72V 100A 60Ah 4.3kWh 10s24p 200lbs.....

Dan said:
Mike, when and if the impending zombie apocalypse were to happen, some time soon, if at all, tomorrow happened, as it surly will, if ever, Would you suggest an electric bike or a gas, ICE motor bike as an urban assault vehicle?

Pros; no transmission/gear reduction. So less parts that can fail. More torque, greater "Bravely run away" speeds and cool/environmentally friendly, factor.

Cons; dead battery. Greatly reducing the "bravely running away" thing.

In these times of troubling world events and impending zombie infestation, this is an important cause to question and address! (if at all)


"I'm building a 2 wheeled Urban Assault Vehicle with dual 40mm grenade ammo cans in the back to hold 70 lbs. of LiPo's (72V 60Ah). When it's done, I'm gonna go crush stuff with it. LMAO"
Click to expand...

Defiantly going to have to be electric. After the apocalypse there won't be any gasoline, and even if there is, there won't be any electricity to make the pumps work. At least we'll be able to charge our bikes with solar panels.
 
biknut said:
Defiantly going to have to be electric. After the apocalypse there won't be any gasoline, and even if there is, there won't be any electricity to make the pumps work. At least we'll be able to charge our bikes with solar panels.
Click to expand...


If at all....

(lol, snork)

Seriously, Why don't gas stations/corporations invest in hand pumps? Power outages happen and are predictable. A hundred dollar hand pump seems like a good investment. And the end consumer does the manual labor! lol

http://www.nytimes.com/2013/09/01/opinion/sunday/squirrel-power.html?pagewanted=all&_r=0

Not for nothing and I hand feed the squirrels in my yard....
 
I have a friend that travels to ND in the winter for Christmas. One thing always along in the tool stash is a hand pump for when/if the stations loose power. Hes used it more than once. Pumping cold diesel is no fun, but its better than sitting doing nothing.
 
kevyleven007 said:
Hope he didn't fry himself zpt
Click to expand...

Oh I already fried myself a few times and it wasn't pleasant at all but the electrical contact with my central nervous system was brief....very brief. These Turnigy's are impossible to run without a sophisticated on-board BMS. The individual cells simply have a mind of their own when discharging and I'm only using two 37V packs! I was gonna load my bike with 20 of them. What a pipe dream that was. LMAO
 
miked826 said:
These Turnigy's are impossible to run without a sophisticated on-board BMS.
Click to expand...
Pretty much any Lithium based pack needs a good a BMS and why DIY pack building is so sketchy.

Despite my electronics background I have been happy just buying well built packs based on tested component compatibility.

EM3ev makes some cool packs, I had 3 custom made for my trikes and used three of the new Triangle packs with no battery or charger issues.

They make their own BMS blocks for their packs and they sell them.
http://em3ev.com/store/index.php?route=product/category&path=42

Maybe they can make you one for your plan, can't hurt to ask.
 
KCvale said:
Pretty much any Lithium based pack needs a good a BMS and why DIY pack building is so sketchy.

Despite my electronics background I have been happy just buying well built packs based on tested component compatibility.

EM3ev makes some cool packs, I had 3 custom made for my trikes and used three of the new Triangle packs with no battery or charger issues.

They make their own BMS blocks for their packs and they sell them.
http://em3ev.com/store/index.php?route=product/category&path=42

Maybe they can make you one for your plan, can't hurt to ask.
Click to expand...

Thanks for the EM3ev link.

I have one 37V pack that has gone from fully charged to almost dead...... without even using it. I just let it sit powered off from a few weeks. Li-Po takes the need for a BMS to the extreme. No other Lithium chemistry battery comes close. LMAO
 
miked826 said:
Thanks for the EM3ev link.

I have one 37V pack that has gone from fully charged to almost dead...... without even using it. I just let it sit powered off from a few weeks. Li-Po takes the need for a BMS to the extreme. No other Lithium chemistry battery comes close. LMAO
Click to expand...

Hey, I stumbled across your thread. I built a 30AH / 74v LIPO pack years ago. I kept the batteries in their parallel arrangement while in storage, and they still held their charge fine. Either you got some bad cells, or there's a few other things you can do to prolong the life of them.

It helps to balance charge every single time, and verify your charger is accurate via DMM. I personally don't like going over 4.1v, and the capacity gained by that extra 0.1v is almost negligible (you already have 80% capacity at just 4v charge). Don't discharge your cells very low if you can help it. Basically, build your pack large and you will not have to run a high "C" rate per battery, nor require as much DOD per trip. It's a win/win. You don't need a high C rating LIPO. Pretty much any of them can do 15C-20C continuous, and that's only 20AH needed for a whopping 300-400A output. Finally, when you store your LIPO's while not in use, keep them below 4v per cell.

Right now, I'm building a 60AH 74v nominal pack, 4.44 kWh. I'm just doubling the size of my previously successful design. I'm keeping packs balanced via passive resistive balancers while charging the whole thing in series at 84v peak (which I plan to cut off early). This is for an electric Volkswagen Sand Rail, but you're attempting very similar levels of battery power.

