I am not an electrical engineer hence the odd question. I can wire and solder though.

I have a dynamo charging a 12v 110AHr starter battery. The dynamo has a electronics that monitor the battery voltage when charging. When the voltage reaches 14.5 the dynamo stops, not an efficient way to charge.

Would it be possible to 'mask' or 'pull down' the battery voltage on the live feed to make the dynamo run longer. I know that one is thinking how will I know when the battery is charged? That will be taken care of, I just need to mask the voltage for about 5min.

I hope this makes sense



  • 2
    \$\begingroup\$ Draw a schematic/diagram. \$\endgroup\$ – winny Dec 16 '16 at 13:48
  • \$\begingroup\$ How is to "make the dynamo run longer" is more efficient than stopping it? Are you trying to overcharge the battery (bad idea)? \$\endgroup\$ – Dmitry Grigoryev Dec 16 '16 at 14:03
  • \$\begingroup\$ Right. Sorry should have given more detail at the start.I'm going to use the starter battery as a buffer for connection to a B2B charger. The B2B needs around 3-4min to start then it will take over the charging of leisure batteries and the starter batt. via the dynamo. The dynamo is obviously inefficient and the B2B will solve this. \$\endgroup\$ – cliff Dec 16 '16 at 14:08
  • \$\begingroup\$ A resistor voltage divider feeding the dynamo monitor point will reduce the voltage it sees... this sounds like a bad idea if it will cause the battery to over charge! \$\endgroup\$ – George Herold Dec 16 '16 at 14:44
  • \$\begingroup\$ ThanksThe 'dynamo monitor point' being the live feed from the dynamo? \$\endgroup\$ – cliff Dec 16 '16 at 15:50

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