My ~12 year old Electric Scooter Project - BladeZ XTR SE

[jetpackjbd]

Just wanted to share a bit about my scooter. I bought it for $20 on Facebook marketplace a few months ago in bad shape as a “fun” project. When I first got it, it was covered in rust, the batteries were dead, and the chain was rusted and broken:

Eventually I cleaned up most of the rust, changed the chain, and replaced the batteries. It worked, and I only spent about $100 in parts for a zippy, unique scooter that could go off-road! And then it started overheating frequently. And then it slightly caught fire…

Haha, whoops… I attempted to make a new brush card from scratch (the piece that’s charred), but I couldn’t get good enough tolerances with basic hand tools. Plus the issue was likely some shorted coils, which would cause the same problem again. The motor is impossible to find online, or anything directly compatible. The only way I could buy it was over the phone, for $150, from the nearly dead company’s warehouse. And it would’ve been a used motor, not even brand new. I have a feeling that even if I bought the same motor, it would eventually suffer the same tragic death. The motor was way too small for the power it made, which makes me think that it was designed like a 12v motor with slightly higher rated thermal coating, and overvolted to 24v. It didn’t even have an internal fan; it was external!
Eventually I decided to just retrofit something else, and the closest spec motor at a decent price was a 500w 24v MY1020 scooter motor for $65 on eBay. While it’s not compatible with the original mounting holes, and is quite a bit larger, it does work. I considered drilling holes into the old mounts to make it fit, but there wasn’t enough space on them. I ended up creating a new mount out of scrap plywood, since I hate working with metal. I don’t have a drill press or a welder so doing it all with a $30 hand drill and old bolts did not sound like fun. After two days working on the mounts, I was finished!



While it’s currently “working”, it still has issues. The biggest issue is that I reused all of the rusty stripped screws. I can’t get the motor in tight enough so I was stranded recently when one out of the two screws fell off. They’re not quite long enough either, so the motor sprocket is a bit off from the wheel sprocket causing the chain to clack and (nearly) fall off at times. When I heard it I thought my electric motor had rod knock. I’ll try to find some new ones at some point. Motor Noise
I plan on doing a bunch of upgrades like changing out the sprocket from a 13 tooth to a 17 tooth. The nut holding it onto the shaft had Loctite on it, and stripped out when I tried to take it off. So that’ll be fun to deal with. I also want to add a seat and turn signals to it at some point. I temporarily got my bike seat to work on it by using a kids push scooter handle as a seat post, but it snapped after a few miles. The hole for a seat is a weird size in the scooter so finding a tube with the right internal and external diameters is difficult. Still, it’s a fun project that’s keeping me busy!

 

[jetpackjbd]

I made a proper seat tube out of some galvanized steel pipe from Ace Hardware! It works pretty well and I have no concerns about it snapping now.
I also bought new bolts that are a bit longer so I can align the motor sprocket to the wheel sprocket, but the chain still makes noise from rubbing on the side of the sprocket. The only thing that has worked to silence it is oil or liquid chain wax. Grease doesn’t help. I can live with occasionally oiling the chain every 50 miles or however often you’re supposed to, but it lasts about a mile before the noise comes back. At this point I’m considering adding a chainsaw oiler and calling it good enough (although my HOA would disagree).
What’s the actual fix for this? Would this be a better question for a regular motorcycle forum?

 

[MorbidlyObeseKoala]

It might be a tension issue or slightly misaligned if one of the sprockets is bent or your motor is a little off kilter. You could also jump ship to a belt drive if you find the right sprockets. Never have to oil those

 

[jetpackjbd]

It might be a tension issue or slightly misaligned if one of the sprockets is bent or your motor is a little off kilter. You could also jump ship to a belt drive if you find the right sprockets. Never have to oil those

Oh yeah, belt drive! I’m much more familiar with belts and they tend to be easier to work on and find parts for. I know for a fact there’s no pulleys made for my motor and wheel though, which means sending it to a fabricator, which means money. I’m also not sure if my mounts could handle the tension of a belt; they’re made of scrap plywood after all.
As of right now I’ve gone about 8 miles without waxing my chain, and the noise hasn’t come back. Maybe it’s not as bad as I thought

 

[jetpackjbd]

Did I kill my battery already? I’ve only used the scooter about 15 times, and have discharged below 50% maybe 3 times. The range seems to have gotten significantly worse; brand new it was around 60% battery after my 5 mile trip, now it seems to be around maybe 30% after the same trip. I know lead acid batteries hate going below 50%, but I didn’t think I’d see significant damage already. I always charge it as soon as I get home so it’s only below 50% for an hour at most.
Maybe I’ll try to revive the old batteries and use them in parallel for more range. Or I’ll pony up the $450 for a high capacity lithium replacement. Getting near a hundred miles of range would be amazing, but there’s no way I’m seeing that money back.

 

[MorbidlyObeseKoala]

Yeah that motor mount could be twisting under the torque of the motor causing some misalignment. If you can get your hands on some aluminum (which is workable with wood working tools), you could make a metal one.

