construction of battery pack instructions

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deacon

minor bike philosopher
Jan 15, 2008
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I had toyed with the idea. If I get to what I think is the right balance of amps and it doesn't seem right I will give that a try thanks.
 

paul

Well-Known Member
Dec 23, 2007
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Kalamazoo, MI
i like your dedication deacon and enjoy learning from what you are doing, hope you get it all figured out to have the perfect electric bicycle battery that fits your needs
 

deacon

minor bike philosopher
Jan 15, 2008
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Here is the latest. I found out that all the power was coming from the 9.5 ah c cells. The new aa cells were not wired rugged enough. So I went back and wired them like I had the C cells and they seem to work now. It was a time consuming process, but it seemed to have worked. I still haven't field tested the batteries but they shop test just fine though the sla pack still turns the motor faster I think but it is getting there.

Here is a tip you can add to the instructions. Heavy duty alum foil, a cereal box, and a glue stick let your imagination run wild. hint think battery connectors to string them into a pack.
 

deacon

minor bike philosopher
Jan 15, 2008
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Well the 200 dollar battery running on all cylinders wasn't enough, but it did do better. I have already paid for enough batteries to double the AH so for the sake of leaning I am going to divide the batteries into two test batteries packs.

One set will be make up of C cell batteries totaling 19ah manufacture's est.
Second set will made of up AA batteries of 18ah again manufacture's est.

I will fully charge them then see which one runs the best. If there is a huge difference in the performance I will make a note never to use the other ones again. I just can't tell since neither of them works well alone now at this time.
 

deacon

minor bike philosopher
Jan 15, 2008
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The cheap home built battery is approaching critical mass. I have 19ah mfg rated c cells and 18am mfg rating aa cells. I can't tell any difference in them. They are going to run the battery at creep without cutting out I THINK. The packs got built too late to actually ride anything today.

I hope to get an idea of how it's going to go for me tomorrow. I have a feeling I'm going to need another 18 ah mfg rated pack.

The truth is that if the packs have a 2c rating I think I need to get to 18ah to draw 25 amps. It is is one c then I need to get to a true amp of 25 amp hour.

At this point I have no idea if the Ah is rated way the heck too much or the c is rated to high. I believe the Ah rating is much lower than they advertise. I believe the bike is operating at about 18ah total which leads me to believe the manufacturer's rating is a least inflated double the true rating.

If I add anther 9ah it should raise it to slightly over twenty if I am right. That would give me pretty close to the 25amps I draw at max draw. So I'm going to add 9ah more to the pack and see what it does. So I guess I will wind up pulling a trailer after all to get all these cell to travel.
 

deacon

minor bike philosopher
Jan 15, 2008
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Kevyleven007 I need to send you a big wet kiss. (well that's a bit much) You were right about the copper. I cleaned out my computer storage area an found lots of power cords. So I saved a couple and cut them off, then stripped the wire out of them. I tore all my homegrown battery packs apart and rewire them with copper wire from those cords. The resistance in the packs must have been fierce, since it seems to have me on the right track.

I haven't had a chance to test ride them, but the wheel spins faster. The real test was: there is that pop when I plug the batteries in now. That sounds like there are more amps on the circuit now, I'll let you guys know what happens next.

I already updated the directions to use copper wire rather than the less conductive aluminum thank to Kevy.

I did get to ride it half my usual short test track before my hands started to hurt. It ran up and down the hills but at less than full speed. probably no more than 20% less and I do have a set to make an addition 9ah which should take it to full speed.

Thanks again Kev. When I get the final 9ah in the loop it should be fine but the cost is going to be equal to the lipo. The only advantage is I can probably do my own battery maintenance to replace a bad cell now and then,

Time will tell what the operating characteristics of the nimh battery are. I wish this cold would leave so I could test it. I used the scooter which has no human power available so I will use the trike next time so I can help it out. What a huge difference the copper made.
 
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minreg

New Member
Feb 5, 2014
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FL
Holy, aluminum foil!
This pack would be so much better if it were soldered.
I have soldered cells with wire but battery bars would be even better.
What gauge wire are you using?
Resistance will be even less if soldered.
 

deacon

minor bike philosopher
Jan 15, 2008
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The wire, if I get all the strands out, which I seldom do, is probably 16 or 18 gauge. It was meant to carry ac current. Actually I was thinking about copper foil like they use in jewelry next.

I soldier but I really don't want to. They tell me the heat might effect the batteries If I get them too hot. What do you know about the conductive glue being sold these days.


I am still working out the details for the actually ah of the nimh batteries from china. Heck they are all from china. Probably coming out the back door of the same factory that makes them for the american name brand labels to go on.

The best deals are from china on the aa 3000 mh if you can survive the shipping from china, which has been a nightmare during the Christmas season. I build in 90 cells units then string the units together. Those are AA but I also built with 30 C cells mfg rating is 9.5.

I THINK the true ah is about 4ah per unit and the volts are about 36. It's a learning experience. More a process than an experience. I built the AA and C packs to be about the same AH so they are about equal in the draw more or less.

The c rating is strange but it will turn the wheels with any amp battery and not over heat. If there is no resistance that is, but the speed of the wheel is definitely linked to the Amps in the battery. So I'm not sure what the C rating is.

