Possible sources for battery repair?

[snydes]

I’d like to start preparing for the worse and looking for potential people/places that may be able to service and repair these batteries should it come to that.

Do we have any thoughts or ideas? Maybe a competent forum member that would consider a side job? Even best case scenario with Alta at some point batteries will be out of warranty and will eventually need attention, so this would be in all our best interests.

 

[privateer703]

So if Alta comes back do you think they would have some battery refurbishment program or just sell new batteries after warranty? If they don't, then there is someone out their who just lost their job of soldering batteries into Alta battery packs. Maybe search monster or indeed for thier
resume.

 

[snydes]

So if Alta comes back do you think they would have some battery refurbishment program or just sell new batteries after warranty? If they don't, then there is someone out their who just lost their job of soldering batteries into Alta battery packs. Maybe search monster or indeed for thier
resume.

That’s a very good idea...

Let it be known to any Alta employees (current or ex) who may be lurking, if things fall apart completely their could be an opportunity for side work here. I for one would be looking for a way to remedy my “code 36” issue, and I’d put money on the fact that there will be more.

 

[bluefxstc]

@snydes if the bike is unusable, I would pull the pack apart like @Mark911 described in his post about disassembling the pack. Guess, and it is 100% a guess based on other posts, is that a cell or two have failed. Should be pretty easy to find the bad cells, just need to take a volt meter to all the cells. You should be able to figure out the normal voltage range for the good cells pretty quick. The bad ones will probably be pretty obvious with really low voltage. In the same post @blbills gave info on what he thought the cells are. Then the only issues is how to solder in the new cells which might not be too bad. If you do replace the bad cells you will probably want to try and match the new cells voltage to the voltage of the cells in the rest of the pack. Doesn't have to be exact as the parallel cells should equal out but better to minimize the difference.

It may be difficult to centralize the repair of the batteries. There are some specialized regulationsand trainingneeded to ship lithium batteries so it could be problematic for individual owners to ship their batteries. Easy for a company to have people to ship the batteries, not so easy for individual users.

 

[WoodsWeapon]

My replacement battery was sent via FedEx in a nice purpose built plastic case. In the event someone were to replace a few cells, we’re assuming the code 36 would clear itself.

 

[datadog]

Please don't recommend that inexperienced people disassemble battery packs. It's very irresponsible., 350 volts can kill you. Lithium battery cells can also catch fire and burn down your house, and your neighbor's house. We take great care to completely discharge packs completely before the cover comes off. There are lots of very dangerous things that can happen if you start taking battery packs apart. Mark911 has experience and good on him, but please, please don't dive into a battery pack with enough joules to kill you.

 

[snydes]

That battery scares me for the exact reasons you mentioned, and I certainly don’t want to tear one apart myself, which is why I’m looking for someone who has the knowledge to do so if things go south with Alta for good. It’s either that or sell the bike for a give-a-way price to someone for parts. Which super-dooper sucks.

 

[datadog]

Code 36 is not necessarily, and likely not, 'bad' cells. It's not a matter of replacing cells.

 

[Rix]

Please don't recommend that inexperienced people disassemble battery packs. It's very irresponsible., 350 volts can kill you. Lithium battery cells can also catch fire and burn down your house, and your neighbor's house. We take great care to completely discharge packs completely before the cover comes off. There are lots of very dangerous things that can happen if you start taking battery packs apart. Mark911 has experience and good on him, but please, please don't dive into a battery pack with enough joules to kill you.

A no $h!t statement here. I made a comment on another thread about converting our machines to a much lower voltage set up, say 20s. If the worst case scenario happens, and I have a failure, and can't get the problem resolved, this is the route I will go, only because if I am running an 84 volts hot off the charger system, and I make a mistake, I wont die.

 

[Mark911]

That battery scares me for the exact reasons you mentioned, and I certainly don’t want to tear one apart myself, which is why I’m looking for someone who has the knowledge to do so if things go south with Alta for good. It’s either that or sell the bike for a give-a-way price to someone for parts. Which super-dooper sucks.

Don't sweat it, if worse comes to worse we'll figure something out. There's always a way. And I agree with DD, batteries tend to go bad slowly and after many cycles (unless they were not properly matched and balanced before module assembly/integration). No, probably a bad wire bond. Those type of process require specialized equipment, operation and constant test/calibration. Test samples are typically pull tested to failure to qualify and validate the setup. Even a change of lot numbers of the wire should require a new calibration and certification. However, the percentage of test samples relative to production output is up to the quality control dept within Alta. But even if it was 100% it's still an indirect indicator as the production bonds are probably not tested or tested at much lower level. It's all a numbers game when it comes to reliability calculations.

 

[Mark911]

A no $h!t statement here. I made a comment on another thread about converting our machines to a much lower voltage set up, say 20s. If the worst case scenario happens, and I have a failure, and can't get the problem resolved, this is the route I will go, only because if I am running an 84 volts hot off the charger system, and I make a mistake, I wont die.

Alta choose a high voltage system for many reasons. The most obvious being the ability of all the high power switching devices/electronics to handle the amperage within reasonable weight, size, efficiency and thermal requirements.

 

[snydes]

Don't sweat it, if worse comes to worse we'll figure something out. There's always a way.

Thanks Mark

 

[MattB]

A no $h!t statement here. I made a comment on another thread about converting our machines to a much lower voltage set up, say 20s. If the worst case scenario happens, and I have a failure, and can't get the problem resolved, this is the route I will go, only because if I am running an 84 volts hot off the charger system, and I make a mistake, I wont die.

