Correct float charge rate?

What type of batteries do you have??

Standard nz70, or deep cycle etc.
Each battery will have its own charge/ float rates found on their makers websites.

cheers

Trains

Hello Moose,

the correct float voltage for lead acid batteries varies with temperature.
The aim of the float charging is to prevent sulfation and self discharge.
If the battery manufacturer's recommendations cannot be obtained, the following is a rule of thumb:

Generally, float voltage needs to be set at between 13.4 and 13.8V @ 25 degrees. -3.8mV/degree/cell.

Ageing AGM type batteries may require slightly higher, around 13.8 to 13.9V to prevent sulfation.
Gel is somewhere in the middle of the road, and flooded require the lowest float voltage (although it won't hurt if set slightly higher because any loss of electrolyte can be corrected).

Don't take the selected output voltage of your charger for granted, as the tolerances can vary quite a bit - verify with a voltmeter with a fully charged battery connected.

You can use the different float selections to compensate for temperature swings.

Best regards, Peter