RC Lipo - anyone making it easy ?

[Old_Dave]

the main advahtage of lipo

Nope...

Its the silly grin you have on your face when your bike becomes fun

 

[johnamon]

Ahh, so the main advahtage of lipo is lots of relativley small purchases vs one big one......much easier to get under the marital radar

ha ha, as Old_Dave said - LIPO is much more fun! But in order to benefit most you will need a new controller - or to reprogram your old one. Also a 250W motor may not draw enough power to make the most of the expensive batteries that you are ordering. My 350W 8fun BPM motor is much improved, but I'm not anywhere near moped territory because the motor simply doesn't have enough copper inside to draw the amps.

Just depends what you want, but lipo's won't entirely remove the need to pedel!

 

[Deleted member 4366]

I also have an icecube57 built harness. It wasn't cheap - I asked for a harness to to allow 18s3p to allow me to run my 6 lipo bricks in either 18s2p or 12s3p - a lot of connections meant an expensive harness, but the job is neater than I would have managed.

This winter I upgraded to lipo, I needed new HK lipos, a DIY meanwell bulk charger, some cheap chinese lipo balancers, a wiring harness, a new (lyen) controller to allow / handle all the current and a new pannier to store the batteries. I've spent nearly £500 in total including shipping and getting really lucky with no customs surprises. Please don't tell my better half the total.. LOL

p.s. Please remember that you'll need a power supply to run the battery charger - they don't tend to work off mains voltage (PITA)

I didn't mean a size for zize comparison. What I meant was power to weight ratio,, so you can run your 500w motor on a 1500g 5aH 44v pack, but you wouldn't go sp far. For some people range isn't so important. I use one of my 5aH lipo packs for testing new motors etc.

 

[KirstinS]

@johnamon

Thanks , I know what you mean re amps. All I actually want is a higher top speed than 15mph , I'd like 20 ish

My commute will soon be much longer and totally flat. Before it is shorter but VERY hilly

@d8veh , ahh got your meaning. Yes I see the lightweight , low ah advantages for certain applications

 

[BAH48]

Reading this thread has made me think, if I bought --

4 packs of these - ZIPPY Flightmax 5000mAh 6S1P 25C at $44 each.

Would this be a good charger -- HobbyKing 4B6 Balance Charger Plus Accessories (200W) 75$

Spec.
Operating Voltage: 11~18v DC
Charge power: 50w x 4
Discharge Power: 5w x 4
Discharge Current: 300mA
Cell count: 1~15 NiXX, 1~6 LiXX, 1~10 pB (Lead Acid)
NiXX Charge termination: Auto, Negative Delta peak
LiXX Charge termination: Auto, Voltage dependent, CC-CV


I would get a 10 Ah battery + charger for $251 --- about £160, and a second 10Ah battery for about £110.

Does this make sense? I am looking at the 500w MAC motor from EM3ev.com and possibly trying the 500w DD motor from the same place.

I'm assuming that I can charge the 4 packs at once - shouldn't be a problem, should it?

 

[smudger1956]

I'm assuming that I can charge the 4 packs at once - shouldn't be a problem, should it?

Yes 4 packs at once, but individually, not as a 24s1p, there are dedicated chargers (Kelly/BMS) that will charge 4 packs in series.

 

[BAH48]

OK - thanks

 

[Deleted member 4366]

Reading this thread has made me think, if I bought --

4 packs of these - ZIPPY Flightmax 5000mAh 6S1P 25C at $44 each.

Would this be a good charger -- HobbyKing 4B6 Balance Charger Plus Accessories (200W) 75$

Spec.
Operating Voltage: 11~18v DC
Charge power: 50w x 4
Discharge Power: 5w x 4
Discharge Current: 300mA
Cell count: 1~15 NiXX, 1~6 LiXX, 1~10 pB (Lead Acid)
NiXX Charge termination: Auto, Negative Delta peak
LiXX Charge termination: Auto, Voltage dependent, CC-CV


I would get a 10 Ah battery + charger for $251 --- about £160, and a second 10Ah battery for about £110.

Does this make sense? I am looking at the 500w MAC motor from EM3ev.com and possibly trying the 500w DD motor from the same place.

I'm assuming that I can charge the 4 packs at once - shouldn't be a problem, should it?