The scooter I built is much lighter and the hub is probably a few watts less, so it ran pretty well yesterday on the battery. It was so cold I had to come in before I got any decent test for range. It did pull some significant hills though slowly of course.

The plan is to jack up the ah one last time over the next few weeks. It will go up by four or five with the next string. then I have another string coming in from China on the slow boat.

When I am able to get this thing on the road consistently, I will have to begin working on the charging system. Since I can not ride it with any consistency, I am charging the pack with two lead acid chargers. Some of the time giving it 3amps at a time. Then after what I think is about the right time, I cut the charge down to one and a half amps for a while. I have a shutoff timer switch I built so I run them one hour at a time.

The weather is too bad to work on the scooter very much but I think it is close to operational. Well it is good for testing I think.
 
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minreg

New Member
Feb 5, 2014
2
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FL
If you are soldering the copper wire to the cells you are done. Only battery bars would perform better and build a rigid pack. Bars are more difficult to solder though. Anything other than soldered copper wire or battery bars is going backward.

You may get some versatility with some other method but you will not get a better battery pack. For performance and safety solder is the way to go.

I have 25 years experience with sub c cells and soldering battery packs. I would expect sub c cells to outperform aa's.

If the rating on the battery states 3000 mah then you need to divide by 1000 to get ah. Or multiply ah times 1000 to get mah. Likely the true ah or mah will be less than stated. Unless you are using high quality cells or have the tools to increase mah.

The only true way to determine mah is by measuring the cell or pack at a known amp discharge rate down to a safe cutoff voltage. But what is really important here is how the pack works when the rubber hits the road. If the packs are built well and charged properly then you should have no problem finding the best pack by the seat of your pants.

Soldering will not damage cells. Been doing it a long time. Holding the solder iron on a cell for a long time is not desirable. But if that is the case then there is something wrong with the prep, technique or tools.
 

deacon

minor bike philosopher
Jan 15, 2008
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north carolina
I know you are absolutely right. I did a little time as a telephone man in my youth, so I'm familiar with hot soldering, but it's too much trouble for the average person and me included.

So if you are going to build a no solder pack, expect to inspect it every couple of months. BE SURE TO USE THE INNER TUBE BANDS FOR TENSION. They are like the springs in a battery compartment of your flashlight or small appliance.



So Far once I switch to copper it has done well enough. I'm going to try it with more battery power today to see how it works. I'll let you know what it's like later.

I have more batteries and copper foil on order now if I need to rebuild the pack I hope I can use copper foil instead of wire.
 

deacon

minor bike philosopher
Jan 15, 2008
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north carolina
I just got the copper foil from a music supplier. It is used to isolate electric guitar pickups or something like that. I bought three feet of it so there is plenty for battery packs. It came glued to a piece of paper like wrapping paper. I probably could have gotten some gold foul at the gift wrap center.

Anyway it seems to be conductive, and I don't have any idea if the backing will at any resistance to it or not.

So we shall see.
 

deacon

minor bike philosopher
Jan 15, 2008
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I will get that next time. I saw some of it advertised. I had no idea th e one I bought had a paper back when I bought it. I did a small test with a couple of batteries. They didn't seem to be to have any loss but you never know till you get it done and check it on the bike.

Mostly I'm worried about it heating and the paper catching. I'm going to be almost sitting on the batteries so it wouldn't be that great to have them go up in smoke. lol

I have the last set of Batteries in NYC and headed this way. When they arrive I'm going to give it a try and see just what I have. I might just jack the voltage up to forty eight volts when I get it working. I will probably be bored when I finish with this project anyway.

That was kind of the point, being able to reconfigure the pack at any time.
 

deacon

minor bike philosopher
Jan 15, 2008
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north carolina
Eureka my last set of batteries came and I have the pack complete. Of course I have to charge the last one. And of course it is going to rain tomorrow so Sunday is my day to test it. I am SO looking forward to riding it.

I will let you know how it does. I am either going to be thrilled with it for the money or file chapter 11/
 

deacon

minor bike philosopher
Jan 15, 2008
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north carolina
I have pretty much co ncluded that nimh batteries are a waste. I think the problem is the they have less than 1c draw. They will not drive the bike though they have plenty of volts left. Usually the volts go down as the amps drain away. So I'm assuming the batteries prevent draw less than half a percent of the amps even at full throttle.

I am going back through soldering the batteries so there is no question that I tried everything. Then I might try to use them a different way.
 

deacon

minor bike philosopher
Jan 15, 2008
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north carolina
I have begun to reassess these batteries. After three poor performance trips. I broke the pack down and resoldered it. I found one cell that was completely dead. So instead of six batteries I took it out with five with an iffy charge and the pack worked better than it ever had. I went two miles and came home with it still running fine.

I still have eighteen amp hours to add back in when I get a new aa battery. I can't believe I didn't have a spare cell. Oh well I have a bunch on order now. The point is that I could take the battery apart and trouble shoot it. I have to replace a one dollar cell and it will be better than it is now.
 

deacon

minor bike philosopher
Jan 15, 2008
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Well this was a bust. I put ten mile on the batteries then when I got home to hook them to a charge they caught fire. I had no idea that dry batteries boiled like that. anyway I'm through with them PLEASE DON'T TRY THIS AT HOME.