48V 20AH battery for sale on ebay in USA any good?

[joe tomten]

On the 48v battery I have I know that I can stick the 4 amp charger on the batt.--> controller leads and it accepts the charge just fine.

Don't know what the limit of regen amperage through the bms would be though. I'm guessing that you'd be fine as long as you don't start at the top of a huge hill with a full battery, cause that part of the bms only shuts down for low voltage, whereas the charger portion of the bms is the one that cuts off when the battery is full.

 

[goasisenergy]

Sorry, I did not get your email, C rate for the 24v 10ah packs is 1.5 as others

 

[dogman dan]

Regen will depend on the bms. Signalab bms such as used by ping can take 5 amps of regen. Ping recomends no more than that. Not sure how you limit amps from the controller, or if the controller does limit it. Lyen could answer for his stuff I'd think.

If regen is limited to 5 amps, I always wonder why bother with it? Makes sense to regen a bms free lipo setup, but never made a lick of sense to me to regen a signlalab bms, since 5 amps for a few seconds is no more energy in that just pedaling a few strokes.

 

[RVD]

Sorry guys but I just bought a 48v 15ah battery last week and I can't recommend it at this time.

I rode to work this morning. I was sort of careful with the battery and didn't go full WOT like I usually do. I mainly kept the bike at around 20 amps or lower according to my CA. Usually, when I ride I sustain more like 30-33 amps for about 30 seconds and then goes down to about 25 amps. Today I was trying to keep it in the 20-22 amp range so that i don't exert this battery too much.

The voltage started at 52.5v according to my DMM. When I got to work, my CA said that I had used 9.5ah. I travelled about 16 miles. Voltage at work was 49v. With sag, the 49v goes down to about 46v or so.

Maybe my expectations weren't quite there but I'm a bit disappointed with this battery for the following reasons:

1) Battery label is different from what is in the picture on ebay and the website. My battery says 15s5p rather than 16s3p. I believe that the 16s3p battery is closer to 57v charged rather than the 52.5v charged that I started with. I wanted to replace my 14s3p lipo so the reduced voltage and power is a disappointment. I expected less power but not this much less. I would have been happy with a 57v battery fresh off the charger but am a bit lukewarm with a 52.5v battery that goes down to about 49v within a few miles.

2) I'm also puzzled with what type of cells are in this pack. I expected 32650 cells but I just don't know if that's what is in here.

Oh well, I took a gamble. Honestly, I don't know much about lifepo4 so maybe my reasoning is a bit off.

I raised some concerns to John (the guy at this company) but he just said that what I have is normal.

Shipping was fast though.

In any case, I will be buying a Ping from now on for my future lifepo4 builds. Even though the Ping is slightly more expensive, i think it's just better to know what you're getting, etc.

 

[auraslip]

Bummer. 16s will be around 53v-54v after fully charged and left to sit for a few hours. And it should drop to ~52v immediately after the load is removed.
The capacity sounds about right... maybe 49v is a little low for 15s @ 66% DOD, but give the pack a few soft cycles to perk up before passing final judgment.

 

[RVD]

ok i'll run a few more tests. this battery seems to be about 52-53 fresh off the charger and goes down to about 50 or so in a few miles.

i think it's actually closer to 48v most of the time (so 45-46 with sag) but my CA did say that it was 49v after 16 miles. i also think i used up more like 60% rather than 66% because when i charged it up, it turned green (fully charged) in less than 3 hours with a 3 amp charger.

anyway, i'll reserve judgement for now. it's not a terrible battery even now...but it could be better.

any idea what kind of cells are in here? is there a lifepo4 cell that is 3ah?

 

[amberwolf]

No way to know, really. Lots of different cells made out there in China that we probably never see here in the rest of the world. It could be all rejects from the 5Ah cell line. :lol: Even the battery pack manufacturer wouldn't be able to know, if they didnt' make the cells themselves (whcih I doubt any of them do).

It does bother me that the battery you got is a different configuration from what they advertise (based on what you said about each of those), and that the company just shrugged you off about it. That's not right; a different configuration could well behave totally differently, becuase the cells used would also be different. Plus the voltage being different is a significant difference in operation, as you've seen.

 

[RVD]

I rode home today in a pretty big headwind. I limited the amps with my CA to 22 amps so it wasn't as fast as usual. However, according to the CA, I used up 12 ah to ride 16 miles.

