A123 36v 20ah victpower custom duct tape pack ?

[AlSpong]

Hi, I just got through reading the entire 7s3p thread after getting really excited with all sorts of potential ideas, but overall I came to the conclusion victpower is not completely sure of the product they sell.

However there are just enough happy stories to keep the interest going , and while I think this may be not too dissimilar to what keeps gamblers addicted ... I continue to Persue an a123. Solution.

I read a post somewhere about someone buying the pre built 36 v 20 ah duct tape pack .
Has anyone else had success here .... The costs of the pack are similar to buying single short tab cells @ 14.70, while the idea of building my own properly is appealing ... So is just being able to use it now and having the work done.

I also don't have the knowledge or tools at this point to test individual cells other than to check voltage, so the appeal of buying bulk individual cells and culling bad ones to make pack is less interesting. If its possiblly been done by someone else( although 50/50by victpowers recent form) to make a good pack I do that

Essentially it seems a lot of people use 36 v for ebikes , and it would be wonderful if any experiences about these duct tape packs could be expressed...... Sorry if this info is available in other threads ...I have not found them .... So love to hear comments and experiences with the victpower duct tape 36v 20ah made from A123 20ah prismatic by someone in china!

Perhaps too it would be great to here a summary of the loose cells vs a duct tape pack if the knowledge , expertise or just thinking time has been committed and you would like to share.
Also anyone got a cheap source for LIfepo4 chargers - victpower supply bms but no charger with this pack .

 

[Spacey]

I wouldn't other with the Victpower built A123 pack. Have tried them and every pack has the positive cable not even attached.

Good job I checked it first!

 

[RayGo]

Check out the prebuilt packs from OSN Power. They cost slightly more than the Victpower packs, but appear to be a better build. It is a simple, clean build that can easily be disassembled in case of repair. However, we are still awaiting feedback on this type build.

The Victpower build is soldered and will be harder to repair but are the cheapest that I have found available. Boils down to which A123 cells they are using.

You can also just order the parts kit from OSN for about $30 (I think that includes the shipping) if you want to build the pack yourself. Then you can choose which type of A123 cells you want to work with.

I plan to build my own pack using the cells with the short tabs with holes.

One other consideration. If you buy a prebuilt pack, it will include a BMS. I don't want to debate the BMS or no BMS issue here. There are whole threads on this topic. However, building the pack yourself allows you to choose whether or not to use a BMS. My preference is not to use a BMS but to monitor the pack with Celllog8s or similar devices.

 

[docnjoj]

I wouldn't other with the Victpower built A123 pack. Have tried them and every pack has the positive cable not even attached.

Good job I checked it first!

Yuk! Spacey. That looks like it was built by chimps. Thanks you for letting us know!
otherDoc

 

[kriskros]

cellman [an ES member]is building a123,20amp packs... i think the price is about $600.00 including bms..charger extra... a good,well known supplier of battery packs... i have had two a 123s ftom him,,excellent

 

[docnjoj]

cellman [an ES member]is building a123,20amp packs... i think the price is about $600.00 including bms..charger extra... a good,well known supplier of battery packs... i have had two a 123s ftom him,,excellent

Absolutely! I may order from him for my next battery. It was interesting to build my own, but it was not much cheaper than Cellman can do it.
otherDoc

 

[arkmundi]

One other consideration. If you buy a prebuilt pack, it will include a BMS. I don't want to debate the BMS or no BMS issue here. There are whole threads on this topic. However, building the pack yourself allows you to choose whether or not to use a BMS. My preference is not to use a BMS but to monitor the pack with Celllog8s or similar devices.

Exactly. Was my choice, an AMP20 self-build with Agnium's kit, no BMS and monitoring with Watt's Up and Cellllogs.

 

[AlSpong]

Thanks for the great responses.
I did not mention that I also looked into English taobao after the links were published in the 7s3p thread
What i found was that while the loose cells and modules are cheaper ,that the approx shipping price I got quoted for loose cells actually made them more expensive than victpower. Toatrends the agent also had a strong reluctance to deal with batteries , and to be fair I did not get an exact shipping price...... They really didn't seem happy to deal with batteries

I am going to check out osn power , can anyone provide a link for that $30 kit?

 

[RayGo]

For the OSN kit info, check this thread link:

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=38761&start=330#p667181

Otherwise here is the info:

Re: A123 20AHr Pouch Cell Battery Build & Info Thread

Postby ambroseliao » Wed Nov 21, 2012 2:15 am
I finally was able to order the circuit board and all the wires, nuts and terminals from Nancy at OSN Power.

The total $ for 2 kits: enough to assemble 2 12S 36V nominal packs was $60 including shipping. I'll post pix when they arrive.

Don't even bother with taobao. It appears to be an internal China website. Then you need an agent as you found out. Shipping to the US will always be expensive due to the hazardous classification of lithium batteries.

 

[AlSpong]

Thanks heaps Raygo......now im swinging back to building my own. That Osn kit looks alright.....thanks for reuniting me with that thread.....interesting stuff going on there in the last week!

 

[Spacey]

Just checking the cell voltages on this pack after the charger says 'I've finished charging all is well let the BMS do its job'.....

Checking the celll voltages came up with a lot of them on 3.85v! Whilst the rest were at 3.3v.

Individually charging the lower cells showed over 3Ah difference in depth of charge. There is no way the BMS would have balanced them in under 2 weeks leaving the high cells...well...very high for too long.

I would advise those wanting these for their bikes to make sure the seller checks the cells, balances them and puts them together with mechanical connections and solder (maybe)...sounds like a job for Cellman.

 

[redstone02]

I wouldn't other with the Victpower built A123 pack. Have tried them and every pack has the positive cable not even attached.

Good job I checked it first!

Same here. The positive solder joint came lose.
The BMS was a POS.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=43887

I used a mechanical joint for the positive post.
Still waiting on the BMS from BMS Battery.

 

[ironmonkey]

Positive terminals breaking loose also happened to me, I crimped it back in using pliers and alot of force (you cant solder it). The battery's are made very messily because its difficult/impossible to solder the alloy terminals of the pouches without using a massive soldering machine and alloy solder.

The battery appears to work as intended, I got no other issues. Especially when I accidentally dropped it 50cm on a concrete floor....

With these Chinese merchants (especially on alibaba) you're a fool to expect warranty. You pay a cheaper price to risk a badly product or a product that may need tweaking. No free lunch guys.

 

[Spacey]

Check the balance of your cells as well. Most are 3 to 4 AH out of balance meaning that your BMS will be holding some cells at 3.85 to 3.9v for the 3 to 4 weeks it will take on constant charge to balance the cells.

 

[bochka]

Go with cellman and you wont regret it. He built a split pouch pack for me and this thing has turned my bike into a beast!

 

[davec]

a123 needs to stop being an asshole and make money of us- lets hope in the near future this changes
every email i've sent -they've ignored - i've talked to their edt re-seller who said 20ah may be sold in the future . lets hope so....they sell to a UK re-seller who overcharges but wont sell locally
i would fire their whole management
regardless- even if the price is a bit higher - it's totally worth it- the legit cells are the best of the crop of any vendor- they will last you at least a year they're safe and pack great amount of energy- that no other cell out there does- as for the grey market cells after sampling a few good ones i will never buy anything grey market again