what kind of fire blanket for lipo batteries?

[brumbrum]

I am going to try out a hard shell back pack for carrying lipo packs for riding my bike, the pack is made for motorcycle riders for back protection. I have individual lipo bags which may do the job, but could make connecting the packs together difficult. Will a normal fire blanket lined inside the hard shell back pack help contain a fire? Or will i need a certain chemical fire blanket?

Andrew

 

[dogman dan]

Unless the pack needs to be stored in a place where a fire would be a disaster, I would not worry too much about it. Nomex is a fireproof fabric, if you can find some. It will take a lot of fire before it burns, so it would be good to have a layer of it between the packs and your back. Bear in mind, when a big pack goes off, nothing really contains it. One pack is not so spectacular, but 1000wh worth is a huge fire. It won't be contained by anything, but at the same time, you don't want to surround it with easy to burn plastic and put it on your back either.

So your real efforts should be towards preventing a fire. The obvious of course, I would never attach a known to be damaged pack to my body. The lipo rules, etc.

But shit happens, particularly a crash or other slip up that drops the backpack. So the number one thing I would be thinking about would be making the pack crashworthy. If it's not hard shell packs, you build some hard shells for them, out of some kind of durable material. Then pad that inner hard pack with something shock absorbent. Build it so you can drop the pack from a 4 foot height, and not crush a corner resulting in a fire.

 

[brumbrum]

Thanks, always with the good advice. I will try and keep the 54v 3ah built packs in lipo bags if i can easily connect the severn packs in parrallel without having to do too much stressing of wires and connectors. If that does not work i will build a frame for the severn packs to stop rubbing and movement and use lots of foam/sponge surrounding the framed pack within the back pack.

Here is the back pack in question.... http://www.boblbee.com/eu/artiklar/kategorilfullpost.asp?ID=946&flik=221&color=729&acc=

But believe me, i payed no where near that much!

 

[dogman dan]

Again, unless the pack will be a storage device, left unattended in a bad place, I wouldn't worry about fire. Not while you ride fire.

If you did get a fire, it would be because the packs bounced around in there and got damaged. So concentrate on completely eliminating that possibility, with an inner hard shell box. You could always line the inner box with material cut from fire bags. Nothing wrong with being safe, but the primary safety is not denting the pack.

There have been a few cases reported where a pack got dropped, or a crash, or bouncing in a basket caused a fire. And one I recall, where a previously over discharged pack caught fire while discharging on a ride. Others happened from shorts. Very few cases of a pack just bursting into flames just sitting there for no apparent reason.

So eliminate those reasons with a good protective inner box, and a way to avoid over discharging them.

 

[brumbrum]

Thanks again. I take my lipos VERY seriously, so i will do everything i can.

I have a CA to keep an eye on voltage and I abide by the rules.

Andrew

 

[John in CR]

Before getting too far into it try a backpack with a wire connected to your bike first. I've done some range extender batteries in a backpack before, and I'm on and off my bikes too much to live with the inconvenience. For long rides or commutes, then I can see it being acceptable, but try it first, even without a battery in the backpack. It will also give you a chance to work out how you'll route the wires and make the connection, which to me is the critical part of making it something you can live with daily.

Once you work that out, and get 10-20 cycles on your packs to weed out any duds, then build your battery rigidly into your pack with easy access to the balance taps, and everything secure and convenient.

 

[brumbrum]

my lipos are tried and tested. They are currently in storage at 3.9 volts. So it will not be a brand new lipo set-up. But as you say the battery connection is the biggest concern. I will keep the controller(with motor connector) and phase wires etc in frame bag and have the battery wire go from there into the back pack with a long enough battery cable to bulk charge while the the packs are in the bag. I will have plenty of motor length wire in the frame bag so a fall off the bike will hopefully pull the the extra length of motor wire out from the frame bag without any tug on any wires(i hope that makes sense?) The motor in question runs sensorless and has been rewired with very strong wiring.

Otherwise I may put everything in the backpack with the controller tied to the back or top of the back pack. The bike will only be used for off road use so not for commuting or short trips, so i am not too worried about the hassle of charging. Of course I will remove the lipo packs for balancing, as i have the packs in bricks of four so I can balance one brick at a time with my multi charger.

The other option is to have the battery connector externally placed i.e just outside the back pack. I use Anderson 50amp connectors and have rubber boots for them which in theory will make them waterproof(in theory!) so that could be worth a try.

