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I have a LiFePO4 power station. I'll t mention the brand because I don't think the issue I may have found is brand specific. Like many such power stations, this has wireless charging pads on top that are enabled when the DC output is turned on. And like a fair number of such power stations...

??? Conductors are rated for current, not voltage. The 2/0 cable I'm using has a cross section of 67.4mm^2. A 1/4×1 inch copper bar has a cross section of 161.3mm^2. More than even a 4/0 cable.

I'm thinking that a fast powerboat will encounter far higher shock loads than a sailboat, regardless of whether coastal or open ocean.

Two reasons, both because these are intended as house bank on as boat: Larger the batteries the heavier, and the harder to move into the out-of-the-way corner these will need to occupy on the boat, and These were the only batteries with Bluetooth, low-temp heating, etc., that came in an...

I was under the impression that LiFePO4 batteries had too flat a voltage profit for estimates of charge from nothing but voltage to be of much accuracy.

The threads internal to the battery are harder to replace. And if you thread in the stud once, and leave it there, you're not damaging the internal threads.

There's a fundamental difference between controlling a motor with resistors vs with PWM that has huge implications for battery life that hasn't been mentioned. Adding resistance inline lowers the voltage presented to the motor and lowers it's speed - but it doesn't lower the current draw...

A lot of people seem to run inverters from 12V batteries as if it were no big deal. But I've been running numbers, and the currents seem extreme. A typical household outlet in the US provides 20A at 120V. That's 2400W. So figure an inverter rated at 2500W. To provide 2500W from a 12V...

Maybe I've been watching too many YouTube videos of Haulover Inlet...

There will be a 12V house bank. A lot of people prefer separate standalone batteries for their bilge pumps, independent of the house bank. I may consider that, someday.

My provisional step-by-step: Move the batteries to a bench in my workshop, where I can easily access them and work on them. Label each battery so I can keep track of which is which. Charge/discharge them until they're at approximately the same voltage. (I have an adjustable constant current...

Consider a boat with batteries you want to charge from shore power. Different marinas have different current limits. Some provide 20A, some 30A, some 50A, some provide two outlets you can combine. If you're cruising, rather than day-sailing out of a single marina, what size charger do you use...

First of all, metric has been an official and legal system of measurement in the US since 1866. Anyone who wants to use metric is free to do so. What the government has not done is to mandate its use - which is not a legitimate function of government. Second, metric units are often...

Yes. This is on a boat, where pretty much everything is tied to a common ground.

EPropulsion's 8960Wh battery is $4400.

I'm thinking a class-T on the positive post of each battery, and nothing much else within the bank. The monitor What makes NO-OX-ID superior to the dielectric grease I already have? I'm having the cables professionally made.

When I looked at Elco, I was looking for pod drives. I didn't think to go back and look again, when I decided to look for outboards. Thanks for the pointer - some of these deserve consideration.

My boat is an odd one - 37 foot length, 8 foot beam, less than 2 foot depth, with leaboards. As shallow as it is, it still has 4000 pounds of keel, but the props are alongside it, meaning you get no propwalk.

Sorry, right. P = V × I So 200W at 120V means 1.67A. V = I × R So 1.67A at 120V means 71.8Ω. I = V ÷ R And 71.8Ω at 12V means 0.167A. I'm seeing 0.5A, which would indicate that the resistance is lower at the lower temperature.

Elco makes inboard motors, IIRC. My boats was designed to have two props, each driven by a 5hp gas engine. Somewhere along the line she was converted to a single offset prop driven by a 27hp diesel. Given that the diesel isn't in great shape, and that she really needs two props to steer at low...

12000 pounds. But she's shallow and narrow, she doesn't need much to drive her. (As in 8' beam and 20" draft - plus leeboards ;) She was originally powered by two 5hp engines. The motors I'm considering are 6kW each, roughly 8hp.

I'm reading Nigel Calder's "Boatowners Mechanical and Electrical Manual, 4th Ed.", and I ran across an idea I'd not seen before - inverter-based boats. That is boats that don't rely on shore-power AC at all, so that all of their AC circuits are powered by inverters running off the batteries...

A simple rice cooker is nothing but a heating element and heat sensitive switch. All the heat goes into heating the water until it boils off, then the switch shuts it off.

My electric razor's wall wart outputs 5V at 1.2A. That's typical for the stuff I have that isn't already USB. My phone, my tablet, and my laptop will all charge at higher voltages, but they negotiate USB-PD directly.

