Lipo connectors for paralell then series , dogman style.

dogman dan

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Here is what I'm trying for paralelling two 5 ah lipo bricks, before series connecting into 20s setup. This isn't a permanent pairing of the bricks, so I haven't bothered with paralell connecting the balance wires yet. I still plan to do any balance charging one brick at a time.

I found it hard to put 45 amp andersons on the fat 8 guage wires on my 30c turnigy batteries so I went to a crimp sleeve you can get at a home warehouse store, and a short piece of 12 guage wire. I also added a couple wires to lead to my LV beepers. So this time on the next four batteries, I have put two sets of 12 guage wires, with andersons. One long one and one short one will hopefully keep me from having as many KFF adventures as I hook em up.

This is the finished set up.

View attachment CIMG0091.JPG

I'm thinking that I'll redo the battery on the right, removing the added wires for the beeper and adding another set of 12 guage wire and andersons. Then when I pair up two lipo bricks, I still have a set of andersons I can use to connect the beeper. I'm not using the balance wires because I am finding the plugs unreliable when just two prongs are used on the plug to the beeper. no beep can mean everythings ok, or everythings unplugged. So I don't use the balance wires to hook up the beeper.

Here's how I did it. You need crimp sleeves, shrink tube, wire and andersons.View attachment parts list.JPG

Then you cut off the bullet plug, and strip the wire. Then put some shrink tube on the wire. I did this because I premade the andersons, so I wouldn't have to work on the energized wire once it's put on the battery. One wire at a time, don't even consider two bare wires on the table at once. :mrgreen:View attachment Cut and strip.JPG

Assemble crimp tube and the two new wires.View attachment ready to crimp.JPG

The first crimp uses the part of the tool with the bump. Crimp the sleeve into a V shape.View attachment first crimp.JPG
 
Here's the first crimp, making the sleeve into a V shape.View attachment 2

After the second crimp, which uses the rounder part of the tool to close the V shape. Crimp hard, and try like hell to pull it apart when done. If good you can't pull it apart. View attachment After second crimp.JPG

Then it's just a matter of shrinking on the tube to cover the bare crimp tube. I used a piece of 3/8, the added another layer of 1/2 tube which easily slips over the anderson connectors later

Here is a pic of the finished lipo brick. View attachment finsihed pack.JPG

The finished set up allows the bricks to be used several ways with no big problems. I don't need a seperate harness to paralell as many as I want, so long as I don't need more amps than the wire size I chose can handle. 45 amps will do for me at this time. If I want more, I am all set to hook up two sets of wires to both anderson connectors, and have up to 90 amps of current avaliable. But for now, at 45 amps, this should work ok, and allow me to have lots of flexibility how I use my lipo bricks.

I expect I'll eventually paralell the balance leads too. I'm not using the lipo daily so for now I don't mind breaking up the pack to charge. But I do have to be cautious when putting it back together. :roll:
 
Good job Dogman, I thought about doing the same thing on my packs to eliminate my jumper harnesses. I am using the 4mm bullets on everything now - they're a bitch to solder. Your crimps look good, hope they don't loosen up. Good Luck
 
Ahh..

How i did it was that i soldered on EC3 connectors to my battery packs from hobbyking ( which were a pain in the ass.. ), which are sold in a 10 or 20 pack, i forget which.

Then i bought parallel and serial EC3 harnesses and used those.

It looks very stock :)

Just another way of going about it, i guess.
 
If I wanted more than 45 amps out of the batteries, then I'd have done it that way. Get 5 mm bullet connectors and make up paralell then series harnesses using them and 8 guage wire from HK.

I figure about 45 amps is all I can reliably push through the motor I'm using without overheating, or having to carry too much battery to finsih the race. So I liked the idea of andersons. Since they have no male or female side, they can do series or paralell connections easy. Bullets have to have a harness made for series or paralell connecting for sure. This method helps lower the number of plugs, each one of which adds some resistance. and adds to the number of places it can come unplugged. In a race, all connections will be taped up to prevent an unplug, except the kill plug.

