I bought a battery charger

[PCeBiker]

I built a vacuum pump for my brakes too,..

 

[Dave Rocks]

 

[PCeBiker]

I used my new power supply to charge my 25ah battery to 54.6v and waited for the current to drop to zero to fully charge it.

I charge my secondary 19ah battery to ~52.5v so that I don't feel obligated to use it if I don't need it.

I have a separate 3 amp UL listed charger that I turned down to ~52.8v so the light turns green at ~52.8v




I finally decided to try and keep track of my voltage, mileage, and distance by taking photos of my display.
I suck at taking notes, and this was the simplest way for me.

Even though I charged the battery to 54.6v the voltage dropped to 54.2v within a few minutes,..

I lost an entire volt in 5 minutes.

You can see the voltage rebound after sitting for a while,..

The battery meter turns yellow below 47v.

It turns orange around 43.5v
I forgot to look to see when.

I found the shade of a tree to pull over and swap my batteries, and there happened to be a brush fire.
It smelled like camping. It was kinda nice.

Installed the 19ah battery.

I arrived home at 6pm with lots of km left on the second battery and a 106 km ride.

I decided to charge my battery at 4:20 because it was time to smoke a Vado.

 

[PCeBiker]

I went for another ride today and made it home Just In Time !!!

@indianajo Why so sad ??

I smoked a Vado at the designated time both trips,..

 

[PCeBiker]

I used my new power supply to charge my 25ah battery to 54.6v and waited for the current to drop to zero to fully charge it.

That turned out to be kinda wrong.

I didn't actually let the current drop to zero.
It was more like a ⅓ of an amp or so, so I figured "close enough".


Today I was fartin around getting ready and the current dropped to 0.018 amps when I was finally ready to go.

The voltage was reading 54.6v on the display when I unplugged the charger, then dropped to ~54.4 - 54.5 volts.

I didn't bother taking a picture, then forgot to check the volts at 10 km, but I'm pretty sure it wasn't anything near 53.5 volts.

 

[PCeBiker]

I took some pictures of the local produce being harvested and some other things over the past few days,..

 

[PCeBiker]

I think that I figured out what's going on with my battery and how it's losing a volt so fast.

I charged my battery up to 54.6 V and unplugged the charger,..

Then I left the power on and let it sit for 10 minutes,..

Then I shut it off for ten more minutes the turned it back on,..

After 43 minutes I started my ride and the voltage was down to 54.1 volts and the motor had not been powered up yet.

All my 3 batteries behave the same way using any charger.

I'm figuring that just the idle current of the controller being powered up for ½ an hour is enough to lose the first volt.
I think that it's normal for that first volt or two to disappear quickly.

This is the discharge graph for a Lithium cell,.

That first 0.1 volt drop from 4.2-4.1 volt is really fast (steep drop-off).
My 48 volt battery "has 14 cell groups in series, so that's 1.4 volts total."
EDIT: My battery has 13 cell groups, so 1.3 volts

Since fully charging a 48 volt battery to 54.6 is kinda hard on the battery anyway, and since there's very little energy in that last 1.3 volt, I've decided to only charge my batteries to 53.3 volts, and wait for the current to drop to zero while charging.

 

[PCeBiker]

I had the battery fully charged to 52.6 volts, so I thought I would do the test again.
(I had to reset the timer and the voltage dropped to 52.5 before I could take the picture.)

Left the power on and let it sit for 10 minutes,..

Shut it off for fifteen more minutes then turned it back on,..

After 43 minutes the voltage was down to 52.2 volts.

And a complete recovery two hours later..

So my results are inconclusive.

I did lose 0.5 volts starting from 54.6 volts, and 0.4 volts starting from 52.6 volts though.
But it's all kind of erroneous.


Maybe I'll I'll install my Watt Hour Meter this winter so I can monitor my batteries more accurately?

I'm sure that there's nothing wrong with my batteries. They all behave the same way.
I guess it would be good to test the capacity of the batteries. The biggest batteries (physical size) are 19ah and 25ah, but the smallest battery (Das-Kit) is supposed to be 21ah.
I dunno? That doesn't seem right?

 

[Taylor57]

I had the battery fully charged to 52.6 volts, so I thought I would do the test again.
(I had to reset the timer and the voltage dropped to 52.5 before I could take the picture.)


View attachment 183733


Left the power on and let it sit for 10 minutes,..


View attachment 183734


Shut it off for fifteen more minutes then turned it back on,..


View attachment 183735


After 43 minutes the voltage was down to 52.2 volts.


View attachment 183737


And a complete recovery two hours later..

View attachment 183736


So my results are inconclusive.

I did lose 0.5 volts starting from 54.6 volts, and 0.4 volts starting from 52.6 volts though.
But it's all kind of erroneous.


Maybe I'll I'll install my Watt Hour Meter this winter so I can monitor my batteries more accurately?

I'm sure that there's nothing wrong with my batteries. They all behave the same way.
I guess it would be good to test the capacity of the batteries. The biggest batteries (physical size) are 19ah and 25ah, but the smallest battery (Das-Kit) is supposed to be 21ah.
I dunno? That doesn't seem right?

I'm guessin you have no trouble replacing a breaker at your breaker box?

 

[PCeBiker]

I'm guessin you have no trouble replacing a breaker at your breaker box?

Lol,..

I just bought this stuff today.
$220 for 250' of NMD90 house wire, 3 breakers and boxes,..