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Topic: Are D cell batteries good for done? (Read 838 times) previous topic - next topic

afedorov


DrAzzy

Drones need to get into the air. Power-to-weight and energy-to-weight ratios are critical. D cells are awful on both measures, and non-rechargible.

All drones I am aware of use lithium ion or lithium polymer batteries.
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slipstick

Nope. Too big, too heavy, not enough current capability, even the high-capacity NiMH rechargeables like that.

Lipos are the only practical solution.

Steve

MarkT

If they were LiPo D cells they would be fine, but I've never seen LiPo in that format.

Specific power of a battery type is measured in watts/kg, and this is the key figure for achieving
flight - even a modest drone may require 100W just to hover in still air, hover flight is the least
efficient kind of flight.  LiPo is the winner for specific power.

For endurance specific energy is the figure of merit - LiPo can usually achieve 5 to 20 minutes
endurance in a well engineered drone, and again is the best there is
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afedorov

Can I damage Li-ion battaries(https://www.amazon.com/EBL-Battery-Charger-Rechargeable-Batteries/dp/B00HV4KFSA/ref=sr_1_1?ie=UTF8&qid=1522871789&sr=8-1&keywords=EBL+840+9V+Li-ion+Ni-MH+Battery+Charger+with+600mAh) if I use them for "on-table" testing? I would like to re-use the batteries I have for first tests.

Will the speed of battery drain "kill" those batteries.

What is the good option for small tests? should I use specific power adapter?

DrAzzy

Those batteries are not designed for high current (they're meant to replace 9v batteries, which have notoriously poor current handling)

You should use batteries designed for RC drones; these will be supplied with a C rating that tells you how fast you can discharge them.
ATTinyCore and megaTinyCore for all ATtiny, DxCore for DA/DB-series! github.com/SpenceKonde
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts, mosfets, awesome prototyping board in my store http://tindie.com/stores/DrAzzy

afedorov

and what about power adapter?

Can I use them for on table testing?

DrAzzy

and what about power adapter?

Can I use them for on table testing?
Provided that the power adapter you are using is rated for the current you are drawing from it.
ATTinyCore and megaTinyCore for all ATtiny, DxCore for DA/DB-series! github.com/SpenceKonde
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts, mosfets, awesome prototyping board in my store http://tindie.com/stores/DrAzzy

MarkT

What part of "LiPos are the only practical solution" did we not make clear?   Read up on the care and
maintanance storage and charging of high power LiPo packs, its not a secret, but you do need to
understand the safety issues.  LiPo batteries need to be stored in fireproof containers, for instance.

On table testing is testing, yes you have to test things, and no they don't know the difference between
being tested and being used because batteries are not sentient!  Also mosts ESCs sense battery voltage and
assume LiPo pack is the supply.
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afedorov

So I will start with these guys - https://www.amazon.com/gp/product/B01M7TX4KS/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

There is no detailed specification about current, but the similar model has:
Load: 3.2A @ 3.7V

Does it mean that I will need adapter that can get ~12A of current for 4 motors? Or I need one that has ~12W of power?

Southpark

#10
Apr 05, 2018, 10:00 pm Last Edit: Apr 05, 2018, 10:07 pm by Southpark
You probably need to do some google search on drone basics.... like batteries used for drones..... battery capacity.... battery voltages...... drone motor power requirements. Speed controller modules etc. Drone or UAV or RC forums are a good start. Important thing is..... don't short circuit lipo batteries.... totally avoid shorting them.... as they can definitely burn things really badly...... even cause whole house to burn. So be very careful with lipos at all times.... even when charging them.

afedorov

That makes sense. Thats why I am planning to start with just power adapter.

INTP

Lithium cells will give more current than any power adapter you'd feasibly consider buying. Plan your build right the first time. There isn't much to "test" anyway.

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