Battery water proofing


enjoythesilenc

Well-known member
Location
virginia
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Its mentioned in here that some of the bike is ISO x rated as waterproof.

I posted when i first got my Alta about worrying about water crossings and was reassured that the bike would be ok, especially after watching the Alta in the abandoned water park video. Unfortunately, there has been a good handful of bikes posted as having water ingress and battery corrosion issues.

I'm wondering if it would be worth it augment the waterproofing supplied by the factory. I'm talking about the people already working on batteries offering another service in the name of preventative maintenance. Why not add dessicant bags on the dry side of the bladder? Why not coat the pcbas, wirebonds etc with a conformal coating? Why not stabilize the r pack wirebonds with a dollop of adhesive? How much respiration volume is required by the battery case? What about some sort of provision to purge the case with compressed nitrogen or argon after a watery ride?

It seems like the hermetically sealed case is a great idea until it fails. then you don't know it failed until catastrophic damage is done. Either need to keep the water or the oxygen out, somehow.
 

enjoythesilenc

Well-known member
Location
virginia
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Water ingress corrosion. No history of drowning.

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enjoythesilenc

Well-known member
Location
virginia
Another battery thread got me interested in looking at humidity sensor data stored in multitool. I see that humidity has been around 35-45% inside the battery when looking at "ride data" I gave my bike a spray down two days ago but avoided the bottom screen area. Its 38% humid at the moment.

If the battery is technically sealed, shouldnt the humidity stay the same as when it was assembled, in theory? Were the batteries sealed up in SF and what is the general humidity there, or were they sealed in a humidity controlled environment?

What humidity throws a code 37?

What humidity levels do others see in their own bikes and is it consistent to local conditions? Is a battery in phoenix vastly different than one in florida?
 

bluefxstc

Well-known member
If the battery is technically sealed, shouldnt the humidity stay the same as when it was assembled, in theory? Were the batteries sealed up in SF and what is the general humidity there, or were they sealed in a humidity controlled environment?
For most humidity ratings, it is a relative percentage number based on temperature. The warmer the air, the more moisture it can handle, so as temperature goes up the relative humidity goes down for a given amount of moisture in the air. I don't know for sure if this is how Alta measures the humidity in the battery pack, but it probably is since it is the most common way of measurement for humidity.

Also, while the pack is rated as "waterproof", I believe that this is only for a certain depth for a given amount of time. I am reasonably certain that there is some slow air seepage into and out of the pack, so the pack will eventually stabilize at the average relative humidity of the environment it is normally in.
 

enjoythesilenc

Well-known member
Location
virginia
For most humidity ratings, it is a relative percentage number based on temperature. The warmer the air, the more moisture it can handle, so as temperature goes up the relative humidity goes down for a given amount of moisture in the air. I don't know for sure if this is how Alta measures the humidity in the battery pack, but it probably is since it is the most common way of measurement for humidity.

Also, while the pack is rated as "waterproof", I believe that this is only for a certain depth for a given amount of time. I am reasonably certain that there is some slow air seepage into and out of the pack, so the pack will eventually stabilize at the average relative humidity of the environment it is normally in.
I looked at multitool data for a 45 minute trail ride. Starting battery temp was 20 degrees and humidity was 40%. Ending temp was 40 degrees and the humidity was 20%.

What do you guess as the volume of air inside the battery?
 

bluefxstc

Well-known member
I looked at multitool data for a 45 minute trail ride. Starting battery temp was 20 degrees and humidity was 40%. Ending temp was 40 degrees and the humidity was 20%.

What do you guess as the volume of air inside the battery?
Data looks appropriate, temp goes up, humidity goes down. No idea the volume of air inside a battery. You could probably get fairly close to the air volume of the battery by figuring out the inside volume of the case and subtracting the volume of the battery modules, but I don't know a number for either. I wouldn't think that the air volume would be very high as air is a poor conductor of heat.
 

C5tor

Chief Comedic Instigator
Location
San Ramon, CA
Fill the battery with water, then drain the water and measure it. Sure, you'll ruin the battery, and possibly kill yourself, but you'd know the volume! Follow me on Facebook for more potentially lethal math tips.
 

enjoythesilenc

Well-known member
Location
virginia
Here is another pressure washing code 37 Does anybody know how to reset code 37

Going back to the picture in post number two. You see the corrosion is on the edge of the battery module. That edge of cells is adjacent to the bottom battery seam on the right side of the bike. It also looks like the water flowed from the edge of the battery inward. From R to L.

If your bike is on its kickstand, the right bottom edge of the battery case is more exposed to the downward blast from a pressure washer than would be the left side of the case. The bike is tilted so any water getting onto the edge of the module would creep inwards due to gravity.

The other possibility to why the corrosion occurs there is some sort of dew point condensation situation. Say there is high humidity inside and for some reason those cells cool first so that is where any moisture inside the case condenses.

There is also a linear border to the spots of blue corrosion on the circuit board. I bet that it corresponds to a ridge on the orange plastic cover. That module sits upside down on the bottom of the pack so any water in that area might be trapped by the ridges of the cover and pool there. It could corrode the surrounding structures if water is just sitting there for any duration.

It might make sense to lay the bike horizontal as a first aid measure if you accidently drown your bike and can't open the battery to dry it right away for some reason. That would potentially drain the aforementioned cell covers that live upside down, modules 0 and 2.
 

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