Edit: Also, consider that your BMS itself might be the culprit in draining your cells in storage. I never used a BMS.
 
Last edited:
Jayls5 said:
Hey, I stumbled across your thread. I built a 30AH / 74v LIPO pack years ago. I kept the batteries in their parallel arrangement while in storage, and they still held their charge fine. Either you got some bad cells, or there's a few other things you can do to prolong the life of them.

It helps to balance charge every single time, and verify your charger is accurate via DMM. I personally don't like going over 4.1v, and the capacity gained by that extra 0.1v is almost negligible (you already have 80% capacity at just 4v charge). Don't discharge your cells very low if you can help it. Basically, build your pack large and you will not have to run a high "C" rate per battery, nor require as much DOD per trip. It's a win/win. You don't need a high C rating LIPO. Pretty much any of them can do 15C-20C continuous, and that's only 20AH needed for a whopping 300-400A output. Finally, when you store your LIPO's while not in use, keep them below 4v per cell.

Right now, I'm building a 60AH 74v nominal pack, 4.44 kWh. I'm just doubling the size of my previously successful design. I'm keeping packs balanced via passive resistive balancers while charging the whole thing in series at 84v peak (which I plan to cut off early). This is for an electric Volkswagen Sand Rail, but you're attempting very similar levels of battery power.

Edit: Also, consider that your BMS itself might be the culprit in draining your cells in storage. I never used a BMS.
Click to expand...

I'm not using any BMS at all. I'm only using passive resistive balancers and they simply heat up and cut themselves off whether they have done their job or not. It the cells go too far out of balance then the passive resistive balancers just give up.

The higher the "C" rating the colder the battery remains under load, plus they were dirt cheap for these batteries here. I also just don't trust the stated "C" rating for any HK lipos. What passive resistive balancers are you using cause mine are pretty much worthless?

24297.jpg
 
Last edited:
Jayls5 said:
Sure, I don't want to hijack, but here are some videos of the work in progress:

"tester pack"
https://www.youtube.com/watch?v=zIOJ-SL8i2w

first motor test after mounting:
https://www.youtube.com/watch?v=j1FgDL69IQE

3rd gear 300A test, sparks from motor:
https://www.youtube.com/watch?v=5q7OQecAtmM

It's 11.5 kW continuous, 23 kW for a minute. More if you force air cool :) Gonna be testing the thing out this week finally. I'm excited.
Click to expand...

Seriously though how do you keep up with the 10,000+ wire connections you have in your battery pack? My head hurts just looking at it all.

You're a better man than me is all I can say. LOL
 
I'm using 4S 5000mAh 20C hardcase packs. It looks like your 148 Wh battery is in the neighborhood of $90. The hardcase packs I have are exactly half the energy at around $24 a pack. This is $48 for the same Wh, albeit a lower C rating. The point is, if you're going to lump a bunch of batteries together for range, your reason for getting a high C rating battery is negated. All things being equal, the nanotech is likely more efficient with a lower internal resistance, but this improvement is quickly negated by the fact you're able to purchase nearly twice as much capacity of the 20C battery.
These are mine (well, 1/3rd of them):
G0a1kV7l.jpg


I have some cheap balancers, one for each set of parallel packs in the series. Link I only plug them in when charging and discharging. Storage, everything is disconnected other than keeping the packs together in parallel.
 
miked826 said:
Seriously though how do you keep up with the 10,000+ wire connections you have in your battery pack? My head hurts just looking at it all.

You're a better man than me is all I can say. LOL
Click to expand...

It's easier than it looks. 30 batteries, 60 wires total. The black bar looking things just form the series connections between the "six-packs" of paralleled batteries. I made them with aluminum bar stock and heat shrink :)
 
Jayls5 said:
I'm using 4S 5000mAh 20C hardcase packs. It looks like your 148 Wh battery is in the neighborhood of $90. The hardcase packs I have are exactly half the energy at around $24 a pack. This is $48 for the same Wh, albeit a lower C rating. The point is, if you're going to lump a bunch of batteries together for range, your reason for getting a high C rating battery is negated. All things being equal, the nanotech is likely more efficient with a lower internal resistance, but this improvement is quickly negated by the fact you're able to purchase nearly twice as much capacity of the 20C battery.
These are mine (well, 1/3rd of them):
G0a1kV7l.jpg


I have some cheap balancers, one for each set of parallel packs in the series. Link I only plug them in when charging and discharging. Storage, everything is disconnected other than keeping the packs together in parallel.
Click to expand...

That's the EXACT same balancer I use. LOL I always have to place it on a bag of ice or it will get so hot it quits working trying to do it's discharge balance.

I'm glad I only bought 2 batteries of them then. Did you ever consider the Chinese A123 batteries instead? How long do you consider "storage" for?
 
There's ventilation holes on the bottom of your balancer. Make sure those vents are facing skyward so the heat can escape it or it will simply quit working until it cools off. I still had to place it on a bag of ice though and it was unbelievably slow trying to do its job. Passive just ain't cut it. There has to be an active solution that doesn't cost an arm and a leg.
 
You must log in or register to reply here.
Back
Top