Designing Battery Cover

[jkvt]

Hello!

Well I can't get a ton of info about a neoprene cover to put over the battery for the winter, so I'm designing one myself. I spent a bunch of time trying to figure out the dimensions and made a prototype the other day, cutting out an old sheet which actually fit pretty well. The only issue I'm stuck on is what to do about the controller at the bottom. Does that go inside the case, outside the case, or do I just put it half inside the case, half out.

Inside the case: The part of the controller closest to the bottom bracket/cranks will never be entirely covered. It's just too tight. I like the idea that the controller is inside the case because it will provide a little more heat, although it never seems to get too warm, so I don't think I need to be concerned with overheating. One thing I am concerned with is condensation in case since the controller itself is not perfectly air tight, but with the bike being stored in the garage, that is probably a concern with or without the case and I think all the components inside the controller are sealed up pretty well, supposedly.

Outside the case: The big issue here is that means a significant part (a few inches down the tube) of the battery would not be covered by the case, so I'm leaning against this option right now.

Part in and part out: Basically I get the entire battery in the case, sealed up pretty good at the highest point of the battery. The lowest part of the battery would be exposed just because it's too tight down there to really wrap the neoprene around it. Basically just the right/lower small side would be left uncovered. This is kind of the way I'm leaning. The sheet cutout prototype thing I mentioned is of this right now... well mostly.

Any thoughts on these approaches? It's getting cold and I don't want to lose range where I don't have to!

 

[jkvt]

Well - went ahead and made something. Mostly happy with how it came out, although I wish I put the ends more on the bottom for looks, but that doesn't matter too much. The only downside to this was cost. $35 for a 2x2 foot sheet of neoprene (nylon one one side and textured rubber on the other). I also spent $21 on some really good quality 3M "velcro" with good rubber adhesive on it, which seems like will hold so I don't need to take it to someone to sew the velcro on. To be fair though there is 10 feet of it, so only a small amount was actually used for this project.

Covers the battery pretty well, including on the short sides. It's not airtight, but who cares. Excuse the messy garage - in the middle of reorganizing it.

 

[theemartymac]

So how has the cover worked out for you? Have you seen much range reduction?

I am going to make one myself this week after a long cold weather ride just above freezing revealed less than 50% of the usual range, and reduced power delivery over most of the trip vs the same route back in Aug/Sept. I have half of an old scrap yoga mat I'm going to use for the concept test before I buy material.

 

[jkvt]

I think it's working pretty well. I haven't used the bike much below 45F, without the cover, but happened to forget to put it on the other day when it was in the upper 30s F during the evening after dark. I noticed a drop in range compared to when the cover is on. It's the only "test" case without it so far but I'm pretty confident it is meaningful because wind wasn't much of an issue and I was on a path I use frequently so there were no hills that would throw things off.

I usually have a good idea of when the voltage drops below 50v and I saw it drop just under 50 after right around 10 or 11 miles in without the cover the other day. This is compared to the 14 or so I typically get since it has cooled down with the cover on. So, I think it is helping. Both of these number are with tire liners, fyi.

For what is worth, in the summer with warmer temps and no tire liners installed I typically hit 50 around 17-19 miles in).

If you are looking for a place to start I can take a picture of the cover laid out, not on the bike. Let me know and I'll take a picture and post it if so.

 

[theemartymac]

I think it's working pretty well. I haven't used the bike much below 45F, without the cover, but happened to forget to put it on the other day when it was in the upper 30s F during the evening after dark. I noticed a drop in range compared to when the cover is on. It's the only "test" case without it so far but I'm pretty confident it is meaningful because wind wasn't much of an issue and I was on a path I use frequently so there were no hills that would throw things off.

I usually have a good idea of when the voltage drops below 50v and I saw it drop just under 50 after right around 10 or 11 miles in without the cover the other day. This is compared to the 14 or so I typically get since it has cooled down with the cover on. So, I think it is helping. Both of these number are with tire liners, fyi.

For what is worth, in the summer with warmer temps and no tire liners installed I typically hit 50 around 17-19 miles in).

If you are looking for a place to start I can take a picture of the cover laid out, not on the bike. Let me know and I'll take a picture and post it if so.

Sure, that would be useful.

 

[jkvt]

Sure, that would be useful.

Here you go. It's not the best picture but hopefully its a place to start. I used 4 or 5mm neoprene. Nylon one one side, some textured grip on the other. FYI the top and bottom of the picture are purposely not straight lines. This helps the cover get around the controller... partially at least. The bottom left is what I use to pull it tight'ish above the high part of the battery on the frame (the part with the lights). The bottom right wraps around the low part of the battery... although honestly it makes putting the cover on a little more complicated sometimes but all in all it takes only about 30 seconds to get it all in place.

 

[Dallant]

Here’s the FAHRER battery cover I bought for my Trek Allant+7.

 

[theemartymac]

Thanks Gang. That's a great place to start.

 

[Alf]

Test battery cover
Tested my 19.2V battery this week around -5C without chilling wind factor. After 23 km in Snow Fatbike trails in Quebec, it was at 32%. Next days(3), same place, same conditions I put over a 6mm neoprene cover home made with velcros. After 68 km it was at 41%. this morning 35 km and it indicates 77%. so the efficiency is really there during cold days.

 

[Fred]

Test battery cover
Tested my 19.2V battery this week around -5C without chilling wind factor. After 23 km in Snow Fatbike trails in Quebec, it was at 32%. Next days(3), same place, same conditions I put over a 6mm neoprene cover home made with velcros. After 68 km it was at 41%. this morning 35 km and it indicates 77%. so the efficiency is really there during cold days.

That's amazing! I never would have imagined such a difference.

When you say 19.2V battery, is that correct? Or by any chance did you mean 19.2Ah battery (at 48V?)

 

[Alf]

That's amazing! I never would have imagined such a difference.

When you say 19.2V battery, is that correct? Or by any chance did you mean 19.2Ah battery (at 48V?)

Ah