Battery wiring

[Lessss]

OK I've two packs of 4, 12 volt batteries. My hub motor and controller run off these. I am adding a 900 watt brushed motor and controller that are 36 volt. I'm going to wire the 36 controller to 3 batteries in each pack. This will leave off 1 12 volt battery in each pack. This 900 watt motor will only be used for hill climbing or pulling out of an intersection.

So the question is how will this affect batery balance for the 2 lone 12 Volts. Since they are still in a 48 volt loop of their own, and in a loop parallel to the 36, they will still be contributing yes? Nothing should get unbalanced from the way I'm going to wire it?

 

[Elmweaver]

Well 1 battery in each pack will not be drained in unison with the others over the course of your ride so they will be unbalanced to some degree. If you were using just one for lets say lights or some small drain then it might not be a big deal but with 3 getting a big drain and 1 each not when you charge at 48V (I assume) then 1 battery in each pack will be overcharged compared to the others.

Thats my theory. Right or wrong. :lol: :lol: :lol:

 

[Lessss]

So having the 12 volt in parallel ith the 36 means it won't get a drain?

 

[Elmweaver]

hmm, to much math for one day has me given me a brain cloud. :lol: :lol: :lol:

Not this thread Lessss but another one.

Ok, I think what I was saying is that when you use the 48 volt leg you are draining all four batteries. However when you switch over to just using the 36 volt leg you are only draining 3 of the 4 batteries so if you use the 36 volt leg a lot more then the 48 volt leg then 3 of the batteries will be drained a lot while 1 will only have a partial drain on it.

When you go to recharge and you use a 48 volt charger which I am assuming you intend to do. 1 battery will be charged before the other 3 are. So there will be some amount of battery unbalance.

What kind of effect that will have on the battery pack I do not know it just seems as though 1 battery will be overcharged by the time you get the other 3 charged.

As always I could be totally wrong. Maybe someone else will jump in and clear it all up for us.

 

[Lessss]

You are catching the fact that that lone 12 V battery is hooked up in parallel with the 36Volt group?

 

[Elmweaver]

Sorry Lessss, I am not seeing the single battery in parallel with the 36Volt groups in the drawing above. I see where your saying it in the drawing but not where it is connected in parallel. Does not sound like a good thing to do anyway.

But I am brain dead tonight I will look again after some sleep and maybe I will see it by then.

 

[Lessss]

Actually I think you're right the 2 lone 12 volts aren't in parallel with the 36's(tricked myself with the diagram). I'd have to run another set of wires. If I'm going to do that I might as well hook the 2 12's into a group of 24. Man that'll be a lot of wires though.

 

[Lessss]

Diagram 2

Diagram3

 

[Lessss]

hmmm, - - would this be 3 parallel 36 volt packs???? What does it do to the 48 v circuit. Oh my head hurts.

Diagram 4

 

[knightmb]

OK I've two packs of 4, 12 volt batteries. My hub motor and controller run off these. I am adding a 900 watt brushed motor and controller that are 36 volt. I'm going to wire the 36 controller to 3 batteries in each pack. This will leave off 1 12 volt battery in each pack. This 900 watt motor will only be used for hill climbing or pulling out of an intersection.

So the question is how will this affect batery balance for the 2 lone 12 Volts. Since they are still in a 48 volt loop of their own, and in a loop parallel to the 36, they will still be contributing yes? Nothing should get unbalanced from the way I'm going to wire it?

Ok, I think I get what you are doing. You have a ton of batteries and two speed controllers. One you want to run one at 48 volts and the other at 36 volts, am I correct?

 

[Lessss]

Correct. The price was right on the unite motor and 36V controller. Already had hub ad 48 and 8 12 volt batts.

 

[Elmweaver]

Lessss, I would not try to get that involved with it. I just don't see the need to go through all that.

I do need to correct what I said last night though. I said it backwards because I did not realize at the time that the 48V was the primary source.

What will happen is that the 4 batteries (each group) will take for example 1 amp drain per mile of riding and the batteries used by the 36V will use 1 additional amp per mile of riding. To make things easy to see.

48V for 10 miles = 4 batteries with 10 amps drain
now along the way you need the 36 V for 3 additional miles.
36V for 3 miles = 3 batteries with additional 3 amp drain.

End of ride has 3 batteries with 13 amps of drain and 1 battery with 10 amps drain per pack. So you plug in the charger and charge all 4.

3 batteries will be fully charged before the fourth is. My concern was that you will over charge the other batteries while trying to get the fourth charged.

There I think I said it correctly that time.

As for wiring a single 12V battery into a parallel circuit with a 36V series of batteries that just does not make sense to me. I believe if you do that the 36V pack will try to make the single 12 volt battery into a 36V one. Probably not going to be a pretty sight.

So your saying how do I solve the imbalance with the battery packs. Best way would probably be to recharge each battery fully as a single 12V battery. I am sure others who have more knowledge using charges with big battery packs can tell us the best way to do it without all that.

 

[knightmb]

Correct. The price was right on the unite motor and 36V controller. Already had hub ad 48 and 8 12 volt batts.

Ok, I'll have to double-check this diagram when I get a chance later today, but I think this will actually cause the batteries to short out.

But let me get my facts straight, you have (8) 12 volt batteries to start with correct? You are trying to get the most amps possible and provide a power path of 36 volts for one controller and 48 volts for another?

