Recommended Battery Case Mod

[Ben Hatfield]

no issue with my wheel, bt lou error message saga continues.  important for every Veteran Sherman owner

I got a modification recommended via eWheels to prevent damage to the bms that can result in this error (bt lou) message. 

the mod is simple, remove the side panels and grind (dremel) out the 3 ribs shown in photograph.  I had a series of emails with eWheels to confirm the area to grind - easy to overthink, but bottom line is just grind out these three on each panel.  more detail in video

 

 

[OliG]

Hello @Ben Hatfield

 

thanks for these info. 
 

As I have pads on my panels, I wanted to clarify : the parts you removed from the panels are on the front or on the back of the wheels when you put the panel back on the wheel?

I suppose that we have to remove the plastic on the side that is in contact with the bms but as there are packs in the front and in the rear on each side, it’s not clear for me. 
 

I hope I was clear. 

 

Thanks for your help. 

[Ben Hatfield]

19 minutes ago, OliG said:

Hello @Ben Hatfield

 

thanks for these info. 
 

As I have pads on my panels, I wanted to clarify : the parts you removed from the panels are on the front or on the back of the wheels when you put the panel back on the wheel?

I suppose that we have to remove the plastic on the side that is in contact with the bms but as there are packs in the front and in the rear on each side, it’s not clear for me. 
 

I hope I was clear. 

 

Thanks for your help. 

you are asking my exact first question when I first got the instructions - and I had to email 2 more times just to confirm

 

The answer?  It is the same spot on each panel.  Don't overthink it.

 

If you have to have a clear answer, the best way I can explain it is this:  All the battery packs at the factory are the same.  So when they are installed - the bms is always on the same side... even when the wheel is flipped around.  

[DjPanJan]

This mean not exist sherman what is imune to this BT lou problem? 

All batches is/can be  theoreticaly afected?

How i understand fall to side can lead to this bt lou error?

@Ben Hatfield photo looks like from veteran factory this mean veteran must know about this vulnerability.

Hmm decision decisions power pads make it better or worst? Becasue what i understand this problem trigger some mechanical press/push/damage to BMS module.

 

 

[OliG]

Sorry @Ben Hatfield but there is still one point I don't understand.

I'm trying to explain myself better. I did understand that the left and right panels were symmetrical of course.

Let's take for example the left side of the wheel.

If you remove the plastic relief from the panels on one side only, when you pull up the panel on the left side, is the area where the plastic was removed in contact with the left front pack or with the left rear pack?

In fact, if you remove plastic from one side of the left panel, the plastic that remains on the other side of the left panel will always press on one of the left packs.

So if it presses precisely on the left pack that contains the BMS, in my understanding, I don't see what the modification will have served.

 

[.....]

@Ben Hatfield Thank you for the info. My pads are above this. Between them and the pedals, it cant hit. I'd imagine a rock could, but this 'mod' could help anyhow. I'll be doing it for mine, as its too simple and couldnt hurt. NO way in hell I'd bother removing pedals, JUST for a simple panel removal. MOre screws= mo' problems... No email from e-wheels for me...

[Ben Hatfield]

11 hours ago, OliG said:

Sorry @Ben Hatfield but there is still one point I don't understand.

I'm trying to explain myself better. I did understand that the left and right panels were symmetrical of course.

Let's take for example the left side of the wheel.

If you remove the plastic relief from the panels on one side only, when you pull up the panel on the left side, is the area where the plastic was removed in contact with the left front pack or with the left rear pack?

In fact, if you remove plastic from one side of the left panel, the plastic that remains on the other side of the left panel will always press on one of the left packs.

So if it presses precisely on the left pack that contains the BMS, in my understanding, I don't see what the modification will have served.

 

Stop thinking which way the wheel is facing.  Just think how a single version of a battery is placed when looking down on it

The BMS side will Always be on right side.  I don't know how to explain it any better.

I guess if there was any doubt, one could just grind out 4 spots - but that really isn't necessary

 

 

[Ben Hatfield]

11 hours ago, ShanesPlanet said:

@Ben Hatfield Thank you for the info. My pads are above this. Between them and the pedals, it cant hit. I'd imagine a rock could, but this 'mod' could help anyhow. I'll be doing it for mine, as its too simple and couldnt hurt. NO way in hell I'd bother removing pedals, JUST for a simple panel removal. MOre screws= mo' problems... No email from e-wheels for me...

I think this issue is rare - but if removing that bit of plastic might really drop those odds further?   and it's super quick and easy to do?  probably wise to take the time. 

Might email eWheels?  see what they say?

[Rawnei]

Mine was already fixed (I opened and checked), it was the latest batch with wider rim and waterproof LCD bought from EUC sale about 2 weeks ago.

[Chriull]

Here the official message from ewheels:

 

[Dominic Winsor]

I watched Adam's (Wrong Way) latest video about his broken Sherman last night, where he has the same issue 'bt_LoY'… and a thought occurred.

If you have hard side pads like Clarke Pads and similar, these press the case lower down, and when the wheel falls on its side more impact will be transferred into the battery case. Looking at my own Sherman, which has soft foam pads from 'EUC Custom Power-Pads', these are mounted higher up (link: my insta), and my leg never touches the affected area. I also think the area would be unaffected if you didn't have pads at all.

I will make the modification anyway, but I wondered if this might be a factor. 

[Dominic Winsor]

I've just done mine now. Hopefully all is well from now on!