So far the crimp sleeves seem to be working well. If you do use crimps, you have to get them just right. I thought about using two of them on each wire, but one seems to be pretty good so far.

I'm really liking this set up at the moment. I can do all kinds of different connections out on the road, without carrying any additional stuff. Kinda cool I thought.
 
Here is my set up for charging and discharging.
View attachment IMAG0074 (Medium).jpg
The short middle connector is what I charge/discharge through. The longer outer connectors is what I use to put the packs in series for 44v 10AH
When charging I disconnect the long outer connectors. This puts the pack into two 22v 10ah packs. I connect all the balance leads together and charger so becomes one big 24 20AH pack at the cell level. Since the balance connectors made the pack into 1 big pack I can then charge to 25.2v @10-11A through the small short middle plug which technically is the middle of the pack. The balance taps distribute the charging power through the pack. The balance taps stay ambient and donesnt get warm. But without the parallel balance connector harness this wouldnt work. YOU MUST DISCONNECT THE PARALLEL BALANCE HARNESS BEFORE PUTTING THE PACK INTO SERIES OR YOU WILL HAVE A KENTUCKY FRIED FACE. The hardest part was to get two 12g wires into one 45A Anderson contact and shoving them into 1 housing. But my crimper did the job perfectly everytime.
 
That looks like a very neat setup, IC57. What do you use when you are riding to keep track or low voltage?
otherDoc
 
docnjoj said:
That looks like a very neat setup, IC57. What do you use when you are riding to keep track or low voltage?
otherDoc

Whistles inncoently. I never have that problem lol. I programmed the LVC of my controller to 40.5v which keeps me at around 3.4-3.5v and still delivers a full 10AH on the dot. I monitor my CA. I dont have any protection at the cell level but if something quirky is happening around the 4AH mark which is near the half way mark for my pack.... If the voltage starts taking a dive I will know something is up with the pack. If by nominal pack capacity its not sitting at 44v I will know something isnt up. I think I will get a few lvc buzzers on my next HK shipment. I dont wanna get cocky about it... knock on wood.. (knocks on some laminate furniture)
 
Interesting IC57. Would you then have to disconnect the 4 balance taps and attach a CellLog to each one? I am trying to avoid disconnecting and reconnecting those miserab;e JST things.
otherDoc
 
@dogman: That's an interesting way of doing it. I'd be curious to see where the most connection heating shows up, if you happen to have an IR thermometer you could point at those connections while you have a load on the setup up near your average and max amp draw.


@icecube57: Even if you don't use a cell-level or pack-level LVC, you could at least put a small comparator setup on each half of your total battery pack. All it has to do is compare one half to the other half, and if one drops more than the other especially under load you at least know you have a weak cell (or bad connection), and can troubleshoot it before it gets too bad and something actually fails. Lee Hart over on the EVDL circuit archives has at least one of these circuits already designed and easy to build.

http://www.evdl.org/lib/index.html
http://www.evdl.org/pages/battbridge.html
 
Though I haven't got that many cycles on lipo, and am still a noob, I'm coming to the conclusion that just watching the CA may be enough provided you have a full charge. One nice thing about the Imax lipo chargers I have is they really do tell me, at cell level, that the pack is fully charged and balanced.

Once you know that, you don't need to watch em too much. All my 8 packs seem to be discharging very evenly. Just keeping an eye on total AH on the CA and total voltage on the CA seems to be all the info I really need, unless I'm trying to get someplace on the last watt. The real need for cell level monitoring is to guard against a cell that never charged going low before the others. Knowing for a fact that the packs are full charged and balanced is a huge step in the right direction. Regular chargers give you a green light that means either A, you are fully charged. Or B, you never charged and have a bad plug. And you ride off with situation B partially charged at best.

I'm running the buzzers, that are telling me when the voltage of the paralelled pack reaches 3.75v average. They really start chirping at 3.5v. I did confirm that they all were popping off at the same voltages more or less. They only read pack voltage, not cell level. So my pack is monitored at 5s. The only way I know the cell level voltages is the charger told me that later.

I'm quite tempted to just have one of the buzzers hooked up, and assume the other 3 are close to the same. So far it has been. As the pack ages, no doubt it will need more monitoring.

