Best way to use Batteries

[BsudRC]

Just got the new Mojave 4s. Is it better to run one 4s battery or two 2s? Are there a benefit to one way over the other?

 

[DavidB1126]

Just run 1 4s. So you don't need to worry about wiring, and you don't need to worry about an extra battery inorder to run it. (And charging up that extra 2s battery)

 

[tntpoof]

I've always run 2 x 2 but you will find that the battery on the closest negative side of esc battery connection will always use more mah /volts than the other .so I rotated them.but 4 cells packs are great. and it would be a series connection. things one needs to know

 

[bill_delong]

• SMC - LVC Adjustments and Packs in Series

 

[BsudRC]

Just bashing around on my track is a higher C rating better or lower?

 

[tntpoof]

I've always used High C rate batteries .others will say its Pure marketing Hog Wash

 

[Greywolf74]

Just bashing around on my track is a higher C rating better or lower?

Higher is better but you dont necessarily have to have the highest ones you can find. Just depends on the workload that theyre under.

 

[STONER RC]

Just bashing around on my track is a higher C rating better or lower?

If you can always run one lipo. Unless you have to use 2 for like 8s 10s 12s. Running 2 lipos in series is a pain. You got to pay attention and switch the lead lipo around. For each run/bash session.

Higher C rating always. The higher the C rating. The more power they put out at once or punch.

The lower C rating is for mostly crawlers. Or something that doesn't need that much power.

 

[Grizz03]

• SMC - LVC Adjustments and Packs in Series

The part I don't understand is that a single large battery has the same cells as a same voltage multi battery in series pack.

Example: a 4s battery has 4 individual cells in series. And 2x 2s battery setup still has 4 cells in series. When it is said that it "sees virtually double the resistance of the first pack" really confuses me. As the current flows from the first cell to the last it still goes through the same amount of cells.

If swapping the packs in a series setup is good in prolonging the batteries, could it be thought that a single pack that you can't rotate the cells around in a series connection cause the same "end" cell to be subjected to the compounded resistance only.

 

[Greywolf74]

The part I don't understand is that a single large battery has the same cells as a same voltage multi battery in series pack.

Example: a 4s battery has 4 individual cells in series. And 2x 2s battery setup still has 4 cells in series. When it is said that it "sees virtually double the resistance of the first pack" really confuses me. As the current flows from the first cell to the last it still goes through the same amount of cells.

If swapping the packs in a series setup is good in prolonging the batteries, could it be thought that a single pack that you can't rotate the cells around in a series connection cause the same "end" cell to be subjected to the compounded resistance only.

I also had that same thought, but after thinking about it for a second, it made sense. Cells internal to a pack have much less resistance between the cells because they are hooked directly to one another with very low resistance material that is only a fraction of an inch long. When you wire two packs together in series, you introduce additional wire and connectors etc. that greatly increase the resistance between the two packs that the internal cells don't have.

In addition to that, internal cells themselves will have variances in IR between the two packs, whereas in a single pack the internal cells are "matched" cells to be as close to one another as possible.

Then lastly you also have to take into account that technically the internal cells of a single pack are also subject to the same problem as two packs in series, it's just a much lesser effect because the cells are matched, and you don't have all the additional resistance from things like extra wire, connectors, etc. The highest IR cell in a pack is the one that will get drained the slowest, which can eventually result in a pack that does not discharge evenly once the IRs variance between each cell is great enough. It's why we dispose of LiPos once we start seeing an imbalance in cell IRs.

Hope this helps

 

[Grizz03]

I agree about using matched batteries. (Purchasing dual batteries at same time almost ensures from same batch)

If you take away having poor connectors what is so bad? Most that ask this question are only bashers and not die hard racers. (But on the other hand aren't racers using saddle packs?)
If it's so detrimental to batteries why do Traxxas, Arrma, Hpi, Losi, etc still make there ESC's with a dual battery connector setup?

I buy and use only matched batteries when running dual. (Same make and Mah). I still have older Traxxas batteries that have the separate balance charge wire and not the new ID style connectors. One is a 3s and the other is a 2s. (Same size cells). I run 5s in my Traxxas Summit, swapping sides each run and haven't had any issues.


