As I have said the A123 packs are less prone to going out of balance. I therefore only have to split the packs when balance/charging. Most the time they are not split and can be charged simply with the two series 6s1p packs joined together using a cheap generic 36v, 1.6amp charger.

 

Probably a monitor attached continously is over kill and I will now just balance them once a month or so.

 

Regards

 

Jerry

Edited October 14, 201114 yr by jerrysimon

I wouldn't leave it on the packs permenantly - even a small 10mah amp draw can draina 5000mah pack in 20 days.

I'm intrigued buy a small charger and just charging the packs in work if I could simply buy a 50.2v charger at say a really low amperage and let it tickover during the day to give me a little bit more capacity.

 

I'm always a bit worried though becasue there's nothing telling the charger that a few of the cells may not be in balance. (Although i've never had any cells any more than 0.02v out)

Scott I have two cheap generic chargers (36v,1.6amps) like these for my A123 6s1p packs connected in series

 

http://farm3.static.flickr.com/2627/4222463501_f58c0945de_o.jpg

 

The above picture shows an early one before I strapped the two together and put a 15Amp fuse in line.

 

I have a charger at home and one at work. I am not sure if this would work for Lipos in their joined up full pack configuration though. I will leave others to comment who use lipos?

 

The A123 cells can go months using this without balancing though it appears that mine had got out of balance after nearly two years. I plan to now balance them using the charger below every few months or so.

Obviously when I use this one I have to split the full pack down into its two 6s1p components.

 

http://farm5.static.flickr.com/4041/4206031683_1ea487c76f_o.jpg

 

Again an early picture before I had taped it all up.

 

Looking again I think the poster NRG charges Lipos in their joined up full pack config based on the picture he posted on my battery build thread.

 

 

http://i94.photobucket.com/albums/l82/_NRG_/other/Bike/E-Bike/DSCF4845.jpg

 

 

Regards

 

Jerry

Edited October 14, 201114 yr by jerrysimon

Hi Jerry, yes thats an early configuration. I still charge all cells in series with a pair of modified Meanwell power supplies and now I use powerpole connectors throughout and balance with battery medics.

Again I'm not convinced about all the folkllore concerning lipos. I've heard of loads of people that let their lipos go down too far without catching fire when they charge them.

 

I think most of the folklore came about when their use became widespread in the RC world. There are some real horror stories about them that may or may not have come about by shorts etc but certainly coupled with poor early batteries and lack of knowledge in handling and charging they where/are potentially dangerous....just three of many on rcgroups....

 

LiPo Fire Pictures - RC Groups

Lipo Fire !!!!! - RC Groups

Li cells can cause a fire - RC Groups

Thanks for all the technical info you guys know your stuff. I can see why these batteries are not used in commercial applications just overly complex for the average user.

 

I think if I do build a few bikes for people then I would go down the BMS Battery route it seems a good way to build a competent electric bike on a budget. I like the look of their frog batteries they seem similar to ones used by Electric wheel and other components seem to be used by other electric bike resellers.

 

My bike has evolved slightly in that I now have an IP68 plug in the top of the battery bottle and the weight is now 13.6kg. I have to say its an absolute joy to ride and really zips around 0-15 in just a few secs up the hills no problem at all.

 

I'm just checking out the range now up to 8 miles and 3.89V. Who knows with enough interest I may turn it into a little side line business based in Exeter, not sure if there are any members in the southwest?

 

Who knows with enough interest I may turn it into a little side line business based in Exeter, not sure if there are any members in the southwest?

 

We have a number of members in the South West, in Devon, Cornwall and Somerset. Most are only occasional visitors to the site. That region isn't well served with e-bike handling cycle businesses, but there are the odd exceptions.

 

Our members map on this link shows 14 members entered in the region, predominantly in Cornwall. Click on their bikes to get their details