found new cheap site for BMS, LiFePO4 & charger up to 18000W

[julesa]

i finally had a chance to use my two chargers from eCityPower.com for a few days now and so far I'm impressed! I got two of the Model EP-A 87.6V 4A chargers in the aluminum cases.

Hi Sacman (or others with the same charger). Do you think this charger would be suitable for bike mounting? I have one on order and I'd like to put it on a seatpost rack for onboard charging. Any idea if the components will be able to handle the bouncing around, or if I could secure components with some hot glue or silicon.

I'd be concerned about water and dirt getting in there. It would be better to keep it in a padded bag or box, and take it out of the box when charging for good airflow.

I just started playing around with mine last night. I didn't have a lot of time but it didn't look like it was kicking over into CV or trickle mode or anything like that. It looked like it switched off completely as soon as it hit the set voltage limit at the end of the CC charge, but I might have missed something. Sacman, are you seeing any current flow at all after the LED turns green?

 

[Sacman]

I didn't have a lot of time but it didn't look like it was kicking over into CV or trickle mode or anything like that. It looked like it switched off completely as soon as it hit the set voltage limit at the end of the CC charge, but I might have missed something. Sacman, are you seeing any current flow at all after the LED turns green?

Well when the LED light on mine turns green the fan shuts off and enters trickle mode or CV (at least I think it's trickle mode). The green LED brightens for 1 second then dims for 9 seconds. And this cycle continues every 10 seconds. So I get some visual cue but I can't verify the charger is actually trickling current to the batt during this mode because I haven't put a meter to it yet.

 

[patrickza]

I just started playing around with mine last night. I didn't have a lot of time but it didn't look like it was kicking over into CV or trickle mode or anything like that. It looked like it switched off completely as soon as it hit the set voltage limit at the end of the CC charge, but I might have missed something. Sacman, are you seeing any current flow at all after the LED turns green?

My headway charger does that too, but if I unplug and replug it after it's been turned off then it seems to switch over to CV mode moving between 86.8 and 88.2 volts. Maybe try that

 

[Sacman]

i finally had a chance to use my two chargers from eCityPower.com for a few days now and so far I'm impressed! I got two of the Model EP-A 87.6V 4A chargers in the aluminum cases.

Hi Sacman (or others with the same charger). Do you think this charger would be suitable for bike mounting? I have one on order and I'd like to put it on a seatpost rack for onboard charging. Any idea if the components will be able to handle the bouncing around, or if I could secure components with some hot glue or silicon.

Yeah I've carried similar plastic cased chargers inside my nylon panniers before on my commutes and they've been fine since the panniers take up a good amount of the shock and vibrations on bumps. But I wouldn't want to mount the charger ridgidly to the bike frame and especially not outside and uncovered where it would be exposed to the elements.

 

[julesa]

DOH! I had my battery pack hooked up to a couple lamps for testing, and it looked like it was working fine. I disconnected one of the e-city BMS sense wires to see if it would cut off current to the lamps. It did. Now it won't come back on at all. Completely disconnected the bms from the battery, reconnected it, still won't come on. Checked connections: all sense wires tested at the point they're soldered into the BMS board, show 3.3v difference from one to the next, and 3.3v from sense wire 1 to the negative end of the pack, as shown in the wiring diagram. Battery positive to battery negative is about 53v. Unloaded, battery positive to BMS load negative tests at 52V. With ANY load, even a Watts Up meter, battery positive to BMS load negative drops to 1.7V.
:-(

Still seems to charge OK. When testing the e-city charger, it still looks to me like it does CC up to the voltage shutoff and then turns off completely, no CV mode, no pulsing. I waited about an hour after LED2 turned green, the Watts Up meter didn't show any more current flow.

 

[patrickza]

Still seems to charge OK. When testing the e-city charger, it still looks to me like it does CC up to the voltage shutoff and then turns off completely, no CV mode, no pulsing. I waited about an hour after LED2 turned green, the Watts Up meter didn't show any more current flow.

I assume you've disconnected the BMS from the battery for a while to reset it. I had a similar problem once before and all it was was my BMS trying to reset. If it's not that then check the physical connections, maybe something is loose in your pack.

