20S balanced Lipo charger 1.5A

hjns

hjns

100 kW
Joined
Aug 20, 2011
Messages
1,284
Location
Basel, Switzerland
Hi all,

I am looking into an easy solution that will give me a perfectly balanced 20S lipo pack. Charging may take 8 hours, so a conservatively discharged (80%) 13Ah pack should be almost or completely recharged at 1.5A charge current.

$(KGrHqF,!qsFCyOZfKsuBQ87)Vq0Gg~~60_12.JPG




This is my intention:
  • I buy 30 pieces of these "intelligent Smart Chargers" for $180.
  • I will put 20 of them in series and connect them with a DB-25 connector to my balancing wires for easy plug and play. I think another ES member already did this (which is where I got the idea), but I can't find that post anymore.
    serial_sm.gif
  • Drive, come home, turn off controller, plugin DB-25 connector, turn on master switch for all 20 chargers, wait for 20 green lights, disconnect and drive again.

Anyone see any issues?

Please, do not start flaming Lipos in your responses, because I really will continue using my Lipos one way or another.
 
Sounds like a cross between Oatnet voltpheaks lifepo4 setup and sacman's 25 pin setup. Man you come a long way fast you must have a rich uncle or your bikes keep you poor.
 
999zip999 said:
Sounds like a cross between Oatnet voltpheaks lifepo4 setup and sacman's 25 pin setup. Man you come a long way fast you must have a rich uncle or your bikes keep you poor.
Click to expand...

Thanks.

I live in Switzerland and work in Pharma. I am not poor... 8) although I only have one bike.
 
Nothing about a DB25 balance harness/connector fostering reliability. I don't see the point in all this? What's wrong with serial bulk charging and just monitor cells for balance and/or identify those going bad?

In addition to 20 different active devices to fail - there's nothing in this system that would actually balance cells to each other. What if a cell starts losing capacity? It's merely gonna appear to be fully charged when your single charger goes green LED. Trouble is, the cell could be very unbalanced with the others in the series string and run a very real risk of overdischarging. All while you "think" eveything's fine in Denmark....

My suggestion would be serial bulk charge and invest in a couple CellLog 8S to log cells while I ride. That information will give you plenty advance warning of cell degradation and let you know when it's time to use one of these chargers or similar to bring up low cell every once in a while.
 
Hi Ykick,

Thanks for the feedback. To address some of your points:

There is nothing wrong with serial bulk charging other than that I feel less comfortable bulk charging at high currents. I have Methods' LVC/HVC system to increase my comfort here. However, it is not a "plug-and-play-everyday" solution for ensuring all cells are at 4.2V.

I take your point of having 20 different active devices that may each fail. I had not thought of that.

I also agree that there is no actual balancing in this solution. However, after all chargers are green, I just assumed all cells would be at 4.2V, resulting in a well balanced string.

I have some CellLogs (5S) to watch voltage, but not the capability to log while riding. I like the logging part, because I don't usually look at the individual cell voltage while driving. I only look at total voltage.

As you can see, you have made me thinking, so thanks for that!
 
I would avoid 4.2V for several reasons the least of which buying room for errors. My max is 4.15V and I'm happy as long as cells are between 4.1-4.15V/cell. Maybe 200-300mAh left on the table, not enough to worry about IMO.

Definitely grab the 8S CellLog and use Logview software to graph cells during rides. Such useful information. A truly smart BMS would compare this information over calendar time to help identify cells that are degrading faster than others in the pack.

It's really important to catch cells dying off. If you do that, you can greatly extend the life of the entire pack. And help avoid fireballs....
 
You forget hjns has a race bike and at this point he likes every pop he can get out of it. And I do belive in 4.15v. Mvly has a dual 1010 charger set up I don't of a thread. But my be one.
 
999zip999 said:
You forget hjns has a race bike and at this point he likes every pop he can get out of it. And I do belive in 4.15v. Mvly has a dual 1010 charger set up I don't of a thread. But my be one.
Click to expand...

Fair enough, but if that's the case why not 4.35V/cell? LOL...
 
hjns you might have one bike but three motors and two contolers or more ? Yes plus 4.2v would cost more in batteries in the long run, for just a short pop. I guess we are still looking for 5v. cell.
 
I bought a few of the 18650 Lion cell chargers on ebay to try them out. The exactly the same thing as you posted but still single cell chargers for Lion cells. Out of the ones I got, some would peak at way more than 4.2V. More like 4.25, 4.35 and even 4.4. They are not the most accurate way of charging Lion cells from what I saw trying the ones I got. Just letting you know.
 
999zip999 said:
hjns you might have one bike but three motors and two contolers or more ? Yes plus 4.2v would cost more in batteries in the long run, for just a short pop. I guess we are still looking for 5v. cell.
Click to expand...

Actually, it is now more like 7 controllers (including a new MethTek Monster 24FET 4110 and a new Zombie Monster 24FET 4115) and a two new bikes to be electrified; another commuter (backup) and a FS MTB based on a Kona Stinky frame.

The backup commuter will start throttle-less with a rear non-sensored Clyte HT3525, driven with a Thun torque sensor connected to a CAv3 and a 6FET unsensored Lyen controller. Intention is that this will be a low profile intermediate power (15S Lipo 10Ah) backup commuter, for in case my Master bike breaks down. If it works, I will add a front 9C 2810 with a similar but sensored 6FET Lyen mini-monster. All Lipos and both controllers will be hidden in a nice pannier bag. Of course, there is no way the hubmotors can be hidden, but low profile it is.

