E-S Stealth Electric Bike Owners

[Justtoby]

what is the Bomber low volt cut out setting with the stock battery?

70 or 72 volts?

Thanks

My battery is a 2011 delivery and is 69v

[Skyline]

what is the Bomber low volt cut out setting with the stock battery?

70 or 72 volts?

Thanks

My battery is a 2011 delivery and is 69v

Hi guys,

just while your on the topic I have a 2012 bomber and the low volt cut out is set to 70v
but I've noticed the battery voltage sag's to 64v -65v even on a fresh battery under heavy acceleration
is this the same on your bikes or should mine be set differently

Thanks

[Hyena]

I'd be worried about a weak cell or 2 skyline if it's dipping that low on a fresh charge.
You have 3 levels of protection, the LVC in the cycle analyst, the LVC in the controller and in the BMS itself. I don't know what the actual BMS trips at but it's usually 2v/cell for lifepo4. For a 24S pack that gives you a theoretical minimum of 48v but you'd never get that low as some cells will always drop off quicker than the others and trigger the LVC. I would have thought a minimum voltage of 60v would be more likely what you'd see, but maybe they're using a different cell count or chemistry. Either way 69v for a 72v pack seems fairly tame but maybe it's to prolong the life of the packs, or leave some reserve. I often set my CA LVC a little higher than it needs to be so if I get carried away and use up too much power without realising I can then pull over and set it a bit lower to 'limp home' on. I think of it like a fuel reserve on a motorbike. You'll know all about it if you have to pedal one of these heavy beasts with no assistance, even sipping 5 amps makes pedalling so much easier.

[Kepler]

Hi guys,

just while your on the topic I have a 2012 bomber and the low volt cut out is set to 70v
but I've noticed the battery voltage sag's to 64v -65v even on a fresh battery under heavy acceleration
is this the same on your bikes or should mine be set differently

Thanks

Doesn't sound right. If the CA is set to 69V or 70V, it will wind off power as it hits this threshold. If you are seeing 64V to 65V under hard accel, then the CA doesn't seem to be doing its thing.

Is this a peak (trough) reading you see recorded in the CA or actually a prolonged condition that you can actually see while the bike under hard accel?

Sometimes you do get unusual peaks or troughs recorded through the CA

[Cowardlyduck]

Whilst were on the topic...what's it meant to be for the Fighter? I've been setting the LVC to between 44 and 48V, but I'm not actually sure what the LVC is set to on the BMS. Anyone know?

Also, won't the pack sag below the LVC on the BMS when under hard acceleration? Or should this never happen?

Cheers

[full-throttle]

BMS would have a LVC for each cell ~2.5V or higher. When it kicks in the power would be lost incl to the dashboard and would need to be powercycled.

The controller has a slightly higher pack-level LVC and the dashboard has an even higher one. None of those need a powercycle.

Not sure about the values.

[Hyena]

Most BMSs dont give you a warning, when they cut out that's it. Some reset when the voltage comes back up (ie from sag under acceleration), some require being physically turned off or unplugged to reset. If you do trip the BMS under hard acceleration you should be able to get a little more range by taking it easy. The BMS really is your last back stop though, depending on how relaxed or generic the controller LVC is. I think crystalyte usually set their controller LVCs at 57v (for the 72v models) - I don't know if stealth change this. When the controller hits LVC it usually tapers right off just before it cuts out - so giving full throttle will see the bike only slowly rolling along and then cuts out all together. The CA cut out is the same, and dials back the current to maintain the LVC voltage until the battery is drained to the point where the resting voltage is the set LVC or breathing on the throttle drops it below. So yeah, properly set up CA and controller LVCs should give you a soft warning before the BMS trips. If the BMS trips because a cell goes bad you won't get this soft warning as the overall voltage may be somewhat maintained.

edit: yeah what full throttle said while I was typing

[Cowardlyduck]

Thanks guy's. Yeah I get most of this. Mainly since my first battery slowly went bad and was cutting out on the BMS at lower and lower AH each time, but I never really paid attention to what that voltage was.
Just need to know what the Controller/BMS LVC is so I can set my CA appropriately and not have to pedal home with no power...again. I swear I've pushed this beast home at least a dozen times now. Getting mighty sick of it.
I think John may have told me the BMS LVC before, but I can't remember. I'll stick with 48V for now and see how I go.

