Ed's 'StreetRunner' Quad Build

Radical Brad

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Sorry, I have not been around much lately, busy with work and clearing snow!
I will have to catch up on this amazing thread soon, but just glancing I must say...

Don't EVER connect batteries in parallel like this!!!!!

If you require more capacity (amp hours) in a given series wired pack, then get larger batteries.
Also, when you are connecting in series, make sure batteries are of the same size, and capacity, especially if you charge them that way.

If you connect batteries in parallel like this, then make sure you have fire insurance and working fire detectors in your house.
I will shout that even louder if you plan to use lithium (ion or iron) packs.

In reality, there should be no reason at all to want to wire them in parallel.

Cheers,
Brad
 
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Sorry, I have not been around much lately, busy with work and clearing snow!
I will have to catch up on this amazing thread soon, but just glancing I must say...

Don't EVER connect batteries in parallel like this!!!!!

If you require more capacity (amp hours) in a given series wired pack, then get larger batteries.
Also, when you are connecting in series, make sure batteries are of the same size, and capacity, especially if you charge them that way.

If you connect batteries in parallel like this, then make sure you have fire insurance and working fire detectors in your house.
I will shout that even louder if you plan to use lithium (ion or iron) packs.

In reality, there should be no reason at all to want to wire them in parallel.

Cheers,
Brad
Thanks Brad. Best to make the mistakes on paper.

I think I misunderstood, that the two methods were somehow used together, (as I laid them out).
After more input and reviewing the video, and others I think this is correct.
I have just changed the battery layout. Hopefully it is correct.

In any case, I won't try it until I've taken it to my local, Battery Mart experts, for confirmation.

 
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My reasoning at this stage for this battery setup, is just this.

I looked into using the Lithium types, the Nissan Leaf Modules and SLA.
I have flipped flopped, back and forth between them. Each has value, but each has draw backs.
Staying within my comfort zone, is one reason I went back to the SLA, and in particular, 12v 20/22ah bats.

I have only limited space to place batteries, and no need to spend $1000's dollars on something, that will sit most of the time.

I stumbled across this method of achieving the voltage the motors need, while increasing the ah that is needed.
The batteries I'm looking at are:


Assuming I have all the specs accurate, then these batteries might be all that I need.
Enter opinions, about that statement.

The parameters I'm looking at are; 12v X 4. Series to meet the 48 volt motor requirement.
The 20/22 ah, to meet the current draw of at least 64 amps.(2 motors @ 32 amps ea). Thus parallel 20/22ah into 80/88ah
The weight of 13 lbs is well within an acceptable weight. (Overall 52 lbs)

The more I read, the more I learn.
The cost and the uncertainty of using the Leaf Modules, has just about ruled them out.
That system, with its charging, monitoring, etc. really is getting away from the simplicity of the build.
 
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Ed. This might finally explain it for you. I was trying to avoid drawing it but here is a quickie. Tote the junctions and voltage between the batteries.



There is no adding of AH capacity with series connection. The round circle is the unlabelled motor. Controller or other switched connections not shown.
 
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Thanks Kevin

Believe it or not, I understand how that configuration works.

What I'm not grasping is the supposed, in ability to increase, volts and ah, both at the same time.
The are doing it in the video. Are they wrong? Timeline 3:13 to 3:31ish

I just finished another diagram showing how 24 volt 35 ah batteries would work, using their connection process.

Let me know what you think. If this doesn't work, I don't know what to think.

 
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I don't like the way they draw their diagrams. I had difficulty seeing what was going on, so I redrew it in a more conventional manner - with a few added annotations.



You can instantly see that they are connected in series/parallel and, yes, 48V/70AH.
 
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I spent about an hour at my local Battery Mart today.

I won't go into detail, just yet.

First, I would like your feedback on the following diagram.
 
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Ed: Those diagrams are so hard to follow. After deconstructing the one above and redrawing it (on paper, not here), the connections are the same as my last-posted image. What you have is 2 series-connected 12V/20AH batteries (providing 24V/20AH), parallel-connected to another pair of series-connected 12V/20AH (giving 24V/20AH). This gives you 24V/40AH. What you don't have is 4 x 12V batteries in series, and you don't have 4 x 20AH batteries in parallel. You have, effectively, 2 x 24V/20AH battery banks in parallel.

