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Discussion Starter · #1 ·
Gonna try to post some pics of interesting projects I get into here. Working on getting our website/FB page back up in anticipation of future endeavors.
This is a Karma with power inverters overheating caused by a low temp coolant loss. Found a cracked weld on front traction motor. Required surgery...thanks to Dave at DC Customs for a sick TIG welding job (see last 2 pics).
Pics show RDM coming out and soapy water and pressure test. Bubbles at leaking weld. Then loaded into truck to fabricator.
 

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Some pics of battery removed and uncovered. And yes its as dangerous as it looks
The battery innards look fascinating. Are the black rectangular components with the green tags the modules we have heard so much about?
 

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The battery innards look fascinating. Are the black rectangular components with the green tags the modules we have heard so much about?
Fab yes you are correct those are the modules each module contains 21 cells . The battery hold three different type of modules .
In Joe's case he had a bad module 10 so we can remove that module and replace it with another module 10 .

If he didn't have a number 10 module you can another module as long as it's part of the set . They contain Postive and negative modules . Also on the side where is looks like a L you can see all the electronics .
 

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Some pics of battery removed and uncovered. And yes its as dangerous as it looks
Anyone who's ever accidentally welded a screwdriver to a car via the ordinary 12V lead-acid battery should have a healthy respect for batteries already. :D

(The Li-ion batteries in EVs—or even cell phones and computers, for that matter—are willing to put out the same kind of current, and in EVs they are generally strung together to make 300 to 400 volts, depending on EV details.)
 

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After I remove the batteries cover I have two sets of gloves I wear until I make the battery safe enough to work on . A set of heavy rubber gloves then a set of leather gloves worn over the rubber gloves rated to 1000 Volts . I also refuse to answer the phone or let anyone near me while I'm making the battery safe to work on . One wrong move it's all over
 

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Discussion Starter · #9 ·
Yes @ct-fiskerbuzz correct about the tool welding trick lol. Actually the first couple times I disassembled the HV battery, I was admittedly worried about touching the wrong thing which is a very real possibility, but the gloves (as clumsy as they are) do help confidence. Its certainly not safe for the untrained.My buggest fear is dropping a tool into it. Its one thing to put your wrench on the wrong bolt of your V8.Its a bad day when your wrench hits the wrong place in this baby. Ive heard the use of the word "vaporize" amongst hv engineers...
 

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Absolutely! Its 1 1/2 times the total amperage of my entire house. So considering a 4 bedroom house has a max 200 amp thats enough to run all electric with a family including dryer, range, A/C, lights etc..
Yes I respect the electron...
 

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Absolutely! Its 1 1/2 times the total amperage of my entire house. So considering a 4 bedroom house has a max 200 amp thats enough to run all electric with a family including dryer, range, A/C, lights etc..
Yes I respect the electron...
Under hard acceleration uphill, I have seen the car consume 165KW, or 550A (at 300V), which would be equivalent to 3 household connections. Another way to think about it is that a typical household uses, on average, around 3KW and when I punch it uphill, my battery can provide that level of electrical power for 55 households. Any way you look at it, there is an incredible amount of power stored chemically in that battery. Two pairs of gloves would be the very least level of protection I would use. I would probably wear a full-body, grounded chainmail personal Faraday cage on top of everything else.
 

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Technically, it's both. Think of "voltage" as "pressure in the straw, hose, water-main, or other water-pipe" and "current" as "cross section" (diameter of the pipe).

When you go over the top of Niagara Falls, the pressure is not very high, but the cross section is enormous. It all pours relatively gently, but there's so much of it that you can drown quite easily.

When you take a regular garden hose and put a sprayer nozzle on it, the pressure goes up. The amount of water coming out from the hose is the same, but instead of pouring gently, it squirts a long way. There's not that much water coming out but if someone aims it at your nose and mouth (and for some reason you can't move), you can drown quite easily.

(This is how high voltage power lines work: the cross section is narrower, which makes it possible to use thinner, cheaper wires, they just have very high electrical pressure. At the local substation, some of the energy flow is tapped off, going into lower pressure "pipes", until eventually a thin, split-off piece of the energy-stream reaches your house at 240 volts of pressure. If they gave it to you at 24 volts, the wires going to your house would have to be ten times thicker. [This is way oversimplified, the "thickness" has complicating factors, but close enough for thinking about it.])

In any case, though, this points out the huge power requirements for automotive transportation: your house gets 100 to 200 amps, times 240 volts. Say 200 x 240 = 48000 watts (48 kW). Your Karma can do roughly 300 x 360 = 108 kW.
 

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Discussion Starter · #18 ·
Technically, it's both. Think of "voltage" as "pressure in the straw, hose, water-main, or other water-pipe" and "current" as "cross section" (diameter of the pipe).

When you go over the top of Niagara Falls, the pressure is not very high, but the cross section is enormous. It all pours relatively gently, but there's so much of it that you can drown quite easily.

When you take a regular garden hose and put a sprayer nozzle on it, the pressure goes up. The amount of water coming out from the hose is the same, but instead of pouring gently, it squirts a long way. There's not that much water coming out but if someone aims it at your nose and mouth (and for some reason you can't move), you can drown quite easily.

(This is how high voltage power lines work: the cross section is narrower, which makes it possible to use thinner, cheaper wires, they just have very high electrical pressure. At the local substation, some of the energy flow is tapped off, going into lower pressure "pipes", until eventually a thin, split-off piece of the energy-stream reaches your house at 240 volts of pressure. If they gave it to you at 24 volts, the wires going to your house would have to be ten times thicker. [This is way oversimplified, the "thickness" has complicating factors, but close enough for thinking about it.])

In any case, though, this points out the huge power requirements for automotive transportation: your house gets 100 to 200 amps, times 240 volts. Say 200 x 240 = 48000 watts (48 kW). Your Karma can do roughly 300 x 360 = 108 kW.
Thanks! I feel much safer now... :-/
 
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