Jump to content

Faster charging


exoplanet
 Share

Recommended Posts

2 hours ago, exoplanet said:

Can i charge my batteries at double speed by connecting two chargers in series before connecting to the wheel?

I am thinking of adding another battery but still only using one socket, but want to maintain charging time.

No. Please do yourself a favor and buy a Charge Doctor. Otherwise you're either going to destroy your wheel or chargers or both :cry2:

  • Like 1
  • Upvote 1
Link to comment
Share on other sites

2 hours ago, exoplanet said:

Can i charge my batteries at double speed by connecting two chargers in series before connecting to the wheel?

I am thinking of adding another battery but still only using one socket, but want to maintain charging time.

Your description (two chargers in series) would double the voltage, not the charge current which you really need. You would probably burn your house down.

As @Marty Backe said, get a Charge Doctor to allow two chargers to be safely combined however you should ensure that even with this you do not charge at a rate above 1C. This is possible on wheels with smaller battery capacities. Doing this is a fire risk and certainly will stress your batteries reducing their lifespan. 0.5C is really the highest I'd want to charge at.

If you don't already have a Charge Doctor and the additional charger then it may just be cheaper to buy a single fast charger.

Edited by WARPed1701D
  • Like 1
  • Upvote 1
Link to comment
Share on other sites

4 hours ago, exoplanet said:

So I connect them in parallell then?

My house is made of concrete and sand and has open air ventilation and a firesafe door to my bedroom as well as gas tight seals.

the gas tight seals would probably leave you air tight with smoke 

just the recipe for suffocation

just get one of the fast chargers instead of doing house burning experiments...

Link to comment
Share on other sites

3 minutes ago, exoplanet said:

yes yes. but what is the difference between a fast and slow charger? the possible amps?

by the way, I sleep on the safe side of  the gas seal in another nonjoining building

a battery has a chemical reaction 

when charging you "charge" the reaction witch releases heat so faster charger more heat too much heat = boom

lithium ion batteries should be kept under 35 celsius 

so if you double it and totally overpower the battery a lot of heat will be made and that can overheat the battery 

then the battery releases all the energy the battery has at once wich is also know as an explosion...

Edited by Shad0z
Link to comment
Share on other sites

Just now, exoplanet said:

indeed. so what are the limits here and what about the new extra battery?

a general rule for lithium ion and lithiom polymer batteries (the kinds used in any kind of electronics)

is about to keep the batteries under 35 degrees celsius or 95 farenheit

if it goes over that just in one little spot in the battery a little too long you will be risking it saying boom

and using two chargers and all of that stuff... yeah youre pretty much asking for an explosion

the battery just needs one spot to get too hot to start a spark and then again... boom

 

Link to comment
Share on other sites

sure. but what is the difference between the fast chargers and the slow ones?

also I i have two batteries, it will take double the time, but with two chargers it will take the same time if i run them into the batteries in parallell.

and if the battery can take double the current, then one can charge one battery about double as fast.

I guess I will have to see the datasheets of the battery packs.

Link to comment
Share on other sites

3 minutes ago, exoplanet said:

sure. but what is the difference between the fast chargers and the slow ones?

also I i have two batteries, it will take double the time, but with two chargers it will take the same time if i run them into the batteries in parallell.

and if the battery can take double the current, then one can charge one battery about double as fast.

I guess I will have to see the datasheets of the battery packs.

i think its the amps

but i wouldnt suggest you do 2 in parralel

are you willing to risk blowing up your wheel and a ffew other things for a little faster charging?

(if it worked we would all be doing it)

Link to comment
Share on other sites

6 hours ago, Shad0z said:

is about to keep the batteries under 35 degrees celsius or 95 farenheit

if it goes over that just in one little spot in the battery a little too long you will be risking it saying boom

I often see battery temperatures far above 50ºC while riding. Also my laptop gets to battery temperatures above 35ºC once in a while. That's bad for duration, but it doesn't seem to blow up the batteries regularly :efee6b18f3:

Newer versions of the charge doctor support to use two chargers in parallel, some support three. The charge current should in general stay below 1C to keep the battery in good shape. 

https://www.ewheels.com/product/chargedoctor-duo-for-v5f-king-song-gotway-inmotion-v8/

http://hobby16.neowp.fr/fr/2016/11/12/chargeur-6a-trots/ 

 

 

