48v 20ah Mr. Lau Chan / Lifepo4.hk pack arrived (May '09)

I don't see any problems with stopping and starting a charge, it could even be good for the battery, letting paralell groups equalize some and keeping the charger cooler. I charged maybe 20 cycles with my lifepo4 charger before I stupidlly fried it. ( I had 110 plugs on both ends, and thought red tape on the dc side would be enought to keep me from screwing up :lol: ) So for about 3100 miles, I've used plain ol sla chargers on my ping. Eventually I tweaked the voltage on my soneil one up to the recomended voltage for my pack. Unless I remember wrong, some of the round cell packs do charge to the same voltage as a regular sla charger. It's using the lifepo4 charger on the sla that is supposed to be bad.
 
Nice ... well it's good to have an emergency backup but I am still not a happy camper - it would cost me $17+ to ship this lifepo4 charger back and no way I am paying $26 to have another shipped.

I am trying to convince him to send me the board inside the charger but he says he doesn't have any - I suspect he just buys the charger from yet another vendor as he needs them. Argh this probably won't end well.
 
you can use the SLA charger until it goes into trickle charge and if it pushes the pack over 58.4-59V then just disconnect. don't ride it if it only charges a little to 53V since you could have low cells in there, and did you ever get a voltmeter so you could measure the current your original charger was producing? did you already ride on this pack?

no need to be insulting to the people who sold you the stuff, they are trying to help as best they can but they just buy the chargers from someone else like you said, so you could try returning it and accept surface freight, and then buy another one airmail from someone like ecitypower who has them so cheap, or maybe look on ebay specifically for chargers. or just buy another charger from emma and see what they charge for it so then you could have a backup once you fix the broken one.
 
Problem is, that might be the food budget he'll be spending. I leave my chargers on all night, and have done so for 12 months now. I must be overcharging some cells, but they seem to take it okay. No runt cells in my pack thank god, but it might be a worse thing to overcharge a not so good cell.
 
The charger is at least a $50 part of this deal, I don't think I'm asking too much for them to get it right the first time around and test it before they ship. $25 right now is a huge amount of money for me, I had to borrow money just to buy the battery in the first place.

I can't tell the output voltage of the SLA charger because if I try to run it directly to my meter it shows something crazy like 1800v. I suspect it doesn't go much higher than 53.x and it doesn't have a pot. inside to increase voltage.
 
I agree, a simple test would insure most chargers arrive ok. Given the conditon of the box though, I'm not suprised it's got problems. I've trashed chargers just carrying them in a bag on the hanldlebars. Controllers seem to be made to take a few bumps, but chargers are not, and often get damage in shipping.
 
I can translate the Chinese label on your battery charger for you since I can read them. It saids "Warning: Internal high current parts inside, do not open" and then:
o Input: 220 VAC/50Hz (IMO, If it is a switch power supply it may takes 110v as well. Try to plug it into your 110V outlet since you have got 0% chance to see if it works or not if you don't plug it in.)
o Output: Suitable for 48V battery group
o Red light indicates electricity, yellow light indicates charging, green indicates fully charged
o Be sure the input output is hooked up correctly
o Be sure the output postive & negative match up correctly
o Forbidden to use the charger inside an enclosure, rain

BTW, I am a Keywin's friend. Let me know if you need any other help. These battery packs are actually made in Shenzhen, China but easier to sell if being marketed they are from Hong Kong. I know because I have friends & connections there too. There is really lots of business opportunities too, but it is just not easy to deal with honest manuafacturers & sellers due to cultural differences I would say. Just my 2 cents. :)
 
needWheels said:
Nice ... well it's good to have an emergency backup but I am still not a happy camper - it would cost me $17+ to ship this lifepo4 charger back and no way I am paying $26 to have another shipped.

I am trying to convince him to send me the board inside the charger but he says he doesn't have any - I suspect he just buys the charger from yet another vendor as he needs them. Argh this probably won't end well.
Click to expand...

Yes, it's definately a good idea to have a spare charger, they're undependable, I've burnt two of them. I always carry a charger when i ride so I can do oppertunity charging, instead of carrying 10 lbs of battery around.

