Fast charging , is it possible and wise?

[everest]

I'm going to be doing a bit of cycle touring this summer and rather than carry lots of batt's, i was wondering if it possible to
quick charge any kind of battery?. I'll probably be carrying something like a 24volt 10-20amp battery or a 36volt 10amp.
I need to recharge this in about an hour or less!!!

I've seen the dewalt stuff, and the fact that it can charge one pack quicky, however i'd have to carry 4 chargers with me!!

so, is it possible to charge a battery quickly? what are the pro's and con's?

is is possible to charge 4 dewalts one charger? this would be ideal.

what's this i found, crazy price, but does will it work, it's a 40a charger?
http://www.cyclone-tw.com/order-E.htm

PSI 20Ah24V LiFePo4 batteriespack in bag+BMS+40A charger ( 30 mins)

has any got one? is it possible? will i explode!

thanks!

 

[Lock]

4C seems to be pushing it... All depends on the the manufacturer and type of lithium chemistry. Cyclone doesn't say which cells are in their packs that I can see.

This site for example:
http://eclipsebikes.com/10ah-lifepo4-battery-battery-charger-p-904.html

offers PSI 10A cells (often called "Headways" here) and states "Maximum Charge Current: 40A"

...but the charge rate on the manufacturers spec sheet that I have for these cells states charge rate s/b only 2C, not 4C... So some sellers might be pushing things perhaps, and it never pays to push *any* cell chemistry TOO much. If you're lucky it might only shorten cycle life.

Hope others will comment!
tks
Lock

 

[Ypedal]

PSI and Headway are not the same cells.. :wink:

The PSI have the male threaded studs sticking out, true 10ah

The Headway have the female end caps and more like 9ah with slightly lower C rate.

 

[everest]

okay, so what these lifeypo4 http://gwl-power.tumblr.com/ all about?

i might take a look at them? seem you can charge them at 100amp? is that just plain crazy..........

 

[liveforphysics]

Anything with very low internal resistance can handle rapid charging.


Many manufactures rate 30-40c LiPo for safe and normal 3-4C charging. That means 15-20min charge time.

You quickly become limited by the amount of current you can pull from a household 110vac socket with a 15amp breaker.

 

[swbluto]

Since he states a desire for a maximum capacity of 500 watt-hours (The highest stated was 24V20Ah), the power to the battery for 15 minutes would be 2kW. I think that's approximately 20A from a house circuit? Oh well, it looks like one might just have to deal with 30 minute recharges.

However, it seems the poster wants an hour charging. A123s and headways would handle 1C charging fine. 2C would be possible with headways, though that may shorten the cycle life due to cell heating, whereas 2C wouldn't be a problem at all with a123s.

 

[everest]

hey, thanks for the replies..

so it can be done? but where can i get such batteries and chargers?

i looked the scib battery, it's looks like science fact, rather than fiction...

http://www.chamberlainecycles.co.uk/products.php?plid=m1b29s343p1679&rs=gb

not that you can seem to get one from anywhere?

 

[Lyen]

I recommend get yourself a portable generator and charge your batteries while you are riding your electric bicycle on the road. Below is what I was going to use for long distance:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=16374
Sorry, I am not trying to sell it on here. But just want to give you an alternative example to quick recharge.

 

[everest]

hey, nice idea, but it's an extra 12kg to carry, but it's worth considering

 

[BMI]

You don't necessarily need high rate Li-Po to be able to fast charge. The lowest C rate cells LiFeTech Energy manufacture (15Ah as pictured) are rated at 10C continuous and 15C peak discharge. These same cells are rated at 5C charge rate, ie, 75A continuous charging current for a 15Ah cell. The charging rate comes down to the LiFePO4 formulation/quality used by the manufacturer and the method of construction of the cell.
View attachment LiFeTech X2E 15Ah Designers Pack.JPG

 

[Jay64]

BMI, hopefully this will be useful info for the original poster and not a thread jack, but what cycle life are you getting out of the batteries at 5c charge rates?

 

[dogman dan]

My new ping 48v 15 ah charges pretty fast with a 5 amp charger. 3 hrs to full charge and another 1/2 hour for balancing isn't too bad. 30 miles, then a three hour break and 30 more can get a long ways in a day.

With a 48v 10 ah headway pack, a full recharge would take about 2 hours with a 5 amp charger. I would think that a ten amp charger with a higher c rate battery like a the headways would be ideal. Ride ah hour and charge an hour would make a nice cycle you could keep up all day I think.

