Lightning strikes or EMP taking out lithium bank

[CharlieJ]

It’s not recommended from a daily management point of view, especially if you have a BMS that performs automatic balancing of cell voltages, but a BMS is not strictly necessary to operate a LFP battery. A working shunt would be useful to know the voltage and current, or at least a multimeter to provide voltage. Keep below 14.0 when charging and above 12.0 when discharging. As long as you’re on your boat all the time you can monitor manually and turn on or off chargers and loads manually.

Bingo!

I designed and installed a very large house LFP battery bank for a 66' aluminum sailing cat. The bank was comprised of native cells and I did not use the BMS to "balance" the cells...balancing was performed manually when warranted. My testing had shown that these cells used at a fractional C discharge rate simply do not go out of balance.

Part of the design was an emergency panel where all the charging device controls and meters were installed. If the BMS was destroyed in a lightning strike or near strike (EMP) then the owner could take over the role of the BMS at this emergency panel. He did not have full functionality, but he was not DIW.

[keelsidedown]

The ground that lightening seeks is outside of your boat (the water or the sky depending on how you view voltage potentials during the various stages of a lightening strike). You run into big trouble when you get into it's way out of the boat (looking at you, deck stepped masts with your in mast wiring being the most immediate path to things like bonded thru hulls, keels, rudder posts, etc). This is typically easier to deal with in a fiberglass boat (at least one very substantial below the waterline thru hull needs to be metal and bonded to mast using heavy gauge copper wire). Metal boats are an entirely different matter, but it boils down to your electrical system negative being completely isolated from the boat hull ground, in addition to the mast having a good lightening strike distribution system (and your battery bank should be well fused... think tesla active fuse), because no matter how good a job was done isolating battery ground from hull ground, a strike will melt wire insulation as a matter of thermal proximity. Fero-concrete boats are one strike away from sinking. At the end if the day lightening is similar to a flash arc hazard. There is plenty of engenering that has gone into mitigating that hazard, so look to the utility sector for solutions. The end goal isn't to save your li-on batteries; it is to keep your cells from rupturing and causing an internal boat fire (YouTube rossmann and battery fire to see what that can look like). Personally, I would treat li-on batteries a lot like propane tanks... something to be housed in a compartment that, if suffers a catastrophic failure, won't sink the boat. I believe there are a couple of cats that keep their battery banks in the outside between the hulls so that, if the batteries caught fire, could burn through deck and drop into the water without sinking the boat.

[goboatingnow]

It should be pointed out that marine li batteries are typically LiFepo4 and are far less susceptible to thermal runaway or fire then other Li chemistries.

[edlepera]

I recently on a fellows sailboat he had the normal bells and whistles. Chart plotter etc. I was helping him clean out a couple of lockers and he had a RDF, two spare VHF radios, ones being a handheld. A fair amount of paper charts too. Including a sextant. When I remark they looked new he said they were his emergency replacements.

[keelsidedown]

Originally Posted by goboatingnow

It should be pointed out that marine li batteries are typically LiFepo4 and are far less susceptible to thermal runaway or fire then other Li chemistries.

This is true, but I would also point out that there are plenty of "lithium" batteries that are nothing more than 18650 cell assemblies with an el-cheapo BMS and a really "robust" looking external case with big car battery style terminals. These also tend to be the most affordable... and wall all know how adverse we are to throwing another thousand into that hole. Personally, I follow DIY Solar Power with Will Prowse on YouTube because he does battery teardowns and is always on the lookout for good deals. The only down side to his channel is that all of his consideration is terrestrial. He had a recent (one week ago) review of a $400 100Ah 12v LiFePO4 that shipped via Amazon. He tore the thing down and pointed out some the (dis)features coming out of the Chinese widget complex.

[keelsidedown]

Originally Posted by edlepera

I recently on a fellows sailboat he had the normal bells and whistles. Chart plotter etc. I was helping him clean out a couple of lockers and he had a RDF, two spare VHF radios, ones being a handheld. A fair amount of paper charts too. Including a sextant. When I remark they looked new he said they were his emergency replacements.