Connecting batteries in series adds the voltage numerically, but the capacity stays the same as the least capacity battery. In this case, they all have the same capacity. Connecting batteries in parallel doe not add the voltage numerically, but it does add the capacity numerically. What you have is a bank of 2 series-connected batteries making 24V/20AH (voltages added, capacity not added) in parallel with another bank of 2 series-connected batteries making 24V/20AH (voltages added, capacity not added). Connecting both of these banks in parallel adds the capacity to 40AH, but the banks' voltage is not added. That value stays at 24V.

If you view my diagram, you can visualise the connections much easier. Obviously, the individual battery voltages are the same.

How does all that sound?
 
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I watch the video
The used 4 x 12v 115ah batteries
And their result was
Parallel 48v 115ah
Series 12v 460ah
series/parallel 24v 230ah
So no magic
But in my unprofessional understanding a serial/parallel conection is a very bad idea.
 
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Series: means that the batteries are connected in series (positive of one to negative of the other, and so on). For those connected in series, their individual voltages add, their capacities do not. The power drawn from them comes through the series string of batteries. If each battery is 20AH, that is all that you get. This can best be understood by drawing the circuit with the batteries "stacked" one above the other, usually positive terminal at the top, negative at the bottom.

Parallel: means that the batteries are connected in parallel with each other (all the positive terminals connected together and all their negative terminals connected together. If each battery is 20AH, each one contributes 20AH and the total capacity is 20AH multiplied by the number of batteries. This can be best understood by drawing the circuit with the batteries side-by-side with all like terminals at the top (usually positive) and the bottom (usually negative).

Series/Parallel: means that some batteries in the collection are connected in series and some are connected in parallel. The final result can be calculated by what I have said above. Whether they are grouped in series "strings" which are then connected in parallel or not, depends entirely on the voltage and capacity required. Connecting batteries in series after separately charging is not a problem. However, separately charging batteries can result in them having slightly different terminal voltages. Connecting them in parallel will result in the higher voltage batteries attempting to charge the lower voltage ones with only their internal resistance limiting that charge current.

Wikipedia extract: An ampere hour or amp hour (symbol: A⋅h or A h; sometimes also unofficially denoted as Ah) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour.

The above translates to a 20AH battery being able to deliver 20A for a period of 1 hour or 1 amp for 20 hours.

At this point, I think I have run out of things to contribute to the subject. Whew!
 
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Good Morning Everyone.

I worked on this subject, late into the night, yet again. Because of the importance of this matter,
I MUST learn ...'WHY'..., in some cases it works, and in other cases, it won't.

Everyone has been very, very, accommodating, and I am learning (and retaining), much about this subject.
But I do not want to wear out my welcome.

For me, and me alone, I must learn the WHY.

Going forward, I must understand WHY, this works in some instances, and not in other instances.
I have thought about experimenting, but truly, I just need the appropriate explanation, that is alluding the question.

The question has been asked to numerous knowledgeable individuals here, as well as, on Endless Sphere, and at Battery Mart. I have learned, (thanks to everyone's input), HOW the series, and parallel circuits work. I've read and watched how these circuits work, and are completed. Some of the information, from different sources, has been contradicting, which has added to my not being able to say,....I GOT IT !

What I haven't learned, is 'why' the example works to a point, then just stops.

In presenting the diagrams, (which is a communication element), without added verbal explanation,
is exacerbating the misunderstanding, or lack of comprehension.

Physical size matters in this, because of the vehicle design. Another reason for wanting to pursue this subject.

So, as I stated earlier, I do not want to wear out my welcome. I am putting this subject to rest for now.
I have a couple of, other irons in the fire, regarding how to obtain power, for my project.

If anyone wishes to contribute more, I am here to listen, but it must be voluntary.
I thank you for your help, to this point. I am truly grateful.

Regards
Ed
 
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Two of us that "slept" on it without sleeping. I woke up this morning and thought that the subject was incomplete. How do e-bike batteries work?

They have heaps of 18650 lithium ion cells in them. Each cell is nominally 3.2V (discharged) to 4.6V (charged) and 3000mAh (3Ah) capacity. They constitute a 36B battery of 15Ah or more. How? Let's build one.



