pcb protection for li-ion battery packs

[javiole]

Hi all,

I've been trying to buy (allbattery.com, batteryspace.com, etc..) some pcb protection to build up my own li-ion battery packs. The problem is the shipping prices they charge, $45 to send from USA to the UK, one 3.7v, one 7.4v, one 11.1v and one 14.8v boards. The total price was about $35 and the postage $45 !!!. Why? I cannot explain that cost. For everything I have bought so far in CPF from USA, the postage has been a decent $5 or so. If it was something heavy I would understand, but we are talking about things which weight is less than 100 grams and fit inside a letter envelope.

then, my question:

does anybody in CPF sells these products? or I will have to buy some hundreds from the factory and start selling them here? does anybody here have the same problem as me?

cheers

[Leow]

I've found them on ebay with reasonable shipping.
I also found someone selling 18650s with Tags which made them easier to solder.

Good luck,

LeoW

[javiole]

Thanks Leow. I found them on ebay too:

http://cgi.ebay.co.uk/PCB-for-7-2V-L...item3ca07fb2a8

the problem again is the postage cost. The item cost $4.20 and the postage $12.50. And they don't combine postage cost if the itmes are not equal. For example you will pay $12.50 for shipping two 7.2v boards but $23 if you buy one 7.2v and one 11.1v.

[wildwood]

Hi Javiole,

Building a Li-Ion Battery is not as simple as it looks, You will have to be ESD protected for a start, all cells have to be from the same batch and also same voltage... goes on and on,
If you would like me to build you a battery OR build youre battery up for you I could do that for you.
Please email me for more information. I live in the UK too

[javiole]

Thanks wildwood.

I've been using a 11.1v li-ion pack I made using one of those protection boards and some unprotected li-ions. It's been working ok for 2 years. Now I need a 14.8v and a 7.4 packs, so I thought to make them as I did before. My problem is not how to make the battery pack, but it is to find protection pcbs at the right price. It is cheaper to get something like this:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...=STRK:MEWAX:IT

than get those pcbs alone. Balancing the batteries in the pack would be a plus but i can live without it as soon as they are individualy protected for over charging....

I have got now a second hand sony 14.8v laptop battery (5 quid) that holds the charge pretty well. I have put it appart and made a battery pack using the pcb that came with it. Ellectonically I left everything as it was, I just changed the shape of the whole pack to fit in a water bottle. It has protection for single cells and thermal protection too. I have charged it with my smart charger and it works pretty well. I think that will be my pack for my tri-p7 for the next 2 years.