Lipos a good option for high performance small pack?

I see. I've never used the PP45 before. Does it not have a spring like the PP50? I guess that's serious bullshit.

I guess I'll solder them into the harness like you did and return the PP45. I guess there is no real downside to this since you can still charge and discharge individual packs through the balance leads and replacement is a snap compared to messing with 18650s. Is that right?
 
Right :D

Yet, under 100A power demand, you can use the stock bullets and tape them. That is perfectly safe and makes a low resistance connection that will not get hot. Make your harness with 75A Andersons and the best 10ga wire that you find.
 
As I have said at first in your thread: RC lipo can deliver very high power. You have to play safe with them. They seem like a cheap solution to some, but they are not. They are fragile and don't have any chance to last half as long as the cheapest round cells. I replace my lipos every year, and charge them under strict supervision all the time. Those who don't, are exposing themselves to a chemical fire.
 
Ha, well, these weren't super cheap. Would have made a pack of Samsung 25R but I want to try out lipo.
 
Charge , only through the Balance Leads ?

Balance leads are .. 22 awg .

How much current can you pass through a 22 awg wire ?



flat tire said:
I guess I'll solder them into the harness like you did and return the PP45. I guess there is no real downside to this since you can still charge and discharge individual packs through the balance leads and replacement is a snap compared to messing with 18650s. Is that right?
Click to expand...
 
I'll bulk charge normally. Yes, you can only charge at limited current using the balance leads.
 
But how much current ?

I am new at using lipo's so I am not being sarcastic, I really want to know.

The only info I have seen is from a RC Flyer / Youtube poster in Australia that charges a low cell in a pack, one cell at a time using only the balance wire for that cell , ... He only pushes 0.5 of a amp through the balance wire.

That is only 1/2 of an amp. at that rate it would take too long to charge a pack for my liking/attention span.


flat tire said:
I'll bulk charge normally. Yes, you can only charge at limited current using the balance leads.
Click to expand...
 
I was charging my pack thru (I think) 22 gage wire for a while. It took about 7 amps before getting "too" warm. So I think you can do a lot better than 500ma even with 24 ga.
 
Soldering metal anderson's is not good enough. You need proper crimping with proper tool : I mean you need COLD WELD.
Solder will just increase your connection resistance... Lead and tin are way below than copper on the conductivity scale... They will heat up beacause of the resistance. Also, as they heat, solder could melt and your connection become loos.

This is what you need for real crimping : [youtube]fQQGjgU2I44[/youtube]
40$ canadian on eBay : http://www.ebay.ca/itm/10-Ton-Hydraulic-Crimper-Crimping-Tool-w-9-Dies-Wire-Battery-Cable-Lug-Terminal-/300991159574?hash=item4614789d16:g:1KUAAOSwA4dWGYDY

Here the reason why : [youtube]3qYZFxQ8Pxw[/youtube]

BTW, with proper crimping, you can pass 120 amps in PP75.
Check specs here : http://www.andersonpower.com/us/en/products/powerpole/index.aspx
Of course, that if you use the biggest wire they recommande (6AWG for PP75).

In my case, I found that I can fit 4AWG in a 6AWG metal anderson's connector. It feels really really tight in there (that's what she said the first time :lol: ).
I'm using real copper welder cable. Not the CCA (Copper Clad Aluminium) scam power cable they sell everywhere these days.
 
ScooterMan101 said:
Charge , only through the Balance Leads ?
Balance leads are .. 22 awg .
How much current can you pass through a 22 awg wire ?
Click to expand...
About 7A per cell.
http://www.powerstream.com/Wire_Size.htm
 
ScooterMan101 said:
But how much current ?
...
Click to expand...
Different LiPo packs can be charged at different rates, but all can be safely charged at a 1C rate (where C= Amp capacity)
My LiPo packs are +1.6kW with 30Ah-40Ah capacities but my largest chargers are 500W so I usually (if not in a hurry) charge at 0.3C rate.
However, I can use multiple chargers on the same packs that approaches 1C.
Obviously I'm referring to bulk charging where I always check balance but rarely have to actually balance charge a battery- about once a year.

