I have a new blue 12/30 charger which is connected in parallel to two Yuasa 95 ah AGM batteries. The connecting cables and fuses used are new good quality and correct amperage. My problem is that the voltage and the current fluctuates continually sometimes by as much as 1volt and 7amps . This happens mostly when charging minimally loaded. If I increase the load by turning on several appliances in my motor home the voltage output stabilises . The voltage measurement on battery farthest from the charger has between 0.05v to 0.08v difference to the charger output. The output of the charger has been set to 50% to suit the Yuasa batteries. Varying voltage also occurs when set power supply mode. Any help would be greatly appreciated!
How did you measure? With Victron machinery or a multimeter? If not the latter, it would be good to do so.
I measured both with digital meters and using the blue tooth app. The readings on the multi meter corresponded with the blue tooth readings. When the motor home heater fan is switched on you hear the speed varying up and down ! My background is as an electronics engineer. The previous Numax charger kept stead output although the cable and fuses have since been up rated to suit the 12/30
Could it be a varying power factor because of the heater fan being an inductive load?
Good point but I have tried all kinds of conditions. Tested first with just the batteries connected with all fuses to the motorhome and solar panels alarm etc removed. With just the batteries connected and no background current drain the charge voltage and current jumps about. If I introduce a considerable load (most 12v equipment in the van turned on) the output stabilises or is stable when you turn the charger on.
I have since researched on line ( l couldn’t get help from my supplier who said it would take 2 weeks to respond!) that it was normal for the charger to pulse voltage / amps, when the batteries are nearing fully charged ( I notice this in float ) . Apparently this is to avoid overcharging and battery damage? I found these seemingly out of control burst of power disconcerting! If the information on the net is true? It would really help if there was some mention of this behaviour in the instruction manual and I could have got help from my supplier ! I am still somewhat sceptical