Even More Batteries!!

[cannonball2]

Thanks guys!

KC, just using the throttles that come with the motor kit. The generic 3 wire unit the 5v type. Upping or lowering pack voltage doesnt affect throttle voltage with most controllers within its operating range. I used my Garmin for 2 charge cycles on the original pack to establish speeds and distance. I calibrated a common digital speedo with the Garmin, its pretty accurate done that way. Living in the flats is about as good as it gets for speed and range. I almost always assist, and usually ride in the 15-20mph range which usually pulls around 5amps on the amp/vmeter at the voltages Im running. My 10.4ah pack is the one with the most mileage ridden, havent gotten a lot of time on the 13.2ah unit yet, and basically none on the commercially produced 15ah48v pack. The 48v pack is somewhat lethargic compared to the 52v packs. Hope to run the 55v pack this afternoon. Slowly climbing the voltage ladder. Will have to change controllers to go any higher. Hope this answers your questions.

 

[cannonball2]

Well guess my battery situation has been finalized. I added another cell to the original homebuilt pack, so I now have two 55v batteries and one 48v. I weighed them on the bathroom scale so Im sure its not exactly accurate but close enough. The purchased 48v weighs 10lbs(as advertised) the 13.2ah weighs 8.5lbs and the 10.4ah 6lbs. A far cry from the 48v15ah, 50lbs of SLAs I have collecting dust! I have enjoyed building the packs. Its kinda cool motoring along on something you built(assembled?). Now its time to enjoy!

 

[deacon]

Okay I'm officially impressed.

 

[silverbear]

I concur with Deacon...very impressive and at a later date I intend to follow your lead. Still debating whether to go full blast with 48 (55) or stay with 36V.. Since the trike build I have in mind is hybrid power (earlier generation golden motor up front and in back a 1950's Villiars midget 2 stroke putt putt motor with a foot start.from a vintage reel type lawn mower). This will be my old guy ride. 36V will probably be plenty and that's what I have a controller for along with three older and quite heavy lead acid 12V batteries. Staying at 36V will keep the cost down and going your route makes it possible for me to dump the lead out and go modern on a budget. I admire your know how and when the time comes will be asking questions no doubt. Thanks again for sharing your knowledge.
SB

 

[deacon]

I'm going to order the batteries right now so i guess Im all in.

 

[silverbear]

Do a thread, Deacon, so that we can follow along. I'll be building mine once I have the trike all together. I'm making it from a 1963 Schwinn American Deluxe step through frame and making up the rear end from a riding mower differential type of axle. But I have a couple of other projects to finish up first so it will be a ways off. How much voltage are you figuring on?
SB

 

[cannonball2]

Thanks for the kind comments guys!
Hope you have recovered fully from the attack of the vicious chain saw SB!

I might add that Lungcookie a forum member used solid copper wire from 12/2 house wiring hammered flat as cell connectors. Thats a great idea and maybe easier than the twisted copper wire. The twisted wire is probably cheaper and maybe a bit easier than stripping 12/2, but 12/2 is so easy to find.

Before you guys buy batteries you might want to post a link so we can be sure you are getting what you need. Stay away(!) from the Chinese high mah batteries like Ultarfire, Trustfire etc. They are junk. A brand name like Samsung, Panasonic, etc. is what you want. Also the cells model# can be looked up up online to get the C rating. If buying used buy from a supplier that has tested the cells. There are new cells that are out there that have been removed from NOS obsolete batteries and detabbed. My modular pack is made from them and performs very well. The higher voltages yield a bit more speed and less amp draw. My 36v 500w 9C cheapy kit runs 930w@62v/15amps. The caps in the controller are 63v and will eventually probably blow, but I have a 72v controller on the shelf when it does.

Last thing to remember is to go slow and keep up with polarity and the bare cell ends, a short that these voltages is spectacular and basically vaporizes any wire/metal involved!

 

[deacon]

http://www.ebay.com/itm/111373801434?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 These are sony so I think they will work. They are used so I don't have a lot to lose. A short in a nimh is a nothing to sneeze at. Smolders with a noxious smoke.

