Scootyb,Johnnieb and yurtle? loss of torque checklist.

[JohnnieB]

Sounds like a PW 28115 charger. (Picture attached)

If so, do yourself and your new batteries a favor and get a DPI or Yewy charger from Scotty.

The PW 28115 and other 36V ferroresonant transformer type chargers are designed to charge Trojan batteries and Crown batteries use a slightly different charge profile. However, the main reason to upgrade to a modern charger is the old ferroresonant transformer type chargers don't fully charge the batteries, they only charge them up to an on-charge voltage that ought to adequately charge new batteries without overcharging old batteries. Basically, they shut off at 45V +/-1V, which may or may not be high enough to fully charge the batteries.

A lead-acid battery isn't fully charged until the on-charge voltage ceases to increase with a charging current passing through the battery. A DPI or Yewy and many other modern chargers use what is called dV/dT (change in Voltage over change in Time) to stop the charge. They monitor the rate of change and when it drops below something like 0.004V per cell per hour, they terminate the charge, so the on-charge voltage at the end of the charge cycle may get up to nearly 50V and the batteries will be fully charged, or very close to it.

Of course, the PW 28115 has kept cart batteries pretty well charged over many years and the life expectancy for battery packs is largely based on using ferroresonant transformer type chargers.

[rsw007]

All batteries under slight hill offroad. Drop to 5.92-5.94v

Forgot to mention I have the stealth differential like 16.99 to 1 ratio.

[rsw007]

Did charge it Friday night and it seems a little better each time its charged. So may just be that batteries aren't broke in yet.

Not sure how to use alltrax software. Thought I was saving a monitor file but can't find it on computer.

[yurtle]

If you know the filename, you can do a search.

[JohnnieB]

Originally Posted by rsw007

Did charge it Friday night and it seems a little better each time its charged. So may just be that batteries aren't broke in yet.

Not sure how to use alltrax software. Thought I was saving a monitor file but can't find it on computer.

Be sure to start and stop the data logging if you want to save a file.
Also, you can specify the file name and where it is to be saved, with the browse button.

The 23" tall tires and 16.99:1 gear ratio you have gives you a 6.9% torque gain, rather than the 21.7% torque loss you would have had with stock gears.

Batteries ought to be charge after each use.

[rsw007]

test

[rsw007]

Originally Posted by JohnnieB

Batteries ought to be charge after each use.

I did that with last batteries and they only lasted 4.5 years. was told I cycled them to many times for no reason. son would ride 1mile around property and recharge after every use.

currently on 5th charge now first three I ran down to 37.3 Friday it was at 37.6 when I charged to get todays readings with 36hours of rest pack was at 38.5 this morning.

trying to do proper break in as per scottyb "carts unlimited site"

[JohnnieB]

Originally Posted by rsw007

I did that with last batteries and they only lasted 4.5 years. was told I cycled them to many times for no reason. son would ride 1mile around property and recharge after every use.

currently on 5th charge now first three I ran down to 37.3 Friday it was at 37.6 when I charged to get todays readings with 36hours of rest pack was at 38.5 this morning.

trying to do proper break in as per scottyb "carts unlimited site"

If you take multiple short trips, put on charge at end of day.
If the trip takes them below about 80% SoC or so, charge after each use, if practical, just don't let them sit overnight partially discharged.

The number of charge cycles used is sort of a rubber yardstick since the charge cycles available is mostly determined by the average SoC maintained.

Attached is a graph showing cycle available vs average SoC over battery's cradle to grave lifespan. The numbers are from the four battery manufacturers listed.

Of course, only taking a number short trips during the day and plugging in the charger after each short trip can overcharge the batteries, but 4.5 years isn't a bad lifespan for a set of cart batteries.

---------
Also, the 75% SoC mentioned in the breaking instructions is a limit rather than a goal. In other words, don't take the SoC below 75% during the first couple dozen uses, but taking them down to 75% before recharging isn't required.

[JohnnieB]

Originally Posted by rsw007

test

I took a look at the data log you posted.

The maximum battery voltage at the controller is only 37.9V. (B- to B+ at the controller)
The max voltage applied to motor is 34.7V. (M- to B+)
Max throttle is 98%. (Check between the pins the Black and White wires are connected to on the controller - Should be 10V pedal up and 6V pedal down)
Max Battery amps was 211.4A and the Battery voltage at the time was 32.1.
Max Motor amps was 211.9A with 32.0V applied.
The difference between Battery V and A and Motor V and A is due to less than 100% throttle.

What was the battery pack voltage as measured at the main Positive and Negative terminals at the start of the test run?

[rsw007]

Johnnie I believe it was 37.8or 37.7 just before hill climb. Rest voltage now 3+ hours later is 38.1.