As always there will be teething problems but I will find a way that works for me.

Thanks for your input. Any other thoughts are welcomed.

 

[dogman dan]

I can't believe you can get away with smothering a controller in a bag. But I understand you don't live in a hot desert, and will ride in the rain a lot more than I would. Still, you need to cool that controller somehow. I'd be thinking in terms of a box with vents, or water sealing it and putting just the wires and plugs in a bag. In the cold wet places, it might work ok to just unzip the bag a few inches.

Andersons work good for a break away wire. One way to make a deadman switch for the EV. If you come off, it's going to stop. I have carried battery in a pack a few times, but don't like the dangling wire. I had put the connector near the seat, so I could run the wire down to a belt loop on my ass, and not tangle an arm in the extra wire. Very inconvenient if you will stop during the ride and get off much. But it can be a good way to carry extra battery for long rides, in addition to a smaller pack on the bike for the short trips.

 

[brumbrum]

I have a commuter bike which runs on 18650 batteries. I want to use the lipo with a magic pie for an off roading bike only. I have always kept my Lyens controllers and others in a bag with no problems. I am also half way through making an ABS press moulded frame container which will overlap the top tube of the frame. I have made 2 wooden moulds so far I now just need an oven big enough to warm the plastic. I also want to firstly try press moulding foam/rubber over the mould and then do the plastic over the top so i have a softer interior. This project will take longer to do as I will have to cut two half circles in each mould side so it fits tightly on the top tube of the bike frame. If I do this the controller will be externalised. i have lengthened the phase wires on the controller already and used self amalgamating rubber tape around all the entrance holes into the controller as well as some silicone before hand. I am taking my time over this project as at least i have a commuting bike with a BPM motor. I would not take my PIE on British roads running 35 amps. I would without doubt get pulled. The pie will be driven to the woods in a truck and then i would let rip!

 

[John in CR]

I have carried battery in a pack a few times, but don't like the dangling wire.

+1 It was always either worrying about slack in the cable getting caught in the rear tire and how bad that could get , or a short wire that was a pain to get on and off the bike or if even shorter a pain to connect once on the bike or forgetting to disconnect getting off. My closest to acceptable wire routing was with the connector up along the top tube with the wire coming from high on the backpack under one arm and forward.

Brumbrum, if you come up with a good solution let us know.

Another issue for me is the limited capacity before the backpack starts getting heavy, and the storage space of the backpack is used up. I can fit more battery easily on any frame, but I care more about comfort and convenience that stealth.

That is a nice looking pack, and once I got it worked out, then I would build the individual packs into one more permanent pack and secure it in there like I have in my swingarm battery enclosure. That would include parallel structure and a set of balance taps for each series group for easy charging and balancing. Batteries really don't like getting banged around, and strapped on my back and banging around is even less appealing. Plus I just don't get all the extra work guys put up with doing all that separate balancing. With parallel at the cell level they stay in better balance, and you can just check them all quickly and single cell charge the group or two that are out of whack...quick and simple instead of an extra hobby fiddling with batteries.

 

[brumbrum]

I will find a way that works for me. I usually use triangle frame bags for batteries wires and controller with success and this keeps everything with a low and balanced centre of gravity and also looking incognito. Though the bike for this topic is a full suspension and there is no room for a a large AH pack due to the shock absorber taking up a bit of room in the frame.

Here is the bike in question when it had a bpm motor and a 6fet controller and a small 54v 8ah pack....

As it now has a magic pie and will be running at higher amps with a 12fet controller i want to free up the bike a bit and put some weight on my back. Obviously longer range and less sag is also important, hence the lipos and not 18650 li-ion batteries that i have always used and built into packs.

 

[dogman dan]

Last place I'd want to move much battery weight for off road riding would be my back. Lots of discussions about this, but I would rather put 6 pounds on a rear rack and ride than on my back.

I skied with packs of all sizes and weights. On skis, even a small pack with just lunch and a snow shovel throws off your balance a lot. It will be exactly the same riding a bike on a tough trail.

Can you still do it? Hell yeah. You sure aren't skiing the back country without food, shovel, and a way to melt a quart of water. And if you are on easy skiing, or easy riding, it does make little difference. If it's the real deal, then you only pay that penalty because going out to ski the avalanche chutes unequipped is suicide.

