Storing Monster Batteries

[Jerold]

In the past run 3S ~5K mah batteries and the easy way to get it close to storage charge is run it down until the ESC cuts me off. It come out about 3.7V pretty consistently. Then I can adjust them quickly with my charger.

However, now I have a limitless with some monster 4S 9500 mah batteries. I don't have the lipo cut off enable turned on. At this point I'm cutting them off early and I need to discharge them to store them properly. I'm finding my LiPo charger (ISDT D2) it takes forever to discharge these. They were about 4V/cell and it took about 16 hrs to get to about 3.8V/cell.

The discharge is limited to 5W per channel and that's why it takes so long.

What do you guys do?

 

[gotnitro]

1) Why are you running the LVC off?
2) You'd simply run them down with the LVC turned on and charge to your storage cap.
3) How long are you storing them?

 

[SrC]

^^^

+1
_______________________________________________________________________________________________________________________
Get yourself a Dedicated Lipo Discharger if you are caught out there with charged lipos. (higher than 3.85+volts/cell)

What I use:

https://www.ebay.com/itm/114802547593?chn=ps&_trkparms=ispr=1&amdata=enc:1jyGcuZvNSCWjrcA8swc91w34&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=114802547593&targetid=4580702891777580&device=c&mktype=&googleloc=&poi=&campaignid=418640321&mkgroupid=1233652283797640&rlsatarget=pla-4580702891777580&abcId=9300602&merchantid=51291&msclkid=ade4b9e9db4d1dc02527dbc6175cf519

 

[Jerold]

1) Why are you running the LVC off?

The LVC is off for a couple of reasons.

First is Auto-Lipo settings doesn't work correctly and has to be set manually. Since I'm swapping between 4S and 8S at the moment manually setting is a pain in the butt. Here is my post about the Auto-Lipo https://www.arrmaforum.com/threads/jerolds-limitless-build.49292/#post-705396 from my build. BTW Castle Still hasn't gotten back to me on my service request.

The second reason is the voltage droop under high load (AKA RC Ripple Voltage) can cause the LVC to kick in too early. I'm currently seeing about 8% droop under load and I'm not sure where that will be when I get it tuned. For now I don't want that limitations and just check the batteries manually.

2) You'd simply run them down with the LVC turned on and charge to your storage cap.

This is what I have been doing with the other batteries. Ideally I would run them down and cut off at 3.4-3.5. They come up to 3.5-3.6V after a rest and then I can charge them up to storage voltage. The other end of that equation is that this is not a car for bashing and hoon, which runs down the batteries quickly. It's built for speed runs and I'm still figuring it out. So I do a few runs and then adjust thing, then continue another day. Over the weekend I was able to run on Friday evening and Sat morning, so I didn't need to run the batteries down.

3) How long are you storing them?

Figure on at least a week, it depends on my schedule and ability to play. This car requires a bit more preparation than The only problems I've had in the past is with heat. I have left some of my 3S 5,000mah charged for couple of three days and never had a problem. However, these are giant batteries and I want to reduce my risk level as much as reasonable.

 

[Jgg12002]

Homemade battery discharger 1156 bulbs with a connector and 5$ lipo alarm set to 3.85/cell. I have about a 1/2 dozen of these so I can rapidly do many batteries at once. Some people say that they aren’t balance discharging but neither is using the truck. I always balance charge, never had a problem.

 

[gotnitro]

The LVC is off for a couple of reasons.

First is Auto-Lipo settings doesn't work correctly and has to be set manually. Since I'm swapping between 4S and 8S at the moment manually setting is a pain in the butt. Here is my post about the Auto-Lipo https://www.arrmaforum.com/threads/jerolds-limitless-build.49292/#post-705396 from my build. BTW Castle Still hasn't gotten back to me on my service request.

The second reason is the voltage droop under high load (AKA RC Ripple Voltage) can cause the LVC to kick in too early. I'm currently seeing about 8% droop under load and I'm not sure where that will be when I get it tuned. For now I don't want that limitations and just check the batteries manually.

This is what I have been doing with the other batteries. Ideally I would run them down and cut off at 3.4-3.5. They come up to 3.5-3.6V after a rest and then I can charge them up to storage voltage. The other end of that equation is that this is not a car for bashing and hoon, which runs down the batteries quickly. It's built for speed runs and I'm still figuring it out. So I do a few runs and then adjust thing, then continue another day. Over the weekend I was able to run on Friday evening and Sat morning, so I didn't need to run the batteries down.

Figure on at least a week, it depends on my schedule and ability to play. This car requires a bit more preparation than The only problems I've had in the past is with heat. I have left some of my 3S 5,000mah charged for couple of three days and never had a problem. However, these are giant batteries and I want to reduce my risk level as much as reasonable.

Well, one way till you get your new ESC would be to run it like you normally do, charge the batt's and see how many MAH you used. Should get you close. Also, leaving a batt fully charged for a week never hurt any of mine. Matter of fact, I still have the OG Venom 5000 3s 20C that still works. Thing is over 10 years old and I've never put it into storage mode lol.. I use it in one of my drones.