Are you sure about the belt sprockets? Belt Cogs for Electric Scooters, Bikes and Go Karts - ElectricScooterParts.com
You'll need to know the shaft type and how the wheel sprocket attaches but this site has a number of options for most of the cheap scooters made in the last 15 years. Not saying it's a sure thing but the my1020 motors are very common, might poke around there just to see. Your Blade Z brand is in the brand section of the site. Their customer support isnt bad either, might even try contacting them and see what their recommendation is for belt drive.


Lead acid is not held in high regard around here, seems to perform very lackluster and be junk in 1-2yrs. You have to be aware of lithium's limitations before using them but they are so much more superior for power/weight. You can still get away under $100 for 36v or lower for the size you could fit in the scooter. A number of off-the-shelf options with a BMS to be had for the lower 24v or 36v.

 

[amberwolf]

I also bought new bolts that are a bit longer so I can align the motor sprocket to the wheel sprocket, but the chain still makes noise from rubbing on the side of the sprocket.

Is the motor mount straight and level? If the sprocket isn't actually parallel to the one it's on the same chain wiht, the chain gets twisted and the chain itself makes noise as does the sprocket face the chain side plates rub against.

You may see shiny wear on the places the rubbing occurs, which may show you what the angle of contact is, to be able to correct it.

If it's just the sprocket being slightly wider than the chain the rubbing and noise will decrease as the sprocket wears away itself and the inboard sides of the chain side plates.

Same for if the chain rollers are larger than the sprocket teeth wells.

If it's just a tight chain (or overtensioned) the noise will decrease as the pins and holes and rollers wear.

If it's a loose chain the noise will probably increase; same thing for the sprocket being too narrow for the chain.

 

[amberwolf]

Did I kill my battery already? I’ve only used the scooter about 15 times, and have discharged below 50% maybe 3 times. The range seems to have gotten significantly worse; brand new it was around 60% battery after my 5 mile trip, now it seems to be around maybe 30% after the same trip. I know lead acid batteries hate going below 50%, but I didn’t think I’d see significant damage already. I always charge it as soon as I get home so it’s only below 50% for an hour at most.
Maybe I’ll try to revive the old batteries and use them in parallel for more range. Or I’ll pony up the $450 for a high capacity lithium replacement. Getting near a hundred miles of range would be amazing, but there’s no way I’m seeing that money back.

SLA is not very good for EV use--it's main reason for continuing to be used is they're cheap and simple, and with no BMS to shutdown during even extreme voltage sag from overloading them, even ones too small for a particular application can still be used, making them cheaper.

Not only do LA not like going below a certain SoC, they degrade whenever they are below full charge; the longer they're below that, the more degradation there is.

Old ones, espeically if they've been left uncharged for any length of time, may have seriously degraded, so you may not get much if anything out of them, especially not for their weight.


To get 100 miles of range (or any other specific amount of range), you should first find out what your usage is, how many wh/mile you use up, on average. A wattmeter will tell you this directly, by taking the Wh reading it gives vs the distance you've travelled. You can guesstimate the Wh/mile if you know the *actual* Ah or Wh capacity of your battery, and running it from full to empty, but it's tough on the batteries if they're LA and especially if they're already failing. (and when not new you can't make a good guess as to their capacity).

If you have a long (mile+) stretch of your path that has a constant power draw and you can measure that power draw (Ammeter or multimeter that can measure the current from battery to controller, while at the same time measuring the voltage of the batteries, you can multiply those two together to get watts. While doing this, time how long it takes you to ride that stretch, and measure it's actual distance. Then you know how many Watts per hour per mile (wh/mile) your system takes for that kind of riding conditions. If tha'ts the worst case conditions, then it will take less for most of your ride, but if you use that worst-case Wh/mile you'll get some spare range when buying a battery.

If you want 100 miles of range, then you'd take that wh/mile and multiply times 100 miles. Let's say it takes you 20wh/mile; that's 20 x 100 = 2000 wh. That'd be a pretty big battery for something like your ride; you might have to carry it in a backpack, or mount it along the seattube; it probably wouldn't fit in the deckspace.

If you're into learning new things, you can build a battery out of used EV-grade cells reasonably cheaply for the capacities you get there, from Batteryhookup for instance (their stuff changes all the time, so keep an eye out for the specific thing you're after and eventually it will show up). I'd recommend some of the ex-car modules made of large-format (pouch, usually) cells, as there are less interconnects and whatnot to deal with. You can leave the module physically as it is (because the modules provide physical support for the cells that they require) , and just bypass any failed cells (often there aren't any, and they're all well-balanced and intact), and make whatever interconnect changes are needed to get the final voltage you're after.

Or you could use the cylindrical-cell packs they get instead, some of which came from scooters or ebikes and may work as-is for your application (or need a new BMS, etc).


For large-format cell-modules, one of these

Samsung 24s Lithium Ion 6kWh Module - 3x 8s Modules

This is the best deal on never cycled, large lithium ion battery modules. For more accurate freight calculations we have packages of 1, 4, 8, and 16 modules. All will fit on 1 pallet. These modules were in storage and never cycled. Every battery we tested was right around full capacity. You can...

batteryhookup.com

gets you three 2kwh 8s (30v nominal, 33.6v full) if your controller can handle that voltage. You'd probably want to wire in a BMS to each module, and use them separately, since they're rather large/heavy to carry more than one on that scooter....but the cells could handle whatever power draw your scooter could put on them, I'm sure, and you could probably even use them without a BMS with a low enough load on them, and not quite fully charging or discharging them. Just periodically check them for balance.

