Splitting a 13S balance plug ?

[aaronlim]

Is it possible to split a 13S balance plug into a 7s and 6s JST-XH balance plugs? I want to use 2 HK celllogs to monitor the cell voltages. I plan to get the 7s and 6s balance plugs from ebay.

The 13S balance plug comes from my BMSbattery limnco 48v15ah with the faulty BMS removed so instead of checking with a multimeter everytime, I can simply use the 2 celllogs. I'm quite surprised at how well this battery retains its balance although I am very careful not to go below 3.6v.

If its possible, what should I look out for when connecting the balance plugs? And and ideas how should I balance them cheaply if they go unbalance?

 

[dogman dan]

Yes it's possible. Starting with the negative, which may be the big negative wire on the bms depending on it's design, wire the negative to the bottom wire on the female plug, when you have the plug facing you so the plastic bumps are up. The down side is the side with the contacts showing.

Then it's cell one + next pin up and so on. The wire on the 7th cell, pin 8 on the top, is also attached to the - of the next plugs cell 8. So that wire gets attached to the + of cell 7 on the first plug, and the - of the next plug. Complete the 6s plug the same way and you now have your pack wired for monitoring as a 7s pack and a 6s pack.

Now if you add some large wires to cells 7 and 8 you could use a lipo charger to charge and balance each half one at a time. Charge half as 7s, then reconnect the charger and do the 6s half.

Another option, would be to bulk charge with your existing 13s charger. Then when it finshes you could use the balance port pins to attach a single cell charger to bring up any low cells at a less than 2 amps charge rate. An RC charger is ideal for this.

In fact, you don't have to rewire the packs balance plugs to do that. But it is real nice to have the plugs so you can just put a cellog 8 on the plug to check multiple cells at one time quick and easy.

With no bms, you will of course have to do very carefull manual monitoring of the pack to prevent overdischarge.

 

[aaronlim]

Then it's cell one + next pin up and so on. The wire on the 7th cell, pin 8 on the top, is also attached to the - of the next plugs cell 8. So that wire gets attached to the + of cell 7 on the first plug, and the - of the next plug. Complete the 6s plug the same way and you now have your pack wired for monitoring as a 7s pack and a 6s pack.

Sorry I don't quite understand. There are 14 black balance wires coming out from this 13s battery as shown in the crude picture above (The white tape is just to hold the loose wire in place). However I also notice that 7s balance plugs have 8 wires and 6s balance plugs have 7 wires, making a total of 15 wires. I'm missing one wire, do I have to share it? Currently I just use a multimeter to go one by one to check all are balanced. Is the above correct?

If any cell goes out of balance I plan to use a cellphone charger which outputs 4.2v 350ma with crocodile cables to top them off. Any idea how long I will have to hold them for with a 350ma current on a 48V15AH battery if say there is a 0.05v difference?

My Shopping list is:
1. 7S JST-XH - http://www.ebay.com/itm/7S-JST-XH-Connector-balance-wire-Cable-CellLog-8-PIN-/150570254994?pt=Radio_Control_Parts_Accessories&hash=item230eafc292
2. 6S JST-XH - http://www.ebay.com/itm/6S-JST-XH-Adapters-for-6-Cell-Pack-7-PIN-silicone-wire-/140442872362?pt=Radio_Control_Parts_Accessories&hash=item20b30c2a2a
3. HK Celllog 8s - http://www.hobbyking.com/hobbyking/store/__10952__Cell_Log_8M_Cell_Voltage_Monitor_2_8S_Lipo.html

Am I missing anything? Should I get more while i'm at hobbyking? How about a Battery Medic to balance them?

 

[t3sla]

These things are your friends
http://cdn.shopify.com/s/files/1/0062/6682/products/0J1038.2000__64179_1024x1024.jpeg?113639

I use them when I'm checking 10/12s packs with single conectors and a batmedic/cell-log/etc.

You still need exetention cables, female to female

 

[aaronlim]

These things are your friends
http://cdn.shopify.com/s/files/1/0062/6682/products/0J1038.2000__64179_1024x1024.jpeg?113639

I use them when I'm checking 10/12s packs with single conectors and a batmedic/cell-log/etc.

You still need exetention cables, female to female

where can i find those things?

 

[aaronlim]

I noticed Battery Medic only does 6s, so I'm thinking if I could do 5s - 5s - 3s so that I can use the battery medic? But the wirings are confusing me.

 

[dogman dan]

I'm not real good with making computer diagrams. But you have it real close. Starting with the negative wire you have the 6s plug correct. The 7s plug would continue that wiring arrangement, but with the same side facing up.

