How do you get the most of of your alternator

[GHA]

The problem with modern high voltage alternators is they have built in temperature compensation to protect the battery, so as the engine heats up they very quickly reduce their voltage to below the battery gassing voltage. In a boat with less cooling than a car this can go below 14v very quickly. So an external regulator is essential to maintain the voltage at the battery bank until it is nearly full,

Which doesn't happen on a 100a alternator as fitted to a beta 35, it will sit at 14.6v.

Anyone else with real world data?

 

[halcyon]

Brian, I have already purchased several CT meters to install as you say. I should be able to get lots of real information
What worries you about my 13amps? This is measured by the solar regulator. My panels are all adjustable so in the Caribbean sun this is our peak input to the batteries. In addition we have a large wind generator as well.

If you are charging at 13 amp I would expect to see 26 volt even into a flat battery bank. 24 volt settled would indicate around 20 % capacity or on a load 50 ish % capacity. When charging a battery you have a electrochemical reaction that requires a potential difference, the charge source needs to be higher than the battery voltage and your 24 volt @ 13 amp does not fit. It is closer to the solar panel supplying 13 amp and the battery supplying 13 amp into a 26 amp load.

Which is why I prefer multiple bar-graphs, you can see what is happening real time, were as most battery monitors will tell what has happened when you stop charging.


Brian

 

[geem]

If you are charging at 13 amp I would expect to see 26 volt even into a flat battery bank. 24 volt settled would indicate around 20 % capacity or on a load 50 ish % capacity. When charging a battery you have a electrochemical reaction that requires a potential difference, the charge source needs to be higher than the battery voltage and your 24 volt @ 13 amp does not fit. It is closer to the solar panel supplying 13 amp and the battery supplying 13 amp into a 26 amp load.
I think we are at cross purposes here. I regularly see over 28v whilst on solar at 13amps input. We generally get up to about 28.4v as a maximum. My batteries have never seen less than 25.2 and that is when I have had a large discharge on them such as the inverter running the watermaker. Over night with the fridge freezer on we don't see them drop below 25.4v even with load on them.

Which is why I prefer multiple bar-graphs, you can see what is happening real time, were as most battery monitors will tell what has happened when you stop charging.


Brian

 

[sailinglegend420]

Which doesn't happen on a 100a alternator as fitted to a beta 35, it will sit at 14.6v.

Anyone else with real world data?

My real world data comes from my Balmar hot-rated alternator which I can switch from external to internal regulator. On internal it quickly falls to below 14v even though I have an engine blower fan directly above the alternator and the alternator is only at 65C.

 

[halcyon]

Fine, it was a comment on your statement

I regularly see 13 amps at 24v when charging with my solar so they should charge up again fairly fast,

Brian