Portable Power Banks

[Bill O]

Originally Posted by john61ct

The profitability of this whole market segment is driven by people trying to avoid figuring out these electrickery details.

But real utility and value will only come after you do.

The voltage of the AC output is just a matter of the right inverter.

The main function of these power packs is energy storage. Whether bought OTS or built DIY, key questions to answer are:

Actual Wh capacity of the batt inside?

How fast a Watts rate allowed flowing in charging, how much out to loads?

What chemistry, expected lifetime cycles?

Replacement battery availability and cost so you don't need to toss the whole thing out?

Once you have good answers to these, you will have a clear idea of what sorts of loads you can power and for how long.

To the extent the unit is very portable,

inherently small and light means low capacity,

you should really be avoiding devices designed for mains anyway, look for 12V versions, likely much lower overall consumption of watts.

Especially if the load device runs off DC internally or has its own battery, it's just silly to use an AC powered DC charger off an inverter powered by a DC source.

A suitable inverter may well only cost the price of one nice meal out, should really have little bearing which portable battery-in-a-box you buy.

Mat Jam,
There is much wisdom in what John is writing. You may want to step back and take a critical evaluation of your system.

Would agree the majority of the land based world runs on 220V and the metric system, while the backbone of a boat is 12V (or multiples of 12V).We have a few land based appliances and use inverters to run these off the house bank, but otherwise we use 12V (or less) to run things. Our nav system runs off of a RaspberryPi (5V) as well as our autopilot and are very efficient. Even the AP pump controller and software have been designed to use much less power than many versions. The laptop we use in the cockpit fro nav. and AP can run off of a 5V plug if the battery starts to go low or can be quick charged w/a 12V brick if needed.

I do like the redundancy in your cooking setup. Obviously the gas and solar have little impact on your batteries, while an electrical cook top would put a big crunch on a 200Ah house bank. We will be experimenting soon w/a low current 12V sous vide/thermal cooker. We can set this up during the day and have a hot meal ready when needed w/very low electrical impact.

You asked about the wind gen. We had our wind gen for awhile and based on our experience will say hands down overall the solar crushes it. This is especially true in low wind areas (and ours is designed for low speed start up). In some storm situations the wind gen produced a lot of juice or while sailing at night, but again the solar is a consistent producer. Comparing the overall cost of adding several more panels (>100W) and more house batteries, you'd still be way ahead than the initial purchase price of a wind gen. (then add more for mounting, etc.).

Seriously look at your system and what you can do to make it more efficient. The portable bank/bricks are nice for a quick charge, but IMO you'd do much better adding more capacity to the house bank to store excess energy and have better capacity for your overnight needs. If you don't have room adjacent to the current batteries, look around to see if you can fit in more elsewhere.


Bill O.

[mat jam]

John, Bill,

I can not thank you guys enough. The wealth of info available from experience is immeasurable.

I am rethinking my options. Electrical is my weakest link and although I can do the electrical myself I have always paid an electrician to do my electrical simply because it is the most dangerous thing on the boat and I want to be sure it is done properly.

My reticence to go wind gen are reinforced by your comments and I will now most likely add more solar panels. I may add more batteries but the logical first step seems to be to switch to Firefly batteries which would be the easiest way to add more usable Ah and the most economical option. Only problem appears to be finding a dealer in the EU.

[john61ct]

At least 4-5 months waiting list.

Likely more practical and economical to just use what's available locally.

Post a new thread asking for reco's giving your location.

[mat jam]

Well that is okay since my current batteries are less than two years old and working well. And a good sign since it means they are in demand with good reviews. They appear to have all the benefits of Lithium at half the cost and without the issues of Lithium or having to change out any components.

Am I missing something?

I do not mind waiting for the right gear. My current batteries replaced gel so did not want to go that route either.

[john61ct]

GEL can also be made to work very well, just need a more specific care regime.

Won't say FF gives **all** the benefits of LFP, but certainly less risky, simpler to get set up, the care regime much more flexible, easier to source stateside and lots less of an up front investment.

Get your order in when the current bank gets below say 75% SoH and you should be fine, at some point their production rate should catch up with rising demand.

But if you can get the PSOC issue resolved in the meantime, just go with Lifeline or Odyssey

[KTP]

FF is twice as heavy as lithium, has the same problems with Peukert's formula as regular lead acid.

It is about half price though. $500 for a 110ah vs $1000 for a 110ah Trojan Trillium.

