Re: [electricboats] Two voltage battery banks on one charger

How many 24 Volt panels do you have?  I assume at least two??

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of Bob Jennings
Sent: Friday, September 4, 2020 4:08 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Two voltage battery banks on one charger

 

With the solar charge them in series Peter. 

 

On Fri, Sep 4, 2020, 4:02 PM Peter Zephyr <Pcbeckett@gmail.com> wrote:

I assume your 48 Volt pack is made up of four 12volt batteries in series.

Do you charge them in series i.e at 48 volts+ or do you charge each 12 volt battery separately?

 

If separately do you connect them all to the same controller and charge them at the same time

 

Rgds  Peter Beckett

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of Bob Jennings
Sent: Friday, September 4, 2020 3:47 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Two voltage battery banks on one charger

 

FWIW, I have a separate 48 volt propulsion bank & 12 volt house bank. I charge both banks with 260 watts of 24 volt panels wired in series using a midnight kid solar controller.  I wired the controller output to a double pole double throw transfer switch. I can pick which bank I'd like to charge & easily adjust the parameters.  

 

On Fri, Sep 4, 2020, 3:12 PM sw via groups.io <v1opps=yahoo.com@groups.io> wrote:

I like the mppt charger because they usually have adjustable voltage and amperage tsp can use for many battery types

 

On Friday, September 4, 2020, 11:55:16 AM PDT, Damon Lane <dlane@posteo.net> wrote:

 

 

DC-DC converters are simple: they produce the lower voltage from the higher voltage, and supply current up to their max rated power throughput. 

On my boat, I have no lower voltage batteries, so if the propulsion bank or DC-DC converter had a problem, I'd have no 12V. That is a problem, and I'm realizing that if I did have batteries at 12V, the DC-DC converter probably wouldn't charge them because the voltage it supplies is too low (13.1V) and it's not a charger. 

So I'll amend my initial comment and say DC-DC converters are simpler if you don't plan to have separate battery banks at different voltages. If you do, I think you do need two chargers. Setting up two chargers and a generator is surely possible, but you may want to consult a book or specialist. I think the generator could be set to trip on at low voltage, but would you want it to if it would come on each morning at dawn, only to charge for a few minutes before the solar would have come on anyway? I would want more complex controls.