 

[julesa]

Hi Patrick,
Do you really have to disconnect your BMS from the battery to reset it after triggering the LVC? At first I only disconnected it for a few seconds, just to rule that possibility out. After reading your message, I disconnected it completely for about an hour, didn't help.

I'm pretty sure all the connections are good... battery+ to battery- is where it should be, about 53V, and testing each of the sense wire connections at the point where they are soldered to the BMS board shows 3.3V between every point. I have another identical BMS I was going to use for building another pack, I guess the next step is to swap the BMS boards. If that fixes it, I guess it's possible I cooked it somehow when I disconnected the sense wire... but seems unlikely that a simple test like that would kill it.

 

[dnmun]

can you post up pictures of where you disconnected the sense wire and this is the 16S ecitypower BMS? sounds like the wire was broken or the trace is broken from the pin to the shunt resistor.

 

[julesa]

can you post up pictures of where you disconnected the sense wire and this is the 16S ecitypower BMS? sounds like the wire was broken or the trace is broken from the pin to the shunt resistor.

Yes, it's the 16S ecitypower resistor bleed BMS. I posted pictures earlier in this thread:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=9054&start=180#p165352
I'm not at home now, and unfortunately I'm leaving on a two week trip tomorrow and won't have much time to work on this before I leave.

I have the sense wires going to ring terminals at the bus bars, and my first test was disconnecting one of the ring terminals at the bus bar. Then when I reconnected it and it didn't come back on, I disconnected the battery negative lead from the negative end of the battery, and unplugged the whole sense wire harness from the board. I waited a few seconds, then reconnected them, sense wire harness first, then the battery negative lead. Later, at Patrick's suggestion, I repeated that process, but left everything disconnected from the BMS for about an hour. Still no joy. You bring up a good point, I'll take a close look at the solder joints and traces the next chance I get.

Thanks!

 

[voicecoils]

Anyone have some experience with this 12S BMS that BMSBattery sells?

http://www.bmsbattery.com/product_info.php?cPath=3_10&products_id=65

They've told me that they can't be run in series. Can anyone confirm this and why? (eg components not rated for 2x the voltage of one unit). For the price, if they really provide 50A cont. 80A pulse, 100A cutout then it could be a decent cheap BMS.

If this has been discussed already and someone can provide me a link, I'd be grateful.

 

[julesa]

Anyone have some experience with this 12S BMS that BMSBattery sells?

Exact same BMS I have except the last four segments aren't populated. Pretty sure bmsbattery.com and ecitypower.com are the same folks.

So this morning I had the BMS unplugged for an hour, hooked it back up to the pack, and I got nothing. When I got home from work, it had been plugged in all day, I hooked up the watts up and lamp again and now everything works great... I HATE intermittent problems.

Thanks for the tips guys. I'll keep you posted as I have time to experiment further.

 

[Doctorbass]

bmsbattery.com and ecitypower.com ARE the same folks.

One is the manufacture and the other is their web store.

Jack from ecitypower confirmed me that.

Same products.

Doc

 

[ryanvm777]

Anybody else notice the "QC" in this picture. LOL :lol:

 

[julesa]

So this morning I had the BMS unplugged for an hour, hooked it back up to the pack, and I got nothing. When I got home from work, it had been plugged in all day, I hooked up the watts up and lamp again and now everything works great... I HATE intermittent problems.

Thanks for the tips guys. I'll keep you posted as I have time to experiment further.

Update: The BMS board was bad. I put the pack on my bike and the BMS would cut out when I'd draw more than about ten amps. After the second time that happened, I took the bike back into the shop and was just about to start testing voltages to make sure I didn't have a low cell (I didn't) and I heard a "pffffft" sound and saw smoke curling up from the BMS. I can't see which component lost its magic smoke, they all look good on inspection.

After replacing the BMS (I bought two) everything is working great, except the charger's fan is not kicking on and the charger is getting so hot that I have to turn it off to let it cool down every few minutes.

I have not yet contacted Jack about these problems. Honestly I'm not sure I will. Hopefully I can fix the fan on the charger myself, and I'll probably just order a new BMS from Headway. I'm not very happy with ecity's quality control... They are so inexpensive, but with shipping costing as much as it does I wish they had charged me a little more and tested this stuff before they shipped it.

