Battery performance dropped off in 2013 Stealth Bomber

D

Damian

1 µW
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Nov 11, 2015
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Hi
Ive got a 2013 Stealth Bomber that has done 5000 Kms on the road it normally gets about 45km out of 18 Ah before the battery dies.
Last few rides the battery died at about 12 Ah and 30km. Im wondering if anyone can tell me exactly what has failed. Not overly technically minded but if I need to replace the whole battery Stealth are asking over $2000. Is it possible or worthwhile to recondition cells (assuming one may be gone are the others going to last much longer) or if I need a replacement battery is there a better value option than buying off stealth. Im in Sydney Aus.
Hope Im not missing answers within the forum Im new to it, I had a good look around but couldn't find my specific answers.
Thanks in advance.
 
One possibility is that the battery is simply out of balance. Try long periods on the charger, up to weeks at a time. In other words, leave it on the charger anytime you are not actually riding it for a few weeks. See if you find it better. But your capacity loss beginning at about two years calendar age is not particularly unusual. So a return to like new is not to be expected.
 
Thanks Dan
When I plug the bike in after a ride the charger turns off at the end of the charge (about 2 hours if down low) is it sufficient to just leave it plugged in or do I need to override anything to keep the charger running ?
 
It could be a defective cell as well. The best option would be take out the pack and measure the voltage on the parallel clusters. I know it's easier said then done...

If any of those parallels cells are way out of balance, it may be triggering the BMS to shutdown...while rest of the cells may still be at 70% capacity. I know, because I had a similar issue with one of my home made packs..
 
Thanks Sonetg
Is It cost effective or worthwhile to pay somebody to replace a cell, does it mean that in a nearly two year old battery the other cells could fail and therefore a replacement battery is a better option ?
If so is there an alternative supplier to Stealth and their $23000 replacement in Australia that anyone is aware of.
 
I don't know if your charger when in green, turns off, or is in constant voltage mode. Nor do I know if it can turn itself back on and keep charging when the bms has lowered the voltage of a higher cell.

But I do know, that no harm should come from trying it, leaving it on the charger 24-7 for a week or so. It can take a very very long time for a bms to balance a pack that is very out of whack.

It's easy, to try this first. It might be all you need. It's not going to return to like new, but 90% of it is quite possible if no bad cells exist.

If it doesn't help any, then on to the next step. measuring each cell groups voltage after a full charge. Try to identify if a cell group is not full. Then charge just that group. This means some disassembly of the battery, at least to access the bms.

The problem is not cold weather, obviously, in Australia in November.
 
just 90% after only 100 cycles....

must be a shit pack no excuses for that one unless the pack was flat and sitting at 40deg for most of those 2 years
 
Damian said:
Hi
Ive got a 2013 Stealth Bomber that has done 5000 Kms on the road it normally gets about 45km out of 18 Ah before the battery dies.
Last few rides the battery died at about 12 Ah and 30km. Im wondering if anyone can tell me exactly what has failed. Not overly technically minded but if I need to replace the whole battery Stealth are asking over $2000. Is it possible or worthwhile to recondition cells (assuming one may be gone are the others going to last much longer) or if I need a replacement battery is there a better value option than buying off stealth. Im in Sydney Aus.
Hope Im not missing answers within the forum Im new to it, I had a good look around but couldn't find my specific answers.
Thanks in advance.
Click to expand...

I don't even know the chemistry or construction of your battery, so I looked online. "72 volt / 20 ah / 1440 wh Lithium Phosphate"

Right away, we see this is a custom battery for your $10,000 bike. You are unlikely to find a standard cheap battery to replace it. It is possible to examine and repair most battery packs, but it does require a skilled person and you still end up with an old battery. I suspect it is not cost effective to repair, by the time you pay for time and materials. Your option of a new $2000 Stealth pack may make sense if you want warranty and known quality (although, it may only last another 2 years).

I looked for similar batteries online, just for pricing. The typical price was $900+ for a no name, no warranty battery from China. You could get 2 of these and use them in series:
http://lunacycle.com/batteries/packs/36v/36v-18650-20ah-samsung-26f-ebike-battery-pack/
http://www.ebay.com/itm/NEW-36V-20A...743965?hash=item2ee6cdd21d:g:GSUAAOSw4HVWDUsD
Or you could reduce capacity and have one unit:
http://www.ebay.com/itm/lithium-72V...250284?hash=item4d399fb76c:g:ICAAAOSw-jhUI3Ko
These probably would not fit your bike, so they are just informational.

I would also suggest suggest explore getting a new battery from someone who builds custom batteries. You may be able to get Eric at Lunacycle to custom build one, since the bike is a high end real product and will need replacements as yours did.
 
So....
My pack has a blown cell

What are thoughts?

Replace cell or bite the bullet and buy a new 2kWh pack from stealth?

Cheers Karl
 
KarlJ said:
So....
My pack has a blown cell

What are thoughts?

Replace cell or bite the bullet and buy a new 2kWh pack from stealth?

Cheers Karl
Click to expand...

Depends on the age of the pack. Since you are not OP, if it happened within first 10-20 cycles replace cell, if you have used it for years, the new cell would be way out of line and would be overstressed. In this case, have it rebuilt, but not $2000 for 2kwh, that is robbery.
Measure your frame and see if this fits:
https://vectorebike.com/bike/battery/panasonic-18650pf-li-ion

Depending on your residence, ask for a local builder to build it, it should cost 1000-1400 max for a better one, even cheaper if they can replace just the cells and keep the bms/case.
 
Bit the bullet and buy a multi meter and test each cell group. Then if the pack is out of balance bit the bullet again and buy a smart BMS, with remote cell group voltage monitor and ability to set a lower top end voltage.

Doesn’t Stealth offer such a smart BMS on their bikes? 10k for a dumb ass BMS, I cannot believe they charge 10k and offer such a low quality battery.

After two years if have been pulling too many amps from the pack could have damaged a cell, or group? Big jumps also have loosened a weld or two? Host of problems.

A local builder could easy build you a new pack. Or restore your pack unless the cells be very specialised or unavailable from no longer in production.
 
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