More than 4-6 pounds, you will be screwed wherever you put it. 10 pounds on a rear rack is unacceptable for difficult riding, and I think it will still be just as bad in a back pack. What works for you though, will depend on the difficulty of the trails, and how much weight that pack has. It won't matter if the trails are relatively easy.

On my current dirt ride, ( a damn Y frame) I put 4-5 pounds on a rear rack, no more. 14s 5 ah. Then if I will carry more, I put up to 9 pounds in a bag on the handlebars. But most rides, I put only another 4 pounds there. 4 pounds in back, 4 on the bars, and I don't have the weight making me crash more. The riding I do is on trails that remind me of skiing through woods. Very much a slalom ride. I built the 10 miles of trails with this kind of ride in mind, to make them suck badly for faster motorcycles and quads. Only the most nimble bike riders can stay on the track and not highside. This makes the quads prefer to ride on nearby dirt roads, where you can go 50 mph. This diabolical type of trail does make me keep my bikes as nimble as possible. When I build a bike wrong, I come home bleeding and knowing I blew it.

Your trails may be much different, and riding with a pack may not bother you.

You have the advantage of being able to still put at least 4-5 pounds in that triangle. I don't see why you couldn't carry 48v 15 ah very comfortably on the frame.

 

[brumbrum]

Ii cannot effing believe it. I just wrote a massive reply with photos and my ipad closed down when i pressed preview........ Dooooooooooh! I will try again when i find the patience!

 

[brumbrum]

OK, one cup of tea later......

In a nut shell this time... Not meaning to sound blunt at any point.

I hate rear racks since first day of ebiking, they make the bike bounce around on the tail too much. I always use frame bags... This is my commuter bike.. Please ignore the bin os sin in the bottom left corner

The triangle pack will only hold 3 bricks if i include shock absorption and wires and there is no room for my 12fet sensorless controller in the same place. I have tried this as an idea....... But must make sure the suspension travel does not exceed the controller.

Each taped up brick is 54v/3ah they weigh 2.4lbs in old money (just over 1kg) i will not mind carrying between 5 and 7 of these on back.

As mentioned in an earlier post i am trying to make a larger triangle case from ABS but this is a long term project.

Heres my local terrain on a rare sunny day....

So i must at least try a back pack, i will put everything in it included the controller in a separate top compartment in the back pack at first and see if it gets hot.

 

[Ricky_nz]

So i must at least try a back pack, i will put everything in it included the controller in a separate top compartment in the back pack at first and see if it gets hot.

By putting the controller in/on the backpack you now have 3 phase wires, 5 hall wires and 3 throttle wires that must all flex and move which is inviting unreliability

 

[brumbrum]

So i must at least try a back pack, i will put everything in it included the controller in a separate top compartment in the back pack at first and see if it gets hot.

By putting the controller in/on the backpack you now have 3 phase wires, 5 hall wires and 3 throttle wires that must all flex and move which is inviting unreliability

Ok, i take that back, not thinking properly. The controller will go in a frame bag with just a long battery wire going into it with plenty of extra battery wire in the frame leaving slack for a tip over/crash. The hard shell backpack arrives monday so it will be all go from there. For all i know, it maybe a wrong move but it will be tried, but hopefully i will be able to continue with my ABS project soon.

I see this idea getting more unpopular by the day Haaaah!

Perhaps a coiled cable could be used like on an electric guitar cable? Does a two core 12awg bendy coil exist?

 

[Ricky_nz]

Perhaps a coiled cable could be used like on an electric guitar cable? Does a two core 12awg bendy coil exist?

I don't know about coiled 12 gauge but the silicon wire from hobby king or your local model shop is really flexible so two runs of it with some flexible sleeving would work ok. You could even use 10 gauge and it would still be reasonably flexible but with lower volt drop although it might be overkill. Maybe you could rig up sole elastic to take up the slack to stop it dangling.
I would definitely install a fuse close to the batteries in the backpack in case the wire is damaged. The silicon wire is very flexible but I believe it can be abraded quite easily.

 

[brumbrum]

Something like compressed air hose coiled tubing may work, as you say HK silicone wire is very flexible.

Not sure what you mean by sole elastic. But i pictured a kind of spring back device like vacuum cleaners sometimes have haah!

Perhaps a coiled cable could be used like on an electric guitar cable? Does a two core 12awg bendy coil exist?