If it didn't cost as much for shipping to me as the 3 modules themselves, I'd get one of these to build a new 16s pack for the SB Cruiser trike (and have one module as a spare).

 

[jetpackjbd]

Yeah that motor mount could be twisting under the torque of the motor causing some misalignment. If you can get your hands on some aluminum (which is workable with wood working tools), you could make a metal one.

Are you sure about the belt sprockets? Belt Cogs for Electric Scooters, Bikes and Go Karts - ElectricScooterParts.com
You'll need to know the shaft type and how the wheel sprocket attaches but this site has a number of options for most of the cheap scooters made in the last 15 years. Not saying it's a sure thing but the my1020 motors are very common, might poke around there just to see. Your Blade Z brand is in the brand section of the site. Their customer support isnt bad either, might even try contacting them and see what their recommendation is for belt drive.


Lead acid is not held in high regard around here, seems to perform very lackluster and be junk in 1-2yrs. You have to be aware of lithium's limitations before using them but they are so much more superior for power/weight. You can still get away under $100 for 36v or lower for the size you could fit in the scooter. A number of off-the-shelf options with a BMS to be had for the lower 24v or 36v.

I might go for aluminum at some point, but I’d have to get something thick to avoid bending it. I’ll do it when I feel like spending a whole $30 or whatever on a sheet of aluminum but for now the scrap plywood is functional. I’ve seen belt drive parts for the motor, but there’s not enough space on the wheel side without some bending.
As for a cheap lithium solution, I’d prefer to have a combined BMS in the battery as well as more capacity. Even at 100-0%, the range on a 12ah battery is only about 12 miles.

 

[amberwolf]

I might go for aluminum at some point, but I’d have to get something thick to avoid bending it. I’ll do it when I feel like spending a whole $30 or whatever on a sheet of aluminum but for now the scrap plywood is functional.

Plenty of scrap metal you can use for stuff like that, depending on your local thrift stores and bulk trash day type of tossouts, or "please take this thing away for free" ads on Freecycle, Craigslist, etc.,

If you have an angle grinder, or a hacksaw and drill and files and a lot of patience, you can for instance cut up the L shaped bracket off the back of an office or desk chair, which is often steel anywhere from 1/4" to nearly a centimeter thick, and usually made a simple flat shape for the majority of it.

There are other sources for such things, too.

If you prefer aluminum, sometimes you can find thick pieces of that in rackmount server stuff or test equipment that may be scrapped at various businesses, or occasionally on CL or FC. You may not even need anything but the rack ears themselves, for something like a 3U or 4U rack, which could have as much as a square foot of material in the two L-shaped mounting ears.

As for a cheap lithium solution, I’d prefer to have a combined BMS in the battery as well as more capacity. Even at 100-0%, the range on a 12ah battery is only about 12 miles.

That's actually pretty good for SLA, especially if it's already degraded.

 

[jetpackjbd]

SLA is not very good for EV use--it's main reason for continuing to be used is they're cheap and simple, and with no BMS to shutdown during even extreme voltage sag from overloading them, even ones too small for a particular application can still be used, making them cheaper.

Not only do LA not like going below a certain SoC, they degrade whenever they are below full charge; the longer they're below that, the more degradation there is.

Old ones, espeically if they've been left uncharged for any length of time, may have seriously degraded, so you may not get much if anything out of them, especially not for their weight.


To get 100 miles of range (or any other specific amount of range), you should first find out what your usage is, how many wh/mile you use up, on average. A wattmeter will tell you this directly, by taking the Wh reading it gives vs the distance you've travelled. You can guesstimate the Wh/mile if you know the *actual* Ah or Wh capacity of your battery, and running it from full to empty, but it's tough on the batteries if they're LA and especially if they're already failing. (and when not new you can't make a good guess as to their capacity).

If you have a long (mile+) stretch of your path that has a constant power draw and you can measure that power draw (Ammeter or multimeter that can measure the current from battery to controller, while at the same time measuring the voltage of the batteries, you can multiply those two together to get watts. While doing this, time how long it takes you to ride that stretch, and measure it's actual distance. Then you know how many Watts per hour per mile (wh/mile) your system takes for that kind of riding conditions. If tha'ts the worst case conditions, then it will take less for most of your ride, but if you use that worst-case Wh/mile you'll get some spare range when buying a battery.

If you want 100 miles of range, then you'd take that wh/mile and multiply times 100 miles. Let's say it takes you 20wh/mile; that's 20 x 100 = 2000 wh. That'd be a pretty big battery for something like your ride; you might have to carry it in a backpack, or mount it along the seattube; it probably wouldn't fit in the deckspace.

If you're into learning new things, you can build a battery out of used EV-grade cells reasonably cheaply for the capacities you get there, from Batteryhookup for instance (their stuff changes all the time, so keep an eye out for the specific thing you're after and eventually it will show up). I'd recommend some of the ex-car modules made of large-format (pouch, usually) cells, as there are less interconnects and whatnot to deal with. You can leave the module physically as it is (because the modules provide physical support for the cells that they require) , and just bypass any failed cells (often there aren't any, and they're all well-balanced and intact), and make whatever interconnect changes are needed to get the final voltage you're after.

