Lithium batteries for J/109 class
Posted: Tue Nov 09, 2021 9:40 pm
Hi. I am Dan Corcoran, a fellow J/109 owner, and a part-time marine electronics writer for practical sailor magazine. In addition, I own a software startup, focused on helping hospitals achieve the highest level of safety and quality (www.SafeQual.net).
Shortly after the J/109 Class Annual meeting the Class Measurer, Bengt Johansson, contacted me to discuss the most recent developments of lithium-ion battery technology, asking if this technology is suitable and ready for future use in the J/109.
He suggested I post a summary of what we are watching for, and the effort to develop new class rules for Lithium. I hear that such a new rule would be no sooner than 11 ½ months from now (e.g. Annual October 2022 meeting).
Are you excited about using lithium for weight savings? Don’t be! If you are thinking of replacing your lead-acid batteries with lithium only to save weight, don’t rejoice just yet. Our 2002 designed boats are not great candidates for these batteries if you are already configured at the class minimum of 150Ahr. With just 150Ahr, the weight savings when safely replacing lead acid with lithium could be negligible.
Instead, you can gain a lot more capacity for the same weight, useful for running your engine less frequently like in a distance race, but I am not writing here to promote this technology, rather share safety issues that concern me if shortcuts are taken in the conversion process.
I recently answered the question, “if lithium batteries are ⅓ the weight of lead-acid, how can you say no weight savings on a J/109.”. Can't we save 50 lbs?
This is the short version of the answer ...
Our boats are not designed for these batteries, neither I suspect are the latest J-boats. If they were so designed, they would have separate 12-volt charging vs. load buses (for safety reasons). Not only don’t our boats do this, but they also share the same red battery cable for (i) starting the boat, (ii) charging the batteries from the alternator, and (iii) providing a battery voltage sense lead to our Balmar regulators, a clear wiring shortcut. (Hint: Fix (iii) with a dedicated 10 gauge wire, and your batteries will charge from the engine faster)
Retrofitting our boats for lithium involves many wiring changes and the incorporation of circuitry to protect the batteries, alternators, and other electronics.
“Drop-In” lithium batteries are advertised as eliminating the need for extensive retrofits, enabling the owner to directly swap out lead-acid batteries one for one. I strongly don't recommend this.
To accomplish this feat the safety mechanisms that would be part of a standard Lithium retrofit, such as battery monitoring, high interrupt capacity fuses, and remote-controlled battery disconnects, are built into the batteries themselves so that the red and black cables to your lead-acid batteries simply connect instead to the drop-in lithium battery.
Lithium batteries don't like many things. They don't like to be discharged fully, they like even less to be charged when they are already very low, they don't like to be charged when they are cold, etc. Like sealed lead-acid batteries, they don't like to be overcharged or short-circuited either. Internal lithium battery monitors also don't like electrical storms that produce EMP pulses, something that lead-acid batteries tolerate very well.
The safety mechanisms in the battery will disconnect the internal lithium batteries from your electrical system if they sense any of the conditions that could cause damage to the batteries. And that’s the rub. That disconnection at best will leave you or your delivery crew without house power until a reset button is pressed. If the reset does not work you have only a starter battery that has silently deteriorated if your charging system isn't wired for two chemistries. If your engine was running at the time of disconnect, your boat's electronics and alternator can be destroyed as the power from your alternator, having nowhere to go, turns into a high voltage spike. In addition to the familiar alternator diode frying issue that happens if someone operates the battery switch while the alternator is running, boat system electronics are fried as well. Then your starter battery is useless, having nothing to power. No ship VHF, nav lights, smartphone chargers, etc. All gone.
At least we have sails. I can't imagine what a clueless powerboater would do. Hopefully, they at least have a towboat contact so it doesn’t become a salvage dispute when they fire off their flares.
In addition to the key challenge of drop-in batteries suddenly disconnecting power to protect the batteries, they are also less idiot-proof, placing demands on you and your crew to know more about your electrical system. For example, assuming the disconnect happened while the engine is off, does the delivery crew know this is the scenario to select the "both" position on the battery switch, the position you possibly labeled "NO".
