In my experience with land-based EVs, a DC-DC converter would be used to
step down the voltage from the propulsion pack to the accessory / house
battery system.
With a 72-volt motor, I am assuming you are planning for a 72-volt
battery system. Doesn't really matter, principle remains the same, but
the input voltage rating changes. However, for illustrative purposes,
something like this might do the job.
http://www.powerstream.com/dc-72v-12v-15a-extreme.htm
(Disclaimer: I have no knowledge of this company or their products;
they just popped first with appropriate content in my web search.)
There are other companies with similar products. Marine rating is not
typical. You can pay less, and presumably get less.
Typical installation is to build your propulsion pack to ensure it is
appropriate to your needs - including a couple of test cruises - and
establish your charging system for that pack. (I recommend a
shore-power option in addition to intermittent sources). I expect your
current wind/solar charging set-up will have to be augmented to charge a
propulsion pack in addition to the current house battery.
Once you are happy with your propulsion pack, and have a sense of how
much power you need to move to the house pack on a continuous / regular
basis, then you can size and order the DC to DC converter. I recommend
you find a unit which can be turned off with an internal switch, rather
than having to be disconnected. Handy when the boat goes into storage
to save your propulsion pack from being drained down to zero.
Also, be aware, Coast Guard electrical safety guidelines become more
stringent if you are using a system rated for higher than 48-volts nominal.
Hope this helps,
Darryl McMahon
On 14/12/2014 3:39 AM, electricboats@yahoogroups.com wrote:
> 2a. Charging house and propulsion batteries Posted
> by:jasonners@me.com jsonners Date: Sat Dec 13, 2014 6:58 pm ((PST))
>
> I have an electric sailboat which currently has solar and wind
> generation. Currently this charging system only charges the house
> batteries.
>
>
>
> Does anyone know a way or specific product I can use to charge both
> systems simultaneously or at least be able to shift back and forth
> between both systems?
>
>
>
>
>
> I have a 72 V motor
--
Darryl McMahon
Freelance Project Manager
