4S LiPo Discharger: A good or a stupid idea?

Thread Starter

jipristt

Joined Jun 4, 2017
18
Hello everyone,

So, here is the story:
I am working on a project and I want to have enclosed battery, works on 5~7A currents and has little battery space. I decided to use a 4S 14.8V 10000mA LiPo battery. The system can be connected to an external power supply and charger to charge the battery or operate on power while battery charges.

Here is the problem:
I am a bit worried about storing the project when battery is full so I thought of making a battery discharge circuit that discharges the battery to 15.2V when device is stored.
For discharging I am thinking to have a circuit that draws ~1A current from the battery (when disconnected from charger and device is off) using a power resistor or a similar load with smaller size.

I am really new in working with LiPo's but I found it to be the most suitable choice for capacity and size.
I'd like to discuss or ask for some advice and opinion on:
1) Having an enclosed LiPo in a project is ok, bad or terrible idea
2) What are some alternatives for that ?
3) Is discharging the battery for storage really needed? How dangerous is to store fully charged batteries?
4) Any ideas for a small load that can draw significant current from that kind of battery?
(So far I tried power resistors but are quite large and some halogen lamps nut those produce a lot of heat and light)

I hope you find this topic interesting and looking forward to read your replies!

Best,
C
 

Picbuster

Joined Dec 2, 2013
982
Hello everyone,

So, here is the story:
I am working on a project and I want to have enclosed battery, works on 5~7A currents and has little battery space. I decided to use a 4S 14.8V 10000mA LiPo battery. The system can be connected to an external power supply and charger to charge the battery or operate on power while battery charges.

Here is the problem:
I am a bit worried about storing the project when battery is full so I thought of making a battery discharge circuit that discharges the battery to 15.2V when device is stored.
For discharging I am thinking to have a circuit that draws ~1A current from the battery (when disconnected from charger and device is off) using a power resistor or a similar load with smaller size.

I am really new in working with LiPo's but I found it to be the most suitable choice for capacity and size.
I'd like to discuss or ask for some advice and opinion on:
1) Having an enclosed LiPo in a project is ok, bad or terrible idea
2) What are some alternatives for that ?
3) Is discharging the battery for storage really needed? How dangerous is to store fully charged batteries?
4) Any ideas for a small load that can draw significant current from that kind of battery?
(So far I tried power resistors but are quite large and some halogen lamps nut those produce a lot of heat and light)

I hope you find this topic interesting and looking forward to read your replies!

Best,
C
The best way to find all answers is producers data sheet.

Picbuster
 

oz93666

Joined Sep 7, 2010
668
There is absolutely no need to discharge lithium batteries !! they are not explosive!
Every laptop and phone on the planet uses these cells and nobody discharges them .

It seems you have chosen a rather large battery I guess you mean 10,000mAHrs , not 10,000mA are you sure you need all this capacity ??

A very small li-po will supply the 7A you need ..... what is this for???? how long will the device run???
 

Thread Starter

jipristt

Joined Jun 4, 2017
18
oz93666 I think most of laptops use Li-Ion and not Li-Po batteries which are a bit safer but offer less capacity compared to size.

Regarding 10,000mA you are right, I made a typo there, sorry for that :)
Is for controlling a device that uses multiple motors, pumps and valves and needs to run for a few hours, that's why the big capacity.
 

oz93666

Joined Sep 7, 2010
668
I was wrong to say all laptops and phones , but a considerable number do use lipo , and there are no real issues reported by the millions of users ....

These cells are not a problem unless you drive a nail into them ... A battery would not be much good if it couldn't hold charge for extended periods without risk of bursting into flames.
 

gramps

Joined Dec 8, 2014
69
While it's not dangerous to store LiPo batteries at full charge, it does somewhat shorten their useful life. That's why it is recommended to place a storage charge into the battery if it isn't going to be used for a period of time, typically a week or more. Personally, I don't place my LiPo batteries into storage. I like them to be at full charge when I need them, and just live with the reduced life span. If you really want to discharge your LiPo battery to a storage voltage while not being used, I would recommend getting a hobby charger designed for LiPo batteries. They will have settings for charging, discharging and storage of the battery.

https://hobbyking.com/en_us/batteries-chargers/chargers.html

https://www.towerhobbies.com/cgi-bin/wti0095p?FVSEARCH=lipo+balance+chargers

https://www.hobbypartz.com/rc-battery-charger-balancer.html
 
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