I'm going to be running a 36v 800watt brushed controller for the friction drive. I run it at 48v some so it will hold it I'm pretty. sure. I read a review and the guy did a lot of mumbo jumbo but concluded they were pretty rugged.

 

[cannonball2]

Those are good cells. If I am remembering correctly they will handle a 2C discharge rate. Doesnt sound like much but theres a bunch of cells! You will want to parallel at least 4 cells(5 would be better) to get a decent AH rating. If you are over volting @48v then you could build a 12ah battery with 64 cells that would give about 52v off the charger. The old FD will really move on the initial charge! You really need a volt/ammeter as the LVC in the 36v controller may be too low for the 48v pack. You will have to practice battery management with these cells as if you pull them too low they are toast, not forgiving like SLAS. There are discussions on charge/discharge voltages seems that 4.15 max charge is close to full capacity with out stressing the cells. Some folks dont pull them down below the mid 3v range. I drop mine to the low 3v range.

If you build the pack in a modular fashion the its possible to balance the 7.4 bricks. My first pack had a BMS but it was probably defective and I removed it. Im sure its way out of balance but it still works about as well as it ever did.

 

[deacon]

I have read all kinds of thing about charging so I'm going to go with no bms and take the loss on the used cells if I have to replace one. I'm a real hands on guy so I don't mind replacing one cell. I thought I would go 10 lines of 6 in parallel.

I don't mind a little time on the charger so I'm going to go with the sla charger and check it till I get an idea of the charging times. Then set my timer to shut it down when it reaches it. I think my sla charges at about 42volts which should be fine for the top end of the cells. Just have to get them off before it goes into trickle charge mode.

I fugure a 6 cell string will give me about 14 ah and that at 2C is more than the 22amp pull of my friction engine. Plus I plan to use my sla as a secondary power source using my right and left switch. I can get the sla at 48v and use it to climb hills for a while. Just have to make sure to have fuses on the power pack. I have a fuse at the controller but I want to isolate the power pack as well.

 

[Easy Rider]

Thanks Cannonball2 for sharing your battery build. Very interesting and educational.

 

[cannonball2]

Thanks Cannonball2 for sharing your battery build. Very interesting and educational.

You are very welcome!

 

[cannonball2]

Deacon, 6 cells in parallel will be nearly 15ah. Thats a nice size pack, but 10 6cell cells is only 37v. You will need 13 6cell cells or bricks for a true 48v battery, thats 76 cells@6 parallel. You could drop to 12ah(5 cells parallel) and need only 65cells. When figuring pack voltage use 3.7v times the paralleled cell count. 3.7v times 13= 48.1v. Your 48v SLA charger will work, but if its like mine it puts 56v. I charge in tandem with my fluke meter and start pulling the charger when the meter reads 55volts to see what the battery is actually holding, usually its a volt or so less than the meter. Its important to get the voltage right as the capacity starts to top as the voltage is nearing 4.2v/cell. 4.2 is 100%. As I remember 4.15 is maybe 95%. under that capacity drops off fast. I think 4.0v may be in the upper 80% range. I had a chart on this but lost it.

 

[deacon]

ah but I want 35v. My motor is 24v and 36 is a nice gentle ride. I kick in the 48 back just for big hills to get the watts up but I try use it short term to cut back on the heating. I hope that it works out to be 36v I'll be thrilled. After I sperement with this thing a while I probably will build something else. Thanks for the advice I hope Mine works as well as yours seems to be. I'm expecting to get my cells by the weekend so maybe next week I will know what's what.

I have 24 36 and 48 v chargers I will toss the 36on it. I think it charges at 41.5 if I'm not mistaken. Im going down to check it now.

 

[cannonball2]

OK. Thought you were running 36v on 48v.

 

[cannonball2]

I finally modded my Magic Pie/Diamond Back to fit the modular battery. It has been doing only work horse duty in the cargo bike. This battery is made(mostly) of the same cells you are buying. These were NOS. I took it hot of the 60v charger @ 63v and hooked up all but the last cell having 54v. The MP controller rejects any voltage over 59.5v(on my meter anyway). I had to ride nearly 6mi to get the voltage down to be able to use the last cell. It was 59.2 when the controller accepted it and it took of better than it did when I started. For a short time of course as the cells soon equalized. It brought the pack back up a few volts. Kinda cool, could be used a a "reserve tank". One could also hook this battery to various(lower) voltage systems and have even more reserve. It would double the range of a 24v. I retaped it in black to make it more stealthy.

