Work with your lipos...

[fpvmiller]

Not against them.

I have made mention before that I have been flying drones for a good amount of years now. Part of that is being more aware of your lipos and their care. Also, many drones (at least mine) are sparse in space for many reasons so voltage alarms can't always be used. Using OSD I had to learn to watch the total voltage and land when my lipo is at the "LVC" point.

That also leads to having properly maintained lipos so that your readings are as close to accurate as possible. I generally do manual discharges and balances before and after charging. I also balance charge always at 1C and I storage charge when the lipo is at room/resting temperature meaning not immediately after it has been discharged.

There are many tricks to maintaining lipos but the time and effort to doing it right means less worry overall about the lipo pack itself. I have also done lipo rescues on single cells within a pack. The lipo rescue is not for the average user and I don't give instructions on how to do it (for liability reasons).

The reason I bring these points up is because recently people have been asking about lipo care/maintenance and performance. I am using my 2x 3s 5000mah dynamite reaction2 lipos that I have been hammering in my infraction. I mean no worry about full throttle pulls from a deadstop. I recently did a run last night and ran the packs to LVC.

The equipment -
xr8 plus
hobbystar 4274 1700kv with a 20t pinion on 46t center diff
2x 3s 5000mah dynamite reaction2 50c lipo
smc precision lipo alarm set to 3.7v connected to the negative lipo

After letting it sit overnight to settle I checked the cells this morning and I personally was not surprised.

That tiny difference (3.73 vs 3.74) is not a concern and even before I charge it I will balance it manually. Then on the charger it will be set to storage mode at 1C. Storage mode usually gets it to around 3.8x volts per cell. Then I manually balance it again and put it on the shelf for the next time it is ready to charge.

I don't think these are the best packs out there but even packs that are maintained properly will give you many cycles to be happy with.

Cheers

 

[Jackjax801]

I recently got one of those venom lipo checkers. It's been working great. Definitely a good purchase to balance cells. Had a brand new 3 cell lipo that wouldn't balance well on my charger. Used the lipo checker a few times and now the cells are consistently within 0.01v of each other.

 

[rflx]

What do you mean by "manually" balancing the cells?

 

[fpvmiller]

What do you mean by "manually" balancing the cells?

There are a couple of methods I use, sometimes in combination.

But the one I do mostly involves literally discharging the pack as a whole and then charging each cell individually up to storage and then balancing the pack as a whole to storage.

It is manual because there is no charger (that I know of) that does this. I have made custom leads for this purpose.

 

[rflx]

There are a couple of methods I use, sometimes in combination.

But the one I do mostly involves literally discharging the pack as a whole and then charging each cell individually up to storage and then balancing the pack as a whole to storage.

It is manual because there is no charger (that I know of) that does this. I have made custom leads for this purpose.

Alright. I hope you don't mind me asking, but.. why? ?

I don't understand the advantage over just letting the charger balance them into storage all at once.

 

[fpvmiller]

Alright. I hope you don't mind me asking, but.. why? ?

I don't understand the advantage over just letting the charger balance them into storage all at once.

My drone background, we can't always fit lipo alarms on the rigs. The best we have most times is an osd (on-screen display) that shows total voltage. The more closely/tightly balanced the pack is the more accurate the total voltage is. That means more runtime down to drone lvc. In drones we discharge our packs down to 3.5/3.6v per cell to get the most runtime especially for racing. If your cells aren't tight your total voltage is inaccurate and you can (and will) kill your lipo. The esc lvc is the same concept...it uses total voltage to average your cell voltage. Guess what happens when one of your cells is not right...premature lvc and possible death.

And that's all to stretch to an average of 3-4 minutes of flying. Expand that to my long range drones where the higher capacity increases flight time but also increases amps to compensate for more weight. If the lipo isn't tight you will see an array of issues with the worst being a lost/downed drone.

Cars is easier to recover but the mentality I have is still "take care of the lipos". I even strap my lipos down inside my current rigs with the same lipo grip tape for added security.

Chargers will balance your packs but not all chargers are the same or even reliable. With people trying to go the budget route (especially on lipos and chargers) you really should put in the extra effort to safeguard against that "budget" lipo and charger. My chargers aren't slouches but I still have years old packs that can balance and hold a charge. No puffs either.

 

[suchtragedy]

Alright. I hope you don't mind me asking, but.. why? ?

I don't understand the advantage over just letting the charger balance them into storage all at once.

I find most of the plug and go chargers people are using when first starting out just don't do this well at all. I bought a used RC off a guy a while ago and it came with two lipos and one of those basic balance chargers that only has led lights and no way to check voltage. When I checked voltage on them one was beyond repair with cells dead and cells way out of balance in the other that took me 20 hours to rebalance and make healthy. Then I had to keep checking it over time to see if the cells were staying balanced and not dropping rapidly as they sat and sadly it was a lost cause as well. When I told the guy he has no idea and swore he always balance charged right before use and storage charged when done.