I don't know about coiled 12 gauge but the silicon wire from hobby king or your local model shop is really flexible so two runs of it with some flexible sleeving would work ok. You could even use 10 gauge and it would still be reasonably flexible but with lower volt drop although it might be overkill. Maybe you could rig up sole elastic to take up the slack to stop it dangling.
I would definitely install a fuse close to the batteries in the backpack in case the wire is damaged. The silicon wire is very flexible but I believe it can be abraded quite easily.

 

[Ricky_nz]

Not sure what you mean by sole elastic.

Oops, I'm guilty of typing while tired LOL 'sole' should have been 'some' elastic or rubber. I guess your idea of air hose or some other pre coiled former to attach the wire to would work as long as its flexible enough.

 

[brumbrum]

No worries mate.
I have seen some polyurethane tubing on the i-net but some gets quite expensive. I will try and see what i can source.

Not sure what you mean by sole elastic.

Oops, I'm guilty of typing while tired LOL 'sole' should have been 'some' elastic or rubber. I guess your idea of air hose or some other pre coiled former to attach the wire to would work as long as its flexible enough.

 

[dogman dan]

To each his own. Keep it light enough and it won't bother you as much. I was just suggesting spreading the battery weight around some, rather than carry a pack that weighs more than 5-6 pounds. For sure, you don't want to carry more than 5 ah on any rear rack.

You might try a rear rack to carry the controller, That's worked for me very well. A light rack, of course. And tweak the shocks if that tiny bit of weight is changing the ride enough to feel. The thing I really like about the rack carry for the controller is that the beam seatpost racks are also a great fender. On a good mud day, I still get some goo on the controller, but very little. And hey, how handy, there's your plug right under your ass.

On my current setup, the battery is only 4 pounds, in the blue box. Controller on the front of the box. Not shown in this pic, is a handlebar bag I can cram 8 pounds into for a long ride.

 

[brumbrum]

To be fair having a rear rack as a fender with controller on is a very good idea to keep mud off, as too is having just a small amount of battery. I will see how it goes when the back pack arrives, and I have contacted 3 companies about supplying coiled/retractable wiring to relieve slack and for ease of getting on and off the bike with batteries connected. Again it is all a balance between doing things on a budget or expensively, and function over form. I like things nice and neat on my bikes. I have been lucky to get my lipo set-up at a cheap price and the hardshell back pack. I think I now need to go out and try a few different combos. If it does not feel right, maybe a rear post rack could be of use as you have shown to take up a little of the weight and to prevent a caked brown arse! Its an ongoing project but i will be trying out a battery cable from the back pack to the controller in a frame bag. If I can get hold of a coiled cable that will take the amps, that will be merrier.

Perhaps it's time to get on with my ABS frame container, that has been designed to take 18ahs i.e 6 packs nice and snug.

I seem to spend more time designing and making rather than riding. But I would not get by without my garage and my tinkering.

 

[dogman dan]

Definitely, trying every combination is half the fun.

Before I got sick, I carried a lot more battery, in boxes on each side of the frame. Now, 5 ah is all I need for shorter rides.

Couldn't pedal with the big saddlebag boxes, and I missed that. So I tried a rear rack carry, and was quite surprised how nice it was with 4 pounds. I had done 15 pounds before, and that sucked.

Pretty obvious, I need to get a real bike, and move that 4 pounds between my knees. All I have is old Y frames, 3 of em. This bike does wheelie easier, so climbing 15 degree grades for long on it is out. My shorter rides don't make it to those hills anymore. On a long ride, the 4-8 pounds on the bars cures the wheelies.

 

[brumbrum]

I got a quote today for 1 metre of coiled cable, 2 core 12AWG......... £76.00.......... yes pounds!

 

[doctorGONZO]

Cheez.

Once upon a time I rode motorcycles fueled by GASOLINE. I have seen how GASOLINE can burn and fry anything it is on. There are plenty of ex NASCAR and Formula 1 drivers who might could be contacted in seances who could verify this. There is no way in Hell that I would deliberately lock a can of GASOLINE on my back and ride a motorcycle.

lipo batteries are as suspicious as GASOLINE in my humble opinion. There is no way in Hell that I would strap a sack of lipo on my back and do anything.

I really believe in taking NO unnecessary risks. I love my life and do not intend to throw it away frivolously.

Of course, anybody else can make a different choice as they choose.