Emergency power for nav lights & radio

[Mycroft]

I'm planning for emergency lithium power either to connect to my usual LED nav lights or to emergency backup nav lights. Also doing double duty to possibly power a backup VHF and charge ipad backup navigation.

I want lithium because it won't lose much charge in between re-charging and it is small for the energy.

At first I liked the looks of the Goal Zero 400, but it turned out to only provide 10.8v on the "12v" outlet!

Now I'm looking at the NOCO Genius Boost Pro. Pluses are that it's small and compact, provides 12.8v and can run the lights and charge up the iPad. Minuses are that it can't be directly charged from a solar panel and that it's only 8ah.

https://www.amazon.com/dp/B06Y5YYMQW

Has anybody researched this and found something better?

[Don C L]

Hmmm.. haven't researched this one, but I have spare portable LED running lights, like bike lights, to use in an emergency, but they have just been sitting waiting. I think they will last a pretty long time on a little battery and you could stock up on those little batteries. If you have solar already you don't want to just get an extra deep cycle 12v battery and let the solar keep it topped off?

[john61ct]

Battle Born G31 "drop-in", possibly in an ArkPak 731 box if you're feeling flush.

Or if you like tiny, OEMtools PPS-X

[Mycroft]

The problem with a G31 for emergency electronics and lighting use is the space it would take up. I would want it up high enough that it wouldn't short out if water came in.

[john61ct]

Well there are many sizes of 12V drop-ins on the market, 20AH and up.

Look at this on eBay http://www.ebay.com/itm/172834794012

A pelican case the right size, keep meters, gadgets right in with it, just don't store it charged past 13.7V if you want max longevity, probably giving up 5% capacity compared to 14V.

[maxingout]

I carried a small battery powered nav light that I could put on my bow in an emergency. During an eleven year circumnavigation, I never used it even once. Still it's not a bad idea to have on board.

I am not impressed with deck level navigation lights in terms of their visibility on a sailboat. I used a masthead tricolor light and kept a spare on board Exit Only as I felt it was more effective than the deck level navigation lights.

My emergency navigation light was more of an attempt to keep me legal going into and out of port if there was some type of electrical problem on board.

By the way, I really like the Slocum 43 design. We sailed with one when we crossed the Indian Ocean.

[SecondBase]

I keep a set of Kayak lights in the nav bag.

[StuM]

Originally Posted by Mycroft

I'm planning for emergency lithium power either to connect to my usual LED nav lights or to emergency backup nav lights. Also doing double duty to possibly power a backup VHF and charge ipad backup navigation.

I want lithium because it won't lose much charge in between re-charging and it is small for the energy.

At first I liked the looks of the Goal Zero 400, but it turned out to only provide 10.8v on the "12v" outlet!

Now I'm looking at the NOCO Genius Boost Pro. Pluses are that it's small and compact, provides 12.8v and can run the lights and charge up the iPad. Minuses are that it can't be directly charged from a solar panel and that it's only 8ah.

https://www.amazon.com/dp/B06Y5YYMQW

Has anybody researched this and found something better?

Where did you get the 8Ah? I couldn't see it anywhere at that link. But in general, you are correct, those "boosters" are OK for high cranking Amps for a few seconds, but they don't store many Watt hours at all. (That's why it is always so hard to find an actual capacity rating at reasoanable discharge rates for them). I doubt that it would give you very long powering nav lights (even LED) and a VHF.

They say it is 22500 J3S (i.e. can deliver 22,500 Joules over 3 seconds). So let's see 22500 Joules = 6.25 Watt hours = 0.5 Ah at 12.5V over 3 seconds. I hope that it can do that more than once before it is flat If it really is 8Ah, then it would be flat after 15 x 3 second bursts.




.

[Mycroft]

Thanks Stu, I was afraid that was correct. It might run LED running lights all night, but probably no radio use.

We love our Slocum! Very solid and very homey!

Looks like I may have to go with a G31 and find someplace to stash it. More research required. :-(

[john61ct]

If so maybe also consider Firefly Oasis, yes heavier but also cheaper at ~$500, considered 'almost LFP' for resistance to PSOC, but likely self-discharges at a bit faster rate than LFP.

[john61ct]

This is a relevant thread from a "van dwelling" forum

http://www.cheaprvliving.com/forums/....php?tid=23546

[bluewatervet]

Google search for "BioEnno" batteries....their 12AH (24 amps max output, excellent for HF/VHF radios in particular) fits in the palm of your hand and weighs 2.5 times less than a comparable deep cycle gel cell. Bad news is they are very expensive....but it is the newest type LiFePo4 design, and is NOT the catch fire type so much in the news of late. Should only be charged using a LiFePO4 compatible charger (at 14.6VDC) for max life, so add on about $21. Total cost on Amazon for example is close to $150 USD. Manufacturer also sell directly to the public. BTW, I have no pecuniary interest in this company....

[john61ct]

Yes BioEnno has a good rep, but I'd want at least 20-30 AH for this OP use case, could parallel of course but. . .

No LiFePO4 (LFP) battery is more of a fire risk than lead, that is only an issue with some other lithium ion chemistries.

All LFP are, for longevity, ideally charged at no more than 13.8V, no float, and stored at low SoC when not cycled.

[bluewatervet]

LFP's (LiFePo) are available in well over 30 Amp draws. Note the manufacturer specifically notes 'do not series or parallel' this technology. (BTW, the numbers I quoted came directly from the company web site....)

[john61ct]

Yes quoting misinformation directly from the mfg, none of them spec for longevity, try to tout "drop in" specs for marketing purposes.

And yes AH capacity at the 20-hour rate is related to the max discharge rate, but very different specs, the latter not so relevant for the OP use case nor for other usual House needs.