[DrBytes]

I've done this too, now. I don't think this mod lowers the shell's strength significantly.

@Dominic Winsor: I had the same thought; if this thing keels over left or right with the thick pads mounted there it would definitely transfer a lot of the impact force onto that area.

Edited May 28, 2021 by DrBytes

[Dominic Winsor]

Time to own up! I did rather rush the reinstallation of my shell and manage to screw partially through the negative battery wire, as it wasn’t properly tucked in  

Fortunately, no major harm done. I used a ‘butt joint connector’ to cut and splice the wire back in, and secure them to the trolley handle with some Velcro to prevent it happening again. Oops. Loose wires lose lives!

I agree, the shell seems pretty rigid even with the mod. 

[Planemo]

Ok so is it possible to buy just a BMS from Veteran? Or anyone else? Dont want to buy a whole new pack obviously. I can change just the BMS and re-wrap the pack no problem.

Edit, given the location of the case mod, I believe the bms in question is always the same part number (C2402S) given that both packs on one side have different bms'.

I think its the 2402 bms which is affected, not the 2401.

Edited June 16, 2021 by Planemo

[fbhb]

11 hours ago, Planemo said:

Ok so is it possible to buy just a BMS from Veteran? Or anyone else?

Wheel Tech Store have always been a reliable Ali seller for EUC's and EUC parts. I've used them multiple times and they do have the BMS currently available on their Ali store, with the option to buy either 2402, 2401 or both:  https://tinyurl.com/Veteran-Sherman-BMS

Edited June 17, 2021 by fbhb

[Planemo]

Cheers for that, might come in handy, would prefer something quicker but if neither of the main UK players can help I think it will have to be Ali.

[Planemo]

I meant to post my further side panel rib mods here, but didn't. Heres a link to anyone interested:

 

[Planemo]

Just to add to this, I pulled my panels again today (I'm nervous with a new wheel, keep checking things) and decided to take out some additional ribbing to that which I did previously. This was based on the fact that one of the BMS's actually has more components on it than the other, further up the board. I missed this point previously. So out came Mr Dremel again, a few minutes and all done. I have highlighted in white the extra bit I did in the pic below:

Its worth noting that on this episode (I have had the panels off about 4 times now) I noticed a small indentation in the foam battery padding that was quite deep, a fair bit deeper than the surrounding rib marks. I traced it back to a moulding nub on a rib, just part of the moulding process. I removed it but it got me thinking...if one of these nubs was on a rib on top of a bms component... maybe a moulding flaw could be more of a problem than the rib itself. In short, Sherman panels need to be checked. I still think removing ribs is a worthwhile mod, and with the extra ones I did today I cant see how any rib could stress a component now. Its all a bit belt and braces now but I am confident that theres nothing that can dig into a bms component now.

[Chriull]

As i just seen this - an alternative solution from @supercurio

 

[Planemo]

Yeah supercurio's answer is neat and simple for sure. My only thoughts at this point are that some of the possibly offending ribs are some distance away from the centreline of the wheel (the ribs highlighted in white in the pic) so whether spacing out the centre of the panel will help enough, I don't know.

[Boogieman]

On 5/10/2021 at 12:01 PM, Rawnei said:

Mine was already fixed (I opened and checked), it was the latest batch with wider rim and waterproof LCD bought from EUC sale about 2 weeks ago.

Mine was also fixed from factory. Latest batch wide rime, new lcd and so on, arrived today after a long delay.

Going through all things before first charge. Found a few misses from Veteran.

1. The fuse eas slightly loose so had to give it half a turn on the screws

2. The battery packs are protected on the outside toward hits but NOTHING on the inside where there are ridges

3. The batteries also stay tight on the bottom rounded corner. Just a slight bump will cause the battery edge to hit the corner.

Solution, added an extra layer of foam att bottom to rise the pack and one layer on the inside where the ridges are

Edited July 6, 2021 by Boogieman

[Boogieman]

On 5/28/2021 at 10:54 PM, Dominic Winsor said:

Time to own up! I did rather rush the reinstallation of my shell and manage to screw partially through the negative battery wire, as it wasn’t properly tucked in  

Fortunately, no major harm done. I used a ‘butt joint connector’ to cut and splice the wire back in, and secure them to the trolley handle with some Velcro to prevent it happening again. Oops. Loose wires lose lives!

I agree, the shell seems pretty rigid even with the mod. 

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

[Boogieman]

21 hours ago, Planemo said:

Just to add to this, I pulled my panels again today (I'm nervous with a new wheel, keep checking things) and decided to take out some additional ribbing to that which I did previously. This was based on the fact that one of the BMS's actually has more components on it than the other, further up the board. I missed this point previously. So out came Mr Dremel again, a few minutes and all done. I have highlighted in white the extra bit I did in the pic below:

Its worth noting that on this episode (I have had the panels off about 4 times now) I noticed a small indentation in the foam battery padding that was quite deep, a fair bit deeper than the surrounding rib marks. I traced it back to a moulding nub on a rib, just part of the moulding process. I removed it but it got me thinking...if one of these nubs was on a rib on top of a bms component... maybe a moulding flaw could be more of a problem than the rib itself. In short, Sherman panels need to be checked. I still think removing ribs is a worthwhile mod, and with the extra ones I did today I cant see how any rib could stress a component now. Its all a bit belt and braces now but I am confident that theres nothing that can dig into a bms component now.

I have heavy ribbing at the top of the battery packs, at the centre. Same on both sides.

[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