My experience with Sun-thing28

[mateusleo]

The cardboard my battery was win also arrived in very poor condition, very flexible, as flexible as a piece of cloth, but the battery was pretty much in the center and it had more styrofoam than your unit does.... This dent wont affect the battery, its just outside, and even if it made to the cell, its very unlikely that it would damage cell's health.

 

[dnmun]

that dent is significant and we need to know where it is located. you maybe should consider opening the shrink wrap there to see if the pouches are dented on the inside of the shrink wrap and if they are you need to have him send you replacement pouches. the BMS should be cut out of the end of the pack too so it is out in the open air.

 

[striider]

Dnmun - it is a small dent on the corner opposite the built in carry handle and BMS side. Here is a picture showing the 2 corners that are dented.

I did a test ride with the battery the other day, and so far I am totally impressed. Had to reconfigure rack setup to accommodate the weight, and rode 28.3 miles on it. This is what my computer showed when I arrived:

On my lipo packs, the voltage is less overall, so the "fuel level" meter seems a bit more accurate.

I can't find my watt meter after my vacation, so I didn't get a good read on the usage, but I did test the resting voltage after the ride: 52.6v

Color me impressed so far. :lol: This will put my mountain cabin within range if I can figure out how to carry all 3 of my batteries. Tubus rack, here I come!

 

[imorton]

I am so glad that you rec'd your battery and that it is working out well for you. I think that other than the long wait for delivery, they are a decent value.

I ordered the same one, but a 48v 15Ah one from Sun-Thing, and it also took 8 weeks, and is working out well. You might want to open up the IEC plug and verify the connections, as mine were pretty weak/poor.

QUICK QUESTION, My scooter has a 25amp controller and I run it on the 48v 15Ah LifePo4 battery. How long can I sustain a 25amp draw without hurting/damaging/harming my Sun-Thing 15Ah LifePo4 battery...(same battery, but 15Ah) ? EX: 1min, 5min, 15min, Continuously...?

Thanks, IAN...

 

[striider]

Imorton - Thanks, yes, those connections were silly - Solder on the end then a screw through the copper below is NOT a proper connection. I ditched that thing right away for Anderson powerpoles.

You would have to ask SunThing for the specs on your battery for your other question but someone here may be able to ballpark it for you.

 

[dnmun]

ok if the dents are on that end where the BMS is located then it may not have damaged the pouches which are set farther back from the edge on that end.

you should open that end and pull the BMS out where it can keep cooler in the open air. also the BMS has a spot where you can install a switch to turn off the battery at the BMS.

 

[mateusleo]

I am so glad that you rec'd your battery and that it is working out well for you. I think that other than the long wait for delivery, they are a decent value.

I ordered the same one, but a 48v 15Ah one from Sun-Thing, and it also took 8 weeks, and is working out well. You might want to open up the IEC plug and verify the connections, as mine were pretty weak/poor.

QUICK QUESTION, My scooter has a 25amp controller and I run it on the 48v 15Ah LifePo4 battery. How long can I sustain a 25amp draw without hurting/damaging/harming my Sun-Thing 15Ah LifePo4 battery...(same battery, but 15Ah) ? EX: 1min, 5min, 15min, Continuously...?

Thanks, IAN...

Well, lets think about C rate, i'll explain really quick what C rate means. C rate is a propriety of batteris that describe the max current u can pull of it. (C rate)*(capacity)=(max discharge current). Example: 15 Ah 3 C => 3*15=45A. Usually batteries have 2 kinds of C rate, continous and burst or discharge (usually 15 seconds). I assume that sun-thing28 are good to be used at about 1.5 or 2C, no more, but i might be wrong. So, i guess pulling 25 A from a 15 Ah sunthing pack is fine even for continuos use, since it will be 25/15= 1.67 C, But avoid going beyond that. Also, sun-thing BMS usually have amperage protection (he said mine saturates the output amps to 30A, which means that even if i try, it wont pull out more than 30A. My pack is 20AH).

 

[markz]

Such a long wait time, he/she sun-thing28 must not have it in stock. Just reselling, or making them.
Good prices though, kind of on the low end of sales for me. sun-thing28 (2881 ) 98.8%, right in the range of %.

 

[imorton]

Such a long wait time, he/she sun-thing28 must not have it in stock. Just reselling, or making them.
Good prices though, kind of on the low end of sales for me. sun-thing28 (2881 ) 98.8%, right in the range of %.

The eight weeks is for shipping by boat, you can get express shipping probably in a two three weeks

I did check the feedback on eBay, and most of the complaints are some of the smaller cheap watches toys etc. From what I can tell on the way feedback, the battery feedback was all good. Mind you all the feedback is about them receiving it and everything was there and look normal, we won't know how the batteries hold out after 2-3-4-5 years

 

[dnmun]

about the C rate. the battery can produce current easiest when it is at full charge. the internal resistance is lowest then.

if you continue to try to extract high current from the battery when it drops in state of charge then there are fewer ions available to carry the current so the internal resistance climbs rapidly.

this is why internal resistance is always measured using a 1kHz oscillator at full charge to evaluate the internal resistance.

so as the battery becomes discharged you should cut back on the discharge rate so that you are not pulling more than 1/2 C when the SOC has dropped into the 40% range. otherwise the heating of the battery from high discharge when at a low SOC will cause shortened life cycles.

 

[imorton]

about the C rate. the battery can produce current easiest when it is at full charge. the internal resistance is lowest then.

if you continue to try to extract high current from the battery when it drops in state of charge then there are fewer ions available to carry the current so the internal resistance climbs rapidly.

this is why internal resistance is always measured using a 1kHz oscillator at full charge to evaluate the internal resistance.

so as the battery becomes discharged you should cut back on the discharge rate so that you are not pulling more than 1/2 C when the SOC has dropped into the 40% range. otherwise the heating of the battery from high discharge when at a low SOC will cause shortened life cycles.

When u say "1/2 C", do u mean 1 to 2 C, or do u mean .5C ?

 

[dnmun]

1/2 =.5

 

[markz]

Well I do not know, its very tempting with free shipping from this guy buts its going to take FOREVER!
Whats his email? I need quicker shipping.
Can I email the guy through eBay?
I believe PayPal is 180 days, eBay however has an "estimated date" for s/h.
So I guess its kinda of a double backup in a way, plus I pay off PayPal with Visa so its a triple backup.

I emailed him through eBay, I hope his english is good

Do you offer a faster shipping method?
I am in Canada, Alberta, so can you ship by air?

Free shipping, plus its LiFePO4 so 2000x+ cycles.
SuPower had this on their website
48V 54.6V 10.5Ah 30A 1000W Lithium Li-ion EV Battery Pack w/ BMS $269.00 but $100 FedEx s/h, plus I think Li-Ion wont hack 2000x cycles.
Or 25r = 36V 37V 42V 7.5Ah 60A 7500mAh Lithium Li-ion Battery Pack same s/h price.
Funny thing is, 2 of them together, adds an extra $30 in s/h.
My ebike is already f'ing heavy.

 

[striider]

I only had contact with him through ebay: sun-thing28 <setech_jr2829naz@members.ebay.com.hk>