Living With Lipos--Safely!

GoldenMotor.com
magwa

magwa

New Member
Jul 14, 2015
61
0
0
Coarsegold, CA
Lungcookie said:
Uh oh.
You guys are forcing me to relearn something about chargers.
http://www.rcgroups.com/forums/showthread.php?t=1253796

Take the pack voltage, multiply the charge rate you want (amps output), equals the wattage of the charger you need.

So for a 25v (6cell) battery at 5amp you would need at least 125w charger.
25v x 5a = 125w

And...
25v(6cell) x 3.2a = 80w
16.8v(4cell) x 4.7a=80w

That 80w charger will still work just take longer.
Sorry Magwa, another knee jerk? I am removing that link to that 80w charger.

You started this fiasco you know...:)
Maybe we will all learn something.
Click to expand...
Hahahahaha! No problem.

I've got two chargers coming.....I'll charge each battery at 3 amps.
What the ****.....I'm retired. I have time.
 
kevyleven007

kevyleven007

Active Member
Sep 25, 2008
1,217
8
38
texas
Lungcookie said:
That PS 180w and up. that seems inexpensive.

That pocket charger would work but it is 50w and has no screen to actually be able to see the cell level voltage, cant discharge or store.
Click to expand...
Yeah that's what I mean by bare minimum. But hey, if its reliable and gets you charged...wouldn't be bad to have just in case or until you can upgrade. Those power supplies are the lowest price I have found. Radio Shack and ham radio etc. are a bit more pricey. I'm still sitting on the fence. Going to wait and see how Magwa does with those 20,000 mega ampers
 
Last edited:
Lungcookie

Lungcookie

New Member
Aug 15, 2013
310
0
0
Oregon
Right, I hope it is all smooth sailing with Magwa.
He is like the test subject.

Right now charging my 10.0/6cell from storage voltage, at 5amps takes about an hour.
Double that for 20.0 then reduce charge amps by almost half.

That 80w may take close to 4 hours to charge the 20.0/6cell.
That much more time to space off the fact you are charging and leave the house or something.
 

Attachments

Last edited:
magwa

magwa

New Member
Jul 14, 2015
61
0
0
Coarsegold, CA
Lungcookie said:
Right, I hope it is all smooth sailing with Magwa.
He is like the test subject.

Right now charging my 10.0/6cell from storage voltage, at 5amps takes about an hour.
Double that for 20.0 then reduce charge amps by almost half.

That 80w may take close to 4 hours to charge the 20.0/6cell.
That much more time to space off the fact you are charging and leave the house or something.
Click to expand...
Yup. Could happen. But probably happens fewer times to those who built their houses 30 years ago and
would have nowhere else to go if the sucker burned down.

Seems strange, but a four hour wait is appealing to me. That's four cups of good coffee sipped slowly
while I read a book...yummmm.

I got the batteries a couple of days ago

I got some "stuff" in the mail today.

A "Common Sense" carrying/charging bag.
Two charging bags of lesser versatility.
The two Accucell 6's
A CellLog8 (lousy...I didn't read the ad correctly..No USB/logging function)
Two backlit voltage alarms;
Two 12" battery balancing plug extensions;
Assorted connectors;

Still waiting for the power supply...It's sitting in Mather, CA waiting for DHL
A few more connectors (XT90 to XT60 for charger(s) ➨ battery(ies)
100W soldering gun
The Bike...still haven't decided on which one.

Took the motor/controller/throttle assy off of the donor bike and gave the donor a nice new front rim. Noticed that
the batteries have 10ga wire from the (wrapped) terminals. Connector to the controller has 12ga. I'll check that
further at first operation.

Checked the cells in the new batteries for the level of "storage charge". They are 3.88, 3.88, 3.90, 3.91, 3.88, 3.87.
Roughly the same spread in the other battery. Checked the Monitor/Alarms for consistency...and those against the
function that DOES work on the CellLog8...That's the monitor/alarm. Fairly close (like .02), but I'm going with the other ones that were dead on.

Set the alarm function for 3.5v on both alarms.

Will probably drop the voltages and balance to 3.8 storage charge as soon as the power supply comes. I haven't plugged the batteries into the chargers yet.
I want the whole charging station (mobile to move it outside) set up before I start with the chargers.

That's it for now. I'm still walkin'.

Left this reply in this thread for follow up by anyone who is watching the safety issue. And, in case anyone wants, for the sake of all, to bounce more
safety stuff off of this progress/hardware configuration.

When the bike comes, I'll move the actual build to a build thread and get out of the way.

zpt
 
Last edited:
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
223
63
Colonial Coast USA.
My bet is the 20ah under typical usage wont need charging that often. Just using my values a round trip to town is around 5mi. I'm pulling 5-6 amps around 20mph. That's a ride time of 15min, or approximately 1.375ah. That's about 14 trips to town or 72 mi!

The down side is you need to use the batteries down to storage voltage with in a reasonable time, so ride long my friend or the packs will spend even longer times on the charger attaining storage voltage. Of course you can charge them to a lower percentage of charge which will make them last just about forever but you will miss the "off charger" rush of acceleration that is so much fun. If there is an advantage to 5ah packs its that you can configure them to short/long range usage just by adding/subtracting them. I can get a couple of trips to town on a 5ah pack if I need to go further I just add some more.

