36v 20ah LIFEPO4 Batteries Supplier

C

ChopperMan

10 W
Joined
Aug 20, 2007
Messages
81
Location
Essex, UK.
Hi All,

I have sourced a supplier of 36v 20ah LIFEPO4 Batteries (2C rated) with 5Ah Charger. Their name is Zhuhai Sanchuan Electronic Technology Co in China.

My question is, has anybody heard of this company, if so what was your experience, and are there any questions specific to these batteries I should be asking.

They have offered a three year guarantee against "burning, explosion and swelling etc." as well as direct replacement of DOA packs.

Any thoughts or ideas would be much appreciated.

These are for my personal use, but being a bit of a serial entrepreneur, I can't rule out importing a much larger quantity to the UK at some point in the future if these turn out to be a quality product.

Many thanks,

Ian
 
http://www.sinoriching.com/s1/products/n_cd.asp

A google search on them brings up a link to a link to another link that ends up here....

Basically i suspect they have access to a factory that makes the packs that you plan to buy.. depending on the price and what you end up with it may be ok or a bad deal....

The only way to know before you plunk down a pile of moolah is to get a sample pack and test it yourself.

If you have kept up with this forum you know very well that quality comes at a price, there are very few cheap meals in the battery industry.

:p
 
Hi Y,

Thanks for your comments. Found them through one of the many 'Made in China' type product websites. They perport to be the actual manurfacturer and have given me contact details for a previous cutomer to get a testimonial.

The photo they sent me of the pack and charger, are very similar to Ocean Cheer posted by 'oatnet' here http://endless-sphere.com/forums/viewtopic.php?t=1994 just taken from a different angle. Pricing was roughly 5% less.

Are there any sort of trick questions I can ask that will confirm the battery chemistry. I would like to try and catch them out. If you come through that then I think I'll have the confidence to lay out my money.

Thanks,

Ian
 
Confirm BMS details..

-max voltage ( can they be conected in series )
-LVC ( Low Voltage Cut-off )
-Ballanacing ( The bms has to ballance the cells on charge )
-Short circuit protection?
-Reverse polarity protection?
-BMS accessible? or sealed into the pack ? can it be serviced or replaced?

Charger: Make sure they send you the right Line Voltage !!!! 120 or 240v !

DOA - Un-acceptable.. packs should be tested before they ship.. Capacity tests using calibrated equipment. Trying to claim a DOA pack from a chinse company can be really hard unless you spend Mucho $$$$ with them.. expect them to claim that the shipper damaged the packs and to file a claim with them... this can be a time and money hog.... = bad..

What will the packs be packaged in? plastic or metal boxes ? what conectors will they use ? ( Anderson PP's are prefered.. RCA jacks suck )

Packaging.. adequate packaging during shipping is very important.. wooden crates? or cardboard ?

Form factor, how are the cells arranged? dimensions.. some shapes are hard to fit inside standard bags/boxes.. always good to ask and plan ahead..

want more ? :p
 
Thanks Y,

You know your stuff, done this sort of thing often?

I have answers for some, they are building the battery box (form factor) to my spec in ABS with leads/connectors of my choosing. The interior, whatever is in there, will be accessible.

I will ask about BMS and Line voltage, I must confess that I had made assumptions in these areas and I now feel rather stupid having done so.

I'll let you know how I get on.

Thanks,

Ian
 
I've plunked down well over half a years salary into this ebike stuff so far, so i've learned a few things.. some the hard way....

Don't assume anything.

ask what the max Amp load the BMS will allow before cutting out ( if you plan to use those on 20 or 40 amp controllers.. that allow slightly more than 20 and 40 amps !!! ) Can they be conected in paralell ?

What you assume and they assume are often worlds apart, litteraly.. always ask.. and confirm... when in doubt.. ask again in a different manner.

When communication gets iffy.. use pictures... ( Don't under-estimate the value of a picture when trying to explain something specific )

Something as simple as a digital camera and MS-Paint can be a great tool !
 