[AKA-None]

Just as an example my rv has about 200ah of house and my electric stove with a single burner on will draw that down in about 20 minutes ymmv

[sail4evr]

leave it alone or add another battery. The longer you keep your batteries at full charge the longer they will last. Batteries are rated for a number of discharge cycles. that would be dischargeing them to 50% or around 12v. If you are keeping your batteries at say 12.3 because of your high charge rate, you will IMO double the number of discharge cycles, doubling the life of your battery

[bcboomer]

+1 on Firefly.
Fisheries Supply had enough stock a couple of weeks ago to send out an ad so supply may be catching up with demand.

[john61ct]

They got 200 of the G31s in, now only 4 left, likely 2-3 months before the next order arrives.

[jsanton]

I appreciate this discussion as I’m in the process of building your system on my vessel. I too have thought about what’s next in terms of what would a bit more solar or battery capacity do for me. I’m a retired electrical engineer so I think a lot.

I have a few ideas in that bucket-
1) if you add a car jump start battery, can we simply add the 100ah battery that we have reserved for starting into the house bank? To feel comfortable with that, I would want to use a solar charge controller that can shed the load if the battery voltage gets too low. That would increase your house bank to 300ah. Anyone have thoughts here?
2) I’m considering adding a dc to dc converter and using that to either heat hot water or run a dc watermaker that I might diy. The idea is that once the batteries are fully charged, the entire panels power output can be harvested. A dc/dc converter can be had for $40. This would be a low output water maker given that with a 3rd panel, we’d only have 300w available.

A couple other observations-
3) I also heard some comments about the ability of solar chargers to bring a bank to 100%. My thoughts are that the solar charge controller is a key piece in the system and investing in the best likely makes the difference.

4) I also avoid using mains as much as possible. I have a 150w inverter that’s plugged in only if needed. When I bought a tv, I looked for one that is powered by a 12v wall wart, then cut off the wall wart. It’s a useful trick.

5) I am also considering a dc sous vide cooker as a nice way to decrease propane consumption. The trick there is to cook in a beer cooler.

[john61ct]

Originally Posted by jsanton

if you add a car jump start battery, can we simply add the 100ah battery that we have reserved for starting into the house bank?

No.

If cranking off House, then put in a Reserve bank.

House bank should all be same model and mfg date.

Jumper packs are for emergency use only, belt $ suspenders, need care / attention / periodic replacement.

Jumper packs are for emergency use only.

[john61ct]

Originally Posted by jsanton

To feel comfortable with that, I would want to use a solar charge controller that can shed the load if the battery voltage gets too low.

What load?

Trying to capture "free excess" energy is IMO fun EE tinkering but rarely significant.

Using LFP and sizing it so you rarely het near full would be more practical.

Why would a convertor be needed?

> I also heard some comments about the ability of solar chargers to bring a bank to 100%. My thoughts are that the solar charge controller is a key piece in the system and investing in the best likely makes the difference.

No, only cheap obsolete SCs aren't adjustable enough, pretty easy to get there with any of dozens of makes using an ammeter.

Now an SC tied to a bank-shunt BM that transitions to Float directly off the bank reaching endAmps,

yes that is ideal, and few makers offer that feature.


Going DC only AMAP is wise IMO, but those with induction cooktops, microwave, dishwashers, clothes driers, inbuilt vacuum cleaner systems of course think otherwise.


> dc sous vide cooker as a nice way to decrease propane consumption. The trick there is to cook in a beer cooler

Another cool project.

FYI each of these ideas deserves its own thread, and a bit of google-** will reveal dozens on each topic to resurrect so you don't need to start your own.


Unless you want to.

[mat jam]

One of the reasons I am reluctant to add another battery is location. I do not have room with my battery bank and would need to locate it near the front of the boat under the V-berth. This would effectively separate my batteries via a long cable which I believe is not recommended. And the battery bank compartment is well protected and close to all my electrical gear.
Also I have a unique setup. I have two battery controls. Battery control 1 - batteries 1,2. Battery control 2 - batteries 2,3. This allows me to isolate each battery or by using Both on both battery controls connect all the batteries. And I have a three battery splitter as well.
I will eventually upgrade to Firefly unless I come across something better. I say this because I did not come across Firefly until recently.

[john61ct]

I would first do a ground-up redesign on that setup if I was going to expand capacity, get a new start with one big matching bank.

Yes, halves in separate locations is not great, but probably less bad than maintaining separate banks with all those switches in between.

Firefly is called for if you have unavoidable chronic PSOC abuse conditions.

Better to eliminate that problem too, if you can.