Or you could use the cylindrical-cell packs they get instead, some of which came from scooters or ebikes and may work as-is for your application (or need a new BMS, etc).


For large-format cell-modules, one of these

Samsung 24s Lithium Ion 6kWh Module - 3x 8s Modules

This is the best deal on never cycled, large lithium ion battery modules. For more accurate freight calculations we have packages of 1, 4, 8, and 16 modules. All will fit on 1 pallet. These modules were in storage and never cycled. Every battery we tested was right around full capacity. You can...

batteryhookup.com

gets you three 2kwh 8s (30v nominal, 33.6v full) if your controller can handle that voltage. You'd probably want to wire in a BMS to each module, and use them separately, since they're rather large/heavy to carry more than one on that scooter....but the cells could handle whatever power draw your scooter could put on them, I'm sure, and you could probably even use them without a BMS with a low enough load on them, and not quite fully charging or discharging them. Just periodically check them for balance.

If it didn't cost as much for shipping to me as the 3 modules themselves, I'd get one of these to build a new 16s pack for the SB Cruiser trike (and have one module as a spare).
View attachment 342734
View attachment 342735

Yep, lead acid batteries are terrible. I bought them because the scooter was designed for them, and they were the cheapest batteries to test with. I do like their simplicity; no special charging or monitoring.
The efficiency seems to be somewhere around 24wh/mi. It’s got 288wh of capacity and seemed to go about 12 miles on a full charge brand new.
The space is very cramped inside the scooter so a typical EV battery module won’t fit, although I might be able to fit some of those LiFePo4 cells that look like flasks. I’m pretty sure that’s what most drop in lead acid replacements use though, and without a spot welder I’m kinda screwed if I wanted to make it myself.

I was thinking of using this at some point. At 24 volts I get around a mile per amp hour, so 100ah should get me 100 miles at most of range. LiFePo4 is ideal for me as they last a very long time and are less of a fire risk compared to other lithium batteries. Their weight isn’t a big deal as they’re still more energy dense then the meaty lead acid batteries they’d be replacing. The battery I mentioned is too tall to fit in my scooter but I could make a new enclosure or just raise the scooter’s deck a bit; it seems like most batteries suitable for my application are too tall.

 

[jetpackjbd]

Plenty of scrap metal you can use for stuff like that, depending on your local thrift stores and bulk trash day type of tossouts, or "please take this thing away for free" ads on Freecycle, Craigslist, etc.,

If you have an angle grinder, or a hacksaw and drill and files and a lot of patience, you can for instance cut up the L shaped bracket off the back of an office or desk chair, which is often steel anywhere from 1/4" to nearly a centimeter thick, and usually made a simple flat shape for the majority of it.

There are other sources for such things, too.

If you prefer aluminum, sometimes you can find thick pieces of that in rackmount server stuff or test equipment that may be scrapped at various businesses, or occasionally on CL or FC. You may not even need anything but the rack ears themselves, for something like a 3U or 4U rack, which could have as much as a square foot of material in the two L-shaped mounting ears.



That's actually pretty good for SLA, especially if it's already degraded.

This whole project is made of mostly scrap so I might as well use some more of it. Now that you mentioned it, I’m remembering I’ve got this vintage oscilloscope case sitting in my room waiting to be thrown out. It’s made of either thin steel or aluminum and is strong enough to hold my weight. It’s funny that you mention old desk chairs, I’ve been looking for free ones in my area with hopes to use one as my scooter’s seat. Might look like a homemade mobility scooter but it’ll be comfortable!

I’m not actually sure about the range as I’ve never taken it all the way to fully dead. My only way of telling battery percentage is a red, yellow, or green indicator which gives me a rough estimate in thirds. There’s no odometer to tell me how far I’ve gone so I can only guess based on what my e-bike displays in the same area. I think I’ve taken it about 10 miles once when the batteries were new, and it showed red under very low loads towards the end of my trip. Judging by the power output of the motor it felt like I could’ve gone another 2 miles or so before the motor would start struggling hard so that’s where I’m getting my 12 mile range from. The original documentation for the scooter claimed a 12 mile range as well, but that was with a very slightly weaker motor with a 12 tooth sprocket instead of my now 13 tooth sprocket.

 

[amberwolf]

This whole project is made of mostly scrap so I might as well use some more of it. Now that you mentioned it, I’m remembering I’ve got this vintage oscilloscope case sitting in my room waiting to be thrown out. It’s made of either thin steel or aluminum and is strong enough to hold my weight.

Which one is it? I've had a few, but have not seen one that has anything you could use for this kind of bracket in it. The strength of their casings comes from the shape and interconnections of all the parts, which you wouldn't have after it's disassembled.

It’s funny that you mention old desk chairs, I’ve been looking for free ones in my area with hopes to use one as my scooter’s seat. Might look like a homemade mobility scooter but it’ll be comfortable!

