Taking a chance on Alibaba (K Power battery)

emotate said:
Interestingly, when I top it off with the 2A charger that came with the battery, when it gets to 54.6v the charger cycles on and off every 2-3 seconds for about 2 minutes then stays off. Is that the BMS balancing doing that? The 5A charger from Lunacycle shuts off and stays off.
Click to expand...

Some chargers have a circuit in them that latches them off, for batteries that don't have a balancing BMS to disconnect the charger from teh battery once it is full.

Some chargers are made for batteries with a balancing BMS--that BMS then controls whether the charger is connected to the battery or not, so it can balance cells.

If you suspect a balance problem, or test the cell votlages and find one, you should use whichever charger allows charging to cycle on and off via the BMS, and let it run until it stops cycling. On a badly imbalanced pack it can take days.
 
no cell voltage measurements so there is no way to know how far outa balnce your pack is but you can manually force the low cells to charge to the other cells by using a resistor or light bulb to drain the charge off of the other cells in the pack while the pack is charging. that forces the low cells to fill up at the rate that is the maximum charger rate.

if cells #4 and #5 are low then put the resistor across from B0 to B3 for a period of time until the voltage drops to the level of 4 and 5 and then put the resistor across B5-B16 to drain them down to the level of 4 and 5. hope that makes sense. it is the easiest and fastest way to force it to balance.

then leave it charging at full charge so the balancing current will allow the battery to naturally balance.
 
The chargers fans turn off at 54.6v and the light turns green. Isn't that normal? The 2A cycles between red and green for a few minutes before going solid green. I thought that was maybe the BMS.
 
My battery came:

$403.75 Battery (48v 20 Ah) http://www.aliexpress.com/snapshot/6834556913.html?orderId=68608758510303

Ordered on: 8/9
Marked Shipped on 8/12
Received via Fedex International Priority on 8/19.
My bathroom scale shows 13.5 lbs.

I am getting 49.2 volts from it. The key lock is nice. It both locks the pack on the bike, and also electrically shuts it off.

IMG_0216.jpg
 
I just checked the specs on that link, that battery is almost the exact same size as my 48v 10ah battery that looks strikingly similar. Is it possible that they packed 20ah in those dimensions?
 
anoNY42 said:
I just checked the specs on that link, that battery is almost the exact same size as my 48v 10ah battery that looks strikingly similar. Is it possible that they packed 20ah in those dimensions?
Click to expand...

Those enclosures are used by everyone. For sure they sell 10 and larger sizes that use the same enclosure. Can you please weigh yours?

I have a V3 CA on order, so I will eventually be able to tell everyone how good this pack is. I have 14 more days of buyer-protection, so hopefully EM3ev will be get my the other parts by then.

I don't expect it to reach its rated capacity, but the more above 16Ah this turns out to be, the happier I will be with it. I don't think I would file a claim unless it was below 17.
 
rsilvers said:
Those enclosures are used by everyone. For sure they sell 10 and larger sizes that use the same enclosure. Can you please weigh yours?
Click to expand...

I'm unable to put it on a scale right now, but the website for my kit lists the battery at 10.58 lbs. If yours ends up being larger capacity I might just upgrade seeing how it's roughly the same size.
 
I received the same 48V 20AH battery from K-Power last Friday. It weighs exactly 13.4 lbs. The case dimensions are 400 x 150 x 80mm as stated in the specifications. Normally the same type of case for a 48V 10AH battery has dimensions of 365 x 150 x 70mm. Because of the additional height (80mm vs 70mm), the 48V 20AH battery case will not fit in your typical rear double bike rack.
 
I bolted mine to a $23 Schwinn rack from Target/Amazon using four stainless 10-32 Philips screws. I am concerned that the rack is not sturdy enough, but all of the better-mde racks were not flat on the bed. I would prefer a triangle battery from Em3EV - though that would be about $1030 delivered.
 