 

[knightmb]

Ok, this is what I could come up with (not sure what type of batteries, so I ripped a picture of a SLA :wink: ) Basically, you will have 4 sets of (2) 12 volt batteries in parallel, in which those are wired in series to give you 36 and 48 volts along the way. This will double the amp/hour and separate out the voltage you need for each controller. Technically, you could run them both at the same time this way, two wheel drive. :lol:

Now, the first problem that you've already mentioned. When running the set at 48 volts, each battery will give it's part to the electrical power and thus all run down equally for the most part. But, when you switch to the 36 volt set, those two extra 12 will basically sit there and do nothing. So all the batteries in the 36 volt set will run down before the (2) idle 12 volt batteries.

This does leave an interesting problem, basically how do you charge them all? Well in this case, you could chance a high amp @ 48 volt charger, but it just means those two extra 12 volt batteries will take a beating upon every recharge since they will not be as depleted as the rest. Another alternative would be to use two chargers, one for th 36 volt set, the other for the 12 volt set. This could work because I did this on my e-bike before because I had a mix of SLA and NiMH batteries at once point long ago.

Another alternative is to simply put the 48 volts into both controllers. I'm not sure how much that 36 volt controller can take, but a simple heat test @ 48 volts should let you know if you should try this or not. Just hook up the 48 volts and turn on the power. Put your hand on the metal fins for the heat sink and if they start to get hot, cut power immediately. It means the controller just won't take the extra power. If it passes the heat overload test @ 48 volts just sitting there, try giving the motor some power for about 15 seconds and feel that controller again. If it's too hot to touch, then it won't work at that voltage because it can't get rid of the heat fast enough. If it's still cool to the touch, then it should be safe to give it a try @ 48 volts and see how it performs. If it's like all the controllers, it probably has heat overload protection. So if it can past those two test without overheating, then using it for a while and if it's starting to overheat it will shutoff on it's own. You'll know 48 volts won't work then.

Picture diagram below, have to click to get the big one (yeah it's big, have high screen resolution ready :wink: )

 

[Lessss]

The motor is a Unite 900 W MY1020 36DC rated speed 2500rpm current 18.3A. Nobody has been able to tell me if the motor would take 48Vs

The controller is Yongkang Jiangchuang JC36

Running both at 48V would be the simplest setup.

Anyone have this controller? Or know if it will take 48V?

 

[knightmb]

The motor is a Unite 900 W MY1020 36DC rated speed 2500rpm current 18.3A. Nobody has been able to tell me if the motor would take 48Vs

The controller is Yongkang Jiangchuang JC36

Running both at 48V would be the simplest setup.

Anyone have this controller? Or know if it will take 48V?

I think the motor would be fine, it's the controller I would worry about. Electric vehicles often have motors in them that only use 48 volts and they pump over 120 volts into them to get up to highway speeds. As long as the motor doesn't over heat, that's the only issue with pumping more power into a motor.

 

[sabrewalt]

Drop your battery fuse to 20 and try it. Then bump it up... At your own risk of course.

 

[Lessss]

I notice alot of 48V bikes have a second battery pack that is only 36 volts. Are they over charging this pack if charging both packs on the same charger at once?

 

[Lessss]

Actually I've been thinking.

Why do I need a second controller at all?

This second motor will ONLY be used to climb hills. It will be turned on only once I start to slow down USING THE HUB BRUSHLESS MOTOR. So Since it is a BRUSHED motor I could hook it directly to the batteries with a simple on/off switch.

Am I missing something?

 

[Mathurin]

Hey, that's brilliant! Just needs to be geared right.
Maybe with a big breaker as switch? Two for one.

 

[Lessss]

Mathurian, why the circuit breaker? Are you expecting a very high amp draw despite the fact there will be two motors pushing the bike?

 

[Lessss]

Hmm odd my very first image is gone on page 1.

 

[Mathurin]

Nah, but a breaker would do double duty as fuse/switch.
You could play with it's value some, too.

 

[bobmcree]

a 36v motor will almost always take 48v. the issue is heating and current limiting. i would just hook it up and watch the temperature carefully while gradually using it harder. a good IR temp meter is almost a necessity these days, and can be had for $29. usually a higher voltage will run more efficiently because the current and thus the resistive losses will be lower.

the best way to tell if a unique controller will handle a higher voltage is to look at the voltage ratings of the big electrolytic caps and the mosfets. most of the fets used in ebike controls will handle at least 55v but there is always one that is unique. even brief testing of a controller with 40v fets at 48v could easily be disastrous. it is much safer to look up the part numbers on the web.l

 

[jackatfsi]

The motor is a Unite 900 W MY1020 36DC rated speed 2500rpm current 18.3A. Nobody has been able to tell me if the motor would take 48Vs

The controller is Yongkang Jiangchuang JC36

Running both at 48V would be the simplest setup.

Anyone have this controller? Or know if it will take 48V?

I have a JC36 (EBay special) and this post has inspired me to take it apart here in real time........

!. The whole board will slide out of the heatsink as the switching transistors are gled to thermal pads that are clamped to the side of the heatsink-enclosure (good idea)

2. This unit has a lot of residue on the board like it wasnt cleaned properly or maby it was sprayed for moisture resistance ??

3. The storage cap is two 1000 microFarad, 50 volt caps in parrellel...should be fine for 36v.....the high current leads have been overlaid w/ heavy solder, which is good....but I can see 4 bad solder joint I'll want to redo....3 on the leads and one on one of the transistors.

4. 2 transistors are STPS20S 100CT CC 025 U MRC 419
2 are P60NF06 CC03X 6 MAR 524
1 small one is 2N5551 B011
the other is 2N5401 B011
the big diode is a 1N5408
the IC has the ident scraped off

I'm hoping to use this w/ a Heinzmann 500W rear hub motor and 3 12V 21AHr GMA batteries from PowerSonic

I'm a complete newbie so any info appreciated.

Jack