Enhancing battery output

[Seneca]

Hello

I just bought this http://conhismotor.com/ProductShow.asp?id=295, and the bike's fine, but the battery is not enough. The voltage dips during load is enormous.
I've googled the battery, and I doubt that this battery can supply 1000w continous output that the motor requires. The ones I've found can only supply 15A continous at 48v, which is too low.
My 48v 15ah Ping battery is much much better, no voltage sag what so ever.

This is how it looks like:
http://www.diytrade.com/china/pd/10154060/High_rechargable_LifePO4_e_bike_battery_pack_48v_20Ah.html

Do you have any recommendations on how to fix this? No replacement batteries exist that can supply the power. Can I add for instance add one or two hobbyking 8,4v lipo-pack in series, to supply the extra juice, or do I need another 48v battery (LiCoMn or LiFePo4) connected in paralell?

Best Regards
Seneca

 

[docnjoj]

Unfortunately those types of batteries are low C-rate cells. You said it yourself that your Ping performs much better. Parallelling another battery of similar output would stiffin the C-Rate and reduce the sag. It is not ideal but could you parallel your Ping?
Also we are assuming that the new battery is in good shape with proper balancing and cells of pretty equal performance. That can be tested for but it will take a bit of work. Do you have either a voltmeter or whatmeter? Celllogs perhaps?

Others will join in with more expertise than I have.
Good luck
otherdoc

 

[wesnewell]

Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum). This will help people help you. Example: Wylie, TX, USA. Without knowing what country you are in it's hard to make any recommendations. Thank you.

How much is it sagging? It's rated for 50A max, which should be plenty. Suggest you test the battery balance first. Assuming it's a 16s lifepo4 pack, you could parallel a 14s lipo pack with it and that should help. Wouldn't charge it over 58V though. If you try and series in more voltage, you will probably blow the caps in the controller which are likely only rated for 63V max.

 

[Seneca]

Wesnewell: I don't have the batterypack listed in the link, I only attached it for a visual reference. The pack I have has 15A discharge Max. I've updated my location.

docnjoj: I have no possibility to check the balancing of the cells in the pack. Honestly, I haven't even opened the pack yet.

The voltage dips haven't been measured accurately. I've seen it on the twist-throttles battery indicator. With my Ping battery, the battery gauge doesn't even move until its almost depleted. With this battery, the guage moves back and forth from Red to All green like a yo-yo when fully charged. It's at Red when at WOT.

Also, when I do a stationary WOT, the spedometer indicates 59km/h without load, and with load (me on the bike, flat surface) it manages only 42km/h. My other 1000w bike manages 45-48km/h with the ping battery.

 

[dogman dan]

It's quite possible that the dip is being caused by just one low cell, or one cell kept low by a faulty bms.

If you can, open it up and get access to the individual cells, or the individual wires to the bms. If all is as good as it can get, great.

But you will still have to run a lower amps to make good use of the battery. Smaller motor, smaller controller, or parallel it with another battery of the same voltage.

Series won't help, since all the amps would still go though one cell of the weak battery.

 

[jerrypa]

I have same kind off 36V battery JL-JD21-10A-36/10-A001 that was bought on 2011.

Do the battery do these when it is overloaded.
- Battery random dies and get back to live when turn the key off and back on? Usualy almost on a hill when max power has taken out.
- Sometimes battery works well after happening but sometimes (after lot load) it start to work in a moment.

Do the battery have own safety circuit that shut down the battery when voltage is too low? I think so.

Battery
http://www.conhismotor.com/ProductShow.asp?id=41

 

[skeetab5780]

You never know what your getting when you get one of those aluminum housed batteries. they used to be stuffed with 8-12AH SLA bricks back in the day.

One thing to notice is that the 48v 10ah has a 4A continuous discharge current!! and the 36v 10ah(with less WH of usable energy) has a 20A continuous discharge,
then again the 48v one also says it can take 50A spikes...I find that hard to believe if it can only handle 4A steady

 

[neptronix]

There are tons of crap underperforming batteries out there. Specs are exaggerated. Cells are not tested and matched. They cut off early. Warranty is a joke ( just ship it to China for $100 and they'll send you another broken battery and ship yours off to someone else.. )

It sounds like some people learned the hard way. Sorry that you had to fall for that. Look for the batteries that have good reviews and take no chances, because there are many sellers willing to ship you a bookend.

Your options are limited to a few things:

1) Test and replace the bad cells.
2) Parallel the battery pack with something stronger, to spread out the load among both batteries.
3) Viking funeral, endless sphere style

 

[jerrypa]

Where i can buy new cells?
Cell Specification 3.7V 2AH
Cell Combination 5-parallel 10-series
Cell Size 18650
Cell Quantity (parallel*series) 50

Its seems like to be warming problem? Because if error comes after lot use it will not work right away but after less use it will.

Edit:
All battery couples voltage was 4V after driving. Perhaps the bms is broken. Where can i find new one?
ps. Fuse isn't at use.

(Controller is 250W or 350W)