 

[olds97_lss]

There are a few dischargers out there you can buy, one balance discharges, the others don't, but wouldn't be any different than running a pack down in your truck (aside from lower amp draw).

Balances: https://www.amazon.com/Discharger-Intelligent-Discharge-Efficient-Dissipation/dp/B07ZD2D8YW

100W: https://www.amazon.com/ISDT-Discharger-Discharing-Capacity-Discharging/dp/B0775PDWZM
200W: https://www.amazon.com/ISDT-Discharger-Wireless-Capacity-Discharging/dp/B07VS2JSN9
250W: https://www.amazon.com/SKYRC-BD250-Battery-Discharger-Analyzer/dp/B087NFJN67

There's also a cheap one that I use that uses 3x50W halogen bulbs to bulk discharge, then a 5w resistor bank inside to finish. It's kind of hokey though. Nowhere to put the 10000F bulbs while it does it's thing. I set mine to run down to 3.7V and when the lights shut off, I unplug and it's usually around 3.8V per cell, then I throw the packs on my charger quick to bring them up/balance to storage voltage.

I screwed the bulbs to the frame of the thing and put an aluminum shield around them so I"m not blinded when I use it. I have a shield on the back now too so if it falls over, the super hot bulbs don't melt stuff.

 

[Jerold]

There are a few dischargers out there you can buy, one balance discharges, the others don't, but wouldn't be any different than running a pack down in your truck (aside from lower amp draw).

Balances: https://www.amazon.com/Discharger-Intelligent-Discharge-Efficient-Dissipation/dp/B07ZD2D8YW

100W: https://www.amazon.com/ISDT-Discharger-Discharing-Capacity-Discharging/dp/B0775PDWZM
200W: https://www.amazon.com/ISDT-Discharger-Wireless-Capacity-Discharging/dp/B07VS2JSN9
250W: https://www.amazon.com/SKYRC-BD250-Battery-Discharger-Analyzer/dp/B087NFJN67

There's also a cheap one that I use that uses 3x50W halogen bulbs to bulk discharge, then a 5w resistor bank inside to finish. It's kind of hokey though. Nowhere to put the 10000F bulbs while it does it's thing. I set mine to run down to 3.7V and when the lights shut off, I unplug and it's usually around 3.8V per cell, then I throw the packs on my charger quick to bring them up/balance to storage voltage.

I screwed the bulbs to the frame of the thing and put an aluminum shield around them so I"m not blinded when I use it. I have a shield on the back now too so if it falls over, the super hot bulbs don't melt stuff.

Thanks this is great info and it helps a lot.

Just looking at the discharge rates 5W (my current setup) is unacceptable. The Skry RC looks great but I do all my charging/discharging outside and the wired PC Super GUI is not useful. So I'm leaning towards 200W ISDT. First I will check my local hobby store first and see what they have.

I'm also working on some XLS tools to help me (and others) do some LiPo Calculations.

 

[SrC]

I have left some of my 3S 5,000mah charged for couple of three days and never had a problem. However, these are giant batteries and I want to reduce my risk level as much as reasonable.

For speed running with dedicated specific lipos, I would not allow the lipos to drop to 3.4v/cell. And I definitely would not let them sit Fully charged for several days. Lipos left at rest/stored with 3.85v/ cell provide better consistent runs. IR's stay lower over the lipos life. Just me.

I never seen any correlation between high ripple volts and LVC. But I don't run CC gear. HW Sensored only. I do use a cap pack. (Lim)
Amp Cutting and LVC appear to be 2 different things IMHO.

 

[Jerold]

For speed running with dedicated specific lipos, I would not allow the lipos to drop to 3.4v/cell. And I definitely would not let them sit Fully charged for several days. Lipos left at rest/stored with 3.85v/ cell provide better consistent runs. IR's stay lower over the lipos life. Just me.

Makes sense, I need to take care of these; not like basher cars.

I never seen any correlation between high ripple volts and LVC. But I don't run CC gear. HW Sensored only. I do use a cap pack.
Amp Cutting and LVC appear to be 2 different things IMHO.

The ESC is not cutting out because of current. . . . yet.

For the LVC setting (I'm sure I'm over thinking this) if I have 8% voltage max droop under load, just add that back into my LVC?

There is a small different between resting voltage and running voltage. Based on experience, the running voltage on my 3S is ~.1-.2V less than the resting voltage. Assuming that holds up with the monster batteries, my target LVC is 3.5V.

Where my actual voltage would be around 1.08%*3.5V = 3.9V/cell.

Thanks this is great info and it helps a lot.

Just looking at the discharge rates 5W (my current setup) is unacceptable. The Skry RC looks great but I do all my charging/discharging outside and the wired PC Super GUI is not useful. So I'm leaning towards 200W ISDT. First I will check my local hobby store first and see what they have.

I'm also working on some XLS tools to help me (and others) do some LiPo Calculations.

I ended up with the Sky RC discharger from my LHS I will try it out soon.

Thank you and AF for all encyclopedic knowledge!