Apollo AV-1 motor heat generation problem with lithium battery

[Gone for diving]

This is incorrect
Max charge for li-ion is 4.2V per cell. a 4S pack is 16.8V and despite the ~15amp load is not likely to drop below 15V when fully charged - which is way higher than an single SLA battery. Which is exactly what Jona was explaining above.

Yes you would be correct for li-ion...
Max charge is 4.2v but nominal voltage is 3.6v max discharge is about 3.2v I believe.... normally use nominal voltage to do math for calculations...

Lithium iron max charge on a 4 pack is 14.4V, (3.6v per cell)
but that is not nominal voltage.... 3.2v per cell X 4 cells is 12.8V.... on use it drops to 3.2 v relatively fast and holds the voltage... anything below 3v, capacity drops fast...

This was for lifepo4 batteries
which is different.... what is nice is these batteries can be used to replace a 12v lead acid in a vehicle and falls nicely in the charging range of a vehicle etc...

My battery is a lifepo4 battery so it's not overvoltage. It is 14.4v with 3.6v 4 cells.

Was trying to point out in this post... that a lifepo4 doesn't stay very long at 14.4v
Because its nominal voltage is 3.2v and will spend most of its burn time around that voltage...


Li-ion and lifepo4 battery
are different types of batteries

 

[Jona Silverstein]

Yes you would be correct for li-ion...
Max charge is 4.2v but nominal voltage is 3.6v max discharge is about 3.2v I believe.... normally use nominal voltage to do math for calculations...





This was for lifepo4 batteries
which is different.... what is nice is these batteries can be used to replace a 12v lead acid in a vehicle and falls nicely in the charging range of a vehicle etc...



Was trying to point out in this post... that a lifepo4 doesn't stay very long at 14.4v
Because its nominal voltage is 3.2v and will spend most of its burn time around that voltage...


Li-ion and lifepo4 battery
are different types of batteries

most Li-ion cells are capacity tested to 2.8v while it is not recommended, they can do it but once the voltage drops below 3.05v it drops fast. All of our packs are capacity tested to 3.0v and we do not recommend anyone discharge below that threshold.

The problem still lies within voltage sag, even on SLA packs we have been able to hit thermal limitations before, the motor simply cannot handle it, this is a result of the ABS body being a horrible conductor of heat. Pitch it down and let it ride. If you want to go fast, Buy/Build a super cuda. Ive clocked over 115mpm on mine...

 

[sh_underwater]

I asked Apollo about the problem with heat generation of the motor.
It seems that the enamel wire of the motor will short-circuit when the motor temperature exceeds 120 degrees.

So I decided to rewind the heat resistant enamel wire.
The heat resistant temperature of the enamel wire will be 220 degrees, and the bearing will be changed to heat resistant.

I am thinking of a full-scale water cooling system in the future.

 

[Jona Silverstein]

I asked Apollo about the problem with heat generation of the motor.
It seems that the enamel wire of the motor will short-circuit when the motor temperature exceeds 120 degrees.

So I decided to rewind the heat resistant enamel wire.
The heat resistant temperature of the enamel wire will be 220 degrees, and the bearing will be changed to heat resistant.

I am thinking of a full-scale water cooling system in the future.

Changing all of the windings doesn't change the fact that a plastic body scooter doesn't have the thermal transfer capacity of an aluminum body. Water cooling is a good idea for the concept but adding more points of water intrusion are a nono in my book. also corrosion and other problems associated with water cooling.

 

[sh_underwater]

I have completed the modification of AV-1.
The motor temperature is less than 90 degrees, no matter how much you drive, towing one diver.
This is the effect of indirect water cooling using seawater.

Also, thanks to the lithium-ion iron phosphate battery, 50% of the battery remains even after two dives.

I can also check the motor temperature, battery temperature, and battery level underwater and on land.
And my AV-1 is neutral buoyancy.

The perfect scooter is complete.


I received a lot of critical comments here, but I was successful. Thanks to everyone for their advice.

 

[happy-diver]

Now to increase horsepower most economically, first some hacking

Then some polishing for what I would suggest is a min 25% increase

Porting and polishing

Better than a bought one!

 

[happy-diver]

How did you seal the through fittings man!

 

[andrespp]

Hello, I am from Japan. I'm writing the document using Google Translate, so I'm sorry if there is any wrong English.

I recently changed the AV-1 battery to a LIFEPO4 52ah.
I used Bluetooth to check the battery level and greatly increased the cruising range.

However, due to the increased capacity of the battery, the motor will overheat and the scooter will not work when running for about 1.5 kilometers underwater.

When I contacted Apollo, the temperature sensor of the motor operates at 110 degrees.

I thought about how to cool the motor.

Use a heat pipe, use a 12v fan for a personal computer, etc.

However, after all, the area around the motor is a closed space, so ventilation is not possible.

I thought about wrapping a copper pipe around the motor and letting seawater pass through, but this is a large-scale work.

The successor model AV-2 indirectly cools the motor with seawater, but is there a way to cool the motor without using the parts of AV-2?

Hello, I own also an AV-1 and had the battery replaced by a Li-ion one.

The old lead battery weighs 11 kg, meanwhile the new one weighs 3.5 kg. So had to wrap the battery with lead weights in order to add some ballast to make the scooter neutral. This lead put around the battery appears to act as a heat sink,

I have been using the scooter for dives of about three hours, up to 50+ meters depth, propeller in pitch 2, saddle mounted, with water temperatures from 12 to 24 celsius with no issues.

 

[cipete]

Hello, I am from Japan. I'm writing the document using Google Translate, so I'm sorry if there is any wrong English.

I recently changed the AV-1 battery to a LIFEPO4 52ah.
I used Bluetooth to check the battery level and greatly increased the cruising range.

However, due to the increased capacity of the battery, the motor will overheat and the scooter will not work when running for about 1.5 kilometers underwater.

When I contacted Apollo, the temperature sensor of the motor operates at 110 degrees.

I thought about how to cool the motor.

Use a heat pipe, use a 12v fan for a personal computer, etc.

However, after all, the area around the motor is a closed space, so ventilation is not possible.

I thought about wrapping a copper pipe around the motor and letting seawater pass through, but this is a large-scale work.

The successor model AV-2 indirectly cools the motor with seawater, but is there a way to cool the motor without using the parts of AV-2?

Appreciate if you can share Apollo AV-1 cooling and modification pictures and diagram please. Thank you