I like having dual batteries. Because when one does go bad I can still use the other in another one of my vehicles. I don't see any real benefit to spending the extra money on a more expensive single battery (and the need to dispose of it when a single cell goes bad) when I can purchase two and still get to keep one when one does go bad.

 

[BsudRC]

I agree about using matched batteries. (Purchasing dual batteries at same time almost ensures from same batch)

If you take away having poor connectors what is so bad? Most that ask this question are only bashers and not die hard racers. (But on the other hand aren't racers using saddle packs?)
If it's so detrimental to batteries why do Traxxas, Arrma, Hpi, Losi, etc still make there ESC's with a dual battery connector setup?

I buy and use only matched batteries when running dual. (Same make and Mah). I still have older Traxxas batteries that have the separate balance charge wire and not the new ID style connectors. One is a 3s and the other is a 2s. (Same size cells). I run 5s in my Traxxas Summit, swapping sides each run and haven't had any issues.


I like having dual batteries. Because when one does go bad I can still use the other in another one of my vehicles. I don't see any real benefit to spending the extra money on a more expensive single battery (and the need to dispose of it when a single cell goes bad) when I can purchase two and still get to keep one when one does go bad.

But I did just buy a Dual pack of 4s for my 4s cars and the two pack was only like 80 bucks. Not bad really and I can charge them both and then just swap them when I hit the LVC. Gives me double run time.

 

[Greywolf74]

If it's so detrimental to batteries, why do Traxxas, Arrma, HPI, Losi, etc. still make their ESC's with a dual battery connector setup?

They design them like that for weight distribution and/or space constraints AFAIK. Can you imagine how off balance an Infraction would be with a 6S pack on one side or a single 8S pack in a Kraton? Also, they don't care if our batteries die sooner or not.

 

[Grizz03]

They design them like that for weight distribution and/or space constraints AFAIK. Can you imagine how off balance an Infraction would be with a 6S pack on one side or a single 8S pack in a Kraton? Also, they don't care if our batteries die sooner or not.

That's the reason why I like the dual battery balanced chassis's over the single sided off-balance of the single sided compartments.


Has there ever been a study showing how one setup is much better than the other? How much sooner do/can they die?
Everything I read is just about "why" because of resistance which theoretically is correct in that resistance hinders performance.

Where is a real world test? A good example would be:
Take 10 pairs of 3s batteries against 10 single 6s batteries with the same cells. You could have a graph of the lifespans of each setup. After so many cycles and seeing if there is a difference in Mah retention and resistance would help settle the debate. If there is only a minor difference I wouldn't consider one setup "a definitive best."
Don't forget to add in the connectors resistance in the graph. Some connectors are much worse than others.

 

[Greywolf74]

That's the reason why I like the dual battery balanced chassis's over the single sided off-balance of the single sided compartments.


Has there ever been a study showing how one setup is much better than the other? How much sooner do/can they die?
Everything I read is just about "why" because of resistance which theoretically is correct in that resistance hinders performance.

Where is a real world test? A good example would be:
Take 10 pairs of 3s batteries against 10 single 6s batteries with the same cells. You could have a graph of the lifespans of each setup. After so many cycles and seeing if there is a difference in Mah retention and resistance would help settle the debate. If there is only a minor difference I wouldn't consider one setup "a definitive best."
Don't forget to add in the connectors resistance in the graph. Some connectors are much worse than others.

All you have to do is go run a pair of batteries, and at the end of the run, go and look at the IRs and the voltage levels of all the cells in each pack. There will be a fairly significant difference from one pack to the other pack.

 

[Grizz03]

All you have to do is go run a pair of batteries, and at the end of the run, go and look at the IRs and the voltage levels of all the cells in each pack. There will be a fairly significant difference from one pack to the other pack.

From my experience and personal batteries that's not true. Here's my proof:

On my SMC 3s 7200Mah batteries I don't see any significant difference. I just ran my truck hard for about 10 minutes. My truck is an Erevo 2.0 with a Castle MMX8s and 1717 1650kv combo. They are old but still have great performance.