If the star of the base/legs appear to be made of wood, you mgiht be in luck wtih any chair you find--every one that I've run across so far has an inner thick steel plate inside each of the wooden shells of the legs. They aren't wide enough to make a single bracket from, but more than one of them could be used to make separate brackets that each support part of the motor. Then you can use the seat itself, complete above the main swivel post, on the scooter.

I’m not actually sure about the range as I’ve never taken it all the way to fully dead. My only way of telling battery percentage is a red, yellow, or green indicator which gives me a rough estimate in thirds. There’s no odometer to tell me how far I’ve gone so I can only guess based on what my e-bike displays in the same area. I think I’ve taken it about 10 miles once when the batteries were new, and it showed red under very low loads towards the end of my trip. Judging by the power output of the motor it felt like I could’ve gone another 2 miles or so before the motor would start struggling hard so that’s where I’m getting my 12 mile range from. The original documentation for the scooter claimed a 12 mile range as well,

Based on the when-new trip info, then assuming it's a 24v system with two 10Ah batteries in series, and given that the Peukert effect means you get maybe half the capacity out of them, then you probably have at best 120Wh in there. (nominal (not full) voltage x actual real usable Ah = real usable Wh). If they're 12Ah batteries, you probably have 140Wh.

So at 10 miles of range for that, or 12 at best, you have something like 12wh/mile power usage.

The claims of manufacturers aren't often credible, as the ones that aren't outright marketing lies or just (bad-math) calculations instead of test results, are usually under highly favorable test conditions that dont' exist in the real world. THere are some honest ones now and then, but I'd still be skeptical about all of them based on what we've seen so far.

The efficiency seems to be somewhere around 24wh/mi. It’s got 288wh of capacity and seemed to go about 12 miles on a full charge brand new.

See above; I suspect it's a lot less than that depending on which SLA you're actually using.

The space is very cramped inside the scooter so a typical EV battery module won’t fit, although I might be able to fit some of those LiFePo4 cells that look like flasks. I’m pretty sure that’s what most drop in lead acid replacements use though, and without a spot welder I’m kinda screwed if I wanted to make it myself.

If you mean Headway cells, the ones that bolt together, you don't need a spot welder. But they suck, not as bad as SLA, but they aren't actually capable of what the manufacturers or sellers claim for them--voltage sag under load means you get a lot less watts out of them at high relative loads.

If you mean regular cylindrical cells, like 18650, 27100, etc., your best bet is to buy one of those EV modules made of that kind of cell, and simply cut the interconnects between sections as needed to reconfigure it into the series/parallel that you need (normaly 7s, and then however many p, for a 24v system; if your controller will take the higher voltage you can use 8s). Then add a BMS to protect the pack (I wouldn't go without a BMS for this type of cell).

I was thinking of using this at some point. At 24 volts I get around a mile per amp hour, so 100ah should get me 100 miles at most of range. LiFePo4 is ideal for me as they last a very long time and are less of a fire risk compared to other lithium batteries. Their weight isn’t a big deal as they’re still more energy dense then the meaty lead acid batteries they’d be replacing. The battery I mentioned is too tall to fit in my scooter but I could make a new enclosure or just raise the scooter’s deck a bit; it seems like most batteries suitable for my application are too tall.

As long as they are capable of more amps (current) than your controller's current limit, by as much as possible, then you can use any battery that will fit your space and doesn't exceed your controller's voltage limit.

Ones generally similar to the SLA in size/shape make it easy to swap them out, so as long as the ones you get are capable of the current, you'll get probably twice the Wh the same "Ah" battery in SLA would give you. So if you have 10Ah SLA and get 10Ah LFP bricks, you'll probably get twice the range--as long as the LFP you get are designed and rated to handle at least twice the current your controller needs, to minimize voltage sag so they don't cut out as they get close to empty.


Just be careful about any battery you buy--first, if it's cheaper, or smaller, etc., than others of it's claimed specs, it's probably not real.


The one you link looks like it's probably real enough based on the reviews there, but it's very big. You'd need two of them, at a total of 80lbs, and your scooter would perform less well (probably by a lot) with nearly a whole person's extra weight on it. (your present batteries probably weigh 10-15lbs at a guess, so take that out of whatever new battery weight there is).

But that's an awful lot of money--a thousand dollars for enough to run your scooter (two times 500 bucks), and that's on sale--they're usually almost $700 each, so $1400.

Unless you seriously require the 50-100mile range, that's a whole lot of dough.


The fire risk is not so much about the chemistry****, as it is about the quality of the cells and how well-matched they are to each other in capacity and resistance, so they all perform the same and don't have some more stressed than others...and then using them well-within their capabilities, not pushing them anywhere near their limits (unlike the way your SLA are used). So for instance if you need 500wh to do what you want, get a pack with at least 750Wh so you never empty it, and you can use a programmable BMS (like JBD, ANT, etc) to keep it from reaching full charge, too (using an 8s pack works best for this option, vs 7s).


****almost all the fires you see are from defective cells or packs, or damaged ones, or ones being abused in some way (even by design of the device manufacturer), and the reason you see more reports about LiPo or other Li-Ion types vs LiFePO4 (LFP) is because there are so very many more packs made of those types. There are characteristics of some chemistries or cell-designs that make a fire with them much worse than with others...but any battery is energy-storage, and can be made to release that energy in a catastrophic way, even SLA, or plain old alkaline cells.

