my yardworks adventure

[davec]

so i set a goal for myself this summer to visit a friend who lives 50km away
to make it there and get back

i had a pretty ghetto old ccm excel bike with a low key cheap chinese controller and a golden motor pro 901 500w on it but no battery
being short on time - ordering good cells online was out of the questions-- locally there weren't that many options for lithium
there was a CT close by so i took the plunge and got 2 x 20vyardworks 6AH to see what it can do....

after i finished connecting my 2 yardworks together- i went out for a spin
at speed of 20/km hr and light peddaling during/stop/starts/hills got me about 19km(not bad)
so i got purchased another 2 bricks for total of 4 - i figured i would be good for 40km

so it took me about 3-half hours- but i got there i peddled for about 10km and did the rest on batteries with no issues....
my configuration was 2 bricks at a time. i had 2 bricks connected and 2 bricks in my back pack- after peddling 10km i got about 20 km and than the lvc kicked in- so i stopped and swapped for the 2nd set
my only regret was not having my CA with me- next time i go on a long trip i will be sure to take it
on my return trip- i ended up staying for few hours @ my friends - during this time i charged these up - my charger essentially was a hyperion 1420 set to lipo and i powered it with PC ATX power supply
I charged a brick at a time on the 5s lipo setting- the brick would not go upto to 21v due to BMS- so when the voltage came up to about 20.3 i just turned it off (all 4 lights came on indicating its full)
interesting thing was when i hit lvc out of the 2 bricks 1 brick still had 2-3 lights while the 2nd brick was down to 1 light.... so the heavily discharged brack took a good 1-2 hours pushing 2-3 amps during charge while the 2nd brick with 2 lights was quicker....about an hour

 

[davec]

some technical details

I got the most useful information here:
http://endless-sphere.com/forums/viewtopic.php?f=2&t=9451&start=15#p146338

apparently these bricks contain LiMn- 5 of them
same stuff docbass is selling- same specs as lipo- so 4.1/4.2 per cell fully charged 3.7 nom
the brick has 3 pin -,C,+
it is very easy to interfact to these pins-- all you need is a terminal connector end (type) tab - male disconnect & than crimp it on the cable
I got a box of 5- and used 10 AWG wire
made one cable to connect the 2 bricks in series(with the terminal ends)- and than made 2 more for (-) end and (+) end

For charging-
i put terminal tab connectors on charger cables for both - & + - and charged one brick @ a time
for charging - connecting to (-) & (+) worked- however based on the thread above i feel it is safer to use (c) & (+) as it charges via the BMS and keeps the cells safe
my charger was a hyperion 1420 hooked to a delta ATX PC power supply
i set it to LIPO
the charger does 2 amps @ 21v so at first i limited my hyperion to this mode (took about an hour) from empty
after that i let it charge at 3 amps with no issues
generally anything between 20.3 to 20.8 means the packs is full (and the light indicators show 4 green lights)- my hyperion was waiting on 21v(for 5s lipo) obviously but i cut it off around 20.8

 

[ColinB]

Good post. I thought of using those batteries too, but decided against it. Nice to know there are good cells in there.

Do you have room to run both sets in parallel? It will lower the current draw for each set and make them last longer and you'll get to go farther.

Colin

 

[davec]

Hi colin,
the bms is limited to 30amp- but it's nice to have it there so you really can't kill the cells
performance wise for a low end e-bike it is ok- i read reviews of these lasting a year & at least you have a short warranty period if they dont
the price is the only drawback(119.00 135/w tax) per brick- when you can get a stick of lipo 10s for 150.00 than can push out 5 times the current......than the choice is clear....but if your stuck and there's a sale on these than it makes sense...

running them in parralel is totally possible- i just didnt have enough connectors left to wire them this way....but it would have been better....when my lvc kicked in after my 20km trip-- i found 1 brick still had a good amount of power left (down to 3 lights) while the other down to 1 light......same deal when my 2nd set ran out of power.. i suppose i could have paired the 2 remaining cells with high charge to get more range... or a parallel setup would of done the trick as well.....
and regarding charging since each brick has a bms and is designed for 20v charger i seperarated them to be safe and charged 1 @ a time

 

[ColinB]

Hi Dave,
The reason that I mentioned running them in parallel is that cells often deliver more of their capacity when run at lower current. For example, a 10ah battery may deliver 9.9ah when you are drawing 1 amp, but only 7ah when drawing 5 amps. It depends on the quality of the cells (I think) as to how much improvement this would give. But it certainly wouldn't hurt.
Colin