This is my favourite charger:
BC168 RC Model Super Speed Li-ion Li-Polymer Li-Fe Balance Charger BC016 | eBay
You need a power supply as well.I use a PC power supply that you can get from car boot sales for about £1.

 

[BAH48]

Looks good - thanks

 

[amigafan2003]

Which is a bit OTT and can be done for a lot less if you learn to solder (or ask a friend)

I don't like soldered anderson connectors. I wanted the security of hydraulically pressed connectors.

 

[Old_Dave]

I don't like soldered anderson connectors

I don't like Marmite

But I do like soldered XT60's

 

[KirstinS]

Ok, i had another thought (which like most won't work due to annoying little things like physics )

What about having my 9ah 36v setup as is but also having a 5ah lipo setup at 44.4 with a switch to choose between the two power supplies

I could use the 36v as the main battery but, on clear stretches when at 15pmh, hit the switch and get more speed

It would add a kg or so to bike but I would not care.

 

[Deleted member 4366]

Ok, i had another thought (which like most won't work due to annoying little things like physics )

What about having my 9ah 36v setup as is but also having a 5ah lipo setup at 44.4 with a switch to choose between the two power supplies

I could use the 36v as the main battery but, on clear stretches when at 15pmh, hit the switch and get more speed

It would add a kg or so to bike but I would not care.

Lots of people have had the same idea. In theory it should work, but I've never seen a report of a successful application. You'd need to find the right high power switch or relay.

 

[amigafan2003]

Ok, i had another thought (which like most won't work due to annoying little things like physics )

What about having my 9ah 36v setup as is but also having a 5ah lipo setup at 44.4 with a switch to choose between the two power supplies

I could use the 36v as the main battery but, on clear stretches when at 15pmh, hit the switch and get more speed

It would add a kg or so to bike but I would not care.

Most people don't do this because it's simpler (and cheaper) just to have a higher voltage battery and a controller with a 3 speed switch, and then program the controller to say 10mph position 1, 15 mph pos2 and 20mph pos3 etc.

 

[benjy_a]

I like the idea of doing this with switched main supply voltage. Would mean better efficiency rather than relying on PWM voltage from controller. Could then be run at constant full throttle - cooler and more efficient controller?

Wouldn't be so hard just with a nice chunky relay, ensuring that the throttle was closed before switching in the second battery.

I do wonder what the effect would be though of the batteries being at different stages of depletion when switching in and out. If your secondary battery is less depleted than the main...what happens when you suddenly connect it in series? Will all the cells attempt to balance very quickly and cause a surge through the relay?

 

[Old_Dave]

Using 'unlike' batteries in series causes issues.... Also a variable LVC on the controller would be agg


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[benjy_a]

Using 'unlike' batteries in series causes issues.... Also a variable LVC on the controller would be agg


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Let's assume that you just use a voltmeter and keep an eye on the state of the battery manually. Also assume that you're using the same battery type (lipo) for the sake of discussion.

What is the result now of what I mentioned...connecting batteries at different states of charge in series?

 

[Old_Dave]

Connecting batteries in series that are at different rates of charge = bad, just like running a very unbalanced pack.. Some cells are going to get hurt


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[benjy_a]

Connecting batteries in series that are at different rates of charge = bad


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Why?

Say you're using lipo with huge C rating, what's the worst thing that can happen? Charge states will not be wildly different, nice high current relay and wiring what's so bad other than a surge through the relay?

What happens when you jump start a car that's so bad? Small spark. I know that's in parallel which is why I ask what the potential problems are with doing this in series.

 

[Deleted member 4366]

I do wonder what the effect would be though of the batteries being at different stages of depletion when switching in and out. If your secondary battery is less depleted than the main...what happens when you suddenly connect it in series? Will all the cells attempt to balance very quickly and cause a surge through the relay?

I think you're making it too complicated. The idea is two seperate batteries - switching from one to the other, not switching them in series. There's no reason it shouldn't work. It'll give extra range because of the extra 240wHs. You'd need a wattmeter or voltmeter to keep an eye on the lipos. The only problem I see is that once you've tried 12S lipos, you'll be running on the 5aH battery all the time.

Go on Kirstin - try it!