Looking for help choosing a battery for crawling

[SaltyDog]

One of the last items for my build I need is a battery. It’s also the part that is the most foreign to me. Currently I’m looking at a 3s 3700mAh 45c, but I’d love some feedback on that before I order one.

What it’s powering:

• 4.0-8.4v receiver
• HW 1080 ESC
• 21T 550 motor
• 7.4v servo

[ferp420]

ok so your hh motor will pull around 40 amps at full throutle servos gona want say maybe 5 amps the hobby wing 1080 can put out 80 amps contiuosly with out a problem

your motor is well with in the limits of the esc your battery should have enuff amps to push the 1080 at full power all the time so to figure that out look at the battery rating
you have a 3700 mah battery that discharges at 45c safely so if the battery is rated corectly you should be able to safely discharge at 166 amps thats about double what the esc will draw you can look up the formula and check to see if what ever battery your using is gona handle the loads of your rig
just leave alittle cusion running the battery at its limits isent good for them ether
so a 3700 mah battery with a 45c discharge is more than enuff to handle that motor and esc combo

crawling isent that demanding on batterys

[Greatscott]

If you are wanting a battery for run time, then go with a higher mha pack, anything north of 5000mha, this will give you two + hours of run time. If you are wanting something a smaller pack to lower CG, to improve actual crawling performance, run with a 1000mha - 2000mha pack. No matter what, given you set up you will want to run 3S.

The only other thing you need to look at is C-rating, crawlers/scalers don't pull a lot of amperage, so a lower C-rating is ok.

[SaltyDog]

Originally Posted by ferp420

ok so your hh motor will pull around 40 amps at full throutle servos gona want say maybe 5 amps the hobby wing 1080 can put out 80 amps contiuosly with out a problem

your motor is well with in the limits of the esc your battery should have enuff amps to push the 1080 at full power all the time so to figure that out look at the battery rating
you have a 3700 mah battery that discharges at 45c safely so if the battery is rated corectly you should be able to safely discharge at 166 amps thats about double what the esc will draw you can look up the formula and check to see if what ever battery your using is gona handle the loads of your rig
just leave alittle cusion running the battery at its limits isent good for them ether
so a 3700 mah battery with a 45c discharge is more than enuff to handle that motor and esc combo

crawling isent that demanding on batterys

Thank you so much for the thought out explanation, really helps a lot. What is the formula used to figure this out? Switch up my battery choice this morning to a 2200 to save on weight which brought me to a 60c

[SaltyDog]

Originally Posted by Greatscott

If you are wanting a battery for run time, then go with a higher mha pack, anything north of 5000mha, this will give you two + hours of run time. If you are wanting something a smaller pack to lower CG, to improve actual crawling performance, run with a 1000mha - 2000mha pack. No matter what, given you set up you will want to run 3S.

The only other thing you need to look at is C-rating, crawlers/scalers don't pull a lot of amperage, so a lower C-rating is ok.

And I was thinking a 3000mAh was going to be too small. Had no idea people run such tiny batteries in these big crawlers, but it makes sense with low gravity.

[ferp420]

Originally Posted by SaltyDog

Thank you so much for the thought out explanation, really helps a lot. What is the formula used to figure this out? Switch up my battery choice this morning to a 2200 to save on weight which brought me to a 60c

i dont want to give you the wrong formula you can look it up but basicly
just multiply the amp hour rating by discharge rate so to simplify things
a 3700 mah battery would be 3.7ah x 45c = somewere around 166a

lets say you went to a 3000mah pack and a 20c discharge that would give you 60 amps to play with

a 1500mah battery with a 30c rating would give you 45 amps you would have to be vary carefull if you went with this set up as your right on the edge

[SaltyDog]

Originally Posted by ferp420

i dont want to give you the wrong formula you can look it up but basicly
just multiply the amp hour rating by discharge rate so to simplify things
a 3700 mah battery would be 3.7ah x 45c = somewere around 166a

lets say you went to a 3000mah pack and a 20c discharge that would give you 60 amps to play with

a 1500mah battery with a 30c rating would give you 45 amps you would have to be vary carefull if you went with this set up as your right on the edge

This is very interesting. So a 2200mAh 60c would actually produce less amps than a 3000mAh 20c despite the 2200’s higher discharge rate.