Cheers

[remf]

Set it at 36V - no more pushing hopefully!

[Cowardlyduck]

Set it at 36V - no more pushing hopefully!

Huh? 36V. Do you mean 46V.

I'm pretty sure I remember the BMS cutting out before 46V though. Maybe that was just the bad battery though. Will see how I go.

Cheers

[remf]

Mine was set at 36V from the factory...as you say the BMS will cut out before the CA LVC so it really is a secondary setting in case you want to set your LVC above the BMS LVC for any reason. If the bike is cutting out prematurely, set it at 36V and the CA cutout won't effect your ride anymore.

[Cowardlyduck]

Mine was set at 36V from the factory...as you say the BMS will cut out before the CA LVC so it really is a secondary setting in case you want to set your LVC above the BMS LVC for any reason. If the bike is cutting out prematurely, set it at 36V and the CA cutout won't effect your ride anymore.

Surely that can't be right. What voltage is yours at fully charged? Mines 58.4V. It usually drops to 54V pretty quickly after only 100mha used. On my commute to work this morning it dropped to 52V by the time I got to work. I had used 10.5AH.

That reminds me...Took some video on my commute to work, will post shortly.

Cheers

[voicecoils]

Since there are already two other low voltage cutouts (LVC) on the bike in the pack's BMS and in the controller, the Cycle Analyst setting can really be anything you want, including 0 volts. The controller and BMS LVC settings are not user adjustable so once you hit one of them, try to power cycle the bike and finish your ride with low throttle use (keep your peak amps down). Failing that, the bike fortunately has pedals!

In general, the less deeply you discharge a battery on a given ride the longer it will last so if your regular rides permit it, a higher LVC setting in the Cycle Analyst could help you extend the life of the battery well past the warranty period. The Stealth factory may also have it's own recommendations about the CA's LVC settings and it's worth remembering that both models have different packs and they have had different types over the years too. Not everyone's bikes on the owner's thread will necessarily have the same settings.

Most LiFePO4 chemistries have the following voltage profile at the cell level @ 25 deg C:

3.65v max charge
3.2 - 3.3v nominal
2.5v cutoff recommended, 2.0v minimum

Here's an example datasheet: http://liionbms.com/pdf/k2/LFP26650EV.pdf

Using that cell level info, you can work out the different charged, nominal and discharged voltages for any size pack.

I find with LiFePO4 cells, after they're fully charged the voltage starts falling to something between 3.65v and 3.2v per cell without any load applied. Then when riding, the resting voltage (when no throttle is applied) will stay close to the nominal voltage for most of the discharge before dropping quickly at the end as the battery nears full discharge. Near full discharge, the voltage will drop significantly under load (hills, accelerating etc) and that's when you're most likely to trip whichever LVC value is set highest. If you check out the first graph in the link above, you'll notice how the discharge curve follows my description.

[remf]

The reason your Fighter is not making it home is you have your Cycle Analyst Low Voltage Cutout too high. Rely on the BMS, get the CA out of the way by setting it low. Voltage fully charged isn't pertinent to this particular scenario.

Cool...we can never have enough vids

[Cowardlyduck]

The reason your Fighter is not making it home is you have your Cycle Analyst Low Voltage Cutout too high. Rely on the BMS, get the CA out of the way by setting it low. Voltage fully charged isn't pertinent to this particular scenario.

Cool...we can never have enough vids

Well the vids might have to wait. I think my work blocks uploads to youtube...it's just sitting there trying to upload.

I usually set the CA LVC higher, then lower it if the batt starts to run low. It definitely wasn't the CA stopping me getting home on the last battery that's for sure. It would be nice to know for certain though what the BMS LVC is set to.