Truthfully, I'd trust a simple circuit that I'd designed and built for something simple like that than I would whatever was going on inside some vendor's black box. But I'd pity the guy who'd try to figure it out after I'm gone...

I'm musing about perhaps putting electric motors on my sailboat, and for that I'd need 48v and a minimum of 200 Ah, preferably 400. So I'm trying to get a sense for what is available. I could do eight Battle Borns, but that would be expensive. And sixteen would be worse.

She has a single prop, offset, and tucked up along the keel. She has no prop-walk to speak of. She simply doesn't steer. She was designed to have two props, and I think she really needs two props.

The is the first of several steps. I intend to replace that 100Ah house battery with a larger bank of LiFePO4, and eventually to replace the diesel with electric. I understand that a single 100Ah lead acid won't push 3kW for very long. But don't expect to have only that single 100Ah for very...

For me, the critical issue might be the risk of unexpected shutdown. There really is no way to know when a BMS is likely to just turn off.

On a boat you really need to look at battery chemistry. Most of the lithium chemistries are unsafe on a boat because they can spontaneously catch fire. A car fire you can walk away from, on a boat you don't have that choice. The only commercially available chemistry that is safe is LiFePO4 -...

Epoch batteries has started a discussion forum: https://www.thebatteryforum.com/ Not much there, yet...

In Calder's diagram there are six wires connecting the four batteries, in the photo there are only four. They are not the same.

I don't agree that most people are full throttling their electric motors most of the time. Half power gives you four times the range. Full power is used on electric boats only rarely.

How many boats that are small enough to push with a outboard can reach 10 knots under sail?

One thought - does your "12 V needs" include the bilge pumps? Maybe it's just me, but I want as few parts, and as few possible points of failure, on my bilge pump circuits as possible.

So it would. Battery capacity: 105Ah Charged voltage: 56.8~58.4V (58.4 is max voltage at full charge) Discharge floor: 20% Tail current: 1~3% Charged detection time: 3m Peukert exponent: 1.05 Charge efficiency factor: 99% Current threshold: 0.1A Time-to-go averaging period: 3m

As to how to balance a battery, the most detailed instructions I've seen are here: How to balance your brand new LiFePO4 battery But he suggests this is necessary only if a battery is out of balance. So I'm looking for suggestions as to how far out of balance is far enough to justify this. I...

Does no one have a considered opinion on this? Could be be right?

Is there any reason why the shunt for a Victron BMV-312 would need to be electrically insulated? It's connected to ground, and there should be minimal voltage drop across it, and given that there's bare ground-connected metal all over, is there any risk? I could, of course, put it in a plastic...

AIUI Epoch's are made by RoyPow, and will has a pretty good opinion of them:

A great many LiFePO4 installs are in the bilge...

Just ran across this: He advocates using both lithium-iron and lead-acid, tied together. Is he right? Does this have advantages? Or is he all wet?

Initially I'll be mostly daysailing from a slip that provides shore power, so it'd not really be an issue. So I could install the motors and the 48V bank, and leave the solar for later. Wisdom seems to rely mostly on regen to charge their 48V bank. ePropulsion's 3.0kW pod is supposed to...

I'm in the basement, working up an electric outboard, prior to installation on my boat. Components: Elco 9.9 electric outboard Epoch 48V 100Ah LiFePO4 battery Epoch 48V LiFePO4 charger Victron BMV-712 battery monitor with shunt The outboard came with pre-made cables for throttle and ignition...

A 10 knot hull speed needs a waterline length of 42 feet. And you aren't going to push a 45+ foot boat very fast with a 6hp outboard.

In a marine environment, you'll want 316 SS, not 304.

I'm currently converting a sailboat to electric propulsion. I have the motors, controllers, and batteries in my basement, wired up and working. Some of the wire I'm using is welding cable and welding lugs that I cut and crimped myself. Welding cable will carry the current, but it doesn't stand...

In the software design world, it's called the Minimal Viable Product. What is the simplest and easiest thing I could build that would provide useful functionality, and move me in the right direction.

According to Calder all Lithium Ion batteries, to include LiFePo4, use organic electrolytes - and they're all flammable. What's unique about LiFePo4 is that the temperatures reached in a thermal runaway aren't high enough to spontaneously combust. They can still runaway and rupture. As for...