[lonleycreeper]

I run both 30c 2200 mah 3s and 5000mah 20c batteries, and never have had a problem with my crawlers. The 5000mah get a bit warmer than I like in my Ryft, but I haven't killed one yet... The safest thing to do is go over on your C rating. But be wary, not all batteries are created equal, and a high C rating is not always accurate.

A 2200 30 c is usually fine for a Brushed Crawler... A 5000 20C for a Brushless... A little more head room for bashers...

I gague my amp rating on the peak amps of the esc. Most rtr's come with a 40-60 amp rated esc for brushed, and 80-120 amp for brushless.

Also the formula for battery amp capacity is (MAH x C) / 1000= amps

So 5,000mah x20C = 10,000
10,000/1000 = 100 amps

[ferp420]

Originally Posted by SaltyDog

This is very interesting. So a 2200mAh 60c would actually produce less amps than a 3000mAh 20c despite the 2200’s higher discharge rate.

um no
2.2ah x 60c is 132amps

3ah x 20c is 60 amps

[WHITE-TRASH]

You guys are way WAY over thinking this. Do NOT buy a big ass battery if you want a capable rig. Big batteries are heavy and will cause you to roll over way before your rig should. I run 2200 4s as my largest pack that gets used in a crawler. I buy lots of smaller packs and change as necessary.

Anything over 45c in a 2000mah or so will be fine. No need to worry about max amperage draw when the rig might see that very rarely when you're bound up and you pin it.

[SaltyDog]

Originally Posted by ferp420

um no
2.2ah x 60c is 132amps

3ah x 20c is 60 amps

Oh ya, not sure where I messed that one up.

Is there any hazard or disadvantage with going much higher on discharge rate? Or will the ESC only pull what’s needed?

[WHITE-TRASH]

Originally Posted by SaltyDog

Oh ya, not sure where I messed that one up.

Is there any hazard or disadvantage with going much higher on discharge rate? Or will the ESC only pull what’s needed?

Esc will only pull what's needed. Discharge rate only matters if it's too small. I run 95-120c 450mah 4s packs in my sporty and pro and they're solid.

[indybama]

Originally Posted by WHITE-TRASH

You guys are way WAY over thinking this. Do NOT buy a big ass battery if you want a capable rig. Big batteries are heavy and will cause you to roll over way before your rig should. I run 2200 4s as my largest pack that gets used in a crawler. I buy lots of smaller packs and change as necessary.

Anything over 45c in a 2000mah or so will be fine. No need to worry about max amperage draw when the rig might see that very rarely when you're bound up and you pin it.

Hey WT, wat kind of run times u get out of your 2200 4s batts? I run 4s trunigy 1400mah 75c n get better than 2 hrs out of 1 batt. Think ive got 5 of them, so im pretty well set all day if i charge all of them

[twade984]

Fwiw, I’ve had good luck with Ovonic batteries on Amazon. I prefer the 1550mah 50c drone pack. Fits “shorty” style battery trays.

https://www.amazon.com/dp/B077PVSVXK...ing=UTF8&psc=1


Sent from my iPhone using Tapatalk

[indybama]

Originally Posted by twade984

Fwiw, I’ve had good luck with Ovonic batteries on Amazon. I prefer the 1550mah 50c drone pack. Fits “shorty” style battery trays.

https://www.amazon.com/dp/B077PVSVXK...ing=UTF8&psc=1


Sent from my iPhone using Tapatalk

Agree with twade, ive got 2 3s 3000mah packs n wotk great

[ferp420]

if i want a light battery i run li-ions but lipos are cheaper and you dont have to make the packs your self
my comp specish crawler im runnin 5000mah li-ion pack mounted to the front links is about the size and weight of a 1500 mah pack only i can run it all day on one charge only down side is the low c rating but for a 45t brushed motor on a ultra light rig it works
once you get out of comp crawling and in to just having fun sometimes even 2 5000 mah batterys arent enuff
some rigs im lucky to get 15-20min of run time out of

[WHITE-TRASH]

Originally Posted by indybama

Hey WT, wat kind of run times u get out of your 2200 4s batts? I run 4s trunigy 1400mah 75c n get better than 2 hrs out of 1 batt. Think ive got 5 of them, so im pretty well set all day if i charge all of them

I get an hour plus out of it but I may or may not drive a bit harder than most.