The opposite of idiot-proof, this is complicated stuff. For example, if you have a lead-acid battery and a lithium battery on your boat, you have to modify your charging to treat each battery differently and be careful not to use the BOTH setting on your battery switch. Using BOTH with the alternator running will silently cook and reduce the capacity of your starting battery, using your stock J/109 shore charger will damage one battery or the other.
Even with TPPL batteries, there are ways to wire your starter battery where the battery is drained by about 1+ Ahr every hour, while the engine is charging your house battery. After 18-hours of motoring, your starter battery may not be able to start your engine next time you need it.
The solution to these challenges lies in a mixture of having two drop-in lithium batteries, instead of one, some additional wiring and protection devices in case both lithiums fail at the same time, protecting your starter battery from mixed chemistries with a smart lead-acid trickle charger, having chosen lithium batteries with remote control panels, and supplemental alarming so you know if a lithium battery has disconnected, leaving you with just one.
Some wiring scenarios will require your lithium battery has 3 connections, a ground, +12v load, and +12v charging. Many lithium batteries come with only two.
Once done safely the weight savings compared to 105 Ahr house and 50 Ahr starter battery may be none, but you will have weight savings if today you race with 2 or 3 105 Ahr batteries. If done right, you could have more idiot-proofing then a stock J/109 electrical system, and a whole lot more usable battery capacity than 2x 105 Ahr, for activities like distance racing and cruising.
Until that day where we have class rules in support of lithium batteries, try to hold back your enthusiasm and avoid drop-in lithium. They are not class legal, not safe enough for you and your crew, and they place the alternator and electrical systems of your boat at risk of destruction.
The batteries may also not be compatible with our future class rules and may not be ABYC marine standards-compliant, an issue if you sell your boat.
It is my intent to design an upgrade to my boat, probably before I help the effort for the new class rule. When I do so, I will be sure to write again and share how to do it safely either to the class or in Practical Sailor magazine. Until then check out the latest December 2021 issue where I write about the Furuno SX200 compass.
Sail Safe, and if you are in the healthcare or investment industry, ask me about my startup SafeQual. I can be reached through Gmail at 516captain.
Dan
J/109 Class | Owner #332 Strider
practical sailor magazine | marine electronics contributor
Shortly after the J/109 Class Annual meeting the Class Measurer, Bengt Johansson, contacted me to discuss the most recent developments of lithium-ion battery technology, asking if this technology is suitable and ready for future use in the J/109.
He suggested I post a summary of what we are watching for, and the effort to develop new class rules for Lithium. I hear that such a new rule would be no sooner than 11 ½ months from now (e.g. Annual October 2022 meeting).
Are you excited about using lithium for weight savings? Don’t be! If you are thinking of replacing your lead-acid batteries with lithium only to save weight, don’t rejoice just yet. Our 2002 designed boats are not great candidates for these batteries if you are already configured at the class minimum of 150Ahr. With just 150Ahr, the weight savings when safely replacing lead acid with lithium could be negligible.
Instead, you can gain a lot more capacity for the same weight, useful for running your engine less frequently like in a distance race, but I am not writing here to promote this technology, rather share safety issues that concern me if shortcuts are taken in the conversion process.
I recently answered the question, “if lithium batteries are ⅓ the weight of lead-acid, how can you say no weight savings on a J/109.”. Can't we save 50 lbs?
This is the short version of the answer ...
Our boats are not designed for these batteries, neither I suspect are the latest J-boats. If they were so designed, they would have separate 12-volt charging vs. load buses (for safety reasons). Not only don’t our boats do this, but they also share the same red battery cable for (i) starting the boat, (ii) charging the batteries from the alternator, and (iii) providing a battery voltage sense lead to our Balmar regulators, a clear wiring shortcut. (Hint: Fix (iii) with a dedicated 10 gauge wire, and your batteries will charge from the engine faster)
Retrofitting our boats for lithium involves many wiring changes and the incorporation of circuitry to protect the batteries, alternators, and other electronics.
“Drop-In” lithium batteries are advertised as eliminating the need for extensive retrofits, enabling the owner to directly swap out lead-acid batteries one for one. I strongly don't recommend this.
