Can you bulid your own Equalizer is a lipo Balance a "f

[cliffp73]

I have to ask, if you hook up all of your cells in parallel wont they all "balance" out? Correct me if I am wrong but wouldn't it be the same if you hooked the cells up in parallel and just waited until all of the cells are the same voltage? I was stilling around trying to think about if I really needed a balancer or not for my TP LiPo's. Thank you very the response.

Edited 12/22/06
Insted of saying a fake I should have said really needed. Just hook them up in parallel. this is the question that I am asking.

[DebianDog]

Well they all will charge and discharge at a subtle difference

Watch the videos:
http://www.helifreak.com/viewtopic.php?t=26242

[cliffp73]

Thank you very much for the link I an downloading them now. Thanks
Cliff

[Pinecone]

That would work, IF you cold separate the pack. Otherwise the negative for cell 2 is the positive for cell 1, so if you hook up parallel, you short out every cell and things will get REAL exciting.

Draw it out.

[cliffp73]

That’s how the wire a balance plug it has the positive of each battery and the negative it run all together. Think of it this way, you have 2 12v batteries for your boat. The trolling motor run off of 24v and the gas motor uses 12v what you do is run the batteries in series and then the gas motor off of one of them for 12v parallel. By no means am I trying to be a smarty, but I did watch Finless and his video (which were great) and the balancer that he was showing gives a good bit of information and I will most likely buy one of them because I don’t want to “test” my theory of what I am saying because I am chicken and well these days I don’t have much faith in ideas like this that I come up with. The only thing that I don’t like about the balancer is that it discharges to bring the cells down to the lowest one. Well what if the lowest one is 2.8v (there might be a protection circuit) well you should not drop your cells below 3v (this is why I am saying that there may be a protection circuit. So what do you do when your lowest battery is below 3v and your balancer will do either one of two things. One it will drop the rest of your cells down to 2.8V (bad)or it will not do anything because it has a protection circuit on it.

My idea. Just connect the cells all together and well it will keep most of the energy that was put in to the pack and it will also bring up the low batteries the 2.8v battery and drop down the higher voltages batteries. Now I might be too low with 2.8v and I may not know what I am talking about, but I think that I may be right and I may be wrong. Just let me know if you know for sure why this would not work and if you know that it will not and why please let me know. I am not doing this to argue I am only writing this post just to see if I know what I am talking about. Thank you every one.

[DavidH]

If one of the cells is 2.8 volts. The pack is no good anyway. So it is a moot point.

David

[cliffp73]

Is it that critical that you do not drop below 3v? I did not know that, i read that it is not good for it but I did not know that it is that bad. Thank you David for the insight (I need to do better on my reading). Well that still doesn't mean you could not hook all of them up in parallel and let them equalize as long as all of the cells are 3v or more. I just can’t see spending the money on something a simple connector would do with in 2 hours. I know that I can "equalize" the batteries with in one minute or a couple of hours depending on how bad the pack is. I was just looking for a reason why it would not work. I thank everyone who is responding and if you think it will work please give me and everyone else your thoughts..

[DavidH]

Cell balancer is too easy and fool proof. See them in use all the time at events. Just makes life easier and less expensive. LiPo packs are not inexpensive to replace. If your going to use LiPo's in an electric powered model. I would suggest a cell balancer.

David

[spork]

I too would suggest the balancer. I use mine while charging. So you wouldn't expect to bring all cells to the lowest level - you'd just charge the higher cells more slowly as a result. But it's also true that if the cells are that far out of balance your visa card may be the only solution.

That being said, I think your idea is a clever one. If you DID decide to do this you'd definitely want some good power resistors between the cells. Otherwise it would try to balance them RIGHT NOW at about 30 amps. Also, it couldn't be done with the way the packs are currently wired. Since they're currently wired in a series, you'd have to break those connections before wiring in parallel, otherwise you'd literally short each cell as Pinecone mentioned.

[cliffp73]

You have a great Idea spork with he resistors I did not think about that and yes you would need it 100%, but you were saying that you would need to break up the pack because of the wiring, but you already have a wire coming from each battery in the balancer connector, All you would need to do it use the negative wire and then there is one wire coming from each positive of each cell. Use a connector so this is not happening all of the time but you would connect one end of the resistors(you need as many resistors as you have cells to the negative and then connect one resistor to each of the positive wires and there you go an equalizer. Actually it is balancing the cells out in reality because it is bring down the high voltage and bring up the lower voltage cell to match at the average voltage. Let me know what you think and what needs to be changed or could be changed. I am thinking that you need one pig tail for the pack you have the wiring diagram for that pack and as many resistors as you have cells in that pack a little solder and just a couple of minutes of your time. I have to admit is it much nicer to have an aluminum case blinking lights and comes from a factory that has done the RnD on these items. Well I think that this is my first topic that actually “means” something. I have all of the ideas in my head and well just now where to discuss them to the same “Type” of people that would be interested in something like this. I am looking for a low cost Equalizer that the guy that can build it and wants to build can do it and use it. I would not suggest leaving it on the battery all of the time but you could in theory leave this unit on while charging or before or after. It would be nicer to have a circuit on this that would tell you the voltage of each battery and let you know when it was done but all you would have to do it measure it with a meter.

I do agree with you 100% David but I am the guy that says "Just asking" you know the guy that likes to ask questions and find out if different things will work or not. It is this simple why not. This could be fool proof but I guess to get it fool proof that you would need to invest the same money that a balancer cost, but actually when I think about it I bet someone could make this type cheaper than the Blinky Balancer and you never know this might be how it does it. There is not a heat sink on the Blinky so how doe sit discharge a battery and not have any where for the heat to go, but then again it really is not that much voltage change in these balancers, if they are in range to use them and charge the battery at the same time.

[spork]

Please give us a diagram of your wiring idea. I have no doubt it could work, but I don't see a way to do it without breaking the series connections first. You can't have a pack of cells simultaneously wired in parallel and series.

[Pinecone]

Theproblem is, you would have to take the pack apart to do it. Each positive it tied to the next cell positive.

Take your boat with 2 12v batteries in series. Not without taking off ANY connection, try to connect them in parallel, without shorting each out out. You can't. If you connect the the negatives together you also conenct the positive of the first battery to its own negative. BIG sparks.

[cliffp73]

PineCone your right I give it will not work, but how does a blancer see each cell?

[cliffp73]

OK i see how they do it they (who ever wires the lipo packs) are taking a lead off of each series connection to read the voltage and well I am lost now, see this is what I was wanting. Someone that would ask me how do you want to do it and draw it out. Let me think just a little while. The balancers has to do it so let me "see" if I can do it and I don't think that I can but I am going to see if I might be able to figure out something.

http://www.fmadirect.com/support_docs/item_1214.pdf here is how FMA wires there packs. And from what I am seeing most of the packs are wired the same way just different connectors so you have to use there product. Let me know if you see the same thing that I am see with this comment.

[WayneBrown]

the balance lead wires are all parallel, only when or if connected will you 'see' the total voltage for the pack. Using a small probe (paperclip) connect a voltmeter to the pin at one corner of the connector, each position right should increase voltage by 3.6v. That said, any pair of side by side spots should show the individual cell.
I guess thats a confusing way of saying the balance lead is one cell per position, with all leads going to a common. Negative to the common, you should be able to see 3.6v at the first position, and increase 3.6v every position beyond that, or 3.6v at any two taps that are side by side.

[cliffp73]

I could not have said it any better Wayne, you did a great job explaining that. I think that the wife is getting me a 450al to go along with my 50 Titan btw. I am crossing everything that she talked with the right person and I am getting what I need if you know what I mean.