Anyways great post @fpvmiller to drive an informative discussion. I came from fpv drones to ground RC like you and noticed right away that in depth battery knowledge in general isn't as well known in the ground RC community as in the drone community. Drones are way more battery intensive and knowing your stuff makes all the difference between flying 10 minutes vs dropping out of the sky so it's really something that gets drilled into you there.

Chargers will balance your packs but not all chargers are the same or even reliable. With people trying to go the budget route (especially on lipos and chargers) you really should put in the extra effort to safeguard against that "budget" lipo and charger.

The bread and butter of this post is for people in this category for sure lol

 

[Vedak]

My Revolectrix chargers do a good job balance charging. Although I do like to balance with the ISDT BG-8S, it will get things settled in within 1-2mv. Although sometimes it can take a while.

 

[fpvmiller]

My Revolectrix chargers do a good job balance charging. Although I do like to balance with the ISDT BG-8S, it will get things settled in within 1-2mv. Although sometimes it can take a while.

"Taking a while" is sometimes an indication of something going on. It is always best to analyze your lipos if/when you can afford the time. When your pack is acting right your charging time should be relatively consistent +/- maybe 5 minutes.

@suchtragedy I agree, it seems the drone side is really more informed about lipo care and maintenance. Nothing wrong with that or bringing that information to the surface side. Another small note to make of was on race days, I would charge my packs 2 hours before the first race. The night before was my usual balance and store process. Others would charge the night before and have them sitting only to have them struggle to make those last 30 seconds because of their voltage sag. At one point I was one of the "hv chargers" but that was a test for my curiousity and it only lasted one race day. I have been on both ends of the lipo spectrum. I have either rescued/maintained lipos or killed them completely for disposal.

 

[Vedak]

"Taking a while" is sometimes an indication of something going on. It is always best to analyze your lipos if/when you can afford the time. When your pack is acting right your charging time should be relatively consistent +/- maybe 5 minutes.

I believe it's just the nature of the ISDT balancer. Most others don't even display a third decimal place. So while one brand will be balancing 3.81/8.83, the one I have is trying to balance 3.811/3.831. <- these are just hypothetical numbers. In the videos I've seen, others have experienced the same.

 

[rflx]

Yeah, a little more lipo talk is certainly a good thing. People come in here with very basic misunderstandings every week.

I did a lot of reading before I bought my first 2 lipos, and spend 140€ on the charger.
So far, I have been getting by with only "basic" care. Using a high LVC setting, storage charging as soon as I can, being conservative about charge current and always using balance mode.

Also, I first found the idea of a dedicated discharger hilarious, but it didn't take long until I bought one ?

@Vedak - my charger is the same, very meticulous about balancing to the second decimal place. Storage charging is fast up to 3.79 and than takes foreeeeever. But hey, I'm usually not in a hurry when storing.

 

[fpvmiller]

I believe it's just the nature of the ISDT balancer. Most others don't even display a third decimal place. So while one brand will be balancing 3.81/8.83, the one I have is trying to balance 3.811/3.831. <- these are just hypothetical numbers. In the videos I've seen, others have experienced the same.

This could very well be true too. Admittedly I never got the need to get any isdt charger/product. At some point in time I became well versed in parallel charging but if I can avoid it, I will, mainly to keep my lipo accountability correct.

Yeah, a little more lipo talk is certainly a good thing. People come in here with very basic misunderstandings every week.

I did a lot of reading before I bought my first 2 lipos, and spend 140€ on the charger.
So far, I have been getting by with only "basic" care. Using a high LVC setting, storage charging as soon as I can, being conservative about charge current and always using balance mode.

Also, I first found the idea of a dedicated discharger hilarious, but it didn't take long until I bought one ?

For drones a dedicated discharger becomes a necessity. There will be days (race or freestyle) where you don't always fly the packs you charged. You don't want to let a fully charged lipo sit fully charged. You can't just fly a 6/7 inch 6s rig up and down your neighborhood street just to discharge your lipo. That's where dischargers come in.

I really would like to see everyone enjoy the RC hobby and the lipo maintenance is just as important as anything else.

 

[Vedak]

Also, I first found the idea of a dedicated discharger hilarious, but it didn't take long until I bought one ?

I fought this idea pretty hard also, but now having used one- can't believe I didn't get one sooner. I tend to charge up a minimum of 4-5 batteries, regardless of whether or not I'll use them up.

With the discharger, I can readily run an assembly line of sorts. Discharge one, storage charge another. By the time a battery is discharged, the one on storage is finished, and the one that was discharged has had a little time to settle down. Then repeat the process for all batteries.

 

[rflx]

I fought this idea pretty hard also, but now having used one- can't believe I didn't get one sooner. I tend to charge up a minimum of 4-5 batteries, regardless of whether or not I'll use them up.

With the discharger, I can readily run an assembly line of sorts. Discharge one, storage charge another. By the time a battery is discharged, the one on storage is finished, and the one that was discharged has had a little time to settle down. Then repeat the process for all batteries.

I usually venture out with 2 packs at the most. But when breakage occurs, having to discharge 2 lipos with a measly 5 Watts was the worst. 10 hours of of runway ambiance.