The only thing I see wrong with your sketch is that the 7s plug should be flipped to face the same way as the 6s plug before you connect the wires.

The 14 wires is right, one - and 13 + Sometimes the bms wires different, but yours has the - on the plug. A ping v2.5 bms will have the - on the main pack - wire. So you would use that 14th wire.

 

[t3sla]

These things are your friends
http://cdn.shopify.com/s/files/1/0062/6682/products/0J1038.2000__64179_1024x1024.jpeg?113639

I use them when I'm checking 10/12s packs with single conectors and a batmedic/cell-log/etc.

You still need exetention cables, female to female

where can i find those things?

where abouts are you located?

http://www.pololu.com/catalog/product/1065

these guys are international, and you can just use the keywords they have to find something closer to home.
I'll take a pic of how I configured mine when I'm at work.

 

[aaronlim]

These things are your friends
http://cdn.shopify.com/s/files/1/0062/6682/products/0J1038.2000__64179_1024x1024.jpeg?113639

I use them when I'm checking 10/12s packs with single conectors and a batmedic/cell-log/etc.

You still need exetention cables, female to female

where can i find those things?

where abouts are you located?

http://www.pololu.com/catalog/product/1065

these guys are international, and you can just use the keywords they have to find something closer to home.
I'll take a pic of how I configured mine when I'm at work.

I'm located in Singapore. So for my case I will get the straight double sided? I can't really picture how this can work for my case without adapters. This essentially simply extends the pins / converts female to male? I would like to see your pic. And where can I get female to female JST-XHs ?

 

[t3sla]

https://www.dropbox.com/s/ej79b38fdbvbrly/2012-10-02%2017.27.14.mp4

 

[aaronlim]

https://www.dropbox.com/s/ej79b38fdbvbrly/2012-10-02%2017.27.14.mp4

That looks exactly like what I need without having the rewire the 13s balance lead. But the plug with the pins look like you made yourself? How would i go about doing this? I have ordered several extention JST-XH 6s do I have to modify them? Or do I just chunk the pins in and mask?

 

[dogman dan]

A cellog 8 could be used in a similar way. Plug in one way, and you can read cells 1-8. Plug in the other way, and read 5-13

You could also make a mcguyvered male plug that would plug right into the 13s plug. bare male prongs could be plugged into the female, then hot glue or tape or whatever could be used to hold the male prongs in place. that 13s male plug, would then lead to your two smaller plugs. one wire shared as we discussed earlier.

 

[t3sla]

you chuck the pins i linked into the female end of a JST plug and slop some hot blue around them, it fits with standard pin spacing.

battery medic / cell-log / random crap all have male ends

So you can get a JST female-female, no idea where mine came from.
Might have come with a charger, the kinda plug that splits from a charger to a parallel board, anyone have any ideas?

It's a great way to diag prebuilt BMS batteries without disassembly.

 

[aaronlim]

have been trying to look for female to female JST cable but there is no such thing on sale. I don't think i will want to split the 13s into plugs anymore after looking at the video.

Will I be able to chop of the border sides of the JST-XH 6s male plug making it like bare male prongs? Or perhaps its easier to solder the bare wires to the bare pins and then glue them - essentially making my own jst-xh male plug?

 

[aaronlim]

been reading up on parallel the balance leads...Will it be possible to parallel combine the 13s balance plug into one 6s plug?

 

[dogman dan]

Only if you like sparks. You'd be paralelling cells while they were still series connected.

You can pull male just prongs out of the housings easily. So you could make your own 13s male jst plug with the bare prongs and some epoxy. Plug em in to the plug, then apply the glue. Use a release like some chap stick on the female side so it's not permanently glued to the female.

Once you have your 13s plug, you can add whatever you fancy on the other end of the wires.

 

[t3sla]

you should be able to make two 6s plugs for series chargings or use a balance charger like this
http://endless-sphere.com/forums/viewtopic.php?f=31&t=41107&start=45

if anyone has modded a 12s/13s/10s pre built pack and added hobby JST ends without splitting the pack, please show me a thread or post some info

 

[dogman dan]

If you are just monitoring, you don't have to split the pack, just splice in jst plugs to the balance wires.

I keep procrastinating on writing up my addition of two 8s jst plugs to my 48v pingbattery for another website. Now I can monitor my ping at cell level with cellog 8's. Pretty simple procedure really. On the v2.5 bms your first wire is the big main - on the bms. then each bms plug wire is a + for one cell. At the middle, the last wire on the first 8s plug is also the first wire on the next one. So that wire to cell 8 has to get two wires spliced on instead of one.

Step one is to identify your wires to the bms, then label each wire by cell number. Then you start cutting wires, and splicing in another wire for each wire on your jst plugs.