Small Dimensions Lipo

[Ajax]

Hi

 

I look for lipo 7.4v which dimensions won't exceed 95x18x15mm. Capacity is not an issue as I can carry few on me during the game. High c rating would be beneficial and mini tamiya is preferred.

 

Would you have any experience with such small batteries? 

 

So far my googling didn't provide any useful outcomes

 

Will be grateful for any suggestions.

 

Cheers.

 

[EDcase]

I've found some small size LiPos on Vapextech

The other place I look is Hobbyking.  Scroll down on bottom left you can enter dimensions you want

[jay1988]

try this 

 

https://www.componentshop.co.uk/batteries/batteries-airsoft/batteries-airsoft-li-po-packs/batteries-airsoft-li-po-packs-74v.html

 

it does give the dimentions and choice of connectors

[jay1988]

try

 

https://www.componentshop.co.uk/batteries/batteries-airsoft/batteries-airsoft-li-po-packs/batteries-airsoft-li-po-packs-74v.html

 

they have the dimentions and you can choose the connector

[L3wisD]

I've merged your two topics into one - you may notice some doubling up of replies.

 

[Ajax]

45 minutes ago, L3wisD said:

I've merged your two topics into one - you may notice some doubling up of replies.

 

Did I start 2 topics? Apologise if I did it wasn't intended. I didn't even notice this.

[Iceni]

7 hours ago, Ajax said:

Capacity is not an issue

Actually capacity is an issue depending on how you plan to use the battery.

Small capacity batteries can only supply low amperage, and you will cap the output fairly quickly if you are planning on using a small battery to say power a tuned AEG.

Plugging an AEG into a battery that can not supply enough amps will cause the battery to overheat. I would not expect any lipo pack to have reliable thermal protection. An 18650 does in the form of a fuse, but a lipo pack is a different animal without the fused top cap.


Capacity and discharge (C) work together to give you the amperage of the battery.

Take a random battery (invented for demonstration).

7.4v 2S 500mAh 15/30C

- 500mAh is 0.5Ah.
- 0.5Ah x 15C = 7.5amps continuous discharge
- 0.5Ah x 30C = 15amps burst discharge

If you plugged that into a stock AEG pulling 10-15amps the chance of an overheating and potentially thermal runaway battery would be high. Dangerously so.

A typical airsoft AEG battery looks more like this.

7.4v 2S 1300mAh 15/30C

- 1300mAh is 1.3Ah.
- 1.3Ah x 15C = 19.5 amps continuous
- 1.3Ah x 30X = 39 amps burst.

The continuous discharge of 19.5 is over the 15amp draw rate, meaning whilst it'll get hot, it should be safe from thermal runaway.


If you are trying to make a performance AEG with uprated motors and ROF then be even more vigilant to amp draw. You simply can't make an M4 pistol that does 25rps, and run it on anaemic batteries, You'll be throwing a pile of burning plastic on the floor after a few bursts.


There are ways around small battery spaces. Tell us what the AEG is, Show us all a picture ect. And people on here will have some form of safe solution that works.

[Ajax]

Thank you gor your reply I am not trying to build a monster I got AKS74U which has only space in front grip to store battery. Original battery has dimensions 95x20x10 and closest I found so far is 101x20x10 which is 1000mah 7.4v and 20/40c so unless I find any even shorter I will give it a try. 

[Skara]

Why don't you rewire it to have the battery sitting between the top cover and the gearbox?

It's the most logical and least expensive route to me than finding weird batteries.

[Ajax]

Because there is no space there. Recoil system takes it and therefore tiny front grip is the only place to put it. And I do not want to spoil esthetic with storing it outside the replica.

[Iceni]

If It's the TM then they recommend the Mini S NiMh battery. Double check those dimensions as I think those batteries are bigger than the dimensions you have listed.

It should be the same dimensions as one of these.

https://www.componentshop.co.uk/8-4v-1600mah-2-3a-nimh-mini-battery-pack-3x2-1.html
 

111 x 34 x 18 mm

If that is correct then you can use a big block lipo.

https://www.componentshop.co.uk/7-4v-1300mah-25c-continuous-discharge-lipo-battery-giant-power-mini.html

 

94 x 31 x 13 mm 7.4v 1300mAh 25/50C

Or one of these monsters might fit as well. I know I can fit these in my Aug that also uses mini s sized batteries.

 

https://www.componentshop.co.uk/7-4v-2200mah-30c-continuous-discharge-airsoft-lipo-battery.html

 

103.6 x 34 x 15.5mm 2200mAh 30/60C  66A continuous discharge, 132A burst.

[Ajax]

Thank you for reply. The replica is made by Bolt and they use wooden grips which as beautiful as they are, they are also but thicker than tm plastic and takes more space. Also they use steel brackets at each end which takes bits  of length as well. Is made card board model of the battery I found and it could fit under condition that it wont arrive with 2m of wires 😅 

 

I will buy it and let you know it it will fit - just in case there are any other aks74u Bolt users here

[Skara]

16 minutes ago, Ajax said:

it could fit under condition that it wont arrive with 2m of wires 😅 

You can still trim the excess battery wire and switch to deans so they take up even less space.

[Ajax]

5 minutes ago, Skara said:

You can still trim the excess battery wire and switch to deans so they take up even less space.

Instruction unclear... soldering iron stuck in the eyeball 😱🤪 the best way to describe my soldering skills LOL but if it will come to this I may increase my house insurance and then give it a try. At the same time I would change mini Tamiya to Deans connector as they take quite some space as well. 
 

I have just placed order with hobby king (thx EDcase) so will wait and see when the package arrives.

[Ajax]

So batteries arrived today, ordered on Sunday - well packed and secured.

 

I mean very well.

Box, in the box some paper and two other boxes in each of them bubble wrap battery and manual.

 

Mean time independent email how to use lipos etc... So far so good.

Also batteries fit like a glove.

Perfect size I can close the compartment without the worry that I squeezed the lipo packs.

As expected 7.4v is not as crisp as 11.1 would be but with the latter (as replica has been powered down to UK legal requirements) It tend to have overspin as the guts and motor are meant for 420fps in full auto.

Nothing I can't live with or the bright side the guts should serve me bit longer on 7.4v

 

for reference this is the battery I purchased for Bolt AKS74U:

 

https://hobbyking.com/en_us/turnigy-nano-tech-1000mah-2s-20-40c-lipo-airsoft-pack.html