Failing that, the bike fortunately has pedals!

Yeah, speaking of which, I might end up needing to bring the bike back into your shop. I can't for the life of me get the dam back end of this thing to run smooth. John sent me some replacement dropout plates, since the previous one's I had were letting the back wheel slide backwards under heavy breaking/regen. Since readjusting the rear wheel, I can't get it running without either the brake rubbing severely, or the rear freewheel making horrible noises due to a bad angle to the front sprocket. I've taken to oiling my rear disc brake to help with the rubbing so that I can pedal without it sounding like I'm grinding salt with the freewheel. I won't trouble John with it again though (unless it gets much worse), since I'll be swapping the freewheel out for a rear derailleur and 7 speed freewheel some time later this year anyway.

Most LiFePO4 chemistries have the following voltage profile at the cell level @ 25 deg C:

3.65v max charge
3.2 - 3.3v nominal
2.5v cutoff recommended, 2.0v minimum

So based on that, I can calculate that the Fighter pack is a 16S pack. 58.4/3.65=16
And the nominal voltage I've seen is more or less correct. 3.3V*16=52.8V
And the LVC could be 40V. 2.5*16=40V

Remf, we might have different packs. I'd assume Stealth would leave things set on a more conservative side, so maybe 43V for LVC on the BMS. There we go, with a little help, I've answered my own question.

Cheers

[Hyena]

I've taken to oiling my rear disc brake to help with the rubbing

Removing the rear caliper will make things much quieter, and yield similar rear braking efficiency

[Cowardlyduck]

I've taken to oiling my rear disc brake to help with the rubbing

Removing the rear caliper will make things much quieter, and yield similar rear braking efficiency

You'd think so, but it actually works. I can still lock up the rear wheel if needed.
Not that I'd recommend it to anyone else.

Cheers

[Justtoby]

I've taken to oiling my rear disc brake to help with the rubbing

Removing the rear caliper will make things much quieter, and yield similar rear braking efficiency

You'd think so, but it actually works. I can still lock up the rear wheel if needed.
Not that I'd recommend it to anyone else.

Cheers

The brake pads will absorb the lubricant over time, you will end up needing to replace the pads and I would suggest the disc too. You need to get it running true.

[Skyline]

I'd be worried about a weak cell or 2 skyline if it's dipping that low on a fresh charge.
You have 3 levels of protection, the LVC in the cycle analyst, the LVC in the controller and in the BMS itself. I don't know what the actual BMS trips at but it's usually 2v/cell for lifepo4. For a 24S pack that gives you a theoretical minimum of 48v but you'd never get that low as some cells will always drop off quicker than the others and trigger the LVC. I would have thought a minimum voltage of 60v would be more likely what you'd see, but maybe they're using a different cell count or chemistry. Either way 69v for a 72v pack seems fairly tame but maybe it's to prolong the life of the packs, or leave some reserve. I often set my CA LVC a little higher than it needs to be so if I get carried away and use up too much power without realising I can then pull over and set it a bit lower to 'limp home' on. I think of it like a fuel reserve on a motorbike. You'll know all about it if you have to pedal one of these heavy beasts with no assistance, even sipping 5 amps makes pedalling so much easier.

Hi hyena,
It's great to get talking to ya I've read all your posts and your knowledge of these bikes far exceeds mine. I would really aprieciate any advice you could give me.
I think you could be right about a weak cell or 2 but the range I'm getting is brilliant. First full cycle:

http://www.youtube.com/watch?v=okmTU9OK ... ata_player

I'm only on cycle 6 of the battery so I've only started to accelerate hard the last few days
And I've noticed that even on a fresh battery the LVC sags under hard acceleration to 65v which slows you down its like coming on and off the power
And on a low battery the VMIN is 60.5v with a reduced top speed.

Now I've noticed that if I feather the throttle and keep it out of the sag above 70v I'll get top speed. Are these the symptoms of bad cells or is this how it should be?
Thanks.