Starting voltage was 52.4v but within a mile or two, it went down to 49.6v where it stayed most of the time. When I got home, it was still at 49.0v. Sag is about 3v so when operating at 20 amps, CA read 46.X volts.

 

[auraslip]

Usually, the batteries have a chemical inhibitor inside them that keeps the batteries fresh while they sit on the shelf. It takes away capacity. Usually it takes a few cycles to get it all out.

 

[RVD]

ok i hope so. is it good to just keep it plugged in for a long time? or should i pull the plug when the light turns green? or should i wait a bit, unplug, and replug to keep topping it off?

 

[joe tomten]

I have experienced a few unhappy surprises when the lvc cut out and I was nowhere near fully discharged.

I think the resting voltage was like 52.3 or something. (average 3.275v/cell, still plenty of capacity left inside) I opened it up, and one cell group was quite low, which is why the bms had tripped.

I had been charging the battery with a 4 amp charger, and not letting it sit for a long time to balance charge.

But when I went to leave the charger on for a couple of days straight, the bms couldn't bring up the low cell, so i finally ended up charging up that cell group by itself, and that helped.

Then for a while I ran it in parallel with another one to keep the discharge depth shallower.

I think I'll bring the balance leads out and watch with cell-logs for a while.

 

[999zip999]

RVD, What you paid for a 48v20ah and a 15s3p ? Something is wrong, my ping off the charger 60.1v then would be 56v after takeing off the the top charge. Who sells a 15s battery ?

 

[RVD]

i bought a 48v 15ah battery from these guys. they sent me a 15s5p battery (at least that's what it says on the label). fresh off the charger it is around 52.5v but within a mile it quickly drains down to about 49.8v and over the course of about 15 miles, it will go down to about 49v and I will use up around 10ah (according to my cycleanalyst) with me pulling roughly 22 amps at WOT. voltage sag is about 3v so at 49.5v, if i am at WOT at 22 amps, it shows 46.5v on the CA.

the charger is a 3 amp charger. The charger seems fine. there are 2 LEDs. LED1 turns red when the battery is connected. LED2 turns green when the battery is charged.

overall, it is not a bad battery but don't expect a battery that is 57v off the charger and running at 51-54v most of the time like i did...or you will be sorely disappointed.

 

[Bubba]

Just a quick update on the two Keling 24v 10ah packs I'm using in series for 48v through the Lyen 12FET, CLyte 408 motor. Wiring is all "stock" but with 45A Powerpoles.

I've got about 700 miles on this build so far.
Controller settings: 30A/70A, LVC 42v, Tolerance 1, block time 2, EBS level 2 (regen enabled for braking).

When fully charged (float) I usually start at about 56.5-57v, (58v if I disconnect the charger at the right time).
9.5 mile ride to work with very gradual decent of 300 feet over route and one small hill of about 40 feet in height.
Minimum voltage after ride (shown on Watts Up meter): 49.2v
Max current: 31.5
Max watts: ~1650
Ah used: ~5.2
Final voltage immediately after arriving at work: ~52.5
Motor housing temp after ride on a 94 degF summer day: ~145 degF. Phase wires slightly warm. Controller COLD!

On return trip (uphill), final voltage is about .5v lower and used ~5.9ah

I forgot my charger one day last week and was able to complete the 19 miles round trip. The voltage afterward was ~46.5v. This is after the battery sat for about 7 hours, but I forgot to check the starting voltage. I'm guessing it had bounced back to at least 53v or so.


Tonight I'm going to try bumping the current draw to 32A/80A and see what happens.

 

[RVD]

i may eventually raise the current setting but for now i'm limiting to 22 amps (1.5C on a 15ah battery right?).

i figure i'll be nice to the battery during the break in period.

even afterwards, i would just bump it up to 30 amps (2C).

 

[mushymelon]

Have you let it charge overnight.

15s5p battery should charge up to 57v>60v

What you have is not normal. John is incorrect.

 

[RVD]

Yes I have let it charge overnight. However, once the light turns green I think it just stops charging. Maybe I should unplug it and replug it in every few hours or so after a full charge?

