Battery survey

We asked a group of voyagers about their vessel’s batteries and their future battery plans

What type of battery setup might make sense for your voyaging needs? We reached out to a selection of active liveaboard voyagers to get a sense of what they are using to power their vessels. Here are their answers to our survey questions.

Ocelot from mast

Jon and Sue Hacking’s cat Ocelot has a complement of solar panels for battery charging.

Jon and Sue Hacking
Jon Hacking has lived aboard the Wauquiez Kronos 45 catamaran Ocelot with his wife and fellow voyager Sue since 2001. Their travels took them through the eastern and southern Caribbean, through Panama, across the Pacific, through Southeast Asia, and across the North Indian Ocean to South Africa in 2007. In 2009, they sailed back across the Indian and have been rattling around Southeast Asia ever since. They document their travels on their website (not a blog) at, and their information for other cruisers is at

Ocean Navigator: What type of batteries do you have installed on your boat (i.e., lead-acid flooded cell, gel cell, AGM, or Li-ion or other)?

Jon Hacking: We started with gels but have now moved to lithium iron phosphate (LiFePO4). When we bought Ocelot in 2001, she had gel cell batteries but they were shot. So, we paid $500 for 660Ah (three 8D batteries) of “factory‑second” gels. Apparently, they’d been on the factory floor too long to sell as new. These lasted well for us, but we replaced them seven years later in South Africa, having to pay $3,000 for 660Ah of top quality Sonnenschein gels.

In theory, these Sonnenschein gels should have lasted 2,500 cycles, almost seven years, if cycled down to 50 percent. We only ever cycled them down about 20 percent (130Ah) and usually much less than that (typically 80Ah/night, mostly from our fridge/freezer), so they should have lasted even longer. When they were eight years old in 2016, however, while motoring across the South China Sea from Singapore to Borneo, the engine started showing low oil pressure. I switched over to the port engine, but the alternator on that engine only had a “dumb” regulator. I’d set the voltage to 13.8v, and that had always been fine, but the regulator didn’t have a temperature sensor. There were 8 amps going into the batteries, but I assumed that number would go down and all would be fine.

Wrong! 8 amps at 12v is 100W, which made the batteries slightly warmer, which caused them to accept more current, which made them warmer, which caused them to accept even more current, etc. It’s called “thermal runaway” and is not talked about much, but it’s one reason why all lead‑acid batteries should have temperature sensors connected to their charging circuits. When I checked an hour later, I had 45A going into our already full batteries, and they were too hot to hold my hand against. In one hour of overcharging, we’d ruined 660Ah of expensive gel batteries, and they only had about 240Ah of capacity left. Lesson learned: Always use a temperature sensor when charging lead‑acid batteries.

Balance batteries

The Hackings use balancing units on each battery.

While researching what to replace my cooked gels with (from the back of nowhere in Indonesia), I came across some Chinese LiFePO4 batteries that we could get delivered to us. We’d been looking at LiFePO4 for a while, but still considered them “bleeding‑edge” and not yet suitable for a cruising boat, but some of the specs were compelling. Discharging lead‑acid batteries below 50 percent will start doing permanent damage to them, so our previous 660Ah gels really only had 330Ah of usable capacity. LiFePO4 batteries can be discharged down to 10 percent without ill effects, so we’d only need a much smaller bank. So, they’re smaller, lighter, and they claimed 5,000 cycles, or over 13 years lifetime. So, in 2017, we bought 300Ah (270Ah usable capacity) of LiFePO4 batteries manufactured by the Chinese company Hi-Power, which now appears defunct.

ON: How satisfied are you with your battery setup?

JH: Not very, but some of that is my own fault. Initially, we loved our LiFePO4s! They were considerably smaller and much lighter than our gels. They charged up really quickly, and the voltage hardly dropped at all as they discharged. Amazingly flat charge/discharge curves, and they sucked up as much current as we could throw at them. Our Blue Sky Energy SB50 Maximum Power Point Tracking (MPPT) solar controller was flexible enough that I could reset the charge‑ and float‑points, so that was easy. I’d recently installed new (and very smart) external alternator regulators. They were both fully programmable and had a LiFePO4 setting. Perhaps more important, they connected to our amp‑hour shunt to sense the current going into the battery, so they knew exactly when the batteries were full and when it was time to switch down to Float. We never plug into shore power, so I didn’t worry about our ancient Heart 1500W inverter/charger. I checked each cell’s voltage periodically. They were always within 0.01v of each other, so eventually I stopped checking.

