John61CT's multi-use portable charging rig

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John61CT

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Jan 7, 2017
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beneteau 36 new london
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
EARTH / GROUND (LACK THEREOF)

Usually the whole system, on both input and output sides, will have no true Earth Ground available.

Batteries' and consumer loads' negative return conductors are all tied together to, here to be called "Vehicle Common" or "Local Reference", unless someone gives me a better term.

Usual the top-level source will be various generators out on boats in fresh or salt water.

Only occasionally dock power poles, but perhaps remote "primitive third-world" supply conditions, so no assurance proper Earth Ground is available.

Other use-contexts include wheeled vehicles - RV / campers, trailers, expedition trucks - and off-grid shacks/tiny homes, but even a 2m rod is not necessarily a true Earth Ground into dry desert earth.

House circuits are DC; AC is not used aboard except for some inverters locally powering specific devices. In other words, when (rarely) connecting the charger / rectifier to grid power, there will be no other local circuits so connected. There are no big expensive combi inverter-charger units, and if there are in future, I would ensure their inputs and outputs are completely isolated while this portable unit is hooked up on either side.
 
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
SAFETY FIRST!

I am yes a noobie virgin on much electrickery basics, especially AC, and yes, I will at some point hire a pro "sparkie" to help assure safety #1.

I want all possible safety features, as if intended to be operated by noob idjits, even more so than me, or future me when early-onset Alzheimer's kicks in (and no not trivializing nor joking about that).

So want to make use of, beyond usual current-only based CP, best practices for Ungrounded operations, including ground fault / leak detection gear, specialized circuit breakers, GFCI / ELCB's, residual current devices (RCD's), etc.

I realize that only some even professional marine electricians will be au fait with the latest developments in that niche.

Obviously basics like following best aviation / marine practices on infrastructure wiring, crimps, fittings etc is a given.
 
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
OUTPUT: I need at least 2200W @48Vdc.

That is a hard requirement, and I really don't want to get bogged down at this point as to why or defending / arguing that voltage choice.

It could go **a bit** lower, between 35V as a minimum, and ideally could go up to 55.2V natively for charging 16s LFP, but if the unit is not adjustable, the "hard max" is 49V.

Top quality regulated stable voltage DC output is essential, from possibly dirty mains inputs.

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DOWNSTREAM
Possible high-current loads may include aircon, charging freezer eutectic holding plates, high-gph watermakers, and charging lead or LFP battery banks. Ideally multiple uses concurrently, if / when the upstream power supply is sufficient.

DC-DC chargers / regulators and buck converters as needed in between, e.g normal House 12V distribution circuits (13.8V for 4s LFP), 24V bow thruster / windlasses as well (27.6V for 8s LFP).

Other less standard conversions are needed for charging USB and USB-C screen devices, laptops and batteries for portable power tools. When these are relatively low-current needs, supplies can be run off power stored in the main LFP bank.

Also various battery maintenance protocols (balancing, equalizing, load testing) on nominal 2V-6V deep cycling PB cells, minimum 200AH, and also 60-180aH LFP cells at ~3.2V.

Of course normal charge cycling duty of assembled banks, usually 400-1600aH @12V, 24V and sometimes 48V. Electric propulsion is a future possibility, but I recognize 48V is at the low end for that, and not likely anytime soon.

Total current pulled by the above loads will be (inherently or explicitly) limited to within what the upstream supply can handle, but I intend for this "top level" charger / rectifier / PSU to include intelligent controls to limit current and adjust voltage on its output as well. If not then current must be limited to 60-63A.

Since I want at least 2200W, that is why voltage must be higher than 35V.
 
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John61CT

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Jan 7, 2017
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beneteau 36 new london
INPUTS: key requirement here is maximum flexibility.

Basically "universal worldwide compatible", include Euro, S.America, Japan, so 50 or 60 Hz, 100-240V or wider. I don't know if I will come across "split phase" 120V/208V often, but it would be nice if I didn't have to worry about checking for it. Also dunno if relevant, but apparently some locations will have a "full 3 phase supply" available at over 200V.

I moreover want flexibility wrt circuit's current available, to get to that 2200+W total current required by making use of multiple 110ac 10A circuits, or separate portable inverter gennies.
 
