Would you use a 48v 10AH LiFePO4 with a 1000w hub motor ?

[1000watt]

I have a Golden Motor 48v 1000w (430rpm) Brushless rear wheel kit and I think my controller has a rating of [36-60V 22A-35A max] but I am not 100% sure of that... My questions is, will my 48v 10AH LiFePO4 that I just bought handle the amps of my setup?

I see on ebay 48v 10ah battery listings mentioning "Fit 48V Motor Wattage: 200 Watt to 480 Watt. 350 Watt suggested."

Here are the specs on my battery:

* Voltage: 48 Volts
* Capacity:10Amp Hours
* Charging Voltage: 60 Volts
* Charging Current: <10 Amps
* Rated Discharging Current: 10 Amps
* Max Continuous Discharging Current: 20Amps
* Max Discharging Current (Peak): 30 Amps 12s
* Amperage Cut-off Protection: 20 Amps

 

[Russell]

If you have a generic 48V/10Ah LiFePO4 battery then I would not recommend using it with a controller much greater than 20A. If you are unsure how many amps your controller will supply then simply look at the max amps logged on your WU meter (you say you have one in your signature). From the length of the controller it's a good bet it's a 12-FET model which makes 35A a distinct possibility. You could modify the controller to output less current by clipping a shunt, restrict it with a Cycle Analyst or buy a smaller controller (this one is cheap; http://endless-sphere.com/forums/viewtopic.php?f=4&t=13659 ).

-R

 

[icecube57]

Thats gonna be a 35A controller. A 48v 10Ah on a generic pack isnt going to do 35A a 15AH would. A 10AH v2.5 Ping could do it just barely.

 

[1000watt]

Well, I haven't received my battery yet, it's currently being mailed to me. What would happen if I ran this setup? Would I risk damaging the battery? or would the controller cutout from not having sufficient battery amperage? I sure would like to use the 10AH if I could... Maybe I will need to get a Cycle Analyst to limit the amps to 20A...

thanks

 

[Russell]

The BMS in the battery should protect it from prolonged high currents. The specs you posted show the BMS will allow 30A for 12 seconds which should be plenty to get you up to speed however where you'll have trouble is on hills when it's not unusual for the controller to go to maximum and stay there, depending of course on throttle position, steepness and length of the hill. You can always try it out and if you rarely have the BMS trip because you don't have a lot of hills then don't worry too much about it. Still prolonged use of any battery near its limit isn't the best thing for battery life so it would be best to keep the current in a range better suited for that battery which as I said earlier is right around 20A max. If you try out the controller and battery combo and the BMS trips frequently then I would recommend if your controller has three shunts wires you snip one to reduce the current allowed. If you don't know what the shunts look like they are the bare raised wires to the left of the red wire in the picture below (this controller has 2).




-R

 

[1000watt]

Yes, snipping one of the shunt wires would be a good way to solve my problem. If I got a better battery some day I could always re-solder the shunt

I just opened up my controller. Looks like I have 2 shunts. I couldn't slide it out of the case because it is glued pretty good on the side. I think I can pry it but I dont want to mess it up. I guess I could snip one of the shunts without having to slide it out. Here is a pic I just took.

thanks.

 

[Russell]

I'm surprised that a 35A controller would have 2 shunts. Anyway once you get the battery hook everything up then apply the throttle and brake and see what the current actually spikes to on your WU meter. You can try to "tune" the max current by making partial cuts to one of the shunt wires with a diagonal cutters.

-R

 

[1000watt]

Ok, I will test it first with my WU meter. So, if I cut (1) shunt I will be down to 17.5A MAX correct? So you are saying to just cut it maybe halfway (NOT COMPLETELY) correct?

 

[Russell]

Here are two identical controllers;

On the first one they cut one of the shunts completely then raised the current to 22A by applying solder to the sides.



On this unit they left the shunts in place but tuned it to 22A by making little cuts in the shunts.



