Bow thruster with relay for charging ?

[moiuk]

9 minutes ago, Tracy D'arth said:

You meant 14.2 VOLTS? You could take that up to 14.8v with open lead acid batteries or 14.4 with sealed LA or gel batteries,

 

The volt drop will get less and less as the current falls as the batteries charge, don't fret.  Ohm's law Volts =Amps * resistance.

14.2volts, yes. OK have increased it.  I am juggling the solar between the BT and the main lesuire batteries,  so the quicker the better for the BT batteries as I still need my main bank to be fully charged by the time the sun  goes down.

 

A few long days of lots of sun, so i will relax and let it do its job.

 

Thanks.

10 minutes ago, nicknorman said:

Yes I would think it is down to the voltage drop in the cables. 14.2v is a bit low anyway, so I would increase to 14.6v, at least while it’s attached to the BT batteries.

Great. I use a different profile for the main bank as they are wet deep cycle, and the BT batteries are sealed lead-acid.    I'll set it to 14.6, and keep and eye on the voltage on the BT batteries, and reduce it down when it gets above 14V.

[nicknorman]

9 minutes ago, moiuk said:

14.2volts, yes. OK have increased it.  I am juggling the solar between the BT and the main lesuire batteries,  so the quicker the better for the BT batteries as I still need my main bank to be fully charged by the time the sun  goes down.

 

A few long days of lots of sun, so i will relax and let it do its job.

 

Thanks.

Great. I use a different profile for the main bank as they are wet deep cycle, and the BT batteries are sealed lead-acid.    I'll set it to 14.6, and keep and eye on the voltage on the BT batteries, and reduce it down when it gets above 14V.

Ordinary sealed lead acid batteries have a relatively high concentration of calcium in the plates, and this raises the gassing voltage to around 14.6v, therefore I wouldn’t worry too much about highish voltages. In order to properly charge the batteries, you need at least 14.4v at the batteries, and held until the current drops to 1 or 2% of capacity. Since the batteries have been left flat for a long time, it would be best to give them a long charge when possible.