10 "Banned" DIY Repairs That Will VOID Your Boat Insurance

[dlandersson]

10 "Banned" DIY Repairs That Will VOID Your Boat Insurance

[Russ]

Yep. Household wiring is no good on boats. Vibration is the key to failure.

I think I also read in Nigel Calder's book that pure solder joints are not recommended either as extreme heat could cause them to fail. I crimp everything and then solder it.

[Ixneigh]

That was interesting. Esp. the part about lithium phosphate batteries. Friend of mine just did the swap out they talked about.

Ix

[Be Free]

The two problems addressed in the video re: lithium batteries is alternator damage due to overheating and unexpected disconnection as well as the consequences of those problems.

The key to not melting down your alternator is to avoid connecting it to something it was never designed to charge. They key to avoiding an unexpected disconnection is to not have switches between the battery and the alternator. Avoiding both of those problems is trivial. I'll address keeping the lithium battery charged a little later.

Your outboard was designed to charge a lead acid battery. While there is a partial overlap in the charge profile, lead acid batteries are meant to be charged at a lower voltage and a lower amperage than lithium. The lead acid charge profile tapers off as the battery is charged; the lithium profile is virtually the same from start to finish. Lithium needs a higher voltage and really prefers an amperage that is close to a magnitude greater than your alternator can provide.

The alternator in your outboard was designed around the needs of the outboard and a lead acid battery. Using your outboard alternator to directly charge a lithium battery is not quite as bad as trying to put a square peg in a round hole. It's more like putting an octagonal peg in a round hole. You can make it work but it's not right.

The fix is not difficult and it is not particularly expensive.

If your keep a lead acid battery wired directly to the outboard you can't blow your diodes due to an unexpected disconnect whether from a BMS cutting the connection or an inadvertent switch to "off" with a battery switch.

Most of the outboards that our boats carry do not have a lot of excess charging capacity compared to the "appetite" of a lithium house bank. That said, I still hate to waste electrons on those (hopefully) rare occasions when I have to run my outboard for hours rather than minutes over the course of a day.

The next problem is how to keep all of those spare electrons from going to waste. The answer is a battery-to-battery charger connected to your start battery that takes the excess capacity of your alternator (after the start battery has been recharged) and feeds it into the lithium house bank in the same way a dedicated shore-powered lithium battery charger would. The output of the B2B charger is identical to the output of an AC powered lithium battery charge albeit at a significantly lower amperage.

Your alternator is happy. Your start battery is happy. Your house bank is happy. Your insurance company is happy. Your checking account is slightly peeved (but when is it not?)

[dlandersson]

Really nice point. I did not know this.

Your outboard was designed to charge a lead acid battery. While there is a partial overlap in the charge profile, lead acid batteries are meant to be charged at a lower voltage and a lower amperage than lithium. The lead acid charge profile tapers off as the battery is charged; the lithium profile is virtually the same from start to finish. Lithium needs a higher voltage and really prefers an amperage that is close to a magnitude greater than your alternator can provide.

The alternator in your outboard was designed around the needs of the outboard and a lead acid battery.

[kurz]

well, theory or did you do it?

I have a LiFe directely connected to the OB, works since 4 years now.

I use a LiFeYPO4, Winston battery. There is absolutely NO electronic inside, no switch.

So an unexpected disconnection will not happen.

The voltage of 14.5V is perfect for loading it.

Overheating dit not happen so far. Reasons? The regulator (Merc 60HP) is water cooled. But even more important reason: The "alternator" of the OB will not give more than 10A. So there is not enough heat anyway.

I use Winston 60AH (you can get it form 40 to 90AH). Is the only battery in the boat. Starting, fridge, AP etc. Solar helps also. Really KIS installation! Starts perfetely the OB. Perfect for small TRAILER boats for saving kg!!! It must be the fist mod that made the boater lighter

[Be Free]

well, theory or did you do it?

I have a LiFe directely connected to the OB, works since 4 years now.

I use a LiFeYPO4, Winston battery. There is absolutely NO electronic inside, no switch.

So an unexpected disconnection will not happen.

The voltage of 14.5V is perfect for loading it.

Overheating dit not happen so far. Reasons? The regulator (Merc 60HP) is water cooled. But even more important reason: The "alternator" of the OB will not give more than 10A. So there is not enough heat anyway.

I use Winston 60AH (you can get it form 40 to 90AH). Is the only battery in the boat. Starting, fridge, AP etc. Solar helps also. Really KIS installation! Starts perfetely the OB. Perfect for small TRAILER boats for saving kg!!! It must be the fist mod that made the boater lighter

Not theory.

I have a lead acid start battery hard-wired to the outboard. There is no way to accidentally disconnect the engine and blow the diodes.

The start battery is connected to a 30A DC-DC charger using a custom lithium profile.

The output of the DC-DC charger is connected to the house bank consisting of two 160AH LiFePO4 batteries (in parallel) after the start battery is recharged. The DC-DC charger only runs when the start battery is fully charged and the outboard is running.

Each of the house batteries have a built-in 150A BMS.

When on shore power the house bank is charged with a 60A lithium battery charger. You are ahead of me on the solar. It's the next major upgrade on my list.

The overheating issue in the video was directed more toward automotive type alternators attached to an inboard engine. The alternator on most outboards is not going to overheat in the same way. As you indicated, they don't really have enough spare capacity to generate enough heat to be a problem. 10A @ 14.5V is only 145W. That's not going to generate a lot of heat.

14.5V is perfect for your battery. That is the top-end of what your alternator is designed to produce so you may see that drop off a bit as the engine ages.

I also used to have my house bank connected directly to the engine when I was using a (very heavy) lead acid house bank. Most of the time it worked flawlessly but as the batteries got older on occasion I would draw the bank down too much overnight and have issues getting the engine started the next day. My current design prevents the problem with the addition of an acceptable (to me) increase in complexity. Like you, I also saved a lot of weight. I'm at least 200 pounds lighter and have almost twice as much usable capacity in my house bank. Definitely a win:win!

"Keep It Simple" was high on my priority list in my last design but this time I added "don't push it to the limit" and "add redundancy" (two items missing in my last design) .

My daughter once explained to me that, "It's not an adventure until somebody bleeds". As I'm getting older I find I have less interest in an "adventure" (I'll leave that to her and her brothers). That's part of why I let the alternator charge the lead acid and the lithium charger charge the lithium. I figure that if everything is being asked to do what it was designed to do it is less likely to break and make me have an "adventure".

[OverEasy]

Hi Be Free!

Did our daughters go to the same school?

My daughter once explained to me that, "It's not an adventure until somebody bleeds". As I'm getting older I find I have less interest in an "adventure" (I'll leave that to her and her brothers). That's part of why I let the alternator charge the lead acid and the lithium charger charge the lithium. I figure that if everything is being asked to do what it was designed to do it is less likely to break and make me have an "adventure".

I’m of an age and “school” where adventure is waking up in the morning and finding the coffee can empty or the creamer ran out…

Best Regards
Over Easy

[Be Free]

Hi Be Free!

Did our daughters go to the same school?

My daughter once explained to me that, "It's not an adventure until somebody bleeds". As I'm getting older I find I have less interest in an "adventure" (I'll leave that to her and her brothers). That's part of why I let the alternator charge the lead acid and the lithium charger charge the lithium. I figure that if everything is being asked to do what it was designed to do it is less likely to break and make me have an "adventure".

I’m of an age and “school” where adventure is waking up in the morning and finding the coffee can empty or the creamer ran out…

Best Regards
Over Easy

I'm pretty sure I would have noticed her. All of our kids were home schooled.