 

[everest]

hey, keep em comming.

I might just order me some lifeypo4 2x12v20amp/h , give me a nice 24volt system

am i correct in thinking the this could produce 500 watts continuous for over an hour?

with a 24volt 20amp charger into these two batteries, i should be able to recharge within an hour , is this correct?

the current draw is of the charger from the wall socket would be about 500 watts? the maximum i can draw from a wall socket is around 2400 watts?

my math's might be completely wrong, i presume when you talking about charging it volts x amps to get the wattage draw?

so this should be okay?

why 24volts? it's just a lot cheaper!! i don't need to whiz along, just chug along.

 

[Doctorbass]

Hmmm fast charging... with A123

All electrons the 15A circuit breaker can take!!


17.5A continuous!

[youtube]y0BtGm5LAiM[/youtube]

When you charge at 1685W to the cells using a single 115V 15A outlet.... you feel great!!

BUt you need a PFC charger or power supply.. That man you need that this charger have the POwer Factor Corrector circuit to ameliorate the efficiency

Doc

 

[everest]

The Dr....., as awesome as ever!!!

wow, so the next limit in electric bikes will be domestic house power supplies.

 

[Lock]

...so the next limit in electric bikes will be domestic house power supplies.

Not necessarily. Not if you employ a "dump pack" or some other way of storing energy (flywheel etc) so that the energy can be bled from the wall at the "slower" rate of... what? it varies? 100A at 120VAC? ... and stored up then "dumped" into your ebike (Extra-Ultra-Super-Duper-Cap) storage all at once...
tks
lOOck

 

[BMI]

BMI, hopefully this will be useful info for the original poster and not a thread jack, but what cycle life are you getting out of the batteries at 5c charge rates?

I would have to check with the factory as to how high charge rates affect the cycle life of the cell. The specification is up to 5C continuous charge rate. The cell specification sheet and discharge curves is attached here for your reference-
View attachment LiFeTech X2E Cell Specification.pdf

 

[AndyH]

I'm going to be doing a bit of cycle touring this summer and rather than carry lots of batt's, i was wondering if it possible to
quick charge any kind of battery?. I'll probably be carrying something like a 24volt 10-20amp battery or a 36volt 10amp.
I need to recharge this in about an hour or less!!!

How large a charger do you want to carry? A 1C charge will give you a 1 hour charge time, maybe a bit more if the pack's out of balance. A 1C charge for a 10Ah pack is 10A; 20A for your 20Ah pack. If you use cells capable of a 4C charge, and you want to carry an 80A charger, you can charge your 20Ah pack in a bit over 15 minutes.

So yes - while the misinformed public/press wants to blame batteries on why EVs won't work, batteries are just fine - we need more big outlets for fast charging!

As an aside, Cyclone and Eclipse carry PSI cells (40138F1A). PSI rates the cells with a 4C/40A max for a 15 minute charge capability. If you choose to use one of their kits, which appear to connect the pack by the terminals, please rebuild the pack so that you're mounting the cells by the cases rather than by the terminals. The terminals are not designed to carry the stress of cells bouncing down the road. That's why PSI created their 'assembly blocks' for solid mounting.

'nother edit... Here's a 24V/40A 1500W capable PFC charger that can be had programmed for LiFePO4 and operated from 110 or 240VAC. Enjoy!

Andy

 

[Lock]

Hi Andy

...and you want to carry an 80A charger...

...errrmm... I seeing weights like 35lbs for a 24V 80A charger... do they come any lighter?
Lock

 

[Doctorbass]

Hi Andy

...and you want to carry an 80A charger...

...errrmm... I seeing weights like 35lbs for a 24V 80A charger... do they come any lighter?
Lock

Mine is 48V ( set to 50) and 35A.. so equivalent of 24V 70A... and weight 4kg ( a Meanwell RSP 1500)

The key is toi find a charger using fans instead of heavy heatsink.

Doc

 

[AndyH]

Hi Andy

...and you want to carry an 80A charger...

...errrmm... I seeing weights like 35lbs for a 24V 80A charger... do they come any lighter?
Lock

Hopefully!

 

[liveforphysics]

3 of these would be able to do 75amps at 24v for you, and would weigh under 10lbs for all 3 together.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290406491822&rvr_id=&crlp=1_263602_263622&UA=%3F*S%3F&GUID=7c0922221250a0aad0b7ed87fd724b00&itemid=290406491822&ff4=263602_263622