If you are ever assigned galley duty on a vessel that leaves the sight of shore, always check the inside of the oven before preheating. It is not uncommon to use the oven as a faraday cage for spare electroics.

[cottonsail]

I took a lightening strike on my Pearson 28 (second version, Shaw design). Destroyed the aerometer and wind angle. Surprisingly that was the only damage, or so I thought until I hauled out. There was thousands of tiny pinholes in the keel. The mast is keel stepped. I still feel I was very lucky.

[Iains boatyard]

Originally Posted by CharlieJ

Bingo!

I designed and installed a very large house LFP battery bank for a 66' aluminum sailing cat. The bank was comprised of native cells and I did not use the BMS to "balance" the cells...balancing was performed manually when warranted. My testing had shown that these cells used at a fractional C discharge rate simply do not go out of balance.

Part of the design was an emergency panel where all the charging device controls and meters were installed. If the BMS was destroyed in a lightning strike or near strike (EMP) then the owner could take over the role of the BMS at this emergency panel. He did not have full functionality, but he was not DIW.

This set up is about the best you will get.
I had my Cat set up like this, Lithium are quite simple battery really. Never used a BMS. The old adage keep it simple there is so much fear mongering about Lithium and excessive uptake of technology in boats.
I have been hit 3 times the last the big one left a 10mm divet in my mast head vapourised every thing up there except the Lightning diffuser! My entire electrical system fried right down to the toilet switch. So that is everything you can think of electrical on your boat. Has to be towed back to a marina. Lost 12 of my Lithium cells either open circuit split cases or plumped up. Switch boards solar panel EMS for the engines LED lights all nav gear etc. Dead in the water.
Bottom line is you will never control lightning. It is all part of the risk in cruising.
So I could still cobble together a battery bank but ….. nothing left to power up.
My Cat was set up with each hull being independent of the other water and electrical but lightning sees no such thing.
If God wants to touch you with his finger ……. Nothing you can do about it.

[Iains boatyard]

Suffice to say I have since sold that boat 3 times was enough.

[goboatingnow]

Originally Posted by Iains boatyard

Suffice to say I have since sold that boat 3 times was enough.

Good move.

[carstendenmark]

More of lightning troubles in thread : Electric propulsion - lightning protection ?

[elandra65]

I remember talking to a electrician in Saint Martin who was proudly telling about a lithium battery install in a Gunboat catamaran. I asked him what would happen to the BMS if the boat was hit by lightning. He went quiet for quite awhile before he said that is likely to be a big problem. As one who lost almost every device with a chip in it after a lightning strike in Papua New Guinea I would be very wary relying on sensitive electronics such as BMS etc. The only devices that escaped being fried in my case were the a.c. circuits and AGM batteries. At least I had backup GPS etc and a large crew to hand steer so we could get back to Australia to fix the mess.

[goboatingnow]

Loosing a BMS doesn’t mean damage to lithium’s follows. Armed with a simple DMM you can quite happily manage the pack manually

[Elleroo]

Originally Posted by edlepera

I recently on a fellows sailboat he had the normal bells and whistles. Chart plotter etc. I was helping him clean out a couple of lockers and he had a RDF, two spare VHF radios, ones being a handheld. A fair amount of paper charts too. Including a sextant. When I remark they looked new he said they were his emergency replacements.

I was wondering when someone was going to comment on this.


I've got an old B&G rdf that travels with me, and a list of printed aircraft nav beacon frequencies. Also carry a sextant and tables, and paper charts, albeit large scale, but enough to get me to safety. A couple of hand held gps units and as above, hand held vhf's and lots of spare batteries. And a beautiful wooden box that holds a Walker Log, with a spare spinner. All that analogue stuff has done way too many miles, but did the job before satnav and leisure craft loran, and can do again.



I see so may cruisers on Youtube(and some very well regarded!) who see all that old stuff as superfluous. Wait until they have a lightning strike mid ocean! I've been there on a big ali raceboat. The ali hull and mast didn't stop all the electronics being fried.



I'm considered a dinosaur by the youngsters, but I'm a dinosaur that can get himself home if all electronics fail 1000miles from port.

[goboatingnow]

Are many RDF stations still transmitting ?