SELLING THE BIKE. IMPORTANT STUFF #1: THE BATTERIES

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I have 15 batteries. 

There are ten 52 v x 16 amp and five 52 v x 13 amp.

The first thing a buyer will want to know is: What condition are these batteries in?

The answer lies in the amount of usable power in each battery. Usable power is defined as how many Watt hours (Wh) will the battery deliver.

Toward this end I will be testing each battery. The test will be:

1st: Fully charge the battery.

2nd: Fully deplete the battery and record the Wh used.

Naturally, these tests will require that I only use one battery at a time instead of my normal multiple battery setup.

Simple as pie.

Wash and repeat 15 times.

BIKE DIARY MAY 29/22

 Guangzhou, China

Today was my 51st wedding anniversary. Marrying my sweetheart was the best thing I have ever done - by far!

I'm old and starting to get very tired. I have decided to retire from biking when I get to 13,000 km. Why that number? It is the distance from Lyon, France to Guangzhou, China. In 2018 they had an e bike race between these two cities starting in Lyon. The distance? 13,000 km. So, in my own mind, I will have completed the race - at least, metaphorically.

Start time 9:00 pm 

Temp 16.1 C

Start Voltage                                 57.8

Finish Voltage                               50.7

Ah                                                 15.50

Trip Distance                                41.80 km

Distance                                      10801 km                                

Time                                             76:49

Av. Speed                                     32.6

Trip Wh/km                                   19.0

Trip Wh                                       790.37

BIKE DIARY MAY 28/22

I must say that it seems very cool for this time of year. And wet. And the forecast for the next two weeks is for more of the same.

Start time 8:30 pm 

Temp 15.1 C

Start Voltage                                 57.5

Finish Voltage                               53.5

Ah                                                 10.95

Trip Distance                                28.11 km

Distance                                      10759 km                                

Time                                             48.22

Av. Speed                                     34.7

Trip Wh/km                                   20.4

Trip Wh                                       570.52

BIKE DIARY MAY 27/22 (Battery Test) (Updated)

Tonight's run was to test my oldest battery. I did that by running it until it was depleted. The battery ran out of juice after using 715 Wh. When the battery was new it had 800+ Wh of usable power. This represents about a 10% loss. Not bad considering the battery is almost 5 years old.

The battery was originally rated for 16 Ah but tonight it only delivered 14.8 Ah. This reduction in Ah is consistent with the reduction in Wh.

Data for tonight is incomplete because of the test.

Start time 8:45 pm

Temp 13.1 C

Start Voltage                                 58.0

Finish Voltage                               40.1

Ah                                                 14.8

Trip Distance                                ? km

Distance                                      10731 km                                

Time                                               n/a

Av. Speed                                     27.7

Trip Wh/km                                   19.6

Trip Wh                                        715.0

UPDATE:

I also measured the number of Wh used per Ah.

So the fully charged battery has 15 Ah it also has 715 Wh of usable energy.

Using the above numbers one would expect the battery to deplete at the rate of 48 Wh per Ah. But this expectation would be wrong.

This is because the battery voltage is also going down as it depletes.

Starting voltage with no load is about 58 volts and final voltage with no load is about 43 volts - a drop 15 volts.

Remember: volts x amps equals watts (or volt/amps).

So 

1st amp x 58 volts =  58 volt/amps

2nd amp x 57 volts = 57 volt/amps

3rd amp x 56 volts = 56 volt/ams

14th amp x 44 volts = 44 volt/amps

15th amp x 43 volts = 43 volt/amps.

(NOTE: it is just coincidental that the total voltage drop and the number of Ah have the same number)

You can see that the 1st two Ah have (58 + 57)115 volt/amps or Wh of usable energy while the last two Ah would have (44+43) 87 Wh of usable energy. 

Conclusion: when you only partially charge your battery the missing Ah have the highest Wh per Ah. So a 90% charge does not mean that you actually have 90% of your energy potential.

BIKE DIARY MAY 25/22

 Start time 8:30 pm 

Temp 17.0 C

Start Voltage                                 58.0

Finish Voltage                               48.6

Ah                                                 25.73

Trip Distance                                60.53 km

Distance                                      10696 km                                

Time                                            103:09

Av. Speed                                     35.2

Trip Wh/km                                   21.6

Trip Wh                                      1307.30

BATTERY CHARGING TIMES

Below is are charts about charging amounts and the time required for 52v 16A Hailong batteries using a Grin Technologies Satiator charger.

I am able to charge 3 batteries simultaneously by using a 3-headed connector between the charger and the batteries.

Charging 3 batteries at a time and using the same charger setting results in a much slower charging rate (trickle charge).

I use the 3-headed charger for convenience because I don't have to connect a new battery to the charger every 3 hours or so.

If you examine the charging times you should notice two things:

1. A slower charging rate results in more Ah stored in the battery. (this is important when long distance biking)

2. These batteries receive about 90% of their charge in the only 70% of the time it takes to get a full charge.

Note: This is not strictly true (but still close for reasons I will explain in a later post)

Also, I want you to examine my diary numbers. A thoughtful analysis will reveal much insight.

            1 Battery                          3 Batteries  simultaneously

 

  Time            Charge amount       Time      Charge  amount    

  60 minutes =  6.85 Ah                 180 min = 20.24 Ah

  90 minutes =  9.61 Ah                 270 min = 29.70 Ah

120 minutes = 12.49 Ah                360 min = 38.53 Ah   

150 minutes = 14.41 Ah                450 min = 46.80 Ah

180 minutes = 15.49 Ah                540 min = 48.54 Ah     

206 minutes = 15.61 Ah                570 min = 48.69 Ah                                                                              

Charge Completed                       Charge Completed

BIKE DIARY MAY 23/22

click on image to enlarge

Start time 8:00 pm 

Temp 20.0 C

Start Voltage                                 58.0

Finish Voltage                               51.6

Ah                                                 12.96

Trip Distance                                30.37 km

Distance                                      10635 km                                

Time                                             51:08

Av. Speed                                     35.6

Trip Wh/km                                   21.7

Trip Wh                                       655.39