 

[deacon]

Well I'm going to test each three pack to see if the voltage is close. Then I'm going to build the six pack from different voltages and let them sit. I expect them to balance themselves since sla does that. Then when I get everything assembled I will run a charger for a short time to see if it will all come up to the charger voltage.

I checked the specs again and they say max charge is 2Amps. The old stupid charger (As opposed to a smart charger) puts out 1.5 amps. The max charge on the cells is 4.2 volts. The charger charges at 41.9 volts probably supposed to be 42 but it should be close enough for redneck engineering. I just have to be around to pull it off when it gets to full, so it will stop tinkling down, I guess.

The plan is to build the six packs first since they already have some solder tabs attached. Then I will wire them together.

Tell me this, why did you guys use wire with that high resistance (12gauge). Unless it is too small I plan to use 14 or 16 gauge. My thinking is that 16gauge wire is good for 115 volt at about 10 amps or about 1000 watts max. The batteries will be pumping 22amps but at 36 volts so even less watts. It looks to me like 16gauge stranded wire would handle the load. So somebody tell me if I'm wrong. Better to be called a dummy by you than burn up the cells.

They also warn to charge in a fireproof container. Do you have any idea how hard it is to find a fireproof box these days. I looked around the shop and found the first tool box I ever bought and it was metal, everything else I bought since then is plastic. Not exactly fire proof.

I'm also surprised that they are being shipped USPS. Left the California sorting center last night. Got to love tracking numbers. It is at the trainstation on a train bound for Atlanta Third fright car from the rear.

 

[Lungcookie]

The MP controller rejects any voltage over 59.5v(on my meter anyway). I had to ride nearly 6mi to get the voltage down to be able to use the last cell. It was 59.2 when the controller accepted it and it took of better than it did when I started. For a short time of course as the cells soon equalized. It brought the pack back up a few volts. Kinda cool, could be used a a "reserve tank". .

Neat! reserve tank.
You guys building modular battery packs may like the R/C Balance chargers, set it and forget it. Only good to 18v though.
Balance with this and bulk charge with your older chargers for the 36v or 48v.
Something like this...
http://www.hobbyking.com/hobbyking/...IMAX_B8plus_Charger_Discharger_1_8_Cells.html

...And I used 10gauge on the battery and 12gauge wire because it can take higher amps without melting down.
Probably overkill, better safe than sorry in my book.
14-16 is most likely fine for lower amps like your running.
That said I am learning as we go. So I am no expert.

I started using a metal ammo can .30cal, you can get them new on Ebay for $15, Blackhawk brand. Maybe more fire resistant than the plywood and duct tape I had going. Some protection if you drop the bike and hit the battery to.

 

[deacon]

God I hope the battery is smaller than a .30 cal ammo can lol. I was hoping for more like an old k-ration box.. I have had wire burn off sla batteries when I didn't have controller or fuses but never of a properly constructed pack so I'm going to go with my box of wire bits lol. If I smoke it. It will mean there was no big wire laying around, I guess.

The wires coming into the controller for 36v 800 watt are about 14 gauge However some of them on slightly smaller watt controllers are 16 gauge. I suppose we shall see what we see.

Last time I laid a two wheeler down the bike was the least of my worries. I wound up in the hospital for a week when I got home some good Samaritan had returned my bike. It didn't have a scratch, The helmet had to be replaced. I flipped a three wheeler I had designed wrong. Several SLA batteries landed on top of me. I blew out a disk that time. That is another reason I was looking forward to these batteries. They probably will hurt less when they fly through the air.

 

[Lungcookie]

As you are building this yourself you can make it any size/shape you want.
You could just use the ammo can for charging if your worried about a melt down.

I had a bunch of the solid core from when this house was built, that was another reason I used it.
For me I would rather over build something and not think about it again than wonder if I am going to cook something out on the road.
That's one reason why the only thing on my bike I have not replaced is the seat post clamp and 3/4 of the rear fender.

ps. a .30 ammo can ain't that huge...not like its stealth though.