HV Battery repair gone wrong

It's sad that some things don't change.

 

Life experience comes with age, some have not really experienced everything yet and it's best to do the stupid things early in life vs later in life.

Those guys that blew their hands off lighting fireworks wished they had a second chance to redo what they did.

Just be careful while you learn, sometimes there are no second chances

 

Some recommendations to run parallel might have come from this forum, but not from me. (I did chime in with some pictures once on a thread somebody else started about it.)

There's no single group of "people like X" in a forum, there are all kinds, giving all kinds of advice, often conflicting. That's one reason it can be risky to start following advice seen in a forum before you've been around it a while for a sense of who are the players are and what are their strengths.

Then, of course, once you start posting, you're one of the players everyone else has to 'place' in the same sort of way.

Frank Westheimer said it best: "A couple of months in the laboratory can frequently save a couple of hours in the library."

-Chap

 

Well,

That's pretty much the response I expected.

This is not the first time I have reminded everyone that battery work is dangerous. It won't be the last. It's too easy for newbie's to read a bunch of posts and watch some videos and think that fixing a battery is simple and without risk.

So for those that follow and not necessarily TexasGen2Prius I'm going to explain what I think is going on with his battery. All I have to work with is what he has posted. This would be easy if I could see the car and battery.

Connecting battery modules in parallel does not work because the modules will all quickly reach the same voltage. This does not mean they have the same state of charge. Once this uniform "surface charge" voltage is reached current stops flowing between the modules.

The OP's parallel harness was carrying enough current to start heating up. That current did not come from the modules being in parallel. A different path must have been inadvertently created. If a module was connected backwards that would create a dead short across 15.6 volts and draw huge amps. It's unlikely that happened because there would have been a huge spark when connected.

The modules can leak electrolyte and then voltage. The first Gen modules commonly leaked at the terminal seals. That was fixed in the second Gen modules. Second Gen modules can crack next to the mounting hole which will ground the positive side of the module. This is a shot of a leaky module that was overcharged just enough to create some pressure.


I suspect the OP's pack has some leaky modules. This would explain why he saw some small sparks between the car body and his harness when it was quickly disconnected. Leaks could have created a path for current to flow through his harness. Using Techstream could have identified a leak without taking anything apart.

This is a puzzler. 28 modules all at 7.8 volts bolted together in series with solid bus bars and a good fuse will produce 220 volts. The voltage sensing lines have nothing to do with this. The wording "can't seem to get 220V on either side of the main line" is odd. What you are looking for is 220V across the main battery lines. For those not familiar with high voltage work note that the meter lines are in good shape and I'm using just one gloved hand. That measurement is across the positive and negative leads on the battery side of the relays.




There is a high voltage leak detection system built into the battery computer. A good explanation of the system can be found here. HV battery isolation question. | PriusChat .

If the OP measured between either battery lead and the battery case he could get a reading that starts at 40 V and bleeds down to 25 V. This is how the leak detection system works. In a non leaking battery the meter will bleed down to zero volts. The reading holding at 25 V indicates there is a leak.

This is acting like the orange safety plug is not properly installed. The OP has disassembled the battery several times so he knows the plug lever has to pushed straight down. That third step closes a low voltage sensing circuit to let the car know the plug is in place. That sensing wire can get knocked out of place and should be checked.

Open


Closed

 

....and he wasn't supposed to just do a whack a mole approach too!

 

I thinknthat is where his problems currently might be lurking-modules may not have being oriented correctly.

 

Brad,

You are a better man than I.

33 years experience in electronics, electrical and heavy industrial electron flowing systems. A hundred or so HV batteries, which, I believe, is probably a cup of water in the bucket compared to yourself. Your post nailed what was going on in my head as I read this thread. The follow-on posts and the inability to troubleshoot such a basic thing as why 28 modules connected in a series circuit isn't providing the expected voltage output confirms your post. It is merely battery modules and wires with a safety disconnect. There is obvious inability to understand the circuit. Without understanding, there is no logical troubleshooting path to a solution.

After reading the first several posts, I was formulating my own post to assist. But.....
Again, you are a better man than I, as my reading of the posts following your post crushed my desire to provide any assistance. Maybe I'm just an as***** too.

 

I have to commend those that take time to explain in writing what I often find it simpler to explain words (in person or over the phone).

There are so many things that I quickly do as part of troubleshooting that could take pages to actually write out the procedure for.

Often I assume that "all the basics have been checked". But in reality when troubleshooting long distance, any number of the basics could be improperly situated.

As strawbrad said, if could see the pack in person itigut be a really quick thing.

In the meantime, happy chasing!

 

It's good to have some people putting in the time with written explanations, because (as we've just seen) there will be people who will come to the forum and skim whatever written info is there and assume it's adequate and go start working, and not actually ask any questions until something is past the point of easy correction, and then those questions are awkward to answer.

I remembered this thread when I just stumbled yesterday on this safety page that seems to appear in similar form at various university physics departments; that there's a particular range of current most dangerous for inducing fibrillation, even more than higher currents, was a detail I hadn't known before.

Electrical Safety: The Fatal Current

-Chap

 

Did you clear the code even if there not one showing this happened to me I just cleared them anyway with the torque app

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At the orange output there's 0v if the the orange plug out or or not push down as the last step. Or if inside the plug are black from arcing (buld Grease) Or 12v missing to turn on the relays.
Each cell should have around 8v on each after you remove the nuts and the orange strip(with the nuts you can tell if any are missing or off) from the back seat the right pair are your higher pairs each pair has to be balance in discharge time (you have to charge all of them the same time how long it take to drop in 10 min then 20min avg fine one that matches) with a head light as your load across each cell one at a time.
I would discharge them and charge them a few times fist to refresh them.
At 1amp or 2amp to avoid heat
If you put paper under them you can find the one leaking I replaced then even know they tested fine. (I had a gasing of the battery problem no errors) can't breath it sucked but got better every day MPG jump with the bad battery lol
I tried just charging them all to the same voltage first. Car hated that lots of codes lights but no codes list cleared and the car drove fine but about balance it the key fixing it right

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Some photo

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