Charger with ability to undercharge / change charge speed - UK Based

flippineck

Finding my (electric) wheels
Jan 31, 2024
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0
Hi All

I am looking for a charger with the ability to undercharge. I would like to charge to 80% to prolong the life of the battery.

I would also like to change the charging speed, so for example charge at 2a when I have time, but able to increase to 5a if I need to charge in a hurry.

Does anyone have any recommendations?

I found this charger that looks good, but US model, so I think something like this with a UK plug:


I am using a 48v 17ah batter below:


Thanks,

Matt
 

matthewslack

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Nov 26, 2021
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Grin satiator. Canada, but will travel. Ebikes.ca. Expensive.
 
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saneagle

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Oct 10, 2010
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Hi All

I am looking for a charger with the ability to undercharge. I would like to charge to 80% to prolong the life of the battery.

I would also like to change the charging speed, so for example charge at 2a when I have time, but able to increase to 5a if I need to charge in a hurry.

Does anyone have any recommendations?

I found this charger that looks good, but US model, so I think something like this with a UK plug:


I am using a 48v 17ah batter below:


Thanks,

Matt
Your battery needs to be FULLY charged to operate properly and have a long life. Without fully charging, the balancing system won't work.

You can buy a decent 2A charger for about £15, which will be cheaper than any special adjustable one.

Another solution is to use a 48v motor controller to reduce the charge rate

 
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matthewslack

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Another way is 2A charger and a timer, and learn how long it probably needs depending on led display or voltage.
 
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thelarkbox

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Another way is 2A charger and a timer, and learn how long it probably needs depending on led display or voltage.
+1 you need a basic segment timer voltmeter and alarm on your phone/watch..


forgive the lesson in egg sucking..

you will have been given some charging performance info such as it will take 2,3,4 or X hours to fully charge your battery, We can assume that this will be from a 'fully' discharged state with a 32v level remaining.
So that indicates your battery takes say for example 2 hours to fully charge from 32v to 42v or at a rate of about 5v ph..

Take a voltage reading of your battery pre charging. If for example its discharged to 37v, then you can guestimate it will take about an hour to fully charge to 42v etc..

set the segment timer for 1 hour as a failsafe, or perhaps 45 mins?? and your phone alarm for 35 mins for you to go and check up on the battery.. 2-3 charges and you will have the hang of it and will probably very good at guestimating the time it takes to charge upto what ever level you want from any level of discharge..
 

matthewslack

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I'm spoilt with my calorie counting Shimano batteries! One bar is 25 minutes on a 418Wh battery and 30 minutes on a 504Wh with my 4.6A fast chargers, 2.5 times as long on the standard 1.8A slow charger.
 

flippineck

Finding my (electric) wheels
Jan 31, 2024
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To add a bit more context:

I already have a smart plug that I use to turn on the charger overnight between 00:00 and 05:00am as I am on an electric car tariff where electricity is much less expensive overnight.

If I had a smart charger that can automatically undercharge it would mean I can plug in and forget, whilst also:
  • Always having a reasonable amount of charge
  • Battery not be sat at 100% charge for long periods of time
  • Charge overnight on the low cost tariff
I'm basically looking for the same workflow as my car!
 

thelarkbox

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Aug 23, 2023
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oxon
To add a bit more context:

I already have a smart plug that I use to turn on the charger overnight between 00:00 and 05:00am as I am on an electric car tariff where electricity is much less expensive overnight.

If I had a smart charger that can automatically undercharge it would mean I can plug in and forget, whilst also:
  • Always having a reasonable amount of charge
  • Battery not be sat at 100% charge for long periods of time
  • Charge overnight on the low cost tariff
I'm basically looking for the same workflow as my car!
ever played with an arduino or similar?
if so or willing to dabble there is a well laid out road map using tasmota open source f/w on your smart device,

Add an additional 5v usb powered wemos d1 dev board with voltage reading circuitry (£10 inc usb psu) to read and publish to your smart socket battery voltage levels in real time simply requiring a rule on your socket to turn off at X volts.


You will need a computer/nas or something to host mosquitto mqtt broker to enable inter device coms, its not taxing and i host mine on a £!0 raspberry pi-0-w.. and you only need it running while charging and reading volt levels.


EDIT btw its worth mentioning OMG OpenMqttGateway when talking tasmota too as OMG opens up all sorts of devices with different communication protocols such as IR RF into smart systems use.