Clark, of Emily&Clark's Adventure YouTube channel, has developed a Battery Bank Manager, designed to integrate lead acid and LiFePO4. Basically, it monitors the LiFePO4 bank, and will connect it and disconnect it at the appropriate times so as to keep the LiFePO4 healthy. In this video he...

That's a thought. Thanks.

I've left these batteries on for several months with no noticable drain. The parasitic draw of even a poor BMS should be far less than you describe.

But not really relevant. If your house bank and inverter is sized to handle the load, everything else is just a matter of charging. And losses or not, shore power is a far more efficient source of charging than an alternator or generator. A galvanic isolator is a poor second choice to an...

Isolation transformers are bulky and expensive.

That was supposed to be:

Pretty much every standards organization charges a pretty hefty fee for the standards - because it costs a fair bit to organize and publish them. These aren't mass market publications, and there isn't a huge demand for them. Somebody has to pay to have them published. I find it frustrating...

I've been thinking about electric propulsion, and have been weighing different options. EPropulsion uses LiFePO4, which seems to be the standard in marine systems. https://www.epropulsion.com/e-series-batteries/ But Torqueedo uses LMO-NMC, which I know nothing about...

No, it wasn't. I have, for example, two 100Ah, 48VDC batteries, with chargers. Each of the chargers draws 12+A at 120VAC. I can run both off a single 30A pedestal, but I can't run much else. I don't, as of yet, have a shore power connector, inverter/chargers, etc. I'm plugging AC chargers...

I was asking similar questions, not long ago. I asked here, and got not much: https://diysolarforum.com/threads/bonding-ground-and-neutral-in-a-solar-generator.36724/ Will Prowse also seemed to be struggling with the issue. His final YT video on the topic: I asked over on Cruisers' Forum...

I'm reading inconsistent advice regarding over-current protection in solar systems. Suppose I'm had a pretty simple system: solar panels => MPPT controller=> LiFePO4 battery => house loads. I'm going to need a class T fuse at the positive post of the battery on the conductor to the house...

I have a small 12V 12Ah motorcycle battery that could serve.

Torqueedo''s batteries are waterproof, rated IP67 - safe to immerse to 1 meter for 30 minutes. And the BMS is programmed to shutdown when submerged. The combination might be safe...

The standard advice when wiring batteries into a parallel bank is that the cables all have the same lengths. But is this in total, or on each side? Suppose I have four batteries that I'm wiring in parallel. I have a positive bus bar and a negative bus bar. I have a cable running from the...

I'm setting up a new Epoch 48V 105Ah battery, with Epoch's charger, and a Victron BMV-712 shunt and battery monitor. Epoch 48V 100Ah heated bluetooth LiFePO4 battery The BMV has a whole bunch of configurable settings. So far all I've changed is the max Ah capacity, the rest are unchanged. Any...

Because there's not much that handles temps of -40 without damage.

I have a new pair of LiFePO4 batteries that have screw terminals. I had some random guy on the internet suggest that I not use the screws, but replace them with short lengths of stainless steel threaded rod, and then use washers and nuts on these to hold down the cable lugs, etc. The idea...

I hadn't planned on removing my existing house bank. I'd planned on running my house and running lights and my bilge pumps from my existing 100 AH lead acid. I'll be using the Bluetti to power my cooking and computers until I have the opportunity to upgrade my house bank to handle the load.

How discussion of how the resting charge of LiFePO4 works as a good float charge for PbO2 seems reasonable enough. But as to his assumption that high-demand currents will be supported by the lead-acid, instead of exceeding the current limits of the lithium I'd need convincing.

My major concern is flooding. If I've got seawater deep enough to short the batteries, I'll have problems enough without dealing with thermal runaway.

It's a Vaitses/Herreshoff Meadowlark - a 37' shallow-draft ketch. Torqeedo's marketing promises Regen when using their batteries. But I'd not expect much except when pushing hull speed on long passages, which for me is a someday maybe.

Have you spent much time in a bass boat? They're not dry.

My boat doesn't have a shore power connector, yet. Connecting to shore power means running a cable from the pedestal directly to the Bluetti. This is, of course, a temporary configuration.

So I'm going to need to find the specified max initial inflow, before I make decisions. It's not in the material I've found, yet.

Max current for this application is 98A.