Yes, it will be interesting to see if any of the wires or connections heat up. If any do, then I have to start over with 8 guage wire everywhere, and higher amp connectors. If that is needed, then I may permanently parallell some packs to minimize the number of plugs, and go to 5mm bullets. A short run this morning, since half the pack is not broken in yet, didn't heat up anything noticeably. I know I need to upsize to run more than 45 amps.

It was fun to pass a car going 35 mph though. :mrgreen: And get the look :shock: 2700 watts is fun!
 
I always ride my packs on a full charge. I never let my packs sit a day and pick up where I left off from yesterday. I always reset my cycle analyst. I always check my cell voltage when I take them off the charger. Not as a whole pack. I check each pack individually. The way my controller is set up with the LVC of 40.5v it gives me 10AH on the nose drained. Once it hits that Im dead in the water and cant do anything. When I come home and check my voltages with my medic none of them are near the 3.3v. Normally 3.6 or more. If I take the pack all the way down below that .. the voltages get scattered but they still are in the safe zone. I can get 10.3 or 10.4AH on a full discharge. They appear to be unbalance with as much as a .2v deviation when fully drained but when I put them on the charger they come back up together and terminated charging at exactly the same voltage per cell with a variation of 0.01v. When im going on long distance rides Im constantly looking at my CA to maintain a certain wattage/amperage and wh consumption. I know how a pack feels when its flat. My pack configuration... The pack feel about 5-6C tops. I have 30C packs. Im not pushing them that hard. I punishing them with these deeps discharges. When you know what your pack can do and you really pay attention while charging and discharging you will know when your pack isnt performing well. Im sorta lipo newb but I well experienced in checking cells and their voltages. I assembled a 24s 20Ah Lifepo4 Thundersky Pack and knew that pack like the back of my hand. Im on my 15th or so cycle with this lipo setup. The jst connectors can be a pain to unplug. I even tell myself that they dont need balancing but I plug the connectors in and watch the cell voltages on my medic cause there be one day where I wont use the medic and will regret it. I suggest you using hot glue or some type of epoxy behind the connector for strain relief. It will make them more durable. i havent had any trouble out of mine

My harness doesnt get warm at all.. well maybe slightly above ambient but its not one of those situations where omg the insulation is sticking together.... Its far from that stage. But im using 12G and pulling 50A at best. The wires are undersized but the runs are so short it will be ok. But the pack gets toasty and stays toasty quite some time after a heavy discharge. Only when I put it back on the charger it cools down.
 
Just took a good run of 13 miles, with lots and lots of hard pulls to simulate a race on a kart track. Using a 40 amp controller, and pulling 2500 watts or more most of the ride, some things got hot, but not the wires or plugs. 12 g seems to be enough for 40 amps. Max spike on the CA was 46 amps. Discharged 8.6 ah on a 10 ah pack. About as far as I ever want to go to try to make em last. 4c out of 30c lipo sure doesn't strain em much. All I could measure pulling 2500 watts was 1.6v of sag. Nice :mrgreen:
 
The images on this thread look really useful but I can't view most of them. Is it possible they could be checked or could someone point me to where they are visible?

Dogman has been really helpful and posted really detailed stuff here which is really helpful for noobs like me, but the photos from the first couple of posts would be soooooooo helpful.
 
A lot of pics got corrupted a while back. Many did get restored, but not this one. Meanwhile my laptop died, and I had never backed up those pics, considering ES the backup. :roll:

So a few critical threads still have no pics.

Meanwhile, I have had a change of attitude, and don't want any packs soldered or crimped in paralell permanently anymore.

So I have taken to making y adapters that have the two bullet connectors on one end, and one anderson on the other. So now I can swap out a single dead pack easier, and I can make adapters for 3p if I want more.

Depends on what the needs are. When I came up with the idea of crimp sleeves to paralell packs, I wanted the wire runs as short as possible for a racing battery pack. At recreational power levels, I can live with more wire and connectors.

I ought to do a retake of the pics, but it's work. :| Right now battling cronic fatigue syndrome, work is really a four letter word.
 
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