 

[RVD]

since this is lifepo4, isn't each cell 3.7v full charged and 3.2v discharged?

so at 15s, this would be 48v-55.5v?

i paid attention this morning and it was 52.4v hot off the charger. at the end of my block it was down to 50.5v. after about 1 mile it was down to 49.7v. after 15 miles, it was down to 48.9v and 9.5ah used.

voltage sag was 3v as usual pulling 20 amps.

 

[Ypedal]

Lifepo4 is fully charged to 100% when it reaches 3.6+ volts, but removed from the charger they settle down to 3.3v or so ( still fully charged ) .. completely drained at 2.0v ... most of the discharge cycle will happen between 3.2 and 2.8v ( depends on C rate of cells and the load )... from 2.8 to 2.0 it drops like a rock..

 

[joe tomten]

How the charger interacts with the battery and the bms is important for keeping cell groups at balanced states of charge.

For example: I've been suspicious about my (4amp) charger's ability to engage with the bms in order to balance cells.

Last night I plugged it in, and it charges the battery pack up by about 450watthrs. A full charge cause I used about 435watthrs yesterday.

But! This morning, I see that the battery pack is sitting there at ~54volts, and I know my charger when it first comes on it reads 56.4v unplugged from the battery.

When I unpluged the charger from the battery (leaving it attached to the wattmeter) i see the voltage drift on down toward zero even though the charger was plugged into the wall. It reminded me of this post which recently resurfaced: { http://endless-sphere.com/forums/viewtopic.php?f=14&t=11718&p=178138#p178138 } where certain chargers were getting confused and not properly engaging with the bms and allowing it to do it's balancing function.

Now, 54volts is a full charge capacity wise (3.375v/cell for the 16s). But I'm thinking, 'huh did the bms get a chance to do any balancing last night before the charger decided to slack off?'

So I plug in my ping charger (60.2v) and go do animals and kids, and a half-hour later the wattmeter sez 60volts, 6 watts still going into the battery, bms at the top is warm to the touch (hence the 6watts) and the bms must have been doing something.

Now, I Unplug the ping charger from the wattmeter (which is still connected to the battery) and the voltage stays there at 60v (which is an _average_ surface charge voltage of 3.75v/cell) and walk off and get us (three) all ready to load up on the longtail. And 15 minutes later the battery is sitting there at 56v (average 3.5v/cell).

So in my case when I was relying on the supplied charger, my batteries were getting way out of balance to the point where I needed to open up the pack and manually charge cell groups to get it back into a balanced condition. Now I use my ping charger, but I don't let it sit there and cook all night at 60.2v. The 4 amp charger that John supplied with my battery wasnt' the one he normally supplies with the 16s15ahr battery. I love it for a faster charge rate, but don't rely on it to properly engage with the bms for balancing.

 

[LI-ghtcycle]

Good stuff in this post, glad to see all the information on this newer battery. I haven't had the opportunity to do any real testing as the battery was purchased and is being used by the customer, however, he has not had any trouble with it and has been very pleased thus far.

I will let you all know if I hear different, but looks like a good product so far.

RVD, I wonder if maybe you got the wrong battery? Maybe it was supposed to be a 16S 3P battery, and the factory sent the wrong one?

 

[RVD]

I asked John about this battery because I was also suspicious and he replied saying that I received the correct battery.

 

[RVD]

ok enough is enough. i emailed john and asked him for either a replacement with a battery that really does charge up to at least 57v (says 60-61v on their ebay ads) or give me a refund. we'll see what happens...

 

[RVD]

They have agreed that this battery is 1 cell short. They have agreed to replace this battery if I send it back to them so I will try that and see what I get.

I will reserve future judgement until I get a new battery from them.

 

[RVD]

The replacement battery arrived last night. It's much better.

It is around 57v hot off the charger and settles down to about 54v. Once I ride for awhile it settled down to around 52v (down to around 50 with sag). Overall, it's about what I expected and is better than the old battery. This one clearly has 1 more cell than the old battery did so it's about 3.7v or so higher.

Overall, I would recommend this company. They stand by their product and they were good to make things right when I was not happy. It is cheaper than Ping and you will have your battery within 1 week of ordering instead of 3 weeks from China so if you're in a time crunch, these guys are a great option.

As for the quality of the battery, I think they are comparable. This battery doesn't have all of the lights on it like Ping but the BMS is internal and seems to work well.