However your charger should top out at 58 volts at least. Even my weak 3 amp charger tops my pack in a couple hours. Just giving you a referance point.
 
lyen said:
BTW, I am a Keywin's friend. Let me know if you need any other help. These battery packs are actually made in Shenzhen, China but easier to sell if being marketed they are from Hong Kong. I know because I have friends & connections there too. There is really lots of business opportunities too, but it is just not easy to deal with honest manuafacturers & sellers due to cultural differences I would say. Just my 2 cents. :)
Click to expand...

Thank you for your insight! I suspected the pack was being drop shipped from somewhere because the EMS label ends in CN instead of HK and Mr. Lau's address is in HK. So perhaps all of our vendors Ping, Cammy, etc. are all buying and reselling or drop shipping for a percentage. Can you tell me why the EMS label says ¥ 2190 ??? If they really spent $320 on shipping that means this pack only cost them $100 or so to build and that's scary indeed. Then there's the cost of the BMS and charger.

I have no problem with products from China, at least from their people, I just have issues with their government and it's weird form of communism and capitalism, telling people how many children they can have, no care about pollution, etc. Some of my neighbors and my landlord are Chinese and if there are going to be stereotypes, in general they are very nice people and my landlord is very hard working but of course there are all kinds of people, lol. I've dealt with many computer vendors years ago in "City of Industry" who are all from China so I am used to the mentality and cultural differences.

Now if by some chance you can help get me a replacement board for inside this unit shipped cheaply, that would be a miracle. Don't need fan, power cords or case, just the board, and I suspect it would cost far less than the $45 I'm being asked to spend to get this replaced. There is a vendor on ebay that sells the same unit so I might ask them if they will sell just the board.

In hindsight if there is anything wrong with this pack in a month or a year, I am totally screwed so I guess this overall was a very poor decision on my part but I was desperate for lifepo4. I am just counting on the fact I might be able to replace an individual cell by myself, although it might take me many hours to do it.
 
The label may be a declaration of the value of the shipped item. $100 to ship it would be about right.
 
dogman said:
The label may be a declaration of the value of the shipped item. $100 to ship it would be about right.
Click to expand...

Ah, very good insight. Though it does say "charge" and "additional charge" and "total charge" which led me to believe there was a surcharge.

I'm back to charging with the SLA charger to see how high and how level it will go.
I guess the SLA charger will never turn off by itself.

update: After another hour I pulled the charger off and to my pleasant surprise the voltage was 54.7v - Of course that's going to come down and settle in the next few hours but I am pleased that the SLA charger will go that high - it must try to charge SLA at 13.7v per battery?
 
five hours later it has settled to 53.5v which is higher than the original voltage when the battery arrived :)

okay now the dumb question, how do I know when the pack is fully charged?
voltage can't be a complete indicator with lifepo4 right?
 
Charge it till the sla charger say's finished. It will take a long time, this is a much bigger battery than you are used to. But in terms of charge time for the number of miles, it will be the same as when you used sla's. I would leave it on the charger, and worry more about getting low cells up than about overcharging with the sla charger. That tiny trickle from an sla charger will take forever to balance a lifepo4 pack, but if will eventually bring up lower cells. Though I have no science to back me up, I'm convinced the good results I have had are related to leaving it to charge all night everyday. I plug in around 1pm, and then unplug the next morning, so it gets about 6-8 hours of daily time on float charge. As far as charge times to expect, my slow sla charger for example, a 15 mile ride will take 8-10 hours to charge. 4-5 hours for my 4 amp charger.
 
voltage is the best indicator. if you do not charge all the way up to 3.65V then the cell is starting from a partially discharged condition. so it is like you only air a tire up halfway, and is harder on the cell than running at high discharge rates, imo.

lifepo4 cells are not like nicad or SLA which are electrochemical cells and lifepo4 stores charge as intercalated ions in the lifepo4 lattice of the cathodic granular materials.

they are not easily damaged by overcharging as are lipo, and they do not catch fire if they are left on trickle charging for long periods as do lipo.

when you trickle charge beyond the 4V level all you are doing is just making heat. there is no place else for the coulombs to go and the anode is already stripped of all the ions available.

if it was lipo at this point, the heat buildup will cause it to overheat and go into thermal runaway which allows the organic polymer to ignite and burn.

your charger voltage will read whatever the voltage is on the cells until it gets to the final CV stage. so charge until it gets to 58.4V.
 