The Kona will be equipped with a CA and my GNG brushless system at 15S 10Ah Lipo. I want a lighter DH bike for real MTB fun. My current Cromotor MTB is too heavy.

And no, I will keep at 4.2V cell level for all my lipo at this moment.
 
mistercrash said:
I bought a few of the 18650 Lion cell chargers on ebay to try them out. The exactly the same thing as you posted but still single cell chargers for Lion cells. Out of the ones I got, some would peak at way more than 4.2V. More like 4.25, 4.35 and even 4.4. They are not the most accurate way of charging Lion cells from what I saw trying the ones I got. Just letting you know.
Click to expand...

Thanks for the warning. Point well taken and I will check the variability of each individual charger if I continue with this.
 
hnjs " although I only have one bike ".Yes I was filling bad as if you only had one bike. I think you better check under you bed because I now you had at lease one maybe under your ? I think of your toys many times.
 
Don't feel bad.

I did check under my bed. And whoops, there are two more MTBs. However, we will be using them for pedal-only exercise.

It is amazing how light a non-E-bike really is. I had forgotten about that, and I really enjoy biking with my son or daughter with just our muscles getting our asses up the hill. Wonderful!

Anyway, the only difference between men and boys is the price of their toys....
 
20 reliable and accurate single cell chargers makes a ton of sense. Expecting accurate charging out of those might not make sense.

A pair of decent 10s or 12s RC chargers to quickly bring them to 4.1v in one or two 10s bundles would work for most of the time. Charge higher for actual races of course. This is part of why I had two packs at the track. The one for the main event was charged to 4.2v, and carefully balanced on race day. The second pack did practice and heats with quick bulk charges.
 
Thanks Dogman. The "reliable" may indeed be questionable when getting these from Asia... Anyway, I will test each single one first with some 1S lipos that I have lying around, and the first charges may have to be in combination with some CellLogs to measure accuracy and variability over time. I am not in a hurry.

9zip9, I currently use an Amperor PSU with one 1010B iCharger. I have my 20S pack already divided into a 2x 10S configuration, so that it is a matter of removing the series-plug and connecting the two 10S packs in parallel for charging with the iCharger. For bulk charging, the actions are as follows:

  1. Shutdown controller
  2. Remove series plug
  3. Add parallel plug
  4. Turn on charger
  5. Push charge button for 2 seconds to start charging procedure
  6. Push charge button again to confirm charge and start actual charging
  7. After charging turn off charger
  8. Remove parallel plug
  9. Add series plug
  10. Turn on controller
  11. Drive

I want to change this to:
  1. Shutdown controller
  2. Connect charge plug
  3. Turn on charger and charge
  4. After charging turn off charger
  5. Remove charge plug
  6. Turn on controller
  7. Drive

See the difference? I do this twice a day, because I charge after every commute. Therefore, reducing the total number of actions makes a real difference for me.
 
My main concern would be, the output needs to be isolated from the input but for safety reasons I would assume this tool be the case. But I think it's an easy way to build a pack charger, hats off to you dear Sir :D about accuracy, probably there's a resister in there somewhere that determines the end of charge voltage, with a bit of luck you can tune it for the desired voltage.
 
hjns said:
Hi all,

I am looking into an easy solution that will give me a perfectly balanced 20S lipo pack. Charging may take 8 hours, so a conservatively discharged (80%) 13Ah pack should be almost or completely recharged at 1.5A charge current.

$(KGrHqF,!qsFCyOZfKsuBQ87)Vq0Gg~~60_12.JPG




This is my intention:
  • I buy 30 pieces of these "intelligent Smart Chargers" for $180.
  • I will put 20 of them in series and connect them with a DB-25 connector to my balancing wires for easy plug and play. I think another ES member already did this (which is where I got the idea), but I can't find that post anymore.
    serial_sm.gif
  • Drive, come home, turn off controller, plugin DB-25 connector, turn on master switch for all 20 chargers, wait for 20 green lights, disconnect and drive again.

Anyone see any issues?

Please, do not start flaming Lipos in your responses, because I really will continue using my Lipos one way or another.
Click to expand...

Some of those cheap little chargers are of poor design and get hot.

I don't like chargers that get hot and if you put 20 of them right next to each other they could get real hot ?

I remember Jeremy had to take them out of the plastic cases and put a fan on his setup like that ?

I would buy just one and test it and if it is one that runs hot I would look for a different one.
 
just found this thread

http://endless-sphere.com/forums/viewtopic.php?f=6&t=147&start=25
 
This is just unwise... Why are you trying to invent something that is worse than you can get something that is much better?
My charging goes like this:
1. drive to a 220V socket
2. plug it in
3. plug it off
4. drive away in 4 hours.
Get a proper charger and BMS. Get a contactor.
 
please don't try and save money now. But save money now and do better my friend. Yes my little voltpheaks are a little different in voltage but i use them in a different way. Plu s you are telling the truth as your neibour told me there are two more bikes and a spare motor thing out back. Plus some more batteries stuff. I got to call him up again. because it looks like a bike factory from my google photo's. i must send more intell over that swiss place as with all my uncle's money in swiss account's. but if it's buying Ebikes i'm all for it.
 
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