I raised the question as to whether it is safe in my original post. If choosing between EPropulsion and Torqueedo, should I eliminate Torqueedo from consideration, solely because of the chemistry. At this point, I'm thinking no. It will remain in the list of possibles.

The boat is currently in a slip and the power station's charger is connected to shore power. All of this is temporary, I will be installing a proper house bank, with inverter, PV charging, etc. It's just not first on my list.

Spd? Pv? Scc?

I'm working on turning an old sailboat into a live-aboard. What I have now is a 27hp diesel, with a 22aV lead acid starter battery and a second 12V, 100Ah lead acid house battery. The only charging source is the alternator (and the trickle charger in my basement, when I pull the batteries over...

Any suggestions as to what screws to use, to connect the spades to the copper link?

I'd place an order for two 48V 100Ah Epochs right now, except their website says "Re-stocking soon". I contacted them and was told they've "made some improvements to the connectors and upgraded the BMS a bit." They expect to have them in stock in 45 days.

It's there any easy/cheap source for the ABYC electrical standards? The standards have requirements for, example, the placement of fuses, but the standards themselves are expensive.

Yes, the shunt connects to battery negative, but battery negative is connected to ground. So there should be no voltage differential between the shunt and any random bit of metal you might contact.

I've been playing with these: MakerHawk Electronic Load Tester The UI allows you to easily set current limits beyond what they can handle. And, of course, the provided cables are crap. I was trying to use one, with 10GA cables with proper ring terminals, to discharge a 48V LiFePO4 battery...

I've ordered four 12V 100Ah LiFePO4 batteries that I intend to configure in parallel. Are there specific procedures I should follow? When installing a vehicle battery, for example, the usual process is to connect the positive terminal first, and then the ground. And if your wrench is conductive...

There are commercially available LiFePO4 batteries that are rated IP67 or better. Of, of course, you could always install them in battery boxes.

Both Torqueedo and EPropulsion provide integrated systems. I'm sure that both can be used with generic batteries, but there'd be some configuration that's need to be figured out. As integrated systems both have advantages and disadvantages.

Why you need a BankManagerPlus for an off-grid ststem

I'm fitting out a sailboat as a liveaboard. This will include as much solar as I can fit. I'm trying to design the solar wiring harness. And I want wiring I won't have to redo from scratch every time I make a change. I don't expect that my first arrangement of solar panels will be my last, or...

I've been musing about some alternative approaches. I've not used either of these, and I'm not sure I'd choose either, but when I get to where I'm mounting panels, I'll certainly consider their approaches. FLINrail+ LightLeaf

You need to use cheaper phones ;)

He seems to have found a very small and very efficient compressor, and he's using to cool a very small space.

There are a number of people who claim that using a solar MPPT Controller works better than a DC->DC Charger. I have no direct experience with either, but it's something I'm going to researching.

Those would work better than simple studs, I think. Thank you.

How many of the cheaper batteries are IP67?

I have a Bluetti AC200MAX, that can supply 12V 30A that I might plug in to the house bank distribution blocks, just to have something to power the bilge pumps if needed. Not a permanent fix, but should work in the short term.

The boat should be grounded, and it should be bonded. Most sailboats with inboard diesel auxiliaries are bonded through the shaft and prop. Older boats would rely on the engine itself to bond the engine's ground to the shaft, though AIUI these days it's preferred to have a direct connection...

I don't need any kind of measurements, what the battery's Bluetooth apps provide is sufficient. For the 12V battery, the 12V 50W bulbs are sufficient. A single draws 5A, two in parallel draw 10A. I found a 48V 80W forklift headlight that should probably work for the 48V batteries.

I have a pair of Epoch B48100Bs and I have no complaints about the batteries, or the chargers. But the app doesn't impress me. Bluetooth connection page displays all Bluetooth devices, not just batteries. Can only connect to one battery at a time. Must explicitly disconnect from the first...

Yes, this is a sailboat. The current load for the 12v house bank is entirely theoretical. Right now, it's just the nav lights. As I build out the boat as a live-aboard, it will change - interior lighting, computer, refrigeration, microwave, induction cooktop, who knows? The motors? I haven't...

I have a pair of Epoch 48V 100Ah LiFePO4 batteries that I'll be installing on my boat to drive a pair of Elco 9.9 outboards. Currently their on a bench in my basement while I test things out. Given that these are for a boat, they're going to need to be slid into odd corners with difficult...