Minimal wiring 12S Lipo setup with balance leads

[kfong]

Here is my setup for a 12S 2P 10ahr pack

Having switched over to Lipos, I needed a safe way to charge them. The only solution I felt comfortable with was to use a quality RC charger. The Hyperion was the one I felt was best designed. I then made a DB25 board to use as the balance plug. Here is the board attached to 4 6S 5000mA Turnigy packs. This setup is a 12S 2P configuration giving you 10ahrs at 48volts. The balance wires are just long enough to plug into the DB25 board. You need a second one at the recieving end of the charger.


As you can see the board is attached to the end of the pack. The balance wires are just long enough to fit. There is enough room for my smart switch which would make this pack completely stand alone. Allowing me to let others use the pack without worry.


The bag used is a Topeak RX. It uses an integrated sliding mechanism for easy removal.
View attachment 2

I padded the pack to protect the lipos


I balance charge during every charge, this setup makes it easy to do.


I could of shortened the wires going from the charger to the DB25 board but the wire pattern is not 1:1. You would need to wire it, instead I just used short balancing cables. I used ribbon cable for the connection between DB25 boards. This allows for hardly any wiring.

I still have boards available for anyone wishing to go this route. Bare boards $10 each. Built $25.
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=12654&start=135

 

[whereswally606]

Very tidy, i like it allot.

I would be interested in those boards however i am going to give it ago myself first. Ive got an 18s2p pack which potentially i might go to 21s2p or even 24s2p. but I am dealing with a hua tong 72v controller so I will start off with 18s.

Go lots of 3s jst connectors which can be soldered direct to veroboard (stripboard) so great for paralleling packs. (my packs are all 3s.

going to build up in 9s blocks cause then the pack can be halved paralleled and charged at 9s4p on my hyperion. Anyway just thought id share and say congrats thats a tidy setup you have made. will post some pics of mine when i get it finished.

 

[sflorlando]

very nice. Can you show some more pics of what you are offering? Specifically the boards.

thanks

Ken

 

[neptronix]

that's super nice.

I opted to go this way, but a bit more crude.

Permanent parallel and series of 5S 5AH packs.. to make 10S 10AH.
The parallel happens even at the balance leads.

Some kits to do this would be nice. It was definitely a bit of soldering.

 

[dogman dan]

Very nicely done indeed!

With a bit more experience, you'll learn to chuck any pack that needs balancing much, and stop fretting about being .01 out of balance. Then you will only need to break out the ribbon cable once a month at most.

Just so noobs understand this clearly, your setup is not paralelling the entire pack to 6s, while the main wires are connected 12s. It's just paralelling each pair of 6s packs, then getting charged with a charger that can charge both 6s packs at once.

It's a subtle difference to understand at first, but you grok it much quicker when you make the mistake and see the huge spark.

 

[cwah]

I'm interested in these board. I have 4 lipo 5S8AH. That would be really handy for bulk charge/balance.

How configurable are these board?

 

[kfong]

I only designed for a max of 21S since that would be the most I could do with the limited pin count. The wiring would be too custom due to the orientation of the packs. You would most likely use pigtails such as these from EPbuddy and solder them to the board db25 board.

Very tidy, i like it allot.

I would be interested in those boards however i am going to give it ago myself first. Ive got an 18s2p pack which potentially i might go to 21s2p or even 24s2p. but I am dealing with a hua tong 72v controller so I will start off with 18s.

Go lots of 3s jst connectors which can be soldered direct to veroboard (stripboard) so great for paralleling packs. (my packs are all 3s.

going to build up in 9s blocks cause then the pack can be halved paralleled and charged at 9s4p on my hyperion. Anyway just thought id share and say congrats thats a tidy setup you have made. will post some pics of mine when i get it finished.

 

[kfong]

The 12S board is $25, the bare boards are $10


You will also need a board for the hyperion charger $20

very nice. Can you show some more pics of what you are offering? Specifically the boards.

thanks

Ken

 

[kfong]

These boards can be configured for a total of 10S as well. You just use the appropriate 5S headers. Any packs from 4S to 6S will work. 7S packs will require use of pigtails since the spacing is too close for the JST connectors. You just need to align them off to the very left as shown here next to the Hyperion balance board. You can see how they have the connectors lined up on the left side.

that's super nice.

I opted to go this way, but a bit more crude.

Permanent parallel and series of 5S 5AH packs.. to make 10S 10AH.
The parallel happens even at the balance leads.

Some kits to do this would be nice. It was definitely a bit of soldering.