Experimentation with the 20ah will probably find the sweet spots for various charging/riding ranges You can probably ride a long way on a low percentage charge, just not as fast.
 
Lungcookie

Lungcookie

New Member
Aug 15, 2013
310
0
0
Oregon
We will have to see how long that 4 hour charge is FUN.

The 20.0 6s looks to have a max charge rate of 2c!
That would be 40amps! what the... is that right?

Don't think I would charge it that fast...myself.

C=capacity/1000
So for 1000 mah LiPo, 1C=1000/1000=1amp.

Magwa looks to be fighting gravity more than you CB2 or I, flats and lower weight.

I am guessing coarse gold cali means hills (LC, looks over at metal detector gathering dust), and magwa may not be petite, no offense magwa. The DD motor will pull more amps. Nice they put 10awg on it.

Heater farm.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=65982
 
Last edited:
kevyleven007

kevyleven007

Active Member
Sep 25, 2008
1,217
8
38
texas
Last edited:
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
223
63
Colonial Coast USA.
I believe those are intended for Li-ion 18650 packs which according to what I have read can be safely discharged to 2.4v, though most users stay above 3.0v. It did say Lipo in the description but 2.4v is pretty lethal to a lipo. Using a BMS with a lipo pack isn't necessary or really desirable. Just be sure the controllers LVC is lipo compatible.

If you are going to build a 18650 battery then a BMS is best.
 
magwa

magwa

New Member
Jul 14, 2015
61
0
0
Coarsegold, CA
Lungcookie said:
We will have to see how long that 4 hour charge is FUN.

The 20.0 6s looks to have a max charge rate of 2c!
That would be 40amps! what the... is that right?

Don't think I would charge it that fast...myself.

C=capacity/1000
So for 1000 mah LiPo, 1C=1000/1000=1amp.

Magwa looks to be fighting gravity more than you CB2 or I, flats and lower weight.

I am guessing coarse gold cali means hills (LC, looks over at metal detector gathering dust),
and magwa may not be petite, no offense magwa. The DD motor will pull more amps. Nice they
put 10awg on it.
Click to expand...
For my first test, I'll probably charge the batteries to balanced 4.0 and make a few runs. I now
have about four different methods (without the battery charger's LCDs) of checking the charge.

Alarms call set for 3.5v.

On the bike, I'll run two of these at eye level. Of all of them, they seem the best in being "dead on".

The power supply just came today and I'm waiting for some XT60>XT90 connectors. Or a bunch
of connectors to match up with the 100W soldering iron.

Also, for a first test, I ordered a bike. Here it is with the front hub p-shopped on it. The batteries will
go in a separate, padded steel lined box on the front rack. The controller will ride in a similar wooden
box on the rack, but heavily vented so it can get some air flow.

After all the testing, I'm pretty sure the bike will be changed out for something lighter.

Yes: Hills in Coarsegold
Yes: I'm anything but petite

Don't think I'll need a "discharge heater".

And, oh, the "fun" part of waiting for the charger is a lifestyle issue. Learned from running fast and
hard for 41 years out there in the cesspool of the business world.
 

Attachments

Last edited:
Lungcookie

Lungcookie

New Member
Aug 15, 2013
310
0
0
Oregon
You can charge to 4.20v/cell.
We are suggesting 4.15v/cell for a longer overall battery life.

All that weight, hub and battery on the front wont help the handling, steering feel any. Guess that's to see the voltmeter.

That 'heater farm' produces negligible heat. Less than a light bulb.
I was just putting out an experiment I did, maybe sparks some ones grey matter.
 
cannonball2

cannonball2

Well-Known Member
Oct 28, 2010
3,682
223
63
Colonial Coast USA.
I agree with LC on the front being a bit burdened with everything up there. The seat post makes a nice mount for a controller and keeps it in the air flow. If the motors wiring will allow length wise controllers mount nicely to the bottom side of the rear rack as do the batteries on top.

Heres a pic of my hunting bike rough out. Every thing is tucked up on the seat post out of harms way and the weight is fairly low. This works well with this bike as it will be pedal less. pedals get in the way in the close brush of this area.
 

Attachments

magwa

magwa

New Member
Jul 14, 2015
61
0
0
Coarsegold, CA
Lungcookie said:
You can charge to 4.20v/cell.
We are suggesting 4.15v/cell for a longer overall battery life.

All that weight, hub and battery on the front wont help the handling, steering feel any. Guess that's to see the voltmeter.

That 'heater farm' produces negligible heat. Less than a light bulb.
I was just putting out an experiment I did, maybe sparks some ones grey matter.
Click to expand...
Right.

But starting at the 3.8 or 4.0 for a test will give me a tasty baseline on those Ah's. Then, after the tests running, I can go to storage voltage.
The only thing I'll miss would be checking the acceleration at 49.8v or 50.4v. With a new/strange bike, and all the weight up front, a 15mph
run makes more sense to start with.

The low and centered weight thing is a major consideration, of course. I can't do anything about the front hub weight, since I already own it.

But design is a funny thing. If everything "front loaded" ruins the feel, or is dangerous, I'll pull back and away from the "esthetics" of the design function.

Main thing is to be safe and, although up front is nice for the volt meters/alarms, longer wires and primary focus on diligence works as well...or better, maybe.
 
You must log in or register to reply here.
Top Bottom