DIY hacked that much for various reasons). So I don’t feel bad at all ranting about it for the Nth time

 

[mrzed001]

A lot of wild speculation here and perfect fodder for a forum. This wouldn't take 10 minutes to solve with some instrumentation. Jumping to conclusions is the worst way to solve a problem.

And how could OP know what to test if there is no theory about what caused it ?
Cant jump with a scope to all problems

Also we are thinking together and it is great !
This is the main purpose of a forum.

 

[Supervstech]

Ok.
This happens ALL THE TIME.
any device without a ground tied to a device generating voltages to or from a device that is isolated from ground will have potential leakages.

Battery chargers, etc.

The issue is you have grounded to frame charging, and grounded to earth boxes.

Connect an earth ground to the vehicle and you wont get shocked.

If the charging cable was connected to the vehicle i bet you wouldnt have a measurable potential...

 

[mrzed001]

Ok.
This happens ALL THE TIME.
any device without a ground tied to a device generating voltages to or from a device that is isolated from ground will have potential leakages.

Battery chargers, etc.

The issue is you have grounded to frame charging, and grounded to earth boxes.

Connect an earth ground to the vehicle and you wont get shocked.

If the charging cable was connected to the vehicle i bet you wouldnt have a measurable potential...

The DC/DC converter is not isolated (link is somewhere here).
It is connected to Eco MPPT port (I would bet not isolated)
If you ground Eco and ground the car .... the result would be a short circuit (and smoke from Eco)
Like if you ground one of the solar cables in a string inverter.

 

[Hedges]

Connect an earth ground to the vehicle and you wont get shocked.

As this setup was wired, you just said, "Ground the PV- input of inverter."

The DC/DC converter is not isolated (link is somewhere here).
It is connected to Eco MPPT port (I would bet not isolated)
If you ground Eco and ground the car .... the result would be a short circuit (and smoke from Eco)
Like if you ground one of the solar cables in a string inverter.

Which would result in bad things happening, because PV- is probably riding negative half of AC waveform.

 

[Supervstech]

As this setup was wired, you just said, "Ground the PV- input of inverter."



Which would result in bad things happening, because PV- is probably riding negative half of AC waveform.

No.
I said connect the vehicle frame to earth ground.
The issue is you are feeling the potential of the earth ground and the vehicle ground.

If you have a device that is pumping out current to the frame of the vehicle, dont use that...

 

[zanydroid]

If you have a device that is pumping out current to the frame of the vehicle, dont use that...

The Ecoflow is doing inverter -> MPPT -> car battery

If the ecoflow is plugged into the wall and the car is earthed to an EGC at the house, that feels like bad news bears because there will be a

eco flow inverter -> N -> N-G (either in ecoflow or at main panel) -> car frame -> battery/ecoflow MPPT path

 

[zanydroid]

If I was working on OP’s setup I would probably stop all work and iteration until I’m sure I understand how to reliably test for unexpected galvanic paths or understand the theory

Joining together 10 random advice from 10 random people on the internet without this work is going to end badly

 

[JWLV]

Unless you are 110% confident of your work and the work of the company that made the devices you are using...

1. Gloves
2. Shoes
3. Thermal imaging camera
4. Eye protection