 

[kfong]

That would be a 10S 2P pack you are doing. You just use 5S headers for the setup instead of the 6S header shown.

I'm interested in these board. I have 4 lipo 5S8AH. That would be really handy for bulk charge/balance.

How configurable are these board?

 

[kfong]

Yep the packs are all paralleled as one big battery that you balance charge. The Hyperion can do up to 14S. You need 2 Hyperions if you want to go to 28S but I'm limited with pin count of the DB25 connector. I don't recommend bulk charging lipos. Too much of a fire risk. Best to use a good RC charger and balance charge. The charger will detect shorted cells and operator mistakes such as wrong settings. Most Lipo fires happen during the charge process. Best to all safety precautions when possible. The charge process isn't any longer if the packs are healthy. It also maintains the health of the pack and warns you if you have battery issues. I don't find a need for a BMS if you balance charge each time and use a reliable low voltage cutoff such as my smart switch. The nice thing about this is there is no longer any concern about connection errors, the big spark and KFF fingers. Simple plug and charge.

Very nicely done indeed!

With a bit more experience, you'll learn to chuck any pack that needs balancing much, and stop fretting about being .01 out of balance. Then you will only need to break out the ribbon cable once a month at most.

Just so noobs understand this clearly, your setup is not paralelling the entire pack to 6s, while the main wires are connected 12s. It's just paralelling each pair of 6s packs, then getting charged with a charger that can charge both 6s packs at once.

It's a subtle difference to understand at first, but you grok it much quicker when you make the mistake and see the huge spark.

 

[cwah]

Why bulk charging lipo increases the risk of fire? I was planning to bulk charge all my lipo :lol:

 

[dogman dan]

Well, when you say "bulk charging" it could mean many different types of setup. Some I consider a bit risky, others I consider a lot safer.

Safe bulk charging is going to slow down at the end of the charge and have a reliable cutoff at the top. Like using the hyperion on the non balancing charge setting. Or using hvc lvc boards combined with a lithium charger set to your pack voltage as the power source. You get that taper down of the amps as the charge terminates that makes it safer.

But if you just hook up a power supply that lets er rip at 10 amps right up to the end of your charge, I'd call that a bit of a risk.

It's kind of like if you drove a car up to the edge of a cliff. You could do 60 mph till your were 1/8 mile away and slam on the brakes, or you could slow down to 20 mph for the last 1/4 mile, and ease up to the edge. One way could go wrong a lot easier.

 

[cwah]

I actually have both:
- I have an hyperion I use only for balance charging
- And I order charger from BMSBattery for bulk charging. There is still a maximum voltage setting. Of course, some cell may charge faster than other and that could lead to problem

 

[kfong]

The main problem with bulk charging is when a cell goes bad and shorts out. You are now overcharging the rest of the packs and now have a possible fire hazard. This happened with my Konion pack that were only bulk charged. Bulk chargers have no way of testing the packs for bad cells and will happily charge a bad pack. Even Hyperion does not recommend bulk charging if balance charging is available.

I only balance charge when possible. This uses the saftey features built into RC chargers. Bulk charging lipos in the RC world is really not considered safe to do. The last thing I want to happen is a fire from a large brick of lipos. The smoke and fire damage will be extensive, even if I was around to put it out. I've seen the damages lipos can cause.

 

[recumbent]

...snip... I ordered a charger from BMSBattery for bulk charging. There is still a maximum voltage setting. Of course, some cell may charge faster than other and that could lead to problem

I also bulk charge with a BMSBattery lipo charger, but check my cells with a "Celllog" weekly to keep tabs on any faultering cells. Second summer of daily rides and never had to balance yet.

Most of us have a "Cycle Analyst" that would warn of a failure anyways. Look down, all-of-a-sudden, 4 volts lower reading is fair warning. You get used to the same number of volts and would notice a big drop like that.

However i'm still thinking of buying Methods HVC/LVC type boards.

 

[kfong]

A Cycle Analyst does not do cell level checking just LVC. I lost my Konions last fall due to a loose spot weld. The voltages given by my CA did not clue me onto the problem. The loss of capacity was gradual as well. These pack were only bulk charged. Had they been balance charged it would of protected the pack from further damage and warned me of the problem. Most lipo fires happen during the charge process and it is the only time I get concerned. I'm nearby, but not there watching it charge. The rest of the time it's in storage or I'm using the bike. I think the safest method is to just use an RC charger with balance taps. It gives you full cell monitoring and will warn you of any bad banks.