 

[jetpackjbd]

Which one is it? I've had a few, but have not seen one that has anything you could use for this kind of bracket in it. The strength of their casings comes from the shape and interconnections of all the parts, which you wouldn't have after it's disassembled.



If the star of the base/legs appear to be made of wood, you mgiht be in luck wtih any chair you find--every one that I've run across so far has an inner thick steel plate inside each of the wooden shells of the legs. They aren't wide enough to make a single bracket from, but more than one of them could be used to make separate brackets that each support part of the motor. Then you can use the seat itself, complete above the main swivel post, on the scooter.



Based on the when-new trip info, then assuming it's a 24v system with two 10Ah batteries in series, and given that the Peukert effect means you get maybe half the capacity out of them, then you probably have at best 120Wh in there. (nominal (not full) voltage x actual real usable Ah = real usable Wh). If they're 12Ah batteries, you probably have 140Wh.

So at 10 miles of range for that, or 12 at best, you have something like 12wh/mile power usage.

The claims of manufacturers aren't often credible, as the ones that aren't outright marketing lies or just (bad-math) calculations instead of test results, are usually under highly favorable test conditions that dont' exist in the real world. THere are some honest ones now and then, but I'd still be skeptical about all of them based on what we've seen so far.





See above; I suspect it's a lot less than that depending on which SLA you're actually using.


If you mean Headway cells, the ones that bolt together, you don't need a spot welder. But they suck, not as bad as SLA, but they aren't actually capable of what the manufacturers or sellers claim for them--voltage sag under load means you get a lot less watts out of them at high relative loads.

If you mean regular cylindrical cells, like 18650, 27100, etc., your best bet is to buy one of those EV modules made of that kind of cell, and simply cut the interconnects between sections as needed to reconfigure it into the series/parallel that you need (normaly 7s, and then however many p, for a 24v system; if your controller will take the higher voltage you can use 8s). Then add a BMS to protect the pack (I wouldn't go without a BMS for this type of cell).



As long as they are capable of more amps (current) than your controller's current limit, by as much as possible, then you can use any battery that will fit your space and doesn't exceed your controller's voltage limit.

Ones generally similar to the SLA in size/shape make it easy to swap them out, so as long as the ones you get are capable of the current, you'll get probably twice the Wh the same "Ah" battery in SLA would give you. So if you have 10Ah SLA and get 10Ah LFP bricks, you'll probably get twice the range--as long as the LFP you get are designed and rated to handle at least twice the current your controller needs, to minimize voltage sag so they don't cut out as they get close to empty.


Just be careful about any battery you buy--first, if it's cheaper, or smaller, etc., than others of it's claimed specs, it's probably not real.


The one you link looks like it's probably real enough based on the reviews there, but it's very big. You'd need two of them, at a total of 80lbs, and your scooter would perform less well (probably by a lot) with nearly a whole person's extra weight on it. (your present batteries probably weigh 10-15lbs at a guess, so take that out of whatever new battery weight there is).

But that's an awful lot of money--a thousand dollars for enough to run your scooter (two times 500 bucks), and that's on sale--they're usually almost $700 each, so $1400.

Unless you seriously require the 50-100mile range, that's a whole lot of dough.


The fire risk is not so much about the chemistry****, as it is about the quality of the cells and how well-matched they are to each other in capacity and resistance, so they all perform the same and don't have some more stressed than others...and then using them well-within their capabilities, not pushing them anywhere near their limits (unlike the way your SLA are used). So for instance if you need 500wh to do what you want, get a pack with at least 750Wh so you never empty it, and you can use a programmable BMS (like JBD, ANT, etc) to keep it from reaching full charge, too (using an 8s pack works best for this option, vs 7s).


****almost all the fires you see are from defective cells or packs, or damaged ones, or ones being abused in some way (even by design of the device manufacturer), and the reason you see more reports about LiPo or other Li-Ion types vs LiFePO4 (LFP) is because there are so very many more packs made of those types. There are characteristics of some chemistries or cell-designs that make a fire with them much worse than with others...but any battery is energy-storage, and can be made to release that energy in a catastrophic way, even SLA, or plain old alkaline cells.

Just wondering, why would I need two of the batteries I linked? It’s already at 24 volts, is there something I’m missing?

 

[amberwolf]

My bad, I saw the shape and style and my brain plugged 12v into the numbers automagically.

 

[jetpackjbd]

My bad, I saw the shape and style and my brain plugged 12v into the numbers automagically.

Gotcha, I figured. It definitely looks like it’s meant for a 12v form factor

 

[jetpackjbd]

I tried my usual route today of ~5 miles, going about 7mph or so instead of around 15mph and sitting down instead of standing. Sure enough, I got home without having gotten a yellow light at all (indicating ~66% battery), whereas I have been getting a red light by the time I’m home (indicating <~33% battery).
I assume that my batteries are too weak to handle a 500w motor, even though the scooter was designed for a 450w motor. I think the reason I was able to get a good range on brand new batteries but terrible range on my next rides is that full throttle (more than the batteries could handle?) for most most of a cycle caused them to degrade quickly. Aerodynamics may be a culprit too, especially while standing, but under 20MPH I wouldn’t expect that much. If I’m right on this, it sounds like I need to invest in that big lithium battery sooner than later.