Western hermit anchorage

Ocelot spends plenty of time in the tropics where solar charging is plentiful.

Our new LiFePO4 batteries came with an expensive Batrium Battery Management System (BMS) that never worked well and eventually corroded into oblivion. Our battery compartment is under the helm and therefore protected —  although certainly exposed to salt air — and the BMS board wasn’t sealed to protect it. My research at the time showed that the LiFePO4s would last longer if only charged to 13.9v. This is true to a point, but LiFePO4 cells were (and are) still new enough that it’s very hard to make them absolutely identical, especially in internal resistance. Since the cells aren’t exactly the same, they don’t accept the same amount of charge, nor do they discharge at the same rate, so the voltage across each cell tends to drift a bit. Therefore, LiFePO4 cells need to be balanced periodically, and this has to happen at higher voltages, typically 14.2 to 14.4v. Since our cells never got to those elevated voltages, the BMS never triggered a balance cycle, and after two and a half years of excellent performance, one cell drifted low — while we had friends on board in a storm. Of course. This eventually triggered an alarm, but not before some possibly permanent damage was done. The Australian dealer that we bought the LiFePO4s from said that we only needed to rebalance the cells.

Eventually, we received and installed some active balance modules from Electric Car Parts Company. I programmed our MPPTs to bring the batteries up to 14.0v for a couple of hours each day to let the balance modules do their thing. After a week, I’d crank the voltage up by 0.1v and let them sit there for a week or so. I eventually got them up to 14.4v (3.6v/cell), which is the maximum recommended charging voltage for these LiFePO4 batteries. As I write this, we’re still using these cells, but I haven’t done a complete discharge test, so I don’t know how much real capacity they have left. My gut tells me not to trust them too far.

ON: What is your usual recharging routine?

JH: In short, we use solar. When we bought Ocelot in 2001, we immediately installed 4x120W = 480W of Kyocera panels above the davits and installed a Blue Sky Energy SB50 MPPT controller to ride herd on them, wiring them in two parallel strings of two panels, as we have very little shading. This minimized wiring losses. But the panels started failing, and in 2008 they were replaced under warranty. Kyocera apparently had some bad panels come out in 2001. We were very impressed with their service. They even picked up the air‑freight to Malaysia!

A few years ago, we added some flexible panels, but they never worked very well. In late 2019, we threw out all of our solar panels and bought new 72‑cell panels, 3 x 400W = 1,200W total, from Powitt Solar. We were a bit leery of buying Chinese panels, but they carry a 12‑year materials and workmanship guarantee, a 30‑year performance guarantee, and at only 50¢/W for top quality monocrystalline panels, they were quite a bargain!

At present, each panel feeds its own MPPT controller. They were just what was available locally in the Philippines, so we’ll probably replace them when we can. Our current charging profile, which is still being evaluated, is to have the MPPTs charge the battery to 13.9v every day, but to also do an “equalize” charge to 14.4v for an hour or so every week to let the balance modules balance the cells. I prefer to have all of my chargers actually measure the current into the battery and to only switch to Float when the current into the battery gets down to 1 percent of the amp‑hour capacity of the battery. Only our ancient SB50 does that. Still, the battery is usually fully charged by 11 a.m., the solar panels having replaced the 80Ah we typically use overnight.

Ocelot is a catamaran with two engines, each with an extra alternator, so we have four alternators. Each is connected to a “Very Smart Regulator” (VSR, the predecessor to the WakeSpeed WS‑500) to protect our batteries, but we rarely need to run an engine just to charge the batteries. We never plug into a dock, or we’d have to charge them for our excess electricity!

ON: What are your future battery plans?