Unlike One Person in this thread I don't mistreat my battery packs where some are over 6 years old with (much) greater than 80% capacity.
 
Mistreating, when that means discharging hard and charging fast, is what lipos are for. :wink:

I mean, why using lipo if you don't need the only advantages they have. Then, no lipo could last me 6 years, for I ride at least 10 000 miles a year, sometimes much more. It is hard for me to finish the year with 4 usable bricks, out of the 16 that I buy every springtime. A very nice summer weather, does mean I will have to buy a few bricks to do the winter.
 
flat tire said:
Who said anyone is soldering the Andersons? I bought a crimper.
Click to expand...

Nobody.
I just though I'd share my finding of this hydrolic crimper. Also Thought I'd contribute to heighten awareness for everybody who made the mistake that I did in the past.
For big gauge wires (4AWG in my case), it seems like most DYI tutorial on youtube tells you that it's best just to solder than crimp, which is a shame. Sure no air.... but solder is not as conductive as copper.
If I have the choice I crimp properly, then add solder
 
MadRhino said:
Mistreating, when that means discharging hard and charging fast, is what lipos are for. :wink:

...
Click to expand...
:lol: how'd you know I was talkin' bout you?
they has some other advantages besides discharge/charge rates, which I do use, like 1.6kW in a 7"x9" enclosure.
chicken/egg?
bike/battery?
Yes, I build my trikes around my battery cases, which are all the same size.battery cages filled up.jpg
 
I do the same. Each battery pack fitting every bike, as most components do. Standardization is making maintenance so much easier.
 
I had a 51v,32ah lip0 pack... when charging for just the 4 time it blew... my woody trike was destroyed, the tarp shed and part of wood shed and a wood fence were badly charred... not sure what caused it,faulty BNS or charger.. be VERY careful with lipo :mrgreen:
 
I'm only charging to 4v per cell with no BMS and will keep an eye on balance so charge fires don't concern me. I doubt I'll ever monitor the bike while charging. I just park it outside on the concrete in front of the CCTV.

I'm more concerned about damaging the pack in a crash, but what can you do? Guess it's time to add a fire extinguisher. :p
 
Charging slowly is not any safety. Yet, that is another acceptable solution, to charge in a fireproof environment. So it won't damage anything but the bike, and badly smoke the neighbourhood. :wink:

For crash damage, you should build with quick release battery. Lipos don't catch fire instantly. They warn with smell and smoke, and when you are there you should have time to save unnecessary damages.
 
MadRhino said:
charge in a fireproof environment. So it won't damage anything but the bike, and badly smoke the neighbourhood.
Click to expand...

Right.

Quick release = cut all the zip ties. lol
 
Lipo is a funny topic.

Lipo tragics seem zealously evangelical about them, and equally foreboding.

I still dont get why, like other cells, it isnt the norm to just by factory packs of them like - 48v 10ah, with bms & charger.

There are some apps in which short life would be well worth fast charging.

While I am at it, it seems BMS temp monitoring while charging is not the norm, yet it seems a critical factor in charge speed limits of cells.
 
A BMS is not safe with large capacity RC lipo. Most of the lipo fires are the result of users trusting charging and protection devices. Lipos were never meant to be used to power vehicles. When we do assemble big packs to power our bikes, we need to be very careful. We HAVE to be there with them charging, or manage a 100% fireproof environment. Even storage has a risk, they belong in a fridge. Ignore those rules, and you better have a very good insurance contract.
 
cycleops612 said:
While I am at it, it seems BMS temp monitoring while charging is not the norm, yet it seems a critical factor in charge speed limits of cells.
Click to expand...

I'm not too happy with the BMS systems available, especially the lack of domestic availability.

Damn lipos are taking forever to ship.
 
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