Li-Po capacity for cooling fans

[Mopsik_Klopsik]

What capacity li-po should I get to power a 2x 40mm server fans. I don't want it to be too heavy as the truck already is . Also I don't want to plug the fans into the receiver because the BEC is 6A while the servo pulls almost 5A.

Is 400mAh enough?

 

[Exc3l]

A server fan pulling 5 amps sounds crazy. It is deffinitly 5 volts and not amps. I have my fan plugged into my reciever because my ESC can do 8a and 8.4v. Send a picture here just to make sure

 

[Greengaunja]

Depends on how long you want it to run for. 1000-1500mah is plenty and will do over an hour easily. It's also small and easy to mount anywhere.. here is some perspective: I have a 2s¾ 2000 mah battery in my SCX10.iii that powers 1 35mm fan, 12 leds, the MyTrick rock lights and my winch. And it easily lasts a 3 hour crawl. Also note the winch, although powered, is rarely used and not exactly using power.

 

[Garcbomber]

I would go 750mah, negligible weight difference. That way if you bash a couple decent size packs back to back it’ll cool down between.

Only one way to find out!

 

[Mopsik_Klopsik]

A server fan pulling 5 amps sounds crazy. It is deffinitly 5 volts and not amps. I have my fan plugged into my reciever because my ESC can do 8a and 8.4v. Send a picture here just to make sure

The servo needs 5A which lefts only 1A for a other accessories like fans. Each fan will probably need around 0.5A, so the BEC is gonna be maxed out. I want to be sure the servo is getting all of the amps it wants.

 

[rotauq]

Your servo will not pull 5A constantly, just peaks. But bec's indeed become unreliant when pushed to their max too often.

I use even smaller batteries for my cooling 300Mah and swap them when they go low. I like being able to cool the car with the esc turned off.
these tiny drone batteries fit everywhere and stay where they should with some dual lock.

 

[Mopsik_Klopsik]

Your servo will not pull 5A constantly, just peaks. But bec's indeed become unreliant when pushed to their max too often.

I use even smaller batteries for my cooling 300Mah and swap them when they go low. I like being able to cool the car with the esc turned off.
these tiny drone batteries fit everywhere and stay where they should with some dual lock.
View attachment 359431

How long does the single 300mAh lasts? And how many fans do you use?

 

[rotauq]

I have many different configurations, depends on the car
It's 3.42Wh so it all depends on how much you pull
A serverfan uses 3-10W a piece. At 10W it lasts only a single pack, whiles at 3W it lasts more than an hour (continously)

 

[kratonwatch]

I have 1300mAh 3s batteries that power 2x 12v 40mm motor fans. I’m thinking about adding a 3rd fan to the ESC, but my max5 @ 8.4v spins the fan fast enough to keep it cool.

I agree with the above statements of 750-1500mah batteries will fit the bill. They’re cheap enough and easy to come by, don’t add a lot of weight and do the job you need!

 

[Mopsik_Klopsik]

Should I ask for a refund? I charged it, then plugged it to a fan. After few minutes I plugged it back to a charger to bring it back to storage voltage and I see this:

Decided to charge it fully again. Same thing as while discharging.

 

[Defense]

Do I need an additional battery for my fans?

 

[Greengaunja]

Do I need an additional battery for my fans?

Need? No. Advisable? Yes.