im a beginner on my first build and want to make a easy charge function without needing to take out the batteries each time, running 3s 5200mah x2 on a sk3 249kv single drive setup with vesc. so how do i do and what do I need? a bms thing? what like a laptop charger tho I’m a student and need to carry charge with me. didn’t know how to create a thread so just posts this here and would be very happy for answers
You can either get Bms (one plug charging)… or make ‘‘VGA port’’ / Miami boards all in one charger…
VGA port charging would happen through one port but you would have to solder the balance leads to the pins of the port… This way you would still get the chance to use your smart charger (which I assume you have)… to charge your lipos…
BMS -> One plug -> No smart charger, just constant voltage source or so…
VGA port ‘‘mod’’ -> One plug for charging (but many smaller wires connected to the port) -> Smart charger
There is a VERY easy way to do this, and it’s how I charge my main board (2 packs of 6s 15000mah each).
- buy a power jack (3.5mm - or whatever the below charger has on the end) and link it into your main power feed to your batteries - not to the balance leads (ignore them), but at the main power output of your joined battery packs. + and -
- buy a cheap lipo charging “brick” rated at your battery voltage, in your case 6s (like mine) . Here is what I use (£13 delivered)
Plug charger into power jack you installed. Walk away and forget it. When it’s charged the LED on the charger will go from red to green.
You do not need a BMS. Everyone is fretting over BMSs. I’ve been using lipos for years and years, well before esc8ing. Unless you have a bad pack, or you regularly run your packs below 3.2 volts per cell they will stay mostly in balance. By mostly, I mean close enough it makes zero difference. If you have a bad pack then no amount of BMS balancing will make it good.
Set your ESC to cut off before your batteries get to 3.2v and you can’t flatten your lipos. On most ESCS choose the middle to cautious cut off setting. If your pack doesn’t seem to run for long before cut off, measure the voltage at rest, and if it’s ok, reduce the cut off voltage, then retry.
That’s it. All for under £14 and dead easy.
I’ve just gone to my shed and metered my two 6S Turnigy Multistar (cheap) 15000mah packs, disconnected. Used all last year, never balanced, always charged as above.
Pack 1: 4.01 4.02 4.00 4.02 3.99 4.01 Pack 2: 3.95 3.95 3.98 4.05 4.04 4.05
Easy close enough to be fine, and I can guarantee they will all settle at 4.2 v when charged.
You need to balance your Lipos every time you charge them. So either install a bms and use a brick charger or go the VGA port with a hobby balance charger. Either way you should never walk away while charging Lipos. You should always keep an eye on them in case the unthinkable happens.
But both was, Will it still balance charge and dont over charge if i leave IT over night? And what do you mena with smart charter?
Ok seems pretty easy then, but are you sure I dont need bms? And how long would A brick charge?
You dont’ need to balance charge them every night. I’ve been non balance charging lots of packs for years.
Up to you if you go for the scare stories or not.
I would not follow @RogerD advice unless you are experienced with RC stuff and how LiPos and your esc operate. You’re just asking for trouble otherwise.
I think this is especially true if the lipos get to rattle inside the enclosure or they may get ‘‘banged up’’ in some way…
A buddy of mine ‘‘lost’’ his drone this way… I believe he left it charging and he did not choose balance charge either… (his charger allowed to charge in non-balance mode)… So when he returned his workshop was full of smoke and basically what was left out of his drone was a pile of coal and burnt material
Non the less… this was a drone which had crashed a couple of times… but yeah the risk is always there to overcharge a battery or something may go wrong if some sort of short happens in the battery itself
Ok, I think I’ll go with bms since I cant take the risk, how ever could someone link som Good reliable stuff that is not overprized, bms, charge brick, charge port and any wires, and if any one has A diagram on how to wire everything would be very helpful
i also think a bms isnt necessary as long as you monitor the cells. you should always be around when charging and charge somewhere you can deal with it if it does blow or somewhere it wont matter if it blows.
get in touch with your inner lipo and feel the lipos after you ride and while charging for any heat. this is on top of watching their voltage when charging.
Lol, u r funny dude
Cannot agree here. IMO you must balance every time you charge, or use BMS. Don’t skimp on something like this to save a few $ and potentially risk lives/property.
I know my GF is super paranoid about fire, so i’ve started using the temp probe for my packs when charging as well to help her feel more comfortable. In pyrex dishes (cheap from value village) as added insurance. Only a few $ to add the temp probe and it will stop charging if the battery exceeds a set TEMP on my iCharger (others have it too like iMax B6ACV2 iirc). Heat is the first warning before catastrophic issues.
I understand being on a budget, but “cheap” and “charger” are not something i’d try to mix…
HTH - GL!
Using the integrated temp sensor on the finger while charging works well. Also I can press on the pack while doing temp sensing with the same finger and see if it’s expanded, and at the same time look with the eyes at the voltmeter and see the voltage the pack is seeing. When charging I think a bms performance can be beat, it’s in an instance when a cell were to be damaged while riding, after its done with me on the charger, that a bms comes into its own and a cell could get damaged and I wouldn’t know what’s going on. I think a simple temp sensor on cells while riding would be a solution as its not going to burst into flames before increasing substantially in temp.
The benefits of not using a bms for me are: more room for batteries (which is a safety feature in a way), less things to break (bms often seem to break), cheaper, I get more aware of what’s going on and …a biggie I think…with this awareness I would know if I have bad cells or a bad cell ruining performance as apposed to riding blindly with a bms and just accepting what it does.
Makes me wonder is there a way to hook a temp sensor up to the vesc simply?
@Hummie The temp thing you mention seems like a good idea… I’ve seen some of these ‘‘heat pads’’ which change color, if they get heated to or above 40C (104F) or maybe even other temps…
ask @Ackmaniac about temp sensor thing… I thing there was this possibility to attach ‘‘motor temp’’ wire/connection… it is just not used up a lot and can be used to measure other things (batteries)
It would be possible to hook up sensors. But you don’t need it for the battery. I attached a external temperature sensor to my pack with laptop batterys and rode it hard for 5 km in my completely sealed enclosure. And the temperature only raised by 10 °C. So with propper Li-Ion cells you won’t face any issues. Even my 10 °C were harmless. If you start riding at 40 °C outside temperatur and climb up the steepest never ending hill and drive full speed until the battery is empty then you might reach it. But i think that’s never going to happen. So simply don’t worry about the battery temperature.
the reason for the temp sensor would be if you run without a bms you can still know if you have a dud cell before it were to get so abused as to possibly vent. hook up the sensor to your phone and it could tell you if something were getting hot. most fires with lithium happen while charging, and you could utilize the temp sensor then as well while bulk charging. If only the cell voltages could be transferred to the phone too.
Sorry to disagree here , but there is no “MUST” in balance charging. You may only be happy balance charging, but it is in no way a must.
You should also not equate cheap = bad/poor. That’s an Apple mindset.
I’ll just sit here and watch for the fires to start happening
@RogerD, please tell me you ride without a helmet
If I’m going to the pub 1mile down the road I keep it around 10mph and ride without a lid.
I never cycle with a lid.
If I go out for a proper skate bard ride (i,.e for the sake of a ride) I wear a lid.
I always wear a lid on a motorcycle.
I take resposibility for my actions, and balance risk with practicality and enjoyment.
I’ve not had a lipo fire, ever. Must be a miracle.