LiPo Discharging and Storage Questions?

[HPIguy]

Okay, so I have a good grasp on charging thanks to you guys. But, I charged a ton of packs planning to fly over the weekend, and the rain prevented that. So, I now have 6 3s packs fully charged sitting around. I damaged a truck pack a long time ago by doing this, so I have a couple of questions.

1. How long can I safely leave a pack fully charged without damaging it?

2. What is a safe discharge rate (to storage voltage) at home using my charger? 1C, 2C, etc?

3. Three of these packs are brand new, never been used, only charged and balanced. I've read to store a new pack at full voltage, until it goes through some cycles first. Is that true? Doesn't sound right to me.

4. Is the recommended storage method still 70% of a packs capacity? In other words, a 2200mah pack would be stored at around 1540mah?

Thanks guys.

 

[robmob]

For the life of my packs, I do the following.

1. I would not leave a pack fully charged unless I intend to use it that day.

2. My charger discharges at 1C and I have never changed it.

3. Never store a pack at full charge.

4. Packs should be stored at 60% capacity.

 

[HPIguy]

Awesome, thanks Rob.

 

[robmob]

Do you have a Hyperion Battery Sentry?

It takes the guess work out of knowing how much charge is in a pack. I try and check all my packs once a month with it when they are being stored. All my LiPo packs rarely move from the 60%, but every time I check my LiFe receiver packs, I notice they drop so I pay more attention to them.

 

[HPIguy]

Do you have a Hyperion Battery Sentry?

It takes the guess work out of knowing how much charge is in a pack. I try and check all my packs once a month with it when they are being stored. All my LiPo packs rarely move from the 60%, but every time I check my LiFe receiver packs, I notice they drop so I pay more attention to them.

I have one on the way. But I have an electrifly version that does what the Hyperion does (but only for lipos) plus it's an external balancer too which is nice as it frees up the charger for the next pack.

And I agree, it's much easier than draggin out and hooking up the charger just to check a pack quickly.

 

[Greywolf74]

I store my lipos around 3.8V per cell and I also discharge at 1C

 

[HPIguy]

Rob, just wanted to let you know I got my battery sentry, and I freaking love this thing! Truly one of those things that once you use it, you'll never know how you got along without it.

 

[jtboogie]

plus it's an external balancer too which is nice as it frees up the charger for the next pack..

When you charge a LiPo shouldn't the battery be hooked up to the charge leads and the balancer at the same time?

 

[HPIguy]

When you charge a LiPo shouldn't the battery be hooked up to the charge leads and the balancer at the same time?

Not if you're just charging it, but if you're balance charging it then yes, that is correct. Since I use a stand alone balancer to free up my charger for the next pack, I simply use only the main power lead. This also lets me charge at higher rates since it's much heavier gauge wire. For example, I can charge my 3s heli packs at 2C (only when at the field, at home I use 1C) , which for my 2200 mah packs would be 4.4 amps. I've read that you shouldn't exceed about 2.5 amps over the balance taps smaller wire, and always check for heat in the balance tap as a sign of too much amperage that could lead to a fire, possibly.

 

[jtboogie]

Sorry HPI I saw that you had the electify, and was thinking about the electify triton I have, and it came with 2 balancing boards. I haven't charged lipos yet with it buy I didn't think could have one balancing and one charging. Actually I thought I had figured everything out about charging lipos from the guys here, but I guess i don't remember why you would just balance a battery and not be charging it at the same time to use.

 

[HPIguy]

Sorry HPI I saw that you had the electify, and was thinking about the electify triton I have, and it came with 2 balancing boards. I haven't charged lipos yet with it buy I didn't think could have one balancing and one charging. Actually I thought I had figured everything out about charging lipos from the guys here, but I guess i don't remember why you would just balance a battery and not be charging it at the same time to use.

No, you're correct. You can't have one on charge and one on balance on the same charger (not any single output charger I know of). The electrifly I have is the external balancer, great little item as well for $20. I only balance my packs once they are fully charged. Others may do it differently or have some other input to offer on the subject. If a pack is way out of balance, then charging first can possibly be dangerous. But if you maintain your packs regularly (I'm overly paranoid after ruining a $50 pack so I balance every charge to be safe) it won't be an issue.

 

[jtboogie]

Thanks for the info man. I too am very nervous about ruining my lipo packs or not charging them correctly. I have had my 2 packs for my summit for a month and haven't messed with them yet because I will admit I am still scared lol. And I also want to get a fireproof box to charge them in. I am trying to learn everything because I want to do things the safe, and right way. I also am wanting to start a build project with my mini recon and drop a 6800 or 8000kv castle micro pro system in it and will only be running lipos. Also with the triton charger I have I don't know if i can just balance a battery without charging it I will have to break out the manual and see if I can run just the balancing cycle.

 

[Greywolf74]

you can get lipo charging sacks off of ebay for about 5-6 bucks and ammo cans for about 10-12 bucks.

 

[HPIguy]

Yep, I use a lipo sack and lay that in a glass baking dish when charging just to be safe.