 

[amberwolf]

SLA are really not meant for high-current discharge, except for those built to do this. Most have thin plates, meant for low-current or standby use. Even their capacity is rated at 1/20C, which means that a 10Ah battery is only 10Ah if it's discharged at 0.05 x 10Ah = 0.5A. The discahrge curve on the manufacturer spec sheet may show how small the capacity gets above that, some stop there because it looks bad.

So if yours are thin-plate types, high current discharge could wear them out faster, but it shouldn't happen on the first cycle. If they were old (date codes often etched or branded into the plastic case) they probably sulfated on the shelf from self-discharge over time and were already damaged from sitting there being unused. Otherwise, unless the discharge rate used on them exceeded the manufacturer's actual specs they should handle it and not be damaged that quickly.


Aero is mostly about crosssection that blocks or deflects the air. The more surface area that has to pass thru the air, the more air is blocked, the more resistance there is, and the harder the power system has to work to go the same speed.

The faster you go, the harder it is to push against the air, and it's not linear--the same amount of extra speed over a certain speed takes much more power than the previous amount of extra speed.

Simulators like those at the ebikes.ca site can show you how the relationships between these things work; you can change the aerodynamics part of the sim to match what your standing vs sitting would be equivalent to, for instance.

But riding at half the speed probably uses much less than half the power, and if sitting makes a smalller frontal area then that also decreases power usage.


The percentage of battery shown on a meter like you have isn't usually accurate, partly because it isn't actually showing you capacity--it is showing you a voltage reference in most cases, and what voltage that is compared to the "empty" voltage depends on what voltage references they used inside it for each light.

What voltage does your battery read at the moment the light changes from green to yellow, and yellow to red?

What do those voltages mean on the discharge curve of the particular batteries you have, on the manufacturer chart? (if there isn't one, you can guesstimate using the reference chart for the same capacity and size and chemistry battery).

Then you can better guess what capacity you actually have left at any particular time.

A voltmeter would be a little better, since you could see the actual voltage at all times, but a real wattmeter would be even better; they're not too expensive, like this one

https://www.amazon.com/gp/product/B013PKYILS

or other similar ones.

 

[jetpackjbd]

SLA are really not meant for high-current discharge, except for those built to do this. Most have thin plates, meant for low-current or standby use. Even their capacity is rated at 1/20C, which means that a 10Ah battery is only 10Ah if it's discharged at 0.05 x 10Ah = 0.5A. The discahrge curve on the manufacturer spec sheet may show how small the capacity gets above that, some stop there because it looks bad.


Aero is mostly about crosssection that blocks or deflects the air. The more surface area that has to pass thru the air, the more air is blocked, the more resistance there is, and the harder the power system has to work to go the same speed.

The faster you go, the harder it is to push against the air, and it's not linear--the same amount of extra speed over a certain speed takes much more power than the previous amount of extra speed.

Simulators like those at the ebikes.ca site can show you how the relationships between these things work; you can change the aerodynamics part of the sim to match what your standing vs sitting would be equivalent to, for instance.

But riding at half the speed probably uses much less than half the power, and if sitting makes a smalller frontal area then that also decreases power usage.


The percentage of battery shown on a meter like you have isn't usually accurate, partly because it isn't actually showing you capacity--it is showing you a voltage reference in most cases, and what voltage that is compared to the "empty" voltage depends on what voltage references they used inside it for each light.

What voltage does your battery read at the moment the light changes from green to yellow, and yellow to red?

What do those voltages mean on the discharge curve of the particular batteries you have, on the manufacturer chart? (if there isn't one, you can guesstimate using the reference chart for the same capacity and size and chemistry battery).

Then you can better guess what capacity you actually have left at any particular time.

A voltmeter would be a little better, since you could see the actual voltage at all times, but a real wattmeter would be even better; they're not too expensive, like this one

https://www.amazon.com/gp/product/B013PKYILS

or other similar ones.

Ohhhh, I didn’t know there was a discharge curve for batteries. I had noticed the effect of speed on range but wasn’t sure what the main culprit was. I had always wondered what the C rating meant on batteries, thanks! That makes a lot more sense now.
As of right now, my battery indicator is good enough. A wattmeter would be better but this works. Since lead acid batteries tell their SOC from mostly loaded voltage drop and not unloaded voltage like lithium batteries, the light is easier to read at a glance than a voltmeter. I’ll try to find a discharge curve graph for my batteries

 

[jetpackjbd]

Oh… uhm I think you were on to something with this “discharge curve” thing…
Specifications

I’m drawing over 20 amps at full throttle… I’m shocked I’ve gotten this good of range then. That said I’m not always on full throttle, probably drawing an average of 15 amps (mostly random guess) but still. Jesus.




Not sure how much I trust the spec sheet, although it seems like real testing results. The seller has numerous errors on their Amazon listing (calling it AGM in the description, putting it under the lithium-ion category) and giving info on the tickle lifespan…

 

[amberwolf]

Specifications
View attachment 342823
I’m drawing over 20 amps at full throttle… I’m shocked I’ve gotten this good of range then. That said I’m not always on full throttle, probably drawing an average of 15 amps (mostly random guess) but still. Jesus.

