Recommended Battery Case Mod

[Planemo]

I am in the process of replacing a bms on a V1 Sherman which had a crash. Disconnection of the right side packs from the motherboard showed the wheel balancing properly and no bt loy error so that pointed me to the left side packs. But there is a bms on each of the two left packs so, which one do I go for? Well, I took a gamble and went for the pack that sits under the heavily modified rib section of the later panels. Removed the heatshrink and all looked ok, very Gotway-esque...

...but whats that? A tiny mark going across the top of the lower chip...?

Hmm...closer look with a macro lens...

and there we have it. The location of this crack directly corresponds to a rib on the panel. One of the same ribs which Veteran removed on the later panels.

Interestingly, Veteran removed more ribbing than one might imagine at first glance. It was only when I got hold of this V1 I could see the differences. On the older panels, the recessed sections have ribs all over, on my later ones there are just a couple. So if you have the early panels, reduce the ribs in all the areas that might hit the components, not just the 3 obvious ribs that you might only see at first glance on the later panels.

Edited August 9, 2021 by Planemo

[Planemo]

In fact I stole Bens original pic to show what I mean...

I actually removed more ribs going further up the panel on mine (which would be the right side on the above pic) as theres additional components on the left side bms. I think I covered that in my previous post/pics though.

[Dominic Winsor]

19 hours ago, Boogieman said:

You cut the wire and spliced it with the worst crimp type there is? (The kind crappy car mechanics use on old cars)

Man that is gutsy. I would for sure weld it (solder), actually dont think i would cut it to start with, the current travels through the thin wires and a splice only acts on outer part of the wires in the full area meaning less area for current to pass = more heat = possible meltdown of the plastic = possible short

I've done 200 miles of riding, including some long steep hill climbs where the temp climbed. I have inspected the crimp and surrounding area several times since it was installed, and it is absolutely fine. There are zero issues to report here.

I did wonder about a splice and solder but meh. The crimp works perfectly.

[Planemo]

19 minutes ago, Dominic Winsor said:

I did wonder about a splice and solder but meh. The crimp works perfectly.

I would have to be with Boogieman on this Dom. I would never, ever use a joint of that sort with the sorts of voltages and currents we are dealing with here. In fact the less joints the better, and certainly nothing less than an XT60. I am sure it works, but if you get a chance to go back in there sometime and solder/heatshrink it, you would put our minds at rest!

[Dominic Winsor]

44 minutes ago, Planemo said:

I would have to be with Boogieman on this Dom. I would never, ever use a joint of that sort with the sorts of voltages and currents we are dealing with here. In fact the less joints the better, and certainly nothing less than an XT60. I am sure it works, but if you get a chance to go back in there sometime and solder/heatshrink it, you would put our minds at rest!

Hmm — Ok. I'll check again later on. I have all the things I need.

Thank you for the concern!

[Dominic Winsor]

5 hours ago, Dominic Winsor said:

Hmm — Ok. I'll check again later on. I have all the things I need.

Thank you for the concern!

Just checked. Still as fresh as the day it was installed. Perhaps I’ll fix this at the weekend. 

[Planemo]

To be fair, a well applied yellow butt crimp could probably handle 40 to 50A. The issue I have with them is applying them properly, as they are only as good as the prep and application. Even a slightly over zealous set of wire strippers could damage some wire strands enough so that after crimping (which doesn't cover the damage) the wire can fracture and fail. In short, the viability of the crimps is 99% down to how well they are applied. I agree that decent soldering still takes some skill, but in doing so I am putting my faith in myself, rather than whether my crimping tool is applying enough torque. It's not even like you can effectively 'test' the breaking strain of a crimp after it's applied. At least you can visibly check a decent solder joint, with a macro lens if you are that bothered. A crimp could be massively compromised without you even knowing it, even if you do give it a gentle 'pull' afterwards (and don't we always do it gently  )

[Dominic Winsor]

39 minutes ago, Planemo said:

To be fair, a well applied yellow butt crimp could probably handle 40 to 50A. The issue I have with them is applying them properly, as they are only as good as the prep and application. Even a slightly over zealous set of wire strippers could damage some wire strands enough so that after crimping (which doesn't cover the damage) the wire can fracture and fail. In short, the viability of the crimps is 99% down to how well they are applied. I agree that decent soldering still takes some skill, but in doing so I am putting my faith in myself, rather than whether my crimping tool is applying enough torque. It's not even like you can effectively 'test' the breaking strain of a crimp after it's applied. At least you can visibly check a decent solder joint, with a macro lens if you are that bothered. A crimp could be massively compromised without you even knowing it, even if you do give it a gentle 'pull' afterwards (and don't we always do it gently  )

To be fair I did give it the full 200lb gorilla treatment. The crimping and the pulling! Rawrrrrr!