Designing drive trains, selecting motors with the correct Kv for a given battery voltage(usually LiPo 4.2/cell for my world) while maintaining efficiency, reliability, and high performance for each application is what I do for a living.

You can't change the Alta to an extremely lower voltage without a huge decrease in performance. The motor Alta selected is of a very specific Kv (Battery Voltage x Kv x est. 90% efficiency = motor RPM) for a 350v system. Even if you install your own 20s motor with the specific Kv needed to drive the rear wheel at an appropriate RPM, the performance would still be degraded substantially. The Alta performs like it does simply because the voltage is so high. Attempting to lower the voltage while maintaining the same performance will ....

- burn up electronic speed controllers
- over heat motors which leads to demag of the motor or complete failure
- over heat batteries / fires!

The only way 20s will work on the Alta is if you plan on severely de tuning to the point of the Alta not being fun anymore.

High voltage = lower current draw
Lower Current draw = less heat

I have a Sur-Ron which is essentially a 110lb electric mountain bike. It runs on 16s and has the power of a decent pit bike. The motor and ESC do get hot so there is not much room for improvement without increasing cell count and installing a new motor/esc. Imagine doubling the weight and only adding 4 more cells.......

Hope that helps you avoid a money pit project.

 

[Mark911]

MattB,
That Sur-Ron looks pretty trick, a mini motorcycle. I considered a M1 Spitzing R but it was a bit more MC than bicycle. I ended up with a Haibike Downhill Pro. They're all a blast!

 

[MattB]

MattB,
That Sur-Ron looks pretty trick, a mini motorcycle. I considered a M1 Spitzing R but it was a bit more MC than bicycle. I ended up with a Haibike Downhill Pro. They're all a blast!

For Sure Mark911! I ride the Sur-Ron daily to get around the ranch, it's just plain fun! I do wish it was just a little bit bigger, as I feel a little crunched up on it.

 

[schwankl]

Ya that Sur-Ron is a Chinese e-pit bike. fine for putzing around, but would not trust doing anything big or technical. I converted a decent all-mountain knolly chilcotin with mid-engine bbshd, fun, and can still get thru some technical stuff, but no replacement for a proper dirt bike with dialed-in suspension. sur-ron or other e-mtb, no real comparison other than they have 2 wheels.

 

[MattB]

Ya that Sur-Ron is a Chinese e-pit bike. fine for putzing around, but would not trust doing anything big or technical. I converted a decent all-mountain knolly chilcotin with mid-engine bbshd, fun, and can still get thru some technical stuff, but no replacement for a proper dirt bike with dialed-in suspension. sur-ron or other e-mtb, no real comparison other than they have 2 wheels.

You missed the point of the comparison.

The Sur-Ron is a 16s - 67.2v pit bike that weighs 110lbs. The motor and ESC on the Sur-ron do get hot when riding.
The Alta is 259lb on a 84s - 350v system. Reducing the Alta to a 20s - 84v battery (very close to the Sur-Ron voltage) would be a bad idea as you are doubling the weight of the Sur-ron and asking for higher performance.

 

[schwankl]

I got ur point about the 110lb pit-bike/Chinese bike, was just pointing out its a toy in comparison to an Alta. Alta has more than 20cells - what’s the 18650 count? 504 ... 126s4p?

 

[MattB]

Yes, we all know its a toy compared to the Alta. That's pretty obvious.

Yes, Alta has many more than 20 cells, it was never stated that the Alta had 20 individual cells. Rix was considering using a 20s 84v battery in his Alta when the stock battery is 84s 350v. It doesn't matter if you have a million cells in a 20s pack, you are still at a very low voltage for the operation of the Alta.

The Alta is 84s - 350v, as far as the actual cell count, we know that the pack is 5.9kWh.... we just need to know the capacity of each individual cell to determine how many individual cells. Without knowing the exact individual cell capacity we can't finish the math. However, Mark911 can probably tell us as he has one disassembled.

If the above was confusing, read up a bit on series and parallel battery configurations. Here are the cliff notes -

Series - If the cells are connected in series, the voltage of the battery will be the sum of the cell voltages. The Alta technically has 84 x 4.2 volt "packs in series" of 18650 cells. How many cells are in each "pack" is unknown without actually counting or knowing the individual cell capacity.

Parallel - If the cells of a battery are connected in parallel, the battery voltage will be the same as the cell voltage, but the current supplied by each cell will be a fraction of the total current. Individual cell capacity and the count of those individual cells configured in parallel is where we get our 5.9kWh rating.


Lets say each cell is 4.2v 1000mah

Parallel :
++++
* * * * = 4.2v 4000mah
- - - -

Series :
+ - + -
* * * * = 16.8v 1000mah
- + - +


And we can also do this.....

++++
* * * * = 4.2v 4000mah +
- - - -
************************* = 8.4v 4000mah
++++
* * * * = 4.2v 4000mah -
- - - -



I hope that helps clarify some things.

 

[MattB]

I got ur point about the 110lb pit-bike/Chinese bike, was just pointing out its a toy in comparison to an Alta. Alta has more than 20cells - what’s the 18650 count? 504 ... 126s4p?

I see you clarified your previous post with more info.

Look schwankl, I'm just helping someone to not make a costly mistake based on factual information. It seems you have a different intent or are confused as to the point.

Your statement "was just pointing out its a toy in comparison to an Alta" was not needed as the Sur-Ron was only posted to show that the pit-bike class was very close to the Rix proposed 20s config for the Alta.

Are we on the same page yet?