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

Btw the following episode of Sailing Uma is all about their battery / converter setup (spoiler, they have a 48v bank and a pair of victron dc-dc converters for the 12v loads).  It's a nice intro to how it's put together. 

https://youtu.be/JHUQiRyVV3Y 

On Sep 16, 2020, at 07:13, jeremy baker via groups.io <childscrick=yahoo.com@groups.io> wrote:

 I think Genasun makes a boost charge controller. There's probably imported ones on Fleabay. Ive had mixed results with the cheap imported electronics and the owners manuals are often ridiculous. Ive not seen a dc to dc "charger" from 72 volts to 12 or 24 volts. Ive seen dc to dc "converter"  from 72 volts to 12 volts. Ive got one on my shelf that I have no use for. It's not very powerful. I think it's 15 amps at 12 volts. I like dc to dc "chargers" because they are adjustable. Converters generally are not. I would not recommend trying to substitute a solar charge controller for a dc to dc charger. They are not designed for that. 

 Any update?. I'd like to build a 48-72 volt EV and am curious what you figure out. 


Sent from Yahoo Mail for iPad

On Saturday, September 5, 2020, 7:52 AM, Peter Zephyr <Pcbeckett@gmail.com> wrote:

Thanks for this explanation.  Can you tell me the model of Boost controller   

Rgds Peter

On Sep 5, 2020, at 10:44 AM, reesekc <kcr@kcrproducts.com> wrote:



I've tried several of the ideas listed on this subject...  what has worked best for me: I presently have 2 x 100w solar panels connected in series to provide 24v plus. I use a "boost" mppt solar controller (requires a minimum of 15v input and provides about 54v max output) to charge my 48v battery bank. The solar is connected all-the-time. I then use a 48v to 12v DC to DC converter to provide boat power. When needed, I plug in a standard 48v Golf Cart Charger into either dock power or my 2k generator. On longer motoring periods, I found that I can hold 3.3 Knots continuously using the generator while still holding the existing battery charge. FYI... I have a Sloop rig 35.5 ft Hughes Sailboat.

On Sat, Sep 5, 2020 at 7:18 AM Larry Brown <elcapitanbrown@gmail.com> wrote:

They make 12v batt chargers that take 48v input.  I have one but haven't installed yet as I still have a separate panel and charge controller for 12v.  I want that real estate back though so I can use for another panel for 48v charging :-)

On Sep 4, 2020, at 10:19 PM, Tommy rochester <troche289@gmail.com> wrote:



Do you know what it's called so I can research it? Our maybe the name of the company?

How do I connect the generator to the charger. The charger I'm using will let me combine wind and solar and it will switch between automatically. I'm not using wind so I'm thinking I could tie in to that spot on the charger. But I need to convert the power from ac to dc for that to work. Honestly not sure of a really good way to do it. 

On Fri, Sep 4, 2020, 10:06 PM CaptainJohn49 <johnschubert0711@gmail.com> wrote:

There is a company in the UK that makes a generator starter when the battery voltage drops below 11.8v the gen set turns on and turns off at 12.8v or so.  All automatic.  I have one but never installed it. Cost was about $75 with a waterproof enclosure.

CaptainJohn49 

On Sep 3, 2020, at 16:00, sw via groups.io <v1opps=yahoo.com@groups.io> wrote:

 Mppt charger maybe cheaper 

On Thursday, September 3, 2020, 14:43, damonalane <dlane@posteo.net> wrote:

I would go with the DC-DC converter as the simpler option, assuming you can buy one that steps down that far: 72V to 12V or 24V. That's how mine is setup, though my motor only needs 48V. I'm guessing with the proliferation of higher voltage motors that converters are available for those systems.

To use another solar controller, wouldn't you need another solar array? And to figure out how many watts of solar panels to give to each controller? With one controller you can put the solar where it works best. Let the controller control all of it, and let voltage flow "downhill" through the DC-DC converter.