If you connect a string of 10 cells of 4.6V/3Ah (charged), in series, you get a 46V/3Ah string. If you do 5 of these, you will have 5 strings of 46V/3Ah batteries. Now, connect those strings in parallel as shown in the diagram, and you will have a 46V/15Ah battery that will be 46V when charged, and slowly drop to 32V when discharged.

Warning: This is simplified. The battery also has BMS circuitry to stop discharge at the pre-determined minimum voltage, stop charge at the pre-determined maximum voltage, and also monitor the charge rate and ensure that each battery is charged correctly and equally. They aren't just connected as in the diagram as shown above and left at that.
 
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Why does it work sometimes and not others? Why does it work and then stop?

It always works. It just follows the rules. The result depends on how they are connected. The required connections depend on the voltage of the batteries and the required output. They must be series connect to increase the available voltage and parallel connected to increase the available output current.

And you are not wearing out your welcome. I had a boss once who said, "I can't understand why you don't understand. I said it clear enough." I answered with, "If you had have said it clear enough, I wouldn't be asking the question." To get an answer, you have to ask the question.
 
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And you are not wearing out your welcome. I had a boss once who said, "I can't understand why you don't understand. I said it clear enough." I answered with, "If you had have said it clear enough, I wouldn't be asking the question." To get an answer, you have to ask the question.
Thanks Kevin
I was an instructor for +/- ten years. I always told my students, it wasn't their fault if they didn't understand.
It was 'my' fault, for not presenting the subject, in a manner that, 'they' understood.

Also, I have just finished an email to https://www.techdirectclub.com/ regarding the use of one of the Nissan Leaf battery packs.

In particular. this one.
https://www.techdirectclub.com/solar-rv-powerwall-nissan-48-volt-battery-g1-lithium-ion-3-5-kwh-66-amh-w-option-and-1-bms-lot-of-7/

We'll see what they have to say.

Additionally, fletcher's last point, made me think I made a 'mathematical' error on my last diagram.
I tried to re-draw it in the manner you like.....but I got lost o_O
So here is the new version.



Thanks again for your comment/patience.

Ed
 
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I need to deconstruct it again but I did notice:

4 x 20AH in parallel = 70AH total. My mental calculator comes up with 80AH total for that one.
If you have 4 x 12V/35AH batteries, you will only end of with 48V if you put them all in series. That means you will have 35AH max.
 
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I need to deconstruct it again but I did notice:

4 x 20AH in parallel = 70AH total. My mental calculator comes up with 80AH total for that one.
If you have 4 x 12V/35AH batteries, you will only end of with 48V if you put them all in series. That means you will have 35AH max.
Yeah ! My Bad

When I change the batteries from 20ah to 35ah, I didn't change it in the box below.
 
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My drawings replicate the same exact battery orientation, that is demonstrated in the video. Look at the video, TL 3:40,

The 'only' difference, 'I see', is my drawing has completed the circuit between #2 and #3 battery, thus completing the series, for 48 volts.
The same series connections as in the video, TL 0 :57. The only difference, 'I see' is the orientation of the batteries.

The why part for me...Its all well and good to say my set up will be like the Forth of July, but with out knowing and understanding, what specific, action (in my drawing) will a cause this short, it doesn't come into focus.
 
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Yeah, but ...

I have re-drawn your circuit, a representation of the physical positioning of the batteries, with a circuit diagram using the battery numbers left to right from your diagram, showing their relative position in my diagram as follows:



What you have drawn, and stands out in the diagram, is 2 of 12V/35Ah batteries in parallel (1 and 3, = 12V/70Ah) which are in series with another 2 of 12V/35Ah batteries in parallel (2 and 4, = 12V/70Ah). The parallel pair 1 and 3, are then connected in series with the parallel pair 2 and 4. This results in the 12V of batteries 2 and 4 adding to the 12V of batteries 1 and 3, to give a result of 24V/70Ah. The only way to get 48V from 4 x 12V batteries is to connect them ALL in series - nothing else. Using these batteries ALL in series will give you a power source of 48V/35Ah.

In the above diagram, the cyan connection can be removed without changing voltage or capacity. It is redundant.

I'm almost getting confused myself. I must have uploaded and deleted the drawing 4 times for text correction.
 
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