Back when I started in this stuff, I was so used to SLA that when I changed to NiCd, then NiMH, then LiFePO4 and later various other LiIon, I was shocked at how much better they were. (I'd used NiMH and NiCd in small projects like sci-fi props, tools, but couldn't get big enough ones for the ebike stuff, so SLA was my only option at the time).

Not sure how much I trust the spec sheet, although it seems like real testing results.

Its' probably accurate for a factory-new battery. Since these things tend to sit around on shelves at warehouses for who knows how long (without any of the required maintenance), actual performance of any particular battery will be less by some amount.

The seller has numerous errors on their Amazon listing (calling it AGM in the description, putting it under the lithium-ion category) and giving info on the tickle lifespan…

Yeah, almost anything sold on Amazon has errors int eh listing, some of them are pretty serious. (it's not just amazon, but they're even worse about it than ebay; I expect this on aliexpress/alibaba/etc.

Even worse, some of the pages are actually for entirely different things than the listing/name and reviews are for, indicating that the page has been re-used for some totally different product at some point, and most of the page not updated. Sometimes looking thru the reviews you can see this has happened multiple times--right now it might be for an ebike part, previously a summer dress, before that a box of eggplant powder, etc.


AGM is a version of SLA (Advanced Glass Mat, Sealed Lead Acid); I expect the seller has no idea what they are actually selling as that's really common, so getting things in the wrong category is fairly minor in the classes of errors. :lol:

 

[jetpackjbd]

Today it went into the yellow after ~1.5 miles and into the red by 3. The range is somehow now a QUARTER of what it was brand new after <15 uses. I fully see why people dislike SLA for these applications. I don’t know if it’ll get me home another 3 miles, maybe if I take it reeeaaalllyy slow like I did for testing last week. Might need another scooter rider to tow me…


Struggling to find a LFP battery that’s able to fit in my limited space with a BMS capable of 30A continuous. I’ve got the space for the equivalent of 2 12ah 12v SLAs, or 6.8”x8.5”x3.9” (little bit of wiggle room on the Z-axis).
I can make an enclosure to fit any size battery I want if I have to, but I’d really prefer not to. The only place I could get it to fit securely is where the deck is (raising it and taking away the ability to stand on it), or a trailer. A trailer would work, however it would mean the trailer can’t be removed without taking away my power source. I guess I could leave the SLA batteries inside it with a battery extension trailer, but I’m not a huge fan of the idea. Maybe.

 

[amberwolf]

Today it went into the yellow after ~1.5 miles and into the red by 3. The range is somehow now a QUARTER of what it was brand new after <15 uses. I fully see why people dislike SLA for these applications.

You might want to check your charger to be sure it's actually charging them, and that each of the batteries is equal voltage. (if they're not equal one of them may be damaged or lower capacity than the other, so the other one never fully charges)

And that the charger is the right kind for the kind of lead-acid you have.

For instance, an FLA charger (for wet batteries like car starters) could damage SLA/AGM, depending on how it's designed. A charger with too high a charging current will boil the electrolyte in the SLA and reduce the capability of them.

A charger with too low a voltage can't fully charge them, and if it doesn't have the correct "float" voltage at the end to help finish charge absorption they might nto fully charge either. Usually a 24v system will charge to around 28.8v at least. (the batteries should be marked with their charge current and voltage on their labelling).

If it's not actually a lead-acid charger it may also not fully or correctly charge them.

 

[jetpackjbd]

Latest update on the scooter build: I’m making a switch to LiFePO4 using two used K2 24V 9ah packs in parallel from batteryhookup.com. I bought one to verify the pack wasn’t junk, and it seems to still have a lot of life left. Waiting on the second one now but I’m expecting it to be at a good capacity as well. Two in parallel will still be stressing the batteries a bit, but just a single battery was able to power the scooter for a while (wasn’t happy about it though). Hopefully the (ideally) 18ah capacity will get me 18 miles range, or more likely 15 miles with a degraded battery given the original 12ah batteries originally gave 12 miles range.

Temporary install of the first battery:



In other news, I found a smashed office printer and stole the scanner light from it. I 3D printed an enclosure for the driver, soldered a power connector to it, and cut an old towel rod to make a light cover that resembles old fluorescent fixtures. I’ve got it mounted on the scooter now to work as a warning light for other drivers. It’s meant for ~24V and is about a foot and a half long which makes it perfect for the scooter. Produces a bright green light which isn’t ideal but it’s enough to warn people I’m coming, plus it should work as a weak, unfocused headlight.


(will attach photo of the light later, don’t have a picture at the moment)

 

[amberwolf]

Sounds kind of like this, where I made a "headlight" just for people to see me by (not much good for seeing with) out of the CCFL slide-scanner light unit of some old scanner. I used a similar unit on the rear first with a red gel and later replacing the CCFL with red LEDs, and with amber LEDs embedded in the ends of each one for turn signals.

Did a lot of other salvaged-stuff work on that bike, some of which went on (in spirit) to the next one, CrazyBike2.

https://endless-sphere.com/sphere/threads/amberwolfs-dayglo-avenger-mkii.15570/