Question on batteries

[Sappo]

Have found some great deals on 2s high capacity 7.4 volt batteries on Ali express, only problem is they are described as being protected, what does that mean and would they be suitable for rc tanks

[Rudinater]

Link would be helpful to see what they are.

[Sappo]

Sorry bout that. Just go to Ali Express and search li ion batteries 7.4 volt. The description is for cameras, vacuum cleaners and that sort of thing. Various amperage listings.The only problem I can see is the connectors would need to be changed

[Sappo]

This is the sort of batteries that I found. Price including shipping is $18 NZ

[Alpha]

Sappo The connector and wire gauge shown in that photo is not sufficient for use in a tank. The ampacity on those components is much lower than what a tank's power system will draw. The Heng Long motors already draw ~2A at max speed without a load on them. Thin wires like those shown in your photo are typically for low current uses such as cameras, toys, etc. You want to be looking for wire/connector/battery cell that can sustain the amp draw of a tank. Typically this is a 14AWG gauge wire or similar thickness, at least a Tamiya connector if not a Deans or XT60, and a cell (and PCB) that can sustain at least 5 amps easily for optimal lifespan.

[SoCalBobS]

From your picture:
1. It appears the main power leads are very thin, and the connector is a JST-PH type, neither of which would be ideal for the tank application - not able to handle the amp load. i would not be surprised to see the wires or plug heat up so much the insulation or housing melts.
2. There is no balance plug or wiring. No way to ensure a safe charging process.
My guess is that it is meant for a very low current draw application, like a phone or similar. My vote is no.

Oops, Alpha posted while I was writing. What he said!

[Sappo]

Hey thanks for that guys, was something I saw while hunting for single 2s 18650 batteries..

[Sappo]

And this is what I found, $52 nz for 2.

[SoCalBobS]

Size issue? Maximum length to fit into the battery bay is 5 3/8" or 13.5cm., not including the leads. Motion RC sells shorty (fits in T-72) 1800mah's for $13 USD, 3500mah for $26 USD, and full length 7000mah for $50 USD, just for comparison. No charger included, though.

[Sappo]

Very true mate,I found some 2800mha for $26 nz also, free shipping as well. Trouble with motion rc is availability, they tend to sell out quickly.

[Olddowl53]

The blue batteries with the small connectors are like the ones that came in my JJRC or WPL trucks. They are between 500 and 800mAH.

[Sappo]

Actually the one's with the small connectors are 2800 mha for portable vacuum cleaners and stuff like that