Normally you definitely do not want to tap a high voltage battery for
use at say, 12 or in this case, maybe 48V when the top end is
108V nominal.
But with a separate charger for the house inverter, (48V ?), and the
60V side, it would work a lot better than just using
a single 108V charger and tapping down at 48V. As long as there is
enough charging power for both battery sides the
two halves should stay balanced.
boB
On 7/1/2021 9:00 AM, Dave Tedeyan wrote:
Dave,
This is for a boat that will stay mostly on the finger lakes and in
the Erie Canal system in upstate NY. Definitely not an ocean boat. But
the plan is to convert it to a full time residence, potentially in the
winter as well.
Cheers,
Dave
On Thu, Jul 1, 2021 at 11:52 AM Dave Angelini Offgrid Solar
<[email protected] <mailto:[email protected]>> wrote:
Less is more offgrid. On a boat, if it is oceangoing, it is a life
or death kind of world. A fire at sea probably will happen at
night in bad seas. Not sure if this is your clients scenario for
their use. An all electric boat sounds a bit scary. How will they
get ashore? I use to give the owner a schematic that showed the
location on the boat of electrical devices, wiring, and disco's.
Hopefully this is for a lake sailor. Although one of the round the
world guys I know tells me that he was never as scared as he was
on a lake one day...Good Luck!
*Dave Angelini Offgrid Solar "we go where powerlines don't"
http://members.sti.net/offgridsolar/
<http://members.sti.net/offgridsolar/> e-mail [email protected]
<mailto:[email protected]> text 209 813 0060*
On Thu, 1 Jul 2021 11:21:51 -0400, Dave Tedeyan
<[email protected] <mailto:[email protected]>> wrote:
Bob,
This is a very interesting idea to have two separate battery
banks in series. I find it odd though that this particular
motor's datasheet calls for 9 12V batteries. I suppose that I
could have one charge controller set for 48V and the other set
for 60V. Although this will also pose the problem of trying to
run the house loads - if I have two 48V inverters that still
leaves one battery that will get loaded less than all the others.
And it seems that everyone else is pointing to the fact that it
seems important to keep the neutral and ground internally
separated in the inverter in a boat, so I'll stick to marine
inverters for this one.
Cheers,
Dave
On Wed, Jun 30, 2021 at 5:30 PM [email protected]
<mailto:[email protected]> <[email protected]
<mailto:[email protected]>> wrote:
If you can't find a single compatible charger, what also
works it to use 2 (two) separate
MPPT charge controllers each with a separate PV array inputs
and connect each CC's
battery to half of the battery bank. This has worked fine
for both OB and MNS controllers
in past years and should with others as well I would
imagine. Set each for slightly higher
voltage than 48V of course.
One thing you may not be able to do might be connecting the
chassis grounds together
depending on how those grounds are tied to the battery
negative and positive lines internally.
Sometimes the internal SPD MOVs can get in the way if their
voltage isn't high enough to handle
the two PV voltages that are seen as in series from the MOV's
standpoint. But those MOVs are
usually sized voltage wise to handle much higher voltage
than, say, 300V which would he the maximum
voltage both CC's would see for 150V max input controllers.
You also cannot use the same remote controllers if they are
not isolated from battery minus except for
the controller that is on the bottom side of the battery bank.
I have seen this method used many times now for 120V battery
banks and also for higher voltage
electric boats. There is quite a bit of this kind of wiring
out there as I remember.
There are some other standards for marine inverters like, UL
458 marine supplement and ABYC ratings.
This includes neutral ground switching like in mobile apps
too IIRC.
Of course, just adding the word "marine" has to increase the
price not matter what the product is.
😁
boB
On 6/30/2021 12:50 PM, Dave Tedeyan wrote:
Hi All,
I am going to be working with someone who plans to
completely electrify a boat. The electric motor is meant to
run on nine 12V batteries, or 108V. The motor manufacturer
recommends a charger that can run on 120V or 240V. But has
anyone seen a charger that can take solar power and directly
charge a battery bank of 108V? The alternative that I see
here is to have two separate battery banks, one for the
motor, and one for house loads. Then we would have the solar
charge a 48V battery bank, and then use an inverter to
charge the 108V battery bank. It seems inefficient, although
that may be the only choice.
A separate but related question: what is special about a
marine inverter? If there is a 5kw charger for the battery
bank, we will need a large inverter to handle this plus
other AC loads, and I am not sure if there are "marine"
inverters this large. And so other than concerns about
getting wet, is there harm to putting a Radian, or a Sol-Ark
on a boat?
Cheers,
Dave
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