Edited by Mono
Link to comment
Share on other sites

I created a y-harness with a volts/amps meter on it. I've been using it every other day or so for a few months now. Works great, exactly doubles the amperage. I can also use it with just one charger and see how many amps are flowing. Cost about $10 in parts, including a step-down converter because the volts/amps meter requires a power supply below 30 volts. Electrically, the chargers are just connected in parallel. The y-portion can be detached and the display is still useful to monitor the charging process even with just one charger.  It's interesting to note that the chargers seem to put out slightly more amps than they're marked for; I get about 2.25 amps from a 1.75 amp charger, and 4.5 amps using two of them, and the kingsong charger marked 2A puts out close to 2.75. I'm pretty sure it's accurate because I calibrated it against two different multimeters. It only reads 3.9A in the picture because it's nearing a full battery.I wouldn't recommend 3 chargers because the wires inside the unicycles coming from the charge port aren't quite thick enough for 6+ amps.

kUEyvf1.jpg

 

Edited by tudordewolf
  • Like 2
  • Upvote 1
Link to comment
Share on other sites

1 hour ago, exoplanet said:

sure. but what is the difference between the fast chargers and the slow ones?

also I i have two batteries, it will take double the time, but with two chargers it will take the same time if i run them into the batteries in parallell.

and if the battery can take double the current, then one can charge one battery about double as fast.

I guess I will have to see the datasheets of the battery packs.

A fast charger will supply more amps than a standard charger. Voltage is unchanged. To double current rather than voltage the chargers must be connected in parallel rather than series (which would double the voltage).  How many amps you need to supply to charge in a set amount of time depends on the size of your battery packs but no charger should charge above 1C charging rate or you are going to have problems. As already mentioned you must also consider the max amp rating of the supporting components such as the charging plug and internal wiring to the cells which may not be able to support high currents for a prolonged time. There are several threads on here where charge port temperature was recorded during charges. 5A was the absolute maximum people felt Gotway components could carry with 4A being a safer option. I imagine other wheels would be the same. 

Just buy a dedicated fast charger or a CD rather than home-brewing a solution and avoid turning your sand house into a glass house. 

  • Like 1
Link to comment
Share on other sites

i think my facts are a little off

i think your laptop can reach over 35 degrees 

i think i was reffereing to "ambient temperture" 

but my point is just buy a charge doctor instead of risking blowing up your house

thats all

Link to comment
Share on other sites

You should also try to find out what cells are being used in your batteries and make sure you are charging within the recommended parameters of the manufacturer specifications. 

For example the Ninebot One E+ has 2 strings of cells in parallel with each string consisting of 15 cells in series.  They are LG 18650 2850mAH cells (15S2P) for its battery.  Each cell has a maximum charge rate of 1C (2.85A per cell or 5.7A for the batteries in parallel).  But this would be considered the 'fast charge' current and you can expect to reduce the life of that battery doing this.  Normal charge is listed at 0.5C (1.425A per cell or 2.85A for the batteries in parallel).

Battery Specs

The Ninebot One P has bigger batteries but they are in the same 15S2P (15 in series 2 in parallel) configuration.  Standard charge for the pack would be just slightly higher at 3A (2 x 1.5A per cell) but fast charge can be much higher at 8A (2 x 4.0A per cell).  

GmRV2U8.png

If you don't exceed manufacturer specs, you won't overheat your batteries (unless you have a damaged cell).  If you do a fast charge you can feel the wires in the EUC between the charge plug and BMS.  If they are hot, too much current.  If they are just slightly warm or cool to the touch, you are OK with the charge current. 

Also note that the max temperature is specified by the manufacturer as well.  For the cells above, they can get up to 50°C or 122°F during charging.

Edited by Cranium
  • Like 3
Link to comment
Share on other sites

If one has various wheels with battery sizes ranging from 840 wh to 1600 wh, which wheel should get the fast charger? The small(er) ones or the larg(er) ones? Given that the fast charger would be incompatible between wheel brands. 

Link to comment
Share on other sites

1 minute ago, LanghamP said:

If one has various wheels with battery sizes ranging from 840 wh to 1600 wh, which wheel should get the fast charger? The small(er) ones or the larg(er) ones? Given that the fast charger would be incompatible between wheel brands. 

thats why i just use a normal charger overnight with a 24 hour plug so i can set it to how many hours i want

Link to comment
Share on other sites

2 minutes ago, LanghamP said:

If one has various wheels with battery sizes ranging from 840 wh to 1600 wh, which wheel should get the fast charger? The small(er) ones or the larg(er) ones? Given that the fast charger would be incompatible between wheel brands. 

eWheels fast charger has adjustable power (amp) output to allow correct charge rate of many different battery sizes. Not much can be done about wheels of different voltage though. But then again buying a second standard charger won't help with voltage differences either. 