Here's photos for proof. Also there was no rest time at all either. Put batteries immediately right on the "view" menu on my Protekcharger to rule out the "let batteries rest to equalize" argument.

Also in the last pic you can see the adapters I'm using because I haven't changed the Traxxas ends to XT90's yet. And as pointed out earlier using adapters will negatively affect the resistance making it actually worse on the batteries.

How are these values any different than a single 6s battery the same age?

 

[Greywolf74]

From my experience and personal batteries that's not true. Here's my proof:

On my SMC 3s 7200Mah batteries I don't see any significant difference. I just ran my truck hard for about 10 minutes. My truck is an Erevo 2.0 with a Castle MMX8s and 1717 1650kv combo. They are old but still have great performance.

Here's photos for proof. Also there was no rest time at all either. Put batteries immediately right on the "view" menu on my Protekcharger to rule out the "let batteries rest to equalize" argument.
View attachment 177037View attachment 177038View attachment 177041


Also in the last pic you can see the adapters I'm using because I haven't changed the Traxxas ends to XT90's yet. And as pointed out earlier using adapters will negatively affect the resistance making it actually worse on the batteries.

How are these values any different than a single 6s battery the same age?

Maybe try emailing SMC and ask them that question. Maybe their electrical engineers can explain it better than I can.

 

[Grizz03]

Maybe try emailing SMC and ask them that question. Maybe their electrical engineers can explain it better than I can.

Why? My test shows what I claimed.
I made a simple comment about it would be nice if a battery manufacturer conduct a test showing the difference in life spans of different configurations. It would show there is or maybe perhaps it's not such a big issue like we're led to believe. Are you dismissing my idea as it wouldn't be beneficial to us the consumers?

Like I have shown and from my experience I haven't noticed any problems. And I'm sure there are thousands more that also run dual batts that aren't having issues either.
I still would rather discard one battery that's part of a dual setup than a single bigger (more expensive) battery when a single cell goes bad.

In my opinion; if running dual batteries is such a frowned upon thing, where are the articles from different sources stating that fact other than from SMC?
If there is any links to them so I could read I would like to read them to help add some more knowledge and insight into this debate.

 

[Greywolf74]

Why? My test shows what I claimed.
I made a simple comment about it would be nice if a battery manufacturer conduct a test showing the difference in life spans of different configurations. It would show there is or maybe perhaps it's not such a big issue like we're led to believe. Are you dismissing my idea as it wouldn't be beneficial to us the consumers?

Like I have shown and from my experience I haven't noticed any problems. And I'm sure there are thousands more that also run dual batts that aren't having issues either.
I still would rather discard one battery that's part of a dual setup than a single bigger (more expensive) battery when a single cell goes bad.

In my opinion; if running dual batteries is such a frowned upon thing, where are the articles from different sources stating that fact other than from SMC?
If there is any links to them so I could read I would like to read them to help add some more knowledge and insight into this debate.

No one said it was frowned upon, there are just certain things to be aware of in order to maximize your LiPos lifespan if you're going to run like that.

 

[WickedFog]

Why? My test shows what I claimed.
I made a simple comment about it would be nice if a battery manufacturer conduct a test showing the difference in life spans of different configurations. It would show there is or maybe perhaps it's not such a big issue like we're led to believe. Are you dismissing my idea as it wouldn't be beneficial to us the consumers?

Like I have shown and from my experience I haven't noticed any problems. And I'm sure there are thousands more that also run dual batts that aren't having issues either.
I still would rather discard one battery that's part of a dual setup than a single bigger (more expensive) battery when a single cell goes bad.

In my opinion; if running dual batteries is such a frowned upon thing, where are the articles from different sources stating that fact other than from SMC?
If there is any links to them so I could read I would like to read them to help add some more knowledge and insight into this debate.

I don't see anyone saying running dual batteries is frowned upon. Just that it is indeed better to run one single pack if possible. Connecting 6 cells in one single battery will have far less resistance than running two batteries in series. That's a fact. But it doedntmean you can't do it and be fine. If all you have is a dual configuration, run it. No need to be argumentative.