Is it ok to charge the battery everyday when it's 50%

Is it detrimental for these lipos batteries?, would you recomend to charge it when it's below 20%?

 

I charge my Bamboo GT whenever I'm done riding for an hour or more, whether it's at 60% or 6%, that way it's ready to shred again when I am!

 

It is not detrimental at all. Best to keep them at 100% so they can balance and be ready for the ride. What kills them is leaving them at 50%, you let it sit for a month or so, and the battery drains dead killing it since the voltage ran critically low. I use my board every day, I run it down to 60% by the time I return from work. I immediately plug it in, allow it to charge and sit on the charger overnight even when its at 100% so it can balance the pack. I unplug in the morning and repeat.

These battery packs are too small to manage the state of charge like that. You need to do this only with an Electric Car that has 50kW/h packs. My electric motorcycle has a 5.7kW/h pack and I still don't manage the state of charge since that is still to small and not worth your wild. Use the pack and replace when you do need to replace it. Most people don't ride enough to burn though the life of the pack honestly.

 

does anyone know exactly how leaving it charge over night actually does and balancing? the charger turns green when board is fully charged and shuts off further charge to the board in order not to over charge it, so how does it continue to balance cells?

 

Yeah the Evolve charger has that feature. I'm not sure if it's the charger that stops the flow of current or the battery pack that stops the charging flow and send a message to the charger to light green.

 

The BMS is what balances the cells, not the charger. Charger shuts down at a specified limit to prevent damage to the pack, but its the BMS who shuts it down. I believe the BMS reads each cell voltage, has a sensing line to the charger or at least control over the +/-, if it sees a cell hitting 4.2v, it shuts the charger down to protect the cell from overcharging.

Its usually good to inquire with the manufacturer and see what they say, and then validate that on your own if you have the info.

For example my Tesla Roadster can balance as long as the battery SOC / state of charge is over 84%. Once it drops below that it won't balance. It does not need to be on the charger to balance. However I have a Zero FX motorcycle and know the battery engineer, he told me that my bike needs to be on the charger, fully charged, and has to sit on the charger for the BMS to balance the cells. My MetroBoard Skateboard I talked to Ilan who makes them. He said the board needs to be on the charger, charged 100% and has to sit on the charger to balance. The BMS has many functions, to stop and turn off the charger, and its in charge of balancing the pack which it bleeds off the higher voltage cells (which are weaker) to match the lower voltage ones (which are stronger). Why the charger needs to be on for some and doesn't for others, we should find out. I'll have to dig in and see if there's any documentation on why it needs to sit on the charger

Here's an example BMS for a skateboard, has the technical specs if you're interested in understanding what it does:

36V 37V 42V 10S 30A 10x 3.6V Lithium ion LiPolymer Battery BMS [36V 10S 30A Lion LiPO BMS] - $34.00 : Lithium Rechargeable Batteries, Battery BMS, Pack Assembling

"The main functions: Over-charged, Over-discharged protection, short circuit protection, over-current protection, with Balancing function."

 

So I came across this link. There are 'smart chargers' which have the BMS inside them instead of on the board. The charger is a mini computer that monitors the voltages of the cells and manages them. I can see in this case why the charger would need to be on. This is a link for RC cars/planes. So sort of the same but not exactly what we have:

Lipo Battery Charging Tutorial

My guess is that we have an onboard BMS, but need to verify that.

 

I was under the impression that there is no need to leave your board on charge after the green light, and they don't mention to leave it on after it is fully charged, and it says not to leave your board un attended while charging, I honestly don't think it is a good idea to leave on charge over night, but again I could be wrong, if you email them and ask these questions you could get a good answer as to how their charger works.

 

yes the BMS is on the board, not the charger

 

Huh? Everything i have heard and read says keeping batteries at "full charge" is not ideal. There are a lot of other variables, though. I do not know the specifics on the evolve board. However, in general, you do not want to keep a li-ion battery at "full charge" ie way over nominal voltage for a long period of time as it will degrade longer-term capacity.

How to Prolong Lithium-based Batteries - Battery University
"The worst situation is keeping a fully charged battery at elevated temperatures."
"Lower charge voltages prolong battery life and electric vehicles and satellites take advantage of this. Similar provisions could also be made for consumer devices, but these are seldom offered; planned obsolescence takes care of this."
and on and on...

As far as cell balance, ive read recommendations to do a "full charge" every so often. Not every time. I have personal experience with an expensive battery pack on this that died i think from keeping it at "full charge" after every use. Also, this is why you see "better" chargers with settings that allow 80% 90% or 100% charge levels, so you do not do a "full charge".

Not sure on the specifics with the evolve boards, though. Havent checked what the charger is doing or what it considers a "full charge" to be yet.

 

Just charge it right up and use it!
If you are storing it over winter and not using keep it at about 50%.
Advice directly from professional lipo battery pack maker.