Thanks Y,

I'll add that to the BMS questions. I am ordering a 36V pack not individual cells, but it can't hurt to get as much info as possible now.... You never know what you might need to try in the future!

I'll be using a 36V to 72V 35A Xlite controller. But I'm not into speed so intend to stick with 36V

I've used the "digital camera and MS-Paint" option already, a picture is worth 1,000 words etc. Within half a day of sending them my sketch, I got a scale drawing of the enclosure showing exactly where and how I wanted all the cables to exsit.

Cheers.

Ian
 
I'd also ask them for a photo of the cells they will be using and dimensions of the cells, Max Charge/Discharge voltage on the cells, etc. Several vendors I have talked to evaporated after getting questions like these...

-JD
 
Hi Y & oatnet,

Here are the questions and answers:

Q: What is the Max voltage, can they be connected in series?
A: BMS is connected in series. The Max Voltage is balanced by the Charger,The single cells' Max Voltage is 3.65V, For 36V Packs, Its' Max Votage is 43.8V.

Q: Does the BMS have Low Voltage Cut-off ?
A: Cut-off Voltage is 2.0V, When the single cells' Voltage is lower than 2.0V (24V for 36V Packs), BMS will protect the packs and cut-off the discharge.

Q: Does the BMS balance the cells?
A: Balancing, It is not the BMS Balance the Batteies, But the Charger is balance the Batteies. and it will make each cells' voltage is 3.65V.

Q: Does the BMS have short circuit and reverse polarity protection?
A: The BMS has short circuit protection & Reverse Polarity Protection.

Q: What is the maximum Amp load the BMS will allow before cutting out? (We have a potential maximum current draw of 40Amps peak.)
A: Yes, The BMS can be bear the potential maximum current draw of 40Amps peak. Actually, Our factory has been produced the 48V,200Ah for the customers. And it can be 500A discharge. At the same time, The BMS' Quality guarantee is 3 Years too, It can be serviced and replaced.

Q: Charger. We need 240V line voltage .
A: Regarding to Charger, It's no problem that the input line Voltage is 240V.

Q: Can you test the batteries and charger before shipping. Capacity tests using calibrated equipment etc.
A: Before we delivery the samples to our customers, We'll do charge and discharge test for our customers.

Q:packaging. I note you are using UPS but what will the batteries and charges be shipped in, wooden crates? or cardboard ?
A: The package will be the cardboard. and it will be packing very well for delivery( Water-proof, shockproof, Press-Proof). As you know, Most of the batteries is shipping by cardboard, and in order to convience and lightpacking, The Cardboard is good choose for both of us.


Q: What is the maximum charged voltage of the 36V pack.
A: The maximum charged voltage will be 43.8V.

Q: What is the minimum discharged voltage of the 36V pack.
A: The minimum discharged voltage will be 24V.

This does seem OK to me, they even called me on the phone to ask if everything was OK......

Any comments are much appreciated.

Cheers,

Ian.
 
Cool.. replies are decent...

I'd re-ask

" Can 2 x 36v packs be conected for 72v ? Will BMS be ok when 2 packs are conected in series ? "

Unless you plan to strictly run 36v that is..

The " Charger does ballancing " part is a bit iffy.. if the charger conects to the pack with a miltipin conector then it should be fine.. if the charger conects to the pack with only + and - then the bms needs to do the ballancing..

:wink:
 
I'd ask for a graph of discharge voltage versus cell capacity at the peak 2C drain rate. Though there's no doubt from the voltages the cells are LiFePO4, a 2C drain rate is very low for this chemistry, and suggests significant voltage sag under typical ebike 35-40 amp drain rates.
A123 LiFePO4 cells have a 30C continuous drainrate and a 60C burst rate, so I'd also ask if these cell's 2C rate is for continuous or burst operation.

Besides reduced power, high voltage sag equates to high internal impedance; high internal impedance means high heat production and reduced run-time; heat production leads to lower cycle life. Excessive voltage sag will prematurely trigger the controller's low-voltage cut-out.