What I’ll probably do is replace the whole wire, or make a small linkage with some XT connectors as I’m more confident doing that. 

[Naz]

Apologies in advance, this question might be redundant but I’m confused regard which battery the shaved down section is supposed to cover. I know the panels can go on either side but does the shaved down portion go over the front toward the headlight or rear (toward the tail light) batteries? 

[RockyTop]

14 minutes ago, Naz said:

Apologies in advance, this question might be redundant but I’m confused regard which battery the shaved down section is supposed to cover. I know the panels can go on either side but does the shaved down portion go over the front toward the headlight or rear (toward the tail light) batteries? 

Forget about front and back. The sides are not mirrored the other side is turned. So you make both panels the same as you see in the picture above. 

[.....]

On 7/7/2021 at 8:47 AM, Planemo said:

I would have to be with Boogieman on this Dom. I would never, ever use a joint of that sort with the sorts of voltages and currents we are dealing with here. In fact the less joints the better, and certainly nothing less than an XT60. I am sure it works, but if you get a chance to go back in there sometime and solder/heatshrink it, you would put our minds at rest!

I agree and have always lived by the idea that solder alone does not make a mechanical connection. Just as a crimp connector alone, makes a mechanical connection but a shitty electrical connection. I have always used crimp sleeves or staples with a proper kline crimper and THEN flow solder into that connection. THEN slide shrink tubing over the entire thing. I cant even fathom how many hundreds of those plastic sleeves I've removed from crimp connectors, prior to use. Can't solder with that plastic sleeve on and shrink tubing makes up for it. Its also impossible to tell if the crimp is PERFECT, if its hiding behind that thick plastic crap sleeve.

[Boogieman]

On 7/7/2021 at 2:09 PM, Planemo said:

In fact I stole Bens original pic to show what I mean...

I actually removed more ribs going further up the panel on mine (which would be the right side on the above pic) as theres additional components on the left side bms. I think I covered that in my previous post/pics though.

I read your post again more carefully.

One BMS PER PACK (so 4 in total :-o ). Then i understand that the additionally removed ribs at the green circle is for the other bat packs IC.

EXCELLENT INFO,  my V2 had that removed from factory as below.

Did you remove even more fins than the ones encircled in your image? You wrote fins even further up, is that needed?

Edited July 20, 2021 by Boogieman

[Planemo]

Yes I removed more ribs than the stock 'modded' panels from Veteran.

This is because:

1. The stock de-rib doesn't take into account the IC's on the other BMS.

2. The stock de-rib doesnt take into account that there are other components sitting proud of the BMS other than the IC's. Not as proud as the IC's I grant you, but proud nontheless.

My approach is what I would call 'belt and braces'

Edit: when I get a chance, I will pull one of my panels and highlight every rib that I modded, as I appreciate that nothing I have posted so far is overly clear... 

Edited July 20, 2021 by Planemo

[MrRobot]

On 7/20/2021 at 2:41 PM, Planemo said:

Yes I removed more ribs than the stock 'modded' panels from Veteran.

This is because:

1. The stock de-rib doesn't take into account the IC's on the other BMS.

2. The stock de-rib doesnt take into account that there are other components sitting proud of the BMS other than the IC's. Not as proud as the IC's I grant you, but proud nontheless.

My approach is what I would call 'belt and braces'

Edit: when I get a chance, I will pull one of my panels and highlight every rib that I modded, as I appreciate that nothing I have posted so far is overly clear... 

Ever get around to this? 

[Planemo]

26 minutes ago, MrRobot said:

Ever get around to this? 

Sorry, no I haven't yet. But I might be able to use one of my old pics and highlight the modded ribs better than I have done previously. I will try and sort that in the next day or so.

[Planemo]

Actually, I just found a gap at work and was able to use Ben's pic (cheers Ben!) again, to hopefully make things clearer. Any questions fire away.

[Planemo]

Further, when I say 'no higher than flat section', I actually went a good 1 to 2mm lower than the flat section on the ribs that aren't on flat sections. In fact, almost removing the rib entirely but still leaving a little for strength although I'm not convinced it's necessary, the panels are pretty tough.

[MrRobot]

On 8/8/2021 at 10:53 PM, Planemo said:

Actually, I just found a gap at work and was able to use Ben's pic (cheers Ben!) again, to hopefully make things clearer. Any questions fire away.

Just out of curiosity why wouldn't you do this symmetrically so you make the same modifications on both sides of a single panel? 

Edited September 14, 2021 by MrRobot

[Planemo]

1 hour ago, MrRobot said:

Just out of curiosity why wouldn't you do this symmetrically so you make the same modifications on both sides of a single panel? 

Because they arent symmetrical.