 

we do the same thing with RC lipos - store at 50-60% - they last a long time in this storage mode (for RC lipos about 3.8V per cell - also this is how they ship from the manufacturer)

 

Does anyone know of a "hidden menu option" to look at the individual cell voltage ? (and more battery / motor info)
(I thought I saw this somewhere - can't remember where)

 

From what I understand you can't ship LiPos as a manufacturer / seller unless they're around 50% due to safety reasons while in transport.

The biggest killer to batteries is heat, worse case is heat with high State of Charge meaning 90-100%.

But if you're really trying to milk the life out of these batteries, don't run it down past 25%, don't charge it above 85%, don't use the accelerator hard below 50%.

So are you really going to be babysitting your skateboard this way, I'm not hence why its too much of a babysitting problem with these small battery packs. If you have ones you're sitting on as backup, yes, 50% SOC and throw them in your freezer! That's the best case scenario for them. Honestly I'd do 65%. The worse degradation curve for LiPos starts rising at 27C and above, 85% SOC and above for some quick facts. There's a lower limit SOC threshold, I believe like I said around 25% SOC and below.

But note that batteries will drop their charge over time, typically 1-5% or more per month, so beware that you're 50% battery just sitting there may go critically low and possibly brick if you don't pay attention to it. I have two large capacity electric bicycles, even charging them to 100% and sitting, they creep down over time so doing 50% does nothing but risk loosing that battery due to low voltage. So then its like, well, what was better? Charging it to 100% and allowing it to sit and a room temp area and have your battery still function x months down the road, or drop it down to 50% SOC, come back x months and find it bricked? So then you have to buy a new one?

Also fast chargers are bad to use habitually on a small battery pack. That eats life from your pack. If you want longevity there, use your slow charger.

And finally keeping your battery fully balanced all the time extends the life of the cells, if you keep your board sitting at a lower SOC all the time, charge then go, the board does not have any time to fully balance. So again, keeping your battery lower in charge which you may think helps your pack is actually hurting it more.

So to wrap up about balancing with our GTs. We can easily find out ourselves if we need to keep the board on the charger during the time it balances or not. We have access to the raw cell voltages. So we can experiment charging for a week with the board at 100% charge, sitting on the charger over night and capture that screen. Then the second part is to charge 100%, unplug immediately after the charger turns green, let it sit over night, and capture the screen and compare how the voltages look. A balanced pack will have the voltages very close to each other, one out of balance will have a couple of cells higher and/or lower than the mean.

But to be honest, you could forget all this stuff above we're talking about and just charge and go, charge and go and everything will be alright. You won't get the maximum performance and life, but most likely you'll get performance and life that will meet or exceed your expectations. Car manufacturers hide the balancing of cells behind the consumer and you need to access a secret screen with a password to see them. My point is they're designed for the average non-geek person to use them.

References:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Shipping Lithium Batteries in 2016: FAQ - Lion Technology

 

Yeah, on my board, i have just been charging it after every ride. The main reason is because the battery is small at 6.5 AH. I typically want max range. However, after a short use, i wont bother charging. Also, I will not let it sit on a charger ad infinitum, because there is risk and technically, it is bad for the battery's longevity anyway.

If you browse Tesla boards, etc. there are various tricks for extending battery life, other than charging up to 100% all the time. That is generally not advised.

Does anyone know the voltage values? What is 100% what is 0%? This is more important to know than what the % number is on the remote anyway.

Typical advice if you have a Tesla. I dont but i like to see what their owners say. I just copy/pasted the headers. The all caps are annoying.
Top 5 Tips to Maintaining EV Battery Life
5. DON’T LEAVE YOUR BATTERY SIT AT A 100% STATE OF CHARGE
4. AVOID DEEP DISCHARGING OF THE BATTERY PACK
3. BE MINDFUL OF EXTREME TEMPERATURE CONDITIONS
2. PLAN AHEAD FOR EXTENDED STORAGE
1. PERIODICALLY FULLY CHARGE AND “BALANCE” YOUR BATTERY

 

it is hard to say exactly what is best and related articles may not reflect how our boards actually run things. There is a BMS on board, this may limit the batteries to not get to 100% , balance them and keep it all in check. The manual states what level to leave your board charged at if you want to store it for a while. would be interested to see if you want to do screen grabs or leaving your board on over night, and see if anything is the difference.

 

Yeah, I think I read about it on one of the Evolve Facebook groups.

When the board is on and connected to the remote, tap left button twice to enter menu. Select and toggle into "More Info".

For Battery Info: Once in the menu, quickly tap right button twice followed by holding the left button until the screen comes up.
For Motor Info: Once in the menu, tap right button twice then left button twice.

 

Well done ! That works thanks

Mine shows this:

 

Glad it worked. I just went to check mine and everything seems to have reset and readings are off, not sure why. I used to have about 60 charge cycle counts and cell voltages similar to yours.