Add more power

[guerney]

Well, the display turns on, testing PAS seems to work when the bike is suspended from the ceiling. The lights all switch on to full brightness... but I'll change the "Current Limit" to 19A before I venture out, when it's a bit warmer. There should be a "Fingers crossed" emoji.

 

[Fordulike]

It's now a 20A bbs01b! Will it explode the battery when I try it later on? If it's ill. It's too cold to try just now.

Although better than controllers of old, the latest BBS controllers are still capable of undershooting or overshooting their set values. Setting a 15A limit could still draw 16 or more amps from the battery in certain conditions, same as it may fall short and only produce 14 amps in certain conditions. For your peace of mind, they certainly don't overshoot enough to be sitting on a potential bomb, but prolonged excessive amp draw beyond the battery's capability, will shorten its life.

I made the mistake of purchasing my first battery with Samsung 29E cells in a 13S4P layout.
After maxing my controller settings, it didn't last very long. Less than 2 years IIRC.

I switched to a pack with LG HG2 cells in a 13S5P layout. This has been far better suited to my BBS02, which can peak at 25 or more amps for extended periods of time.

At the end of the day, don't worry about it. If the battery is poorly, you'll have problems no matter how you program the controller. Then it's time for a new one, unless yer handy (and brave) at replacing cells

 

[guerney]

Although better than controllers of old, the latest BBS controllers are still capable of undershooting or overshooting their set values. Setting a 15A limit could still draw 16 or more amps from the battery in certain conditions, same as it may fall short and only produce 14 amps in certain conditions. For your peace of mind, they certainly don't overshoot enough to be sitting on a potential bomb, but prolonged excessive amp draw beyond the battery's capability, will shorten its life.

I made the mistake of purchasing my first battery with Samsung 29E cells in a 13S4P layout.
After maxing my controller settings, it didn't last very long. Less than 2 years IIRC.

I switched to a pack with LG HG2 cells in a 13S5P layout. This has been far better suited to my BBS02, which can peak at 25 or more amps for extended periods of time.

At the end of the day, don't worry about it. If the battery is poorly, you'll have problems no matter how you program the controller. Then it's time for a new one, unless yer handy (and brave) at replacing cells

That's good to know about the current draw of BBS controllers! I might try it out for an hour or so, to see if a Bafang bbs01b drawing about 19A is what I want - but quite honestly I don't really need all that power anyway. It copes fine at 15A, even when carrying very heavy loads uphill. After zooming up a steep hill or three, I plan to set it back to 15A. If I must have 19A, I'll bear that in mind when purchasing my next battery. I can't see my present battery exhibiting any signs of ill health, it has a worrying odour, but in all other respects it's been fine. It smelt like this when it arrived last year brand new. I can't imagine that a failing battery would have coped with being charged up every other day and powering the bike for over 1400 miles (so far).

 

[guerney]

Is there some sort of battery wrap material available which is heat conductive, but electrically insulating?

 

[guerney]

I made the mistake of purchasing my first battery with Samsung 29E cells in a 13S4P layout.
After maxing my controller settings, it didn't last very long. Less than 2 years IIRC.

That surprises me, I thought Samsung cells were the best? But I don't know much about ebike batteries...

 

[Fordulike]

That surprises me, I thought Samsung cells were the best? But I don't know much about ebike batteries...

Samsung do make great cells, but that particular cell wasn't suited for my needs.
The Samsung 25R cell would have been better.

I hadn't researched enough at the time and paid the price for purchasing the wrong battery pack.

 

[guerney]

I'm startingto wonder if the stress of the battery pack bouncing about within the case, has broken down the adhesive to a liquid-like state - it might not have been heat? Those wires are on the sides after all. Liquids might be more flammable. Seems nuts that flammable paper is used... I suppose the combusting temperature of the paper must be lower than that of the battery cells?

 

[guerney]

This tape is used as heatsink backing adhesive for LED lights, and could be used to wrap a battery, were it not double sided sticky tape, and quite thin:

Pardon our interruption...

 

[guerney]

The BMS looks like it is 22a continuous so one could go 20a if the programming allows.
The stains I would lift the paper insulation covering to look, does it smell of electrolyte ?

The battery has just finished charging, the charger shone a green LED, and the display is showing 41.9V, I guess this is a healthy voltage? It's been charged and used quite a lot all year since new, and it was as smelly when new, as it is now.

Aside from the smell, it seems ok? But to be on the safe side, I'll set the controller back to 15A for the time being - until I buy a second battery. It's my only daily commuting vehicle.

 

[Nealh]

Now the paper has been lifted it looks like heat is causing the paper glue to weep through. The sense wires with heat sleeves are laying directly across the interconnectors.

 

[guerney]

Now the paper has been lifted it looks like heat is causing the paper glue to weep through. The sense wires with heat sleeves are laying directly across the interconnectors.

Is that bad practice? Is it something which needs fixing or re-organising? I've learned to solder (a little) recently, but I don't fancy my chances at reorganising those wires!

 

[guerney]

Now the paper has been lifted it looks like heat is causing the paper glue to weep through. The sense wires with heat sleeves are laying directly across the interconnectors.

Maybe I should add thicker heat insulating material around those wires? If so, what sort of product could be used?

 

[guerney]

Now the paper has been lifted it looks like heat is causing the paper glue to weep through. The sense wires with heat sleeves are laying directly across the interconnectors.

Would wrapping kapton tape around those wires protect them adequately?

 

[guerney]

The paper is an insulator /protector and is quite hard wearing.
Re use the paper if poss and use a wrap or two of kapton tape to bind it again.
Once lifted it depends what the cells look like and whether leaking has occurred, leaking will show up as the cell wrap will be bubbly/rough. Electrolyte smell I can't describe but any smell is abnormal as cells don't smell.

Should I cover completely with kapton tape? Would that make the battery pack too hot?

https://www.reddit.com/r/ebikes/comments/a0iksa

 

[Nealh]

I don't lay wires across interconnectors, I either lay them between or through the cell/gaps where I use spacers. Kapton tape to insulate against heat transfer.
The interconnector material may be heating up as it may not be capable as a very good conductor thus heat is then conducting through the wire insulator material to the paper causing the glue bleeding, that's why folks use copper now as it heat flows nicely through it being 3 or 4 x more conductive then steel/nickel.

 

[guerney]

The paper is an insulator /protector and is quite hard wearing.
Re use the paper if poss and use a wrap or two of kapton tape to bind it again.
Once lifted it depends what the cells look like and whether leaking has occurred, leaking will show up as the cell wrap will be bubbly/rough. Electrolyte smell I can't describe but any smell is abnormal as cells don't smell.

Will 100mm wide do the job?

Pardon our interruption...

 

[Nealh]

For my batteries I use a 0.4mm fibreglass sheet top and bottom as an insulator.

 

[Nealh]

Kapton one can use what ever width one wants to, I tend to use 20mm for most of my builds.
The laying of the sense wire across is a bit crap, but I suspect the interconnector material may be a bit below par and is getting quite warm with higher current.

 

[guerney]

For my batteries I use a 0.4mm fibreglass sheet top and bottom as an insulator.

Is this the stuff?

Unclad 12" x 6" (304 x 152mm) G10 FR4 Fibreglass Sheet 0.40mm Thick. DIY PCB | eBay

The material is from whole sheet and is not off cut or scrap. Commonly used in the manufacture of Printed Circuit Boards this robust material.

www.ebay.co.uk

 

[Nealh]

Yes FR4.