nlspace
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Re: Onboard charger capacitors failed

Wed Oct 28, 2020 4:48 am

A "bad boy" is a bare bones chargger cheap hack that some EV folks used to avoid buying a proper EV chargging device, an example schematic from 2006,

Image

The juicce box falls into that class in my opinion: notice the lack of fuses or other protection, notice the useless current sensor on both output lines to the car (reads zero current, so what's the purpose) ; notice the tiny screws holding the large crimp terminals on the AC input to the contactor (the red one looks to be cocked) can you imagine 60A running thru that junction?; notice the missing components on the circuit board (what was the design for those parts and why are they missing?); do you see any controller chips? This is what happens when someone copies bits and pieces of stuff from other designs without really knowing what they are doing or how stuff works. Take stuff off to lower the cost--"hey it still works, don't need it."

For example if you were to look inside your OEM EVVSE you will find a zero current sensor such as this, but on the AC input lines in order to check for a ground and detect ground faults--it doesn't do any good on the output leads. Also you would find fuses on both AC inputs.

coulomb
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Re: Onboard charger capacitors failed

Wed Oct 28, 2020 5:24 am

nlspace wrote:
Wed Oct 28, 2020 4:48 am
notice the useless current sensor on both output lines to the car (reads zero current, so what's the purpose) ...

For example if you were to look inside your OEM EVVSE you will find a zero current sensor such as this, but on the AC input lines in order to check for a ground and detect ground faults--it doesn't do any good on the output leads.
? Won't it still detect residual current faults caused by leakage outside the unit?

Perhaps there are small leakages to ground in the unit (perhaps small Y capacitors), which might cause nuisance tripping if it was on the AC input leads?
2012 Leaf with new battery May 2019. New to me June 2019.

wxmatt
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Leaf Number: 023861

Re: Onboard charger capacitors failed

Thu Oct 29, 2020 1:28 pm

Upon further review, I don't think the seller is going to make me send the unit back, and I feel like I have to do ALL of my due diligence before spending $1,400 on a new OBC, so I'm getting my multimeter back out!
nlspace wrote:
Sat Oct 24, 2020 8:39 am
When you pull the board there are some diode voltage checks that you can do to make sure the waffle plate is not damaged.
I'll likely pull the board tonight or tomorrow depending on time.

nlspace wrote:
Wed Oct 28, 2020 4:48 am
A "bad boy" is a bare bones chargger cheap hack that some EV folks used to avoid buying a proper EV chargging device
I'm planning on purchasing a new EVSE, because I don't believe it can be a coincidence that I have two blown on board chargers AND an EVSE that was an early JuiceBox without some of the protective components you mentioned. If you have a prefered brand/model, I'd appreciate it. I'm still doing some research, but I don't want to bog the thread down too much with that tangent, yet.
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

goldbrick
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Re: Onboard charger capacitors failed

Thu Oct 29, 2020 4:26 pm

Since we're on the subject of substandard EVSE, does anyone here have a strong opinion about the OpenEVSE unit?

wxmatt
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Re: wxmatt's OBC failure

Sat Oct 31, 2020 7:20 am

Update on the Frankin-charger:

I got all of the components removed that need to be transplanted from the used charger chassi with the blown capacitor and coolant leak to the chassis from my original charger Without the coolant leak. I have figured out that the white box on the side is extremely difficult to open, even with the screws removed, so I plan to transfer that portion from the used charger to my original charger chassis as well. That way, I will keep the bottom board (and differences related to it) and the white box together from one chassis to the other.

As discussed, I have ordered a pair of replacement capacitors one necessary, one spare:
https://www.digikey.com/en/products/de ... K/5881170

I’m also on the prowl for the right type of RTV (staking compound). To the best of my guesstimation, I’ve determined it’s possibly RTV167. I haven’t been able to find a tube of that for under like 30 bucks. If that’s what it takes, it’s what it takes, but I was wondering if something like this would work: https://www.amazon.com/dp/B00065U8CY/re ... FbXA4B6PW .


nlspace wrote:
Sat Oct 24, 2020 8:39 am
When you pull the board there are some diode voltage checks that you can do to make sure the waffle plate is not damaged.
I have done some basic comparisons between the two boards, and in particular attempting to do the checks we had previously discussed to verify that those components work. To this point, the only component that I have been able to prove failed is the exploded capacitor on the “new“ salvage board. I have not been able to detect any other trauma, and certainly not the level of what happened to my original waffle plate.

Thank you very much for all of your help.
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

nlspace
Posts: 321
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Re: Onboard charger capacitors failed

Sat Oct 31, 2020 7:59 am

The electrical or electronic grade of RTV on a pcb is called "neutral cure" that doesn't release acetic acid during the curing process. This is to prevent etching and corrosion that could damage metal traces or component leads or solder joints. This is similar to why rosin core flux is used in electrical solder versus the acid core flux of plumbing solder. Don't want no acid on your board.

Most home and automotive type RTVs are acid cure. The neutral cure products do cost more but work great and are worth it compared to the time and cost of repairing acid damage.

It looks like your Loctite product is neutral cure, it releases MEK. Here's the MSDS link

http://industrialbolt.com/msds/loctite/ ... /18718.pdf

wxmatt
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Re: Onboard charger capacitors failed

Sat Nov 07, 2020 11:24 pm

I know it’s been a few days so I wanted to give an update…

Yesterday I got the old component desoldered from the board and replaced the capacitor on the bottom board with a new one. It’s not a process I’ve ever done before, so it took me a while to get it done and I ultimately had to break/force the pins off of the solder in the hole that I was not able to suck out. I put in the new component, I soldered it on pretty quickly and then used the “ultra gray” RTV along the sides to secure it.

I took the “new” bottom board and put it in the original charger chassis (N0A -> N5A). After reconnecting all of the internal components, I took the white box from the side and moved it as well (N0A -> N5A). After reinstalling it in the car, it works, and the car shows no errors!!

Thank you for your help in helping me resolving this. I took some videos and I would like to put together a video walking through what I did, but that’s gonna take some time.
2012 LEAF (White) - Purchased in 11/14
2010 Rogue (Black)
1987 BMW 325i (Red)

nlspace
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Re: Success--Onboard charger capacitor Replaced

Sun Nov 08, 2020 7:34 am

That's great news i'm glad to hear it, good job on replacing the parts and getting it working.

It can be difficult to get enough heat into parts on such a large board with lots of thick copper traces. i use a 150W solder gun for such applications with copper wick to remove the excess solder.

The RTV helps hold the bigger parts in place and damp out road vibration that could crack the solder joints.

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Marktm
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Re: Onboard charger capacitors failed

Sun Nov 08, 2020 8:46 am

goldbrick wrote:
Thu Oct 29, 2020 4:26 pm
Since we're on the subject of substandard EVSE, does anyone here have a strong opinion about the OpenEVSE unit?
I've used mine for several years now. I've also modified it to facilitate usage as a solar energy controlled charge controller - using the included RAPI tools. I've not kept up with recent designs - have there been any significant changes? - don't really know. It's a great unit. Maybe not the most "professional" look, but really robust.
2012 Leaf SL; 46,000 miles. Battery replaced November 1st, 2016.

goldbrick
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Re: Onboard charger capacitors failed

Sun Nov 08, 2020 9:23 am

Thanks Marktm. That is what I thought and I'm glad to hear it since I already bought mine. I haven't hooked it up yet since I want to put a sub-panel in the garage first. Plus, charging at work is free.....

I don't know of any very recent updates but the hardware certainly looks well designed and it is certainly looks well engineered but I haven't worked on analog circuits for about 35 years.

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