Is my on board charger working correctly?

[Crawler487]

What is the highest voltage that 36 volt batteries should hit while charging, before it starts hurting them? Im not sure on the exact voltage(I will check later this week) but the last time I tested my on board charger, it had my batteries at somewhere around 50 to 54 volts after being plugged in for about and hour.

[Sir Nuke]

between 45 to 48v

[JohnnieB]

What charger?
What batteries?
What temperature?

For Trojan batteries, 2.79VPC (Volts per Cell) is the max listed on their charge profile, but they also say that the on-charge voltage should be increased by 0.028VPC for every 10°F below 80°F. (A 36V pack has 18 cells)

If your charger is uses dV/dT technology or is temperature compensated, you have Trojan batteries and the electrolyte temperature is 40°F, you might see 54V at the end of the charge cycle.

[Crawler487]

It is a Lester electric onboard charger and I have Trojan T-105s. how would i measure the temperature?

[JohnnieB]

Originally Posted by Crawler487

It is a Lester electric onboard charger and I have Trojan T-105s. how would i measure the temperature?

Model# of Lester charger? They made several on-board chargers and they don't all work the same.

Remove the filler cap on the center cell and insert the thermometer or thermocouple in the electrolyte, being careful not to touch the plates.
Of course, you have to rinse it off good afterwards because the electrolyte is about 30% sulfuric acid.

[Crawler487]

The model number is: 26690 the serial number if you need it is:151002623 and at exactly 50 volts the batteries are at 71.5 degrees, the are gurgling and burping a lot too

[JohnnieB]

The 26690 is an SCR type charger, and it may very well be using dV/dT to terminate the charge, so the voltages you are seeing may be normal.

Give Lester a yell and ask them what the max output voltage normally reached is.
Phone: 402.477.8988
E-Mail: Service@LesterElectrical.com

[Crawler487]

They are closed so I'll try to call them tomorrow.