Edit #2.. doh! charging needs to be off in order to read the battery voltage, not really an issue just a wee logic change.. computers are pretty flexible when it comes to that ;)
 
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AndyBike

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Az.

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I already have a smart plug that I use to turn on the charger overnight between 00:00 and 05:00am as I am on an electric car tariff where electricity is much less expensive overnight.
I hope you don't use this smart plug at home and don't put your life at risk just to save few pennies.

 
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AntonyC

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Apr 5, 2022
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Easier still is to reduce your 2A charger output to 80% with a couple of diodes, no time estimation needed. They'll need a heatsink and a switch to short them for a full charge, which is preferable because fast charging shortens battery life.

Fast chargers make most sense at cafe stops I reckon. I haven't tried this one but it's quite compact and fairly priced.

A 4A or 5A charger weighs as much as an extra 4Ah of 48V battery but takes an hour to find those Ah. Much of the time a bigger battery makes more sense.
 
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flippineck

Finding my (electric) wheels
Jan 31, 2024
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I hope you don't use this smart plug at home and don't put your life at risk just to save few pennies.

No, my bike is in an external garage, which would be a shame to burn down, but not life threatening
 
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flippineck

Finding my (electric) wheels
Jan 31, 2024
8
0
ever played with an arduino or similar?
if so or willing to dabble there is a well laid out road map using tasmota open source f/w on your smart device,

Add an additional 5v usb powered wemos d1 dev board with voltage reading circuitry (£10 inc usb psu) to read and publish to your smart socket battery voltage levels in real time simply requiring a rule on your socket to turn off at X volts.


You will need a computer/nas or something to host mosquitto mqtt broker to enable inter device coms, its not taxing and i host mine on a £!0 raspberry pi-0-w.. and you only need it running while charging and reading volt levels.


EDIT btw its worth mentioning OMG OpenMqttGateway when talking tasmota too as OMG opens up all sorts of devices with different communication protocols such as IR RF into smart systems use.

Edit #2.. doh! charging needs to be off in order to read the battery voltage, not really an issue just a wee logic change.. computers are pretty flexible when it comes to that ;)
Interesting, in truth this looks too technical for me!
 

flippineck

Finding my (electric) wheels
Jan 31, 2024
8
0
Easier still is to reduce your 2A charger output to 80% with a couple of diodes, no time estimation needed. They'll need a heatsink and a switch to short them for a full charge, which is preferable because fast charging shortens battery life.

Fast chargers make most sense at cafe stops I reckon. I haven't tried this one but it's quite compact and fairly priced.

A 4A or 5A charger weighs as much as an extra 4Ah of 48V battery but takes an hour to find those Ah. Much of the time a bigger battery makes more sense.
Sorry, i don't understand how to do this. In truth I was hoping to find a charger like the Luna cycles one that has the options to change the %age, and charge rate.
 

flippineck

Finding my (electric) wheels
Jan 31, 2024
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Pingk

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Dec 15, 2023
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Your battery needs to be FULLY charged to operate properly and have a long life. Without fully charging, the balancing system won't work.
Most of the wear on a battery happens at the extremities of full/empty. For best battery longevity you want to keep it between 20-80% (or 40-60% for longer storage), and top it up to 100% for BMS balancing every couple of weeks.
It's unlikely that a quality battery would get unbalanced from a few partial charges.

My plan is to save up for a grin statiator so I can have multiple profiles for this reason
 
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guerney

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Sep 7, 2021
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Other than Luna (~ £100) and similarly priced ones on AliExpress, and the excellent Satiator (~ £250), you could ask a favour of this seller:

48v Adjustable (97% 90% 80% and storage charge) (1AMP to 3.9AMP) Fanless waterproof ebike charger.

He's basically giving them away (I'd offer more) and he might do a 320W 5.5A version, see here for second opinions. Very portable too.
Very interesting. Here's a 36V Mean Well HLG-240H-36A.


56216
 
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flippineck

Finding my (electric) wheels
Jan 31, 2024
8
0
Other than Luna (~ £100) and similarly priced ones on AliExpress, and the excellent Satiator (~ £250), you could ask a favour of this seller:

48v Adjustable (97% 90% 80% and storage charge) (1AMP to 3.9AMP) Fanless waterproof ebike charger.

He's basically giving them away (I'd offer more) and he might do a 320W 5.5A version, see here for second opinions. Very portable too.
I have messaged this seller, if he doesn't come back I might do myself, as looks relatively straight forward!