How much Capacity do you have on hand ? Wh

Cleaning up the house yesterday i realized just how much energy i have in here... quite something...

For those who dont know how to calculate it..

V x Ah = Wh
1000wh = 1 kwh

example:

I have a total of 22 x 6S 5ah lipo packs, this means 24v x 5ah = 120wh x 22 packs = 2640 wh = 2.6 kwh

7 x 24v 10ah PSI packs = 240wh x 7 = 1680wh = 1.6 kwh

A2B metro = 36v 10ah = 360 wh = 0.36 kwh

eZee 36v 10ah pack is another 0.36 kwh

48v 24ah LiFePo4 foil pouch pack = 1152wh = 1.15 kwh

36v 20ah x 2 LiMn = 1440wh = 1.44 kwh

Total = 7.51 kwh !!!

Not counting loose cells of various kinds laying around.... i'm sure i have another kwh in that pile...

12 x 6s 5000mAh zippies - so far no bad cells or puffies and going strong.

Once I started counting between my two homes = 3520wH

About 2kwH of that RC Lipo. The rest mix of EBK Life and F cell NiMh. Didn't bother adding up the SLA but who cares?

I have about 3kwh.

"How much capacity do you have ON YOUR EBIKE" is probably a more interesting question. In my relatively big triangle (frame size 21") I can stuff up to 880wh and the controller, and keeping the total width to 3.75". In my smaller triangle (frame size 15"), 450wh and the controller, same 3.75" width.

Like Sam said, the whole KWH is on the trike. Soon going to double that so I can take at least one 100 mile ride next spring.

And yeah, I didn't count the old SLA bricks that are still laying around.

yeah.. i have a few hundred lbs of lead, gathering dust in the shed lol..

Ypedal said:

I have a total of 22 x 6S 5ah lipo packs, this means 24v x 5ah = 120wh x 22 packs = 2640 wh = 2.6 kwh

Click to expand...

So you're using 4.0V per cell for LiPo? I would use 3.8V to calculate capacity, given these discharge curves:


I'm running 18S3P with 5AH packs, so that's 18*3.8*3*5 = 1,026 WH.

dennyt said:

Click to expand...

dennyt, did you test and generate the above chart? Or was it provided by the manufacturer?
Sorry for getting off topic.

for simplicity sake i roughlied it.. :lol: ,. 48v on 12 cells made form 2 x 6S packs.

Hmm. If I only count stuff that is actually tested as working at least enough to run a minimal ebike assist, and I use the "nominal" voltage for the cells and the "nominal" Ah:

SLA:
8x 12V 17Ah
2x 12V 20Ah
5x 12V 31Ah (including two in the powerchair)
I guess that's almost 4KWh, though probably 2-3KWh actually usable due to Peukert. :lol: Probably lots less since they're kinda old. Let's call it 1.5KWh. Not a lot of power for all that weight.

NiMH:
1x 36V 9Ah
2x 24V 13Ah
Given their age, and thermal damage, it's probably down from the original 948Wh by maybe half, so let's call that 500Wh. Still useful, though.

LiFePO4:
1x 48V "20Ah", more like 12Ah or so really.
Age, bad cells, etc., call it 500Wh. Still very useful, as it'll get me almost 20 miles without pedalling.
Oh, and the Thundersky cells, 10x 60Ah, 32V nominal. almost 2KWh, but ATM that's not all that usable for the bike motor setups I have, because the voltage is too low. Working on a setup that *could* use it, that will be similar to the one I bought it for in the first place.

Experimental LiPo-type pack, something like 1.6KWh capable. Best of them all so far.

Then I've got a bunch of LiCo cells I'm still testing, but would probably be 800Wh or so.

Couple boxes of old NiCd toolpacks that I have yet to get to weeding thru, but there is probably another 250-500Wh still usable in there, if I ever find time to do anything with them.



Yet, even with all that, it seems like I never have enough battery around for the really long distance (for me) trips I sometimes think I want to try.

SamTexas said:

dennyt, did you test and generate the above chart? Or was it provided by the manufacturer?
Sorry for getting off topic.

Click to expand...

I grabbed it off google images. Some people have posted similar graphs here, using RC chargers that can produce such discharge curves. Here's a better one from Neptronix:
http://endless-sphere.com/forums/viewtopic.php?f=3&t=33335&hilit=lipo+cliff&start=15#p485023

dennyt said:

...So you're using 4.0V per cell for LiPo? I would use 3.8V to calculate capacity, given these discharge curves.

Click to expand...

Real world lipo discharge curves on my "Turnigy" packs this summer was around 3.9 volts per cell. I rarely drained my 16AH packs to 3.8 Volts per cell.

After a total of 2,000 miles on the same lipo packs, only once did i drain them to 3.8 volts per cell.

Lipo cells start to go out of balance when drained past 3.8 volts, and i bulk charge them all at once.

Never did i have to balance charge them all summer long. Curious to see what they look like after storage through winter.

recumbent said:

Real world lipo discharge curves on my "Turnigy" packs this summer was around 3.9 volts per cell. I rarely drained my 16AH packs to 3.8 Volts per cell.

After a total of 2,000 miles on the same lipo packs, only once did i drain them to 3.8 volts per cell.

Lipo cells start to go out of balance when drained past 3.8 volts, and i bulk charge them all at once.

Never did i have to balance charge them all summer long. Curious to see what they look like after storage through winter.

Click to expand...

All true, but you weren't using more than 70% of the capacity of your pack. If you're trying to calculate capacity with an "area under the trapezoid" method, you need to use the average voltage over a full discharge cycle.

the poll choices are pretty wide apart... like horseshoes and grenades.. close is good enough ! :lol:

Hmm, don't have an EV yet. But if you include Computer UPSs, about 1.8Kw (server grade ones).

2 x 6S 5000 MAh Zippy's for a whopping 220Wh is all I have right now.

(yeah I still pedal a lot )

-R

660wH here. Can get a whole 10 miles out of my trike...