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
MISC REQUIREMENTS

Reliability, long-term heavy use in the field.

Compact, cool and quiet as possible would be nice.

As would cheap!

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Note I am **not** asking the brain trust here to necessarily answer the general "how can I accomplish all this?" question.

The above is just background use-case information for my more specific queries, and for this thread to function as a place for the more general "big picture" discussions that are just distractions in the other threads.

However, all constructive suggestions are most welcome here, especially links to resources for me to learn more, or contact info for professionals qualified to help on a paid basis, via PM if you like.

Just saying, "give it up, it's too hard", not so much :cool:
 
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
SycloneDriver said:
I just don't see a good reason for feeding a boat with rectifiers when normal shore power is available.
Click to expand
Not sure what you mean, hopefully above posts clarify my use case, in particular see the OUTPUTS one.

The rectifier is just a DC PSU, converting from (rarely available) AC power inputs, just like a charger.

> Why do you want to do this?

I do not have AC powered distribution, 99% of consumer loads run off DC, just a few small inverters locally power AC devices.

My only real need for AC inputs - whether from genset or occasional grid power - is to charge the battery bank. However when there is **enough additional** current available, I will take advantage by opportunistically also powering bigger loads, like freezer holding plates or a high gph watermaker,

just as when solar output is available after the LFP bank is full enough.
 
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John61CT

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Jan 7, 2017
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beneteau 36 new london
SG said:
I'm confused about how this system is supposed to work (on a boat)?
Click to expand
Please read the above background info and see if that clarifies things for you.

> What sized battery bank of what kins of batteries, etc?

Extracted from above, post marked OUTPUT:

battery maintenance protocols (balancing, equalizing, load testing) on

nominal 2V-6V deep cycling lead cells, minimum 200AH

also 60-180aH LFP cells at ~3.2V.

normal charge cycling duty of assembled banks, usually 400-1600aH @12V, 24V and sometimes 48V
 
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
bawlmer said:
OK. I'll bite again. The only way I can see this happening is with this scenario.
The 48 volt supply is driven by AC dock power. The dock (earth) ground is attached to the AC side of the PS for safety reasons.
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Please read the above, 2nd post.

There will very rarely be any Earth Ground, most charging from AC will be from generator, on the hook or on land, both off grid.

> There can be no reference to earth ground on the 48VDC output side.

Confirmed.

> You will need a schematic and a statement from the manufacturer to confirm that.

"Need" in what sense? Are you saying it is not possible to verify it with a DMM?

> My question now is "what in the world are you going to do with 48VDC on your boat?"

See above post marked OUTPUTS.

> A DC to DC converter that would handle any kind of current reliably would be really expensive and would add an unacceptable level of complexity in a marine environment.

I only need such high current for a short time to get the main bank charged.

The lower voltage draws are not high current.

I know nothing about golf cart devices, but will check them out.
 
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John61CT

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Jan 7, 2017
92
beneteau 36 new london
Have a lead on a stack of 3kW lab grade adjustable PSUs all setup and working, no "assembly required" like the TDK Lambda ones.

They are not ideal, since one unit delivers so much power rather than stacking units fed from separate 115Vac circuits, these require 230Vac which will not always be available.

They are also very large and heavy, designed to be mounted in a rack.

But they're going so cheap, and are of such famous high quality, I think I shouldn't pass them up, certainly can recoup my costs when I get a better setup put together.

Their specs on input requirements:
200-250 Vac, 48 to 62 Hz

Either single phase, only two wires, or to get full 3000W output
3-phase, requiring 3-wires
plus "ground" / reference / common

It is an American company and design

America vs the rest of the world create their "240V" differently

https://www.bluesea.com/support/articles/AC_Circuits/87/Differences_in_USA_and_European_AC_Panels

https://diy.stackexchange.com/quest...hree-phase-240-v-and-standard-household-240-v

My questions:

Do these differences matter to my ability to plug this PSU in using just plug adapters?

Would it be feasible to shop for a transformer to convert 110 to 220V?

What about "Digital Phase Converters" to convert from single phase to 3-phase power?

For those concerned I might start fires or kill myself, thanks but, I will get a pro to do wiring and check my setup out, Safety First!

I just want to make sure I'm not throwing money away on stuff I can't use.
 
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