A low quality 36v NiMH pack can lose 1/3rd of it's energy this way, becoming, in effect, a short-lived, overheating-prone 24 volt pack.

And then there's still the issue of trusting the company to provide accurate specs....
 
ChopperMan said:
Wow, do you guy live on this forum :D
Click to expand...

Sharing the same cell, we're virtual prisoners here of the Endless-Sphere. But no, we're not queer. :shock: :)
 
xyster said:
I'd ask for a graph of discharge voltage versus cell capacity at the peak 2C drain rate. Though there's no doubt from the voltages the cells are LiFePO4, a 2C drain rate is very low for this chemistry, and suggests significant voltage sag under typical ebike 35-40 amp drain rates.
Click to expand...

I'd like to see that too, since I can't duplicate it, and these cells sound very much like my OC cells - 2c, 3.65v, etc. The cell also looks like a wider version of the OC pack's 15ah cells, what ah are they? Also, did they give you dimensions, weights on the cells? Beyond that their responses look credible.

The one test I got with the Ocean Cheer pack on my TF showed sag from 39.1 to 34.1 (note - I erroneously reported sag from 4x.x v, but realized later that was peak charge voltage that quickly burned off), only a little better than my TF's NiMh battery's sag to 33.1v.

I wish I could have it built with 13 cells instead of 12, but the BMS/Charger don't look built for it - ask though, see if they can do a custom voltage for you!

Also ask for a picture of the charger, see if it looks like mine, if so you might have a better idea of what you are getting involved with.

Also on the OC pack, they put the exposed male pins on the battery, and the covered female pins on the connecting cable - since the battery is out in the world, that is the part that needs the female connector.

-JD
 
oatnet said:
The cell also looks like a wider version of the OC pack's 15ah cells, what ah are they? Also, did they give you dimensions, weights on the cells? Beyond that their responses look credible.

I wish I could have it built with 13 cells instead of 12, but the BMS/Charger don't look built for it - ask though, see if they can do a custom voltage for you!

Also ask for a picture of the charger, see if it looks like mine, if so you might have a better idea of what you are getting involved with.

Also on the OC pack, they put the exposed male pins on the battery, and the covered female pins on the connecting cable - since the battery is out in the world, that is the part that needs the female connector.

-JD
Click to expand...

Hi oatnet,

Yes the charger looks exactly like yours, 10 red cables with a female connector on each end and a non-descript ABS enclosure. They are 20Ah cells. Also, they have promised to include a waterproof cap for the male charger connector sticking out the battery.

Dims : 28cm X 95cm X 21cm 36V 20Ah 7.8Kgs

They have said they can build any V and Ah configuration I want and into any enclusure I like. WHEN I buy in bulk. This would also include any connector type and configuration I need.

This would no doubt warrant a considerable investment on my part and although I find that more than a bit dawnting, if these work out as well as I hope and i could forge some business partnerships in the UK (or elsewere), these appear a viable supplier.

I suppose the trick would be to find an encloseure and connector combination that would suit the majority of hobbyists and custom ebike builders.

Who would like to make the first suggestion :)

Cheers,

Ian
 
The company have confirmed that these packs can be connected in parallel or series, 36V, 40Ah or 72V, 20Ah packs. They commented "The BMS should be OK, but, we would prefer to build packs to these specifications so we can provide a full warranty."

It suggests they wouldn't honor their warranty if used in either combination, which is probably fair enough.

I have now placed my order for two 36V 20Ah packs and chargers. Delivery 3 weeks via UPS.

My new Puma powered chopper will be nearing completion then, so they will get plenty of testing. I'll be starting a build thread soon.

Cheers,

Ian
 
ChopperMan said:
Hi oatnet,

Yes the charger looks exactly like yours, 10 red cables with a female connector on each end and a non-descript ABS enclosure. They are 20Ah cells. Also, they have promised to include a waterproof cap for the male charger connector sticking out the battery.
Click to expand...

Greetings Ian!

Yeah, they are probably coming from the same factory. I still don't have my Ocean Cheer packs sorted out, so I hope you have better luck.

-JD
 
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