I would suggest seeing where you are then tuning with the second method.

-R

 

[monster]

run your bike lights from the battery (4 x MR16). if you see the lights dim when you accelerate then you are over stressing the battery.

 

[dogman dan]

I agree that a 10 ah ping is best used with a weaker controller, such as 15-20 amps. When cruising on flat ground your motor should be pulling about 15 amps so you are going to average about 1.5c discharge rate. That will be the case even with a 35amp controller. The stress on the battery will be for short busrsts when starting up, or for long periods when you climb hills. So how much strain on the battery will depend on where and how you ride. If you ride in a city with lots and lots of stop and go, or have a big hill to climb your battery will be too small. Length of ride will mattter too, If you have a long ride across the city that will be harder on the battery than a short one. You can get away with higher discharge rates if the cycles are lighter, and the rates aren't really high.

But if you have a small town or medium city in the flatlands, and ride only 5 miles per trip, you should be fine even with the 35 amp controller. A 5 buck harbor freight ampmeter for a car can be wired into the bike temporarily to see what kind of amps you are pulling. I suspect you have a 22 amp controller, that can spike 35 amps for a few seconds before it ramps back down to 22, like when climbing a hill. If you have easy riding, this should be fine with the 10 ah ping. You may get a few less cycles than with a 15 or 20 ah ping, but if you get 700 cycles of 10 miles that's still 7000 miles. If you need more range and power, start saving for another 10 ah lifepo4, and run them in paralell connection. Sla's or something cheaper could also be paralelled if you have some around.

 

[grindz145]

for the sake of longevity definitely modify the shunt. The ping may do it but you might not immediately see the effects until your capacity drops off after 30 cycles or something to that effect.

 

[TMaster]

Hello I am new to the forums here, and I just bought the same kit 1000watt has with that silver controler. I took the back cover off and mine also has 2 shunts, but there is another spot for a 3rd shunt. Would there be any benefit to adding a 3rd one to the board? I plan on using a lot more capable battery. Or would adding a shunt be too much for the controler and burn it out? The kit came with a 30 amp fuse to go to the battery.

 

[mwkeefer]

Don't cut or solder the shunt - your looking to limit at 22-30A do it in Parameter Designer and reprogram your infineon to the proper level - it's not permanent like shunt mods and you can play with various ranges to see outcome / result.

-Mike

 

[Russell]

Don't cut or solder the shunt - your looking to limit at 22-30A do it in Parameter Designer and reprogram your infineon to the proper level - it's not permanent like shunt mods and you can play with various ranges to see outcome / result.

-Mike

You make it sound like reprogramming a controller is a simple matter anyone can do. The funny thing is my E-BikeKit/Infineon controllers were sold to me in the condition shown in the photos I posted above with one "adjusted" to 22A by soldering and the other by cuts to the shunts. Soldering is quick and easy to do and it's definitely not permanent since I have "adjusted" one controller a half-dozen times with solder.

-R

 

[tostino]

Programming is something easy that anyone can do... If they have the programming cable.
So is soldering the shunt though. I did a bit of both to my 12 fet infinion. I put some 4110s in, beefed up all the traces, and modified the shunt.
I went from 3.8mohm stock down to 1.8mohm at first (and 55a programming limit), and then I saw that when full throttle at a start, my shunt was pumping out 21.8w of heat (at 110a). I just got lowering it again from 1.8mohm to 1.05mohm, and lowering my current limit in software to 35a.

It should give me a current limit of 126a, and the shunt should "only" make 16w of heat .

My motor loves it's amps!

Anyways, just saying that a good mix of both is needed for fine tuning.

And no, I would not run 10ah lifepo with anything above a 15-20a peak controller. However, I wouldn't run 10ah of crappy lifepo either :wink:. If you want a small battery pack like that, i'd go with higher quality cells, otherwise i'd try and save for a bigger battery.