 

[Vedak]

This could very well be true too. Admittedly I never got the need to get any isdt charger/product. At some point in time I became well versed in parallel charging but if I can avoid it, I will, mainly to keep my lipo accountability correct.

I think this is where having a good charger plays a big role. I almost always parallel charge, in my experience all my batteries have been very close together. In this category we've come a long way as well. 15+ years ago, albeit not lipo at the time- I was charging with some very questionable setups. This is where I would suggest a person new to the hobby spends a little more money, vs straight to an 4s-8s rig, and $20 charger.

I usually venture out with 2 packs at the most. But when breakage occurs, having to discharge 2 lipos with a measly 5 Watts was the worst. 10 hours of of runway ambiance.

oof 5 watts discharge? that's painful

 

[fpvmiller]

@Vedak I use to parallel charge like crazy. My chargers can do it no issues. I just found that for me keeping a system consistent was more beneficial (especially in racing) than charging as many packs as possible.

@rflx 5watts discharge is too little lol I have a 300watt discharger than can actually do 4 packs at one time. Mind you it's not a "ready made" discharger lol but it is within safe parameters and 4 packs using 300watts of discharge actually is easier for the cells vs 1 pack using the full 300watts

 

[jkflow]

Not going to argue the way people treat there lipos out of abundance of caution. More power to you (or your lipos)! A good rule is always, if it works for you keep doing it.

My oldest pair of lipo's is now 8 years old and still going strong (Plane use, not car). Balancing only makes technical sense at the end of the cycle
or in odd cases where you do high C charging. Outside those scenarios it adds no benefit but it doesn't hurt either.

Technically, the Lipo can care less if you individually charge and balance or do it as a pack. This is like filling up a glass of water, place 3 next to each other and fill them individually or one at a time, the end result of having 3 full glasses of water is the same, only difference is the time to get to that point. Crude analogy of what is happening inside a lipo. They can't absorb more in either scenario. If you level them off in between (aka balance) again it adds no benefit.
Unbalanced cells are only an issue if you either do high discharge or charge due to the 'dynamic' internal resistance.

Dis-charger, built my own and yes it always comes in handy (resistors, heatsink and fan). My chargers can only do ~ 20W of discharge and that would take forever. My DIY dis-charger is at 5 Ohm and in use for 4S and 6S, lipo alarm for low level.


I' dealing with measurement systems on a daily basis, if you think that you are getting 2 or 3 digit accuracy without a yearly calibration you are in for a surprise. You are not getting what you are seeing, for RC and Lipo purposes it's 'good enough' over the lifetime of the charger/checker. Keep in mind that a difference of 0.05V, at full charge, is negligible, it is easily spend in the first 30sec and it will balance itself if your packs are matched.
One good habit is to use the same setup all the time, at least you minimize your errors.

Parallel charging, done it and keep doing it on my smaller lipo's. Only recommended for people that understand the technical issues i.e. unbalanced packs etc. easy to ruin your day quickly.
Biggest setup I do it on is ~ 600W but I prefer doing them individually. Pure comfort level for myself.

Point of this post, do what is working for you! Technically it's best to balance and store your lipos in correct charge state, standard process with a charger is all that is needed. Everything else is personal preference after you have the basics covered.

 

[fpvmiller]

@jkflow Very well put points. Nothing to argue against it. I would like to point out that, again, some of the recent posts regarding lipo and lvc was what motivated me to start this discussion. With the blx escs it is based on the cell average determined by the total voltage. If a user just hit balance charge and went straight to running without first verifying their pack cells (like you said 0.0x is negligible) they may be in for a surprise if one of their cells was not actually balancing right. I have seen cells take a charge only to drop off dramatically as soon as it comes off the charger. This is where the extra care comes in. This is also where the total voltage does play a huge role. Again I completely agree, "do what works for you". Just gotta be a little more attentive in some areas.

 

[rflx]

@rflx 5watts discharge is too little lol I have a 300watt discharger than can actually do 4 packs at one time. Mind you it's not a "ready made" discharger lol but it is within safe parameters and 4 packs using 300watts of discharge actually is easier for the cells vs 1 pack using the full 300watts

I was originally going to build something myself. But then I noticed that, in terms of material cost, I couldn't beat a 30€ ISDT Discharger. So my laziness won and I just bought that
Plus it's handy that it stops roughly at storage voltage.

Can't nearly do 300W of course! But it's sufficient for me.

 

[jkflow]

@fpvmiller. Totally agree. ESC's are your last defense at best. If you reach the stock LVC level damage has already been done.
Owner needs to know state of their packs and these little voltage checkers are a life saver, as long as you take them for what they are, cheap checkers. You can't force accuracy into a stick though.

DIY dis-charger, by all means it wasn't worth it in the end for myself tbh. Could have bought a 50W version for maybe $20 more. For me it's more part of the hobby and scraping up leftovers to make something work. In hindsight, I had a BEC to power the cooling fans and ended up buying everything else ?, the plan started out a little different. I've spent maybe ~$30 total but I know what I got and can push it if needed. I could scale it up easily but I don't have a need.