[Cowardlyduck]

The brake pads will absorb the lubricant over time, you will end up needing to replace the pads and I would suggest the disc too. You need to get it running true.

Yeah, well I bought some purpose made disc break cleaner today, and that seems to help also. Works for now, but I will need to get it all trued eventually.

Vids finally uploaded. Took ages. It's just some of the better sections of my daily commute to/from work. They aren't especially exciting, but thought I'd post anyway.


Bike path Leichardt/ Haberfield


Drummoyne


Bike path Hunters Hill - Going north


Ryde & Hunters Hill - Going south - I hit 70kph down this hill.


Recently flooded bike path in Hurlstone Park.

Cheers

[Justtoby]

I wonder if the caliper Is 100% straight, if the wheel is correctly aligned.

Would straighten the wheel by measuring each side of the wheel rim to the swing arm and remove the brake pads, see if the disc is now sitting equidistant from each side of the caliber, if not then maybe the mounting needs a small shim to straighten the caliper?

[korpin]

I have seen a lot of people commenting on the stealth bombers rear suspension as being old fashioned or not as capable as a three pivot suspension but they may be forgetting a bomber does not need the extra pivots since it has no rear derailuir and therefore no chain slag to worry about....I am thinking about getting a bomber but cannot test drive one here in los angeles...did see the fighter though in hollywood when the factory rep was there....here is something cool these guys are down the street from me and coming out with some interesting things that are NOT on their website yet: http://www.hi-powercycles.com/product.s ... egoryId=28

[korpin]

]was wondering if anyone remembers the post about a few hundred posts back where they talk about getting a bomber from some place in germany i think?..does anybody know if they have a website or contact info?:

What`s up wih 2011 prices? the price tag have doubled since last year! Major setback for me

Email i received:

"Dear Bikers,

I need to give you information on the bikes which you have seen on http://www.stealthelectricbikes.com .
We are the distributor of the bikes in Benelux ( Belgium , Netherlands, Luxembourg) and we give information to the manufacturer of the bikes in Australia if there are requests for information for countries which are surrounding us in Europe, for example Germany, France, UK and Spain.
As you have noticed there are 2 kinds of bikes the Bomber with a 4,5 KW engine and the Fighter with a 2.2 KW engine.
Stealth standard bike starts at € 8490 ( excl VAT) for the Bomber and € 5990 ( excl VAT) for the fighter.
You can have upgrades if you want.
We have to charge you for Air Freight ( Delivery at the Airport the nearest to your Home) about € 500. There are also costs for handling at the airport and in some countries " Duties" . Next to all this there is VAT.
Delivery time is about 8 weeks.
If you want more information please let me know !"

2010 pricelist:

IMG_8303.JPG

stealth.zip

[Justtoby]

You can test ride one in USA, you may need to jump on a cheap flight to another state, I can put you in touch with the factory guys, they are brilliant blokes and they can hook you up with the nearest dealer who has stock.

You can also test ride a bomber or fighter in the uk.

The suspension is well beyond my ability as a rider and has loads of adjustability. I think motor cross bikes have a similar setup and work fine, I had a yz125 a few years back that was pretty much the same design and you could do 6ft high jumps and hardly notice the landings better riders could do much, much more.

[Kepler]

I have seen a lot of people commenting on the stealth bombers rear suspension as being old fashioned or not as capable as a three pivot suspension but they may be forgetting a bomber does not need the extra pivots since it has no rear derailuir and therefore no chain slag to worry about....I am thinking about getting a bomber but cannot test drive one here in los angeles...did see the fighter though in hollywood when the factory rep was there....here is something cool these guys are down the street from me and coming out with some interesting things that are NOT on their website yet: http://www.hi-powercycles.com/product.s ... egoryId=28

There have been a few threads on the product. Here is one http://endless-sphere.com/forums/viewtopic.php?f=4&t=34984&hilit=hi+powercycles

It will be interesting to see if they make any inroads.