Yeah. I already ordered a stronger rack and will put this on my son's bike. There is no way this will hold up if the bike is ever leaned over. Even if I carefully lean it on the ground the rack will be over-stressed.

I do like how this one is low for a 26-inch wheel only though, and I hope the new one is not too high.
 
rsilvers said:
Yeah. I already ordered a stronger rack and will put this on my son's bike. There is no way this will hold up if the bike is ever leaned over. Even if I carefully lean it on the ground the rack will be over-stressed.

I do like how this one is low for a 26-inch wheel only though, and I hope the new one is not too high.
Click to expand...

What rack did you order? I'm also looking to upgrade mine. I'd like one at least as wide as our battery (150mm).
 
http://www.amazon.com/gp/product/B000FIE3WI?psc=1&redirect=true&ref_=od_aui_detailpages00

It claims to be 9.3 inches wide. That is 236mm.

You should wait until Tuesday when I see if the plate will mount on it.

I am using four 10-32 stainless philips screws from Lowes. I drill four holes in the plate. On the other side of the plate, I use four stainless/nylon lock nuts with a stainless washer above and below it. I then put that through four drilled holes in the rack, with four more washers and stainless/nylon lock nuts under that.

There is some rattle on my current install from the heavy battery bouncing on the mount plate. I may just put a bungee cord around it all to prevent that but if you can think of another way (maybe electrical tape on the plate to stop the metal-to-metal contact), that would be good.
 
I just ordered this same battery 48v 20ah, just wondering if the plug show on the bms can be used to power the motor/controller? my idea was to use a 10 gauge power cord and cut the other end off to simply wiring from battery to motor/controller
 
I can't follow what you are asking. It came with a plug with a short section of wire on it.
 
The Topeak arrived. It looks nice and strong enough. Problem is, I want the battery to be 2.5 inches closer to the seat post and 1.5 inches longer. Notice how far away it is, and it is not even level. If I leveled it, the battery would be very far from the bike.

IMG_0282.jpg


The Schwinn rack was perfect for orientation but I wish it had more reinforcements. I may take my chances with the Schwinn. Maybe I could wrap the Schwinn struts with pre-preg carbon fiber.
 
Here is the fit of the $23 Schwinn rack on my bike:

Note that I am using four thick cable ties to attach it to the frame.

IMG_0283.jpg
 
rsilvers said:
The Topeak arrived. It looks nice and strong enough. Problem is, I want the battery to be 2.5 inches closer to the seat post and 1.5 inches longer. Notice how far away it is, and it is not even level. If I leveled it, the battery would be very far from the bike.

IMG_0282.jpg


The Schwinn rack was perfect for orientation but I wish it had more reinforcements. I may take my chances with the Schwinn. Maybe I could wrap the Schwinn struts with pre-preg carbon fiber.
Click to expand...

That Topeak rack looks smaller than what the specs claimed (Measures 9.3-by-16.1-by-13.6 inches (W x H x D) ). Looks like the battery is hanging over the sides and off the back. I was planning on mounting the controller between the seat and the battery on the rack straps for good airflow. My controller has been getting awful hot being in the same bag as the battery. Looks like that rack would give you enough room to mount the controller under the rack, if you leveled it.
 
The double racks that fit our battery case are starting to become more available. Have you considered one of those?
http://www.aliexpress.com/store/product/Bike-bicycle-Battery-rack-Rear-Shelf-Rear-Rack-Rear-Carrier-for-36v-48v-battery-suitable/604490_32444998729.html
 
I didn't know of it, but it looks good. I am just not sure how it would fit into my bike near the seat area. I may wait and see if the Schwinn rack breaks.
 
Bend the front part of that topeak rack down, so you can mount the battery further forward. If that won't work, then raise the rack surface with a piece of wood so you can mount the battery forward. rack, 1x6 wood, then the battery.
 
Battery is already too high on the Topeak as it is.

If I bend aluminum tubing again there is a reasonable chance it will just break.
 
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