Lithium Battery Upgrade

[jimmy alonso]

Tested (200 watts) ice maker today seems the starting inrush current was a too much for the 500 watt inverter. About 7 to 8 amps @ 120 volts AC. Got overload alarms.
Ordered a 800 watt Victron today.

[OverEasy]

Hi Jimmy Alonso!

Got a Question or two for you along the lines of inverters….
Given a situation: If one wanted to run a variable load for say a digital control induction cook plate that had a max rating of 1500 watts
Q1: What type of inverter would be appropriate to not damage the cook plate?
A full sine wave or a modified sine wave type?
Q2: When thinking about inrush currents would a 2000 watt inverter rating be sufficient?

Thank in advance for your thoughts!

Best Regards
Over Easy

[jimmy alonso]

Tried again running the ice maker today after retightening the wiring no over load alarms. Canceled the 800 watt mainly because it is much larger than the 500 Watt.

I had ordered a Induction one burner cooktop. Operator manual stated uses 400 watts on lowest setting. And 1200 watts on high. When I tried it on low it would run at 400 watts then would go to 1200 watts for a few seconds then return to 400 watts and would repeat this pattern. Didn't notice inrush current that i can remember on the cooktop. Had thoughts about having one on the boat.

Thing to look at on inverters a 1000 watt will have a spec of continuous watts less than the 1000 watts.


Go for a full sine wave always.

[NiceAft]

I don’t claim any serious knowledge of lithium batteries. I do remember hearing warnings about rough handling can contribute to them exploding. Excess heat seems to be another cause. Our boats can get really hot. I’m not doing anything but seriously inquiring. I’m looking to learn from any who have far more knowledge than I. How safe are they in the heat that can build in our boats. MacGregor trailers have leaf-springs; not very good at a smooth ride.When trailered, our boats bounce rather hard.

When the burst into flame; they burn intensely hot.

[kurz]

Don't talk about lithium...
We use LiFePo4. They are save.

[NiceAft]

Don't talk about lithium...
We use LiFePo4. They are save.

Apparently a different type of Lithium battery.
https://www.solarchargingbattery.com/bl ... 0batteries.

Kurz,

Do you have any quick, high discharge needs?

[kurz]

Yes starting the OB!

[NiceAft]

So, no refrigerator or freezer.

[jimmy alonso]

Hi Ray.
Have a Ruuvi temperature sensor on the boat..hi temp today 99 Thermal runaway is a lot higher.

Are you near the bridge that got knocked down

[NiceAft]

Hi Jimmy,

No, that catastrophe is in Baltimore, MD. We’re in the Philly area.

We are taking a 17 day cruise of the Chesapeake this Summer, and are going to Baltimore’s Inner Harbor. We will see what happens. We are already thinking about plan B.

Please say hi to your family.

[trswem]

Hello. Are you running from a fuse panel to a fused switch box? I’ve been thinking through this exact scenario on my rebuild. Is going fuse to fuse like that a best practice, or am I overthinking the diagram?

Thanks!

[OverEasy]

Hi All

Just a thought….there are no absolutes in this aspect, just perspectives…

Personally I’ve found the use of “fuses”, especially when designing new systems, to be an unnecessary PITA even for limited use systems.
Resettable “circuit breakers” are often times a much better option.

A “fuse” and associated mounting hardware take up as much volumetric and panel space as a “circuit breaker” does. So no real difference there.

A “fuse” and associated mounting hardware and a couple spare “fuses” initially cost about the same as does a comparable “circuit breaker”. So no real difference there.

The difference is when a circuit overload occurs…
—> A blown “fuse” has to be removed, then the proper replacement “fuse” found (from wherever one has remembered that it was squirreled away… you did buy spares right?) and then replaced ( hoping that you didn’t lose the cap piece)… and hopefully whatever caused the overload in the first place was resolved before the new fuse was put into service…(you did get a couple spares right?)
—> A resettable “circuit breaker” can simply be reset with the push of a button or lever… no looking about for anything and nothing more to buy as spares, no disassembly/reassembly required and you can repeat the process as many time as needed if needed.

So why use fuses?

Just a thought …..

Best Regards,
Over Easy

[McGamin80]

@OverEasy

"So why use fuses?"

Fuses will blow way faster than a circuit breaker will trip. Lead acid batteries can put out 600 plus amps @13V+. 7.8kW can destroy many electronics in microseconds. That is the main reason, fuses will limit current to just the blow current. AC from the grid is different from DC as it's 50-60Hz, meaning there are rest cycles built into the wave form of AC. Plus with AC higher amperage results in less heat dissipated per watt. There are more reasons circuit breakers are more fit for grid power as fuses are in marine or auto applications. Around salt water, personally I would want fuses that blow rather than circuit breakers.

"Q1: What type of inverter would be appropriate to not damage the cook plate?
A full sine wave or a modified sine wave type?
Q2: When thinking about inrush currents would a 2000 watt inverter rating be sufficient?"

A2: An induction heating device will not allow infinite current through the circuit as an electric motor will. Much of an electric motor current control is dependent on back EMF. Think of regenerative braking, as the motor spins it creates a flow of electrons against the flow from the source. The same is true of a motor starting to run, as it sits idle when current is applied to it, voltage across drops and current flows to what is allowed by the resistance of the wire windings alone. This is why Lifepo4 12.8V batteries with BMS's at 100A or 150A can't be installed on these systems, or why generators give starting wattage and running wattage. Induction heating devices create no back EMF, so they have to have an internal resistance that doesn't increase. So use anything over 1500w continuous to power that stove.

A1:An induction device will resist a change in current. Even a modified sine wave inverter would work fairly well on one as it will alter the wave form itself smoothing it out kind of. There will be a power loss as with a square wave modified sine wave. A 1500W inverter would loose about 450 Watts capability for a resistive circuit, less loss with an inductive or capacitive circuit with a square wave but since most modified sine wave inverters have stair steps in voltage change and not square waves, then you could get away with a 1600W modified sine wave inverter. If it has a square wave form then go with a 2200W or greater continuous power rating. But a 1500W pure sine wave inverter would handle it no question.

[McGamin80]

@OverEasy

"Sheesh! This got complicated for an old geezer like me…
I’m still working up to figuring out simple solar panels to charge my two lead acid batteries and mounting my little Honda generator for the Admiralty A/C when we boondock away from a marina on longer trips…"

It can be complicated at first. Solar panels will put out double the voltage so you need a charge controller that will regulate the voltage to what your battery requires. 20V will cook a lead acid or lithium battery pretty fast. So never hook those solar panels directly to your battery.

The type of charge controller depends on the amount of time you are on the water. Are you staying 2 days? 2 Weeks? 2 Years? If you are just going out every once and a while like just overnight, then you could get by with a PWM charge controller to solar charge the battery while you are at the marina/house and supplement heavy loads with your generator. If you are staying for weeks, that could get difficult. So you would probably want an MPPT and a larger Lifepo4 battery in that case. Then there is how much power you will need at any given time during the charging day? If you are running 500W, then you can get most of that from panels as it dips into the battery if you use a larger Amperage controller.

I am currently outfitting a new to me 89 Mac 26D and have been going through this too. I have a background in electronic engineering, so if I can be of any help to you by answering some questions or giving you resources to learn how it all goes together then let me know. I'm new to the lithium battery scene though. I have spent about 2 weeks learning about it between fiberglass/gelcoat repairs.