JH: Good question. We’re still thinking about this. We’ll soon replace our balance modules with a proper BMS. It also does active balancing, but only at much less current than the dedicated modules. We’re trying to get new LiFePO4 batteries from RJ in China, as they have a good reputation, but the pandemic is interfering with the shipping to us in the Philippines. We want to go with at least 400Ah, but the prices are coming down to less than $3/Ah delivered, so we’re considering some interesting possibilities. If we go to, say, 1,000Ah and add another couple of 400W solar panels above the bimini to bring our capacity up to 2KW, we could convert to an all‑electric galley, add an electric dive‑compressor, or even run a small air conditioner just off the solar system. Hmmm…


Dream Time

The Hockley’s Cabo Rico 38 Dream Time has solar, wind and towed water generators.

Neville and Catherine Hockley
Neville and Catherine Hockley set sail from New York in 2007 on Dream Time, their 1981 Cabo Rico, and in 13 years have sailed 48,000 nautical miles. They are near the end of their world voyage and are currently refitting their boat in Florida while COVID-19 restricts movement. They plan to close the loop and sail back to New York next year. To learn more about their voyage and cruising gear, visit their website at:

Ocean Navigator: What type of batteries do you have installed on your boat?

Neville and Catherine Hockley: Dream Time has two 12-volt 235-amp hour Exide Gel house batteries and a single 12-volt Optima AGM Redtop starter battery.

ON: How satisfied are you with your battery setup? How well does it work for you?

N&CH: We’re extremely happy with our power arrangement. Our batteries have performed remarkably well during 13 years of world voyaging. The vast majority of our time has been unplugged and far from the dock, either passagemaking or at anchor, so we rely on them heavily. Thankfully we’ve never had an issue, and our house batteries are 11 years old and still going strong.

 ON: What is your usual recharging routine?

N&CH: We’ve found a balance on Dream Time between amp consumption and renewable energy. When we’re anchored in normal tropical conditions, we rarely need to run our generator; we have two 85-watt solar panels — tiny by today’s standards, but they fit neatly above our bimini (we don’t want Dream Time looking like an overloaded pack mule). We also have a D400 wind generator — an impressive upgrade from our old Ampair wind turbine — and have recently added a rebuilt Aquair tow generator to our charging inventory.

Dream Time Batteries

Dream Time has two 235-amp hour gel cell batteries.

On a sunny tropical day at anchor, we can expect 10 to 12 amps from our solar panels and another 10 to 15 amps from our D400 if the trades are sporty. That’s more than enough to keep our boat charged, run our 12-volt watermaker every two to three days and the inverter a few hours each night. When we’re sailing (averaging around 6 knots SOG), in addition to our solar and wind turbine, our towed generator provides another 5 amps. This doesn’t sound like much, but we crossed the Atlantic this year from the Mediterranean, down the West Coast of Africa and over to the Caribbean — 4,000 nautical miles while operating our autopilot RAM, Chartplotter, sailing instruments, fridge/freezer compressor, lights, VHF, AIS, and mobile devices. Not once did we have to run our engine or generator for power or propulsion! We left a totally green wake.

Our house batteries have lasted so long — our previous gels also lasted 10 years — because they rarely fall below 60 amps. Nowadays, Dream Time is powered almost entirely by the sun, the wind and the sea.

ON: What are your future battery plans? 

N&CH: As our house batteries are more than a decade old, they don’t owe us anything. We’ve had great success with gels, so when the lights begin to dim, we’ll get a fresh set.


McCampbell Soggy Paws

The McCampbells’ voyaging boat, Soggy Paws, is a St. Francis 44 Mark II cat.

Dave and Sherry McCampbell
After a career as a U.S. Naval officer, Dave, along with Sherry, an industrial engineer and computer programmer, left Florida in May of 2007 and headed west across the Pacific via the Panama Canal. They spent seven years getting across in their 1980 CSY 44 monohull. By 2015, they were ready for a newer, faster, more comfortable boat, so switched to a 2004 St Francis 44 MK II catamaran. They have spent the past six years exploring much of eastern SE Asia, making a number of significant modifications to their new cruising home. During that time, they have been as