 

[dnmun]

you never put the voltmeter probes on it and it died by itself?

you were able to get it to charge the battery and then it died? were you able to discharge through the BMS? do you have any pictures of the BMS and especially so we can see how it is laid out.

now your charger is dead too? did you measure the voltage on the charger?

 

[julesa]

you never put the voltmeter probes on it and it died by itself?

you were able to get it to charge the battery and then it died? were you able to discharge through the BMS? do you have any pictures of the BMS and especially so we can see how it is laid out.

now your charger is dead too? did you measure the voltage on the charger?

I did discharge through the BMS a little but it cut out when I pushed the throttle past about halfway to WOT. After the second time it did that, I took it back inside, and just as I got out my meter, it died before I measured anything. I think I unplugged the controller or something right before it blew. Nothing that should have killed it. It looks exactly like the pics I posted earlier in this thread -- no visible burned areas or visibly damaged components. But the magic smoke escaped, and it wasn't working right to begin with, so I'm just gonna chuck it and buy another. At these prices, I figure I can't expect perfection.

I never really got a chance to charge the pack -- the cells were charged out of the box.

The charger is fixed now -- the fan case was cracked and the blades were rubbing on it, so they wouldn't turn and it was overheating. There was no damage to the case of the charger itself... Anyway, I pushed it back into shape, applied a little superglue, and voila, it is working fine. There is a fuse holder on the case but while I had it openn I noticed it it wasn't wired to anything inside...

After replacing the BMS and fixing the charger fan I've done a few charge/discharge cycles riding around the neighborhood on this bike. Fun!!! Now I just need to get another BMS and get the other bike built.

 

[mwkeefer]

Don't chuck it !!!!

PM me to arrange LEGAL POST and I will pay the postage... I need the parts and teh included charger. If you check around the forums you will notice I rather enjoy finding the flaws in designs and making them known (or having the vendors fix em)...

Regards,
Mike

 

[julesa]

Don't chuck it !!!!

PM me to arrange LEGAL POST and I will pay the postage... I need the parts and teh included charger. If you check around the forums you will notice I rather enjoy finding the flaws in designs and making them known (or having the vendors fix em)...

Regards,
Mike

I wasn't considering chucking the charger, after all I just got it working properly. As for the BMS board, I should probably put it in the spare parts bin, just in case I blow something on the other ecity BMS I have. Sorry if I got your hopes up.

I ordered a new V1 BMS from Ping for the other bike. $47 plus shipping.

 

[pm_dawn]

Hello all!

I have had some really bad experience with BMSBATTERY.
I have ordered over two weeks ago and they have not sent me anything yet.
First I ordered 4 38120 cells and a 4-cell BMS. That was the 17th of Sept.
The week after I ordered 8 more cells and one more 4-cell BMS.
I have explicitly asked them for speedy handling of my order to get the stuff on its way before there one week of national holiday that started yesterday.

DO YOU THINK THEY MANAGED TO DO THAT?

I was so mad yesterday when I read there mail about not getting the order on its way before the 9th of Oct.
I have two customers that are waiting for packs that I'm building for them.
I probably have to order the cells and BMSes from another company to get it done before my customers grow tired of waiting.

Unless they shape up seriously and start giving some customer service I CANNOT recommend this supplier.

Regards
/Per Eklund

 

[Doctorbass]

Hello all!

I have had some really bad experience with BMSBATTERY.
I have ordered over two weeks ago and they have not sent me anything yet.
First I ordered 4 38120 cells and a 4-cell BMS. That was the 17th of Sept.
The week after I ordered 8 more cells and one more 4-cell BMS.
I have explicitly asked them for speedy handling of my order to get the stuff on its way before there one week of national holiday that started yesterday.

DO YOU THINK THEY MANAGED TO DO THAT?

I was so mad yesterday when I read there mail about not getting the order on its way before the 9th of Oct.
I have two customers that are waiting for packs that I'm building for them.
I probably have to order the cells and BMSes from another company to get it done before my customers grow tired of waiting.

Unless they shape up seriously and start giving some customer service I CANNOT recommend this supplier.

Regards
/Per Eklund

I think that two week is not so bad. Often it depend if they need to assemble your product like custom or larger battery, but in your case it seem that it's BMS and individual cells. I would give them one more week before complaining. I already received order from china in 30 days....

Doc

 

[TPA]

If I am not mistaken, they do not stock the items they sell. You order...they buy your order from the factory....then ship to you. If the item you order has to be made by the factory, you will wait a while.