To accomplish this feat the safety mechanisms that would be part of a standard Lithium retrofit, such as battery monitoring, high interrupt capacity fuses, and remote-controlled battery disconnects, are built into the batteries themselves so that the red and black cables to your lead-acid batteries simply connect instead to the drop-in lithium battery.
Lithium batteries don't like many things. They don't like to be discharged fully, they like even less to be charged when they are already very low, they don't like to be charged when they are cold, etc. Like sealed lead-acid batteries, they don't like to be overcharged or short-circuited either. Internal lithium battery monitors also don't like electrical storms that produce EMP pulses, something that lead-acid batteries tolerate very well.
The safety mechanisms in the battery will disconnect the internal lithium batteries from your electrical system if they sense any of the conditions that could cause damage to the batteries. And that’s the rub. That disconnection at best will leave you or your delivery crew without house power until a reset button is pressed. If the reset does not work you have only a starter battery that has silently deteriorated if your charging system isn't wired for two chemistries. If your engine was running at the time of disconnect, your boat's electronics and alternator can be destroyed as the power from your alternator, having nowhere to go, turns into a high voltage spike. In addition to the familiar alternator diode frying issue that happens if someone operates the battery switch while the alternator is running, boat system electronics are fried as well. Then your starter battery is useless, having nothing to power. No ship VHF, nav lights, smartphone chargers, etc. All gone.
At least we have sails. I can't imagine what a clueless powerboater would do. Hopefully, they at least have a towboat contact so it doesn’t become a salvage dispute when they fire off their flares.
In addition to the key challenge of drop-in batteries suddenly disconnecting power to protect the batteries, they are also less idiot-proof, placing demands on you and your crew to know more about your electrical system. For example, assuming the disconnect happened while the engine is off, does the delivery crew know this is the scenario to select the "both" position on the battery switch, the position you possibly labeled "NO".
The opposite of idiot-proof, this is complicated stuff. For example, if you have a lead-acid battery and a lithium battery on your boat, you have to modify your charging to treat each battery differently and be careful not to use the BOTH setting on your battery switch. Using BOTH with the alternator running will silently cook and reduce the capacity of your starting battery, using your stock J/109 shore charger will damage one battery or the other.
Even with TPPL batteries, there are ways to wire your starter battery where the battery is drained by about 1+ Ahr every hour, while the engine is charging your house battery. After 18-hours of motoring, your starter battery may not be able to start your engine next time you need it.
The solution to these challenges lies in a mixture of having two drop-in lithium batteries, instead of one, some additional wiring and protection devices in case both lithiums fail at the same time, protecting your starter battery from mixed chemistries with a smart lead-acid trickle charger, having chosen lithium batteries with remote control panels, and supplemental alarming so you know if a lithium battery has disconnected, leaving you with just one.
Some wiring scenarios will require your lithium battery has 3 connections, a ground, +12v load, and +12v charging. Many lithium batteries come with only two.
Once done safely the weight savings compared to 105 Ahr house and 50 Ahr starter battery may be none, but you will have weight savings if today you race with 2 or 3 105 Ahr batteries. If done right, you could have more idiot-proofing then a stock J/109 electrical system, and a whole lot more usable battery capacity than 2x 105 Ahr, for activities like distance racing and cruising.
Until that day where we have class rules in support of lithium batteries, try to hold back your enthusiasm and avoid drop-in lithium. They are not class legal, not safe enough for you and your crew, and they place the alternator and electrical systems of your boat at risk of destruction.
The batteries may also not be compatible with our future class rules and may not be ABYC marine standards-compliant, an issue if you sell your boat.
It is my intent to design an upgrade to my boat, probably before I help the effort for the new class rule. When I do so, I will be sure to write again and share how to do it safely either to the class or in Practical Sailor magazine. Until then check out the latest December 2021 issue where I write about the Furuno SX200 compass.
Sail Safe, and if you are in the healthcare or investment industry, ask me about my startup SafeQual. I can be reached through Gmail at 516captain.
Dan
J/109 Class | Owner #332 Strider
practical sailor magazine | marine electronics contributor