Really appreciate all the advice. Okay I ran the charger until it shutoff.

I tested the battery voltage immediately after and it was 55.0v so that must be the limit of the charger.

Battery seems to be settling and voltage after an hour is 53.7v / 16 = 3.35

I will test the groups a little later after it settles some more.
 
that is the normal resting potential. how many charge cycles do you have on it? maybe after a few cycles it will finally balance and the low cells will get pulled up closer to the high cell which is shutting off the charge.

i think eventually it will get to 58.4V or more. don't deep discharge it yet, just take it easy for the first dozen or so cycles. buy another charger too, you can never have too many.

get one of the 200 or 400 watt ecitypower chargers, they are cheap.
 
I think I have read around here that the duct tape 18650 packs never get to 58.4 but I could be wrong. The prismatics get that high but not the 18650's

(and yes the pack is brand new, hence the start of this thread, I know I have to "break it in")

I can't afford to buy anything more for it right now, not for a while, hence the huge disappointment that the charger it came with is apparently somehow broken and I can't afford to pay them to ship another. If I didn't have this SLA charger I'd really be up a creek...
 
needWheels said:
lyen said:
BTW, I am a Keywin's friend. Let me know if you need any other help. These battery packs are actually made in Shenzhen, China but easier to sell if being marketed they are from Hong Kong. I know because I have friends & connections there too. There is really lots of business opportunities too, but it is just not easy to deal with honest manuafacturers & sellers due to cultural differences I would say. Just my 2 cents. :)
Click to expand...

Thank you for your insight! I suspected the pack was being drop shipped from somewhere because the EMS label ends in CN instead of HK and Mr. Lau's address is in HK. So perhaps all of our vendors Ping, Cammy, etc. are all buying and reselling or drop shipping for a percentage. Can you tell me why the EMS label says ¥ 2190 ??? If they really spent $320 on shipping that means this pack only cost them $100 or so to build and that's scary indeed. Then there's the cost of the BMS and charger.

I have no problem with products from China, at least from their people, I just have issues with their government and it's weird form of communism and capitalism, telling people how many children they can have, no care about pollution, etc. Some of my neighbors and my landlord are Chinese and if there are going to be stereotypes, in general they are very nice people and my landlord is very hard working but of course there are all kinds of people, lol. I've dealt with many computer vendors years ago in "City of Industry" who are all from China so I am used to the mentality and cultural differences.

Now if by some chance you can help get me a replacement board for inside this unit shipped cheaply, that would be a miracle. Don't need fan, power cords or case, just the board, and I suspect it would cost far less than the $45 I'm being asked to spend to get this replaced. There is a vendor on ebay that sells the same unit so I might ask them if they will sell just the board.

In hindsight if there is anything wrong with this pack in a month or a year, I am totally screwed so I guess this overall was a very poor decision on my part but I was desperate for lifepo4. I am just counting on the fact I might be able to replace an individual cell by myself, although it might take me many hours to do it.
Click to expand...

Can you take a picture of the EMS label from the shipping box? This way, I can give you a more accurate answer regarding the shipping cost. There are tricks Chinese people used from the mainland to delivery either quickly and/or the most cost effective way such as carry this battery with them and go across the border from the mainland (Shenzhen) and ship it out in Hong Kong since the currency exchange rate in Hong Kong is lower than it is in China. Also, export tax rates & delivery speed are potentially better depending on the weight, size, and type of the item(s). Since Ping Battery is in Shanghai, he does not have the luxury to walk across/over the border line between Shenzhen & Hong Kong so he has to charge a little more for shipping. As for the production cost and the quality of the battery, I am unable to disclose the information due to we are all in businesses of some kind and I do not want to drop a hammer on anyone of them. The key is if you are willing to buy it, then it is how much you think it is worth. I myself is currently using the 4 x Dewalt DC9360 A123 batteries for commute in San Francisco on a 2007 Dahon Cadenza folding bike with a BMC motor + sprockets on the left side of the rear wheel. I kept my batteries intact & simply top off in less than an hour with the Dewalt chargers.

As for the circuit board for your charger, I do not think you would want to go that route since people kept making different revision everytime they found glitches on the product. Therefore, you will most likely getting something that is incompatible with you charger enclosure.

