Author Topic: When to recharge Lipo Battery ???  (Read 2379 times)

Offline diverdon

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When to recharge Lipo Battery ???
« on: October 15, 2020, 04:12:36 PM »
..I need a genius ... Trying to figure out how low to let a lipo battery go before charging ... I don't want to charge it to often but also don't want to get caught 1/2 way thru my ride and have the battery go flat ..Charged my old battery every 5 trips or 30 miles ...Think I was charging to often ... New 52 volt battery 13 AH has lights on it for 0-100 % ...Red is still 25% 3 more green lights for 50-75
 and 100 % ... I am guessing these batteries are like the drill etc batterys that run great right to "the end" then just cut off at a certan voltage ...
        Be nice if there was a voltage I could leave home with and know I have enough juice to make it ... Thinking the only way to sorta figure this out is thru logging wattage usage which is not what I want to do ...Ugh !! ...I have the Black Pie 5 on a 26 inch cruiser and I am a 250 lb fat ass if that helps anything

     Thanks For any help , Don J.
« Last Edit: October 15, 2020, 05:29:41 PM by diverdon »

Offline Bikemad

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Re: When to recharge Lipo Battery ???
« Reply #1 on: October 18, 2020, 06:08:13 PM »
Hi Don,

It is better for the battery if you don't let it go below 20% and also don't store it for long periods above 80%.

I use a cheap and simple battery capacity gauge to give a rough indication of the remaining battery capacity and I suggest that you try using one of these:


For your 52V battery you would need to set it to L14 (14 cell groups in series) for a typical lithium pack or F16 (16 cell groups in series) if yours is a LiFePO4 battery.

Alan
 



Offline diverdon

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Re: When to recharge Lipo Battery ???
« Reply #2 on: October 30, 2020, 02:38:52 PM »
Thanks again for the help .... I got a digital voltmeter for the handlebars ...With the chart I found on here I can track the state of charge and the % used on each ride .. I'm thinking recharge at %35 ..Little afraid to let it go much lower ??? I have read where full charge for the first few cycles 3-4 to let the battery balance ...then 80% most of the time after that

Offline Bikemad

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Re: When to recharge Lipo Battery ???
« Reply #3 on: October 30, 2020, 06:08:49 PM »
As the cell balancing on most BMS units only occurs at the very end of a full charge, it might be better to give it a full charge at least every couple of weeks to prevent the cells from going too far out of balance.

A full overnight charge prior to being used the following day should prevent it from being stored in a fully charged state for too long.

Charging when it reaches 35% sound like a good idea to me, as I am currently using a Hailong bottle mount battery that looks the same as the one on the back of your bike:


My battery level indicator has 4 LEDs that light up when you press the test button, but the BMS shuts off the power because of low pack voltage while 2 LEDs are still lit. ::)
My battery gauge is currently showing 32% but I still have 3 LEDs lit up when I press the battery indicator button. :-\
So, if it only has 3(or less) LEDs lit at the end of a ride, I always top it up before I next use it again rather than risk running out of battery during the ride.

Alan
 

Offline diverdon

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Re: When to recharge Lipo Battery ???
« Reply #4 on: November 02, 2020, 04:53:13 PM »

    Thank You for your reply ....I have learned a good way to get some rain ....Fully charge your battery and next morning rain for sure ...
 
    charged battery till volt meter read 58.3 charger was still charging but I stopped it there for worry of overcharging ...next morning it had dropped to 57.4 ...Should I have topped it off ? Thinking it needs a full charge for the battery's to balance ..I can charge a 1 or 2 or 5 amps using 2 amps and 1 amp for the last volt or so ...

Offline Bikemad

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Re: When to recharge Lipo Battery ???
« Reply #5 on: November 02, 2020, 08:12:07 PM »
charged battery till volt meter read 58.3 charger was still charging but I stopped it there for worry of overcharging ...next morning it had dropped to 57.4 ...Should I have topped it off ? Thinking it needs a full charge for the battery's to balance ..I can charge a 1 or 2 or 5 amps using 2 amps and 1 amp for the last volt or so ...

Hi Don,
If you're fully charging the battery in order to balance the cells, you must allow the battery to complete the entire charge cycle.

Your charger should not be able to overcharge the battery as it's output should be accurately regulated to 58.8V.
The battery's BMS should also prevent individual cells from being overcharged if some cells reach their maximum 4.2V/cell before the other cells.

Your charger initially uses constant current mode for the majority of the charge until the battery voltage reaches 58,8V. At this point it should continue to charge at a constant fixed voltage (58.8V) to allow the cells to balance correctly.

During the constant voltage mode (balancing stage) the current will automatically decrease until all cells are at the same ~100% capacity.
The LED will sometimes alternate between Green and Red (might be Yellow or Orange instead of Red on some chargers) during the constant voltage phase until the cells are all evenly balanced and maximum capacity has been achieved.
When the charging current being drawn from the charger drops below a certain amount, the charger's LED should remain constantly on Green to indicate that the charging and balancing has been successfully completed, unless you have a North American charger that actually shuts off the charger's output when maximum battery voltage is initially reached (or your battery has a faulty BMS like mine :().

Alan
 

Offline diverdon

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Re: When to recharge Lipo Battery ???
« Reply #6 on: November 04, 2020, 10:58:53 AM »
Thanks Again Alan ,,, I am sure learning ..so up to 58.8 is ok .. So Apparently I have not fully charged this "New" battery yet ... I got worried when it went over 58 as the chart reads that is fully charged .. Next time I will let it go ...this is a Luna charger if you've heard of them ..It can be set for 80 - 90 - or 100 % charge ...With the chart you gave me I could do the same thing with the voltmeter .. Oh well ..This is really interesting ...Thanks again for the help .... Don J.