  • Like 1
Link to comment
Share on other sites

6 minutes ago, Shad0z said:

thats why i just use a normal charger overnight with a 24 hour plug so i can set it to how many hours i want

I do the same thing, and that works very well.

However, what I was thinking was more specific: you have two wheels to choose from (KS16s or a Gotway MSuper 1600), and you would charge sometime during your trip. Which fast charger do you buy and why?

I can argue myself one either way; of course the 1600 on long trips, but the KS16s is far more flexible for anything shorter and is more likely to run out anyway.

Link to comment
Share on other sites

The chargers output is 120w and 61V, 1.9A

I guess the voltage gets transformed down to 4.2 By the board.

I now have an extra battery. I am plannning to connect them in series.

The overcurrent alarm, would it still go crazy and shut the device off even if the battery(ies) can provide more current?

Link to comment
Share on other sites

2 minutes ago, exoplanet said:

The chargers output is 120w and 61V, 1.9A

I guess the voltage gets transformed down to 4.2 By the board.

I now have an extra battery. I am plannning to connect them in series.

The overcurrent alarm, would it still go crazy and shut the device off even if the battery(ies) can provide more current?

I would make the friendly Advice that you get some REAL good knowledge about battery/electrics before you start tinkering on your wheel. „connect them in series“??? Really...i would say parallel is the better idea.

The charger should provide 63 Volt (4,2 x 15)...And Nope, its not transformed down to 4,2V.

15 cells in series are 63 Volt, so they need that high voltage when charging.

To the overcurrent alarm...to be honest, i dont know the board of an 9b exactly, but i would guess, thats more of an alarm that goes off if the battery sag that much, that they come into the empty range. So Nope, that would not go that fast to trigger it, IF you have connected all correctly.

What kind of second battery you have? you can not connect those batterys if they are a different cell type! Also it is extremly important that both packs are on the same voltage before connecting!!!!

Otherwise you have good changes to blow them both up!

Dont get me wrong....from your comments here the probability of a massive failure is very high!

  • Like 1
  • Upvote 1
Link to comment
Share on other sites

I think you should stop whatever you are trying to do? With respect it seems you know just enough to be dangerous.

No voltage is transformed to 4.2V. The cell bank is 63V (15 * 4.2v cells connected in series probably based on the charger voltage). It operates as a single 63V pack.

I don't know where you intend to connect the battery (a pack of cells I assume) in series but you will double the output voltage on discharge (bang goes the wheel) or only be supplying half the required voltage necessary if using a 61V charger (the cells would only get 2.1V each, this is undercharged and results in unstable cell chemistry and BMS shutdown). Either way you will break something with potentially catastrophic results.

Stop. Do some reading. Take some courses. Then try again. Parallel. Not series!

  • Like 2
Link to comment
Share on other sites

I am thinking I will connect positive with positive wire and negative with negative wire from the two battery packs. I will make sure to not short the wires. I will solder them together  and have one output like there is now, going into the board. So fully charged or fully empty? I am looking for a range extender in this instance. I think I will get an ebike for higher speeds.

Link to comment
Share on other sites

15 minutes ago, exoplanet said:

Yes. And you are a cautious german:) It is another ninebot battery pack. Should I discharge the packs completely before connecting them, or should I fully charge both of them?

Thank you for the information.

By the way. do you think the sticker on the charger is lying? that is actually provides 63V?

Also, Why could one potentially not just make a 63V battery pack from double A batteries and hook that one up?

The cautious german would say fully charging  them :-)

Nope, the sticker is surely not lying. In the states or god knows where else.....for whatever reason ...9b seams to provide only chargers which charge the wheel only to 90%! They are doing the same with the S2! 63 volt in europe, 60/61 in the usa...so no real full charge!

For the last question:

Because they are not capable of the needed amp rates. if you connect cells/packs of different amp types together, they are not drawn equally, etc etc etc.....failure, blow up, whatsoever will follow!

So, now the cautious german is out :-)

Edited by KingSong69
  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...