There is a trick you can try that would cost you very cheap or next to nothing. But I am not responsible if something go wrong. It is to add a high power resistor (10W or so) with enough resistance to lower the voltage to trigger the low voltage detection of your existing SLA charger. This way, your SLA charge will charge up you LifePO4 battery faster since the charger will theoratically keep pumping the battery instead of switching to the trickle charge mode.

Lastly, you are not totally screwed because you are not the only one here in an adventure for the DIY project. I am sure we the Endless Sphere members will provide great help to keep you going. Before you extract your pack. You may want to draw yourself a wiring diagram from every single cell to the BMS. Take notes & pictures of every single step you take it aparts would also help. Learn to solder with a soldering iron is a must. :)
 
After letting it settle for many hours this is the new balance, not so good
I assume my meter is simply rounding on the 100th place
I know that I'll have to charge a few more times to get it better.
Has anyone written a little tool to calculate the differences really quickly? If not, I'll make one.

53.5
50.2
46.8
43.5
40.1
36.8
33.5
30.1
26.8
23.4
20.1
16.7
13.4
10.0
6.7
3.3
 
needWheels said:
After letting it settle for many hours this is the new balance, not so good
I assume my meter is simply rounding on the 100th place
I know that I'll have to charge a few more times to get it better.
Has anyone written a little tool to calculate the differences really quickly? If not, I'll make one.

53.5
50.2
46.8
43.5
40.1
36.8
33.5
30.1
26.8
23.4
20.1
16.7
13.4
10.0
6.7
3.3
Click to expand...

You don't have to babysit your battery pack. You will get difference measurement because the chemical inside the battery cells may not be fully settled. Instead, you should try to stress the battery and check again after 50 charge/discharge cycles and/or in 3 months period. What you really want is to make sure the BMS has enough room to release the heat from the FETs + heatsinks.
 
It is sad to hear you have got broken charger. Be prepared that replacement charger could be noisy, but at least it should charge pretty quickly.

You could measure voltage difference on BMS wires, just measure voltage between BMS wire 1 and 2, then between 2 and 3, 3 and 4 and so on, or for already measured data, create a spreadsheet with formula to calculate voltage difference.
 
needsWheels, these guys over in Asia are making plenty of $ money from Americans. You should get a free charger as a customer courtesy. He should take your word as true and not require return first.
 
Thanks for the feedback everyone, I really do appreciate it.

The 4806 charger is definitely not doing anything as I went for a longer journey today, pack was 52.5v when I got back and the charger refused to do anything even after a couple of minutes. Had to put the SLA charger on and it will take all day.

I am not sure what will happen with the charger but all I know is right now I don't have the $$$ to even ship it back and I don't know if he will ship me one without getting it first. I don't even care if he sends it by ship instead of air if it was a free replacement.

Personally I don't know if it should come out of Lau's pocket even since he didn't ship it and he wasn't the one who packaged it so poorly, I think the factory should ship me a charger from China but he may not have a good enough relationship with them to ask/demand that.

In fact that reminds me I have to call EMS today and complain about the rough treatment for what little it's worth, but I can't even find a USA number for them so I guess I have to call the post office.
 
Oh hey dogman, have you ever had the BD36 controller cut out?

Today I went in the opposite direction, something I've never even attempted with my SLA because there are rolling hills, not very steep or high but enough to make the battery work for it.

After 4 miles the bike suddenly went dead. But get this - it went dead on one of the flats AFTER the hills, not on a hill. At no time did I exceed 21mph according to my cyclometer.

At first I thought, ruh roh, it's the BMS. I didn't have a voltmeter with me unfortunately to test.

But the BMS wasn't really HOT, it was just very very warm. And it was "open air".

My controller bag however was a bit toasty. It is possible the BD36 controller overheated and not the BMS?

It's never, ever happened before but my SLA were never up to the task of giving the controller full amps ever before.

In any case, a minute later it was working again, I took it much easier on the way home.

So eight or nine miles today and one cutoff.

Oh here's another question, since I stupidly still have a piece of 18 gauge wire in my circuit to the controller, what does the controller do if it wants AMPs but can't get them through the undersized wire? Does it cutoff? Is that maybe what happened?
 
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