I waited about a month for my charger, but I anticipated the wait since most things take a while to arrive from china.

Point is...if you need something from china, order ahead of time.

 

[Ultraman]

I've also waited a while for my stuff from ecitypower . I made 4 orders (2 battery packs and a bunch of chargers). The shortest wait time was about 3 weeks for "stock" chargers, about 4 weeks for custom chargers and about 5 for each of the packs. Jack Du has maintanied good communication I have to say, even though it's not as speedy as buying something from a domestic supplier.

 

[Ultraman]

Which reminds me, I should post some test results for the two lifepo4 packs I bought from Ecitypower. I got a 36v 15ah pack in May and it's servide me well after about 50 charges. Using it on a front 9continents hub motor. No issues.

I was concerned about the capacity of my 48v 12ah pack I received to replace the SLA's on an e-scooter. With Jack's encouragement I took it apart and tested the cell voltages after a charge and discharge cycle. I used the Ep-J charger set to 58.4v. Here's the results:

Date: 22.09.30
Capacity in Ah 10.57
Voltage after full charge (4Amps) 54.3
Voltage after full discharge (1.5Amps) 50.8

Full Charge Full Discharge
Cell 1 3.42 Cell 1 3.21
Cell 2 3.42 Cell 2 3.21
Cell 3 3.42 Cell 3 3.21
Cell 4 3.42 Cell 4 3.21
Cell 5 3.41 Cell 5 3.21
Cell 6 3.42 Cell 6 3.21
Cell 7 3.33 Cell 7 3.11
Cell 8 3.42 Cell 8 3.21
Cell 9 3.42 Cell 9 3.21
Cell 10 3.41 Cell 10 3.21
Cell 11 3.41 Cell 11 3.21
Cell 12 3.17 Cell 12 2.77
Cell 13 3.41 Cell 13 3.21
Cell 14 3.42 Cell 14 3.21
Cell 15 3.42 Cell 15 3.21
Cell 16 3.42 Cell 16 3.21

Average 3.40 Average 3.17


You can see that the pack's pretty well balanced overall. BUT, there's that weak cell #12 that I'm worried about. Also, should I be concerned that I'm only getting 10.6 amp hours out of it before LVC at around 51v? I emailed the results to Jack and will post if there's any plan to resolve the issue.

 

[Orphee]

Hello
I ordered a BMS with capacity balancing and a charger with ecitypower
Jack Du answer to questions but ... I'm still waiting !!! one month if very very long
So I will never buy again with ecitypower.

 

[mwkeefer]

Ultra,

LiFePo4 wants to be cutout at a voltage no lower than 2.625v per cell. Either your BMS is hedging on that a bit and cutting out at 2.77v or that voltage is after discharge and without load (load having touched 2.625v). I know many people who don't discharge LiFePo4 below 2.9v per cell under load to increase the life cycle capcity (number of recharge cycles) I fall into that camp.

I would say either cells 7 and 12 are bad or just really out of balance with the pack...

Try charging the cells individually 7 then 12 unit they reach 3.42v or the current draw from the battery drops to 6% of starting current.

If the cells don't reach the proper v... they are likely bad. If they get really close 3.4 maybe even 3.8 it's okay (probably). For bad ones, replace em.

Once they reach the proper v 3.42, combine them back into the pack and let the normal bulk charger do it's job... then perform your test again... with a bit of luck the cells are just out of balance badly (can be caused by dozens of things even with a properly designed bms) and this will have restored them to their fellow brothers capacity.

If you really want to "KNOW" your battery... Do your test but on each cell as an individual... that will show you what your really working with and is how you should rate cells when building a pack. Finally... if you can, increase the current of the test load to 1 or 1.5c that will really weed out the weaker cells.

3.4 - 3.42 is okay for the top end... personally I never charge past the 3.40 mark but in my LiFePo4 pack... I paralleled a new pair of 6S charge and a std lipo 6s balance tap into my LiFePo4 and I use my iCharger 1010B+ to charge it bulk mode @ about 5A rate (1/2c) the cool part is, I balanced manually (as I indicate above) once about 2 months ago... since then I have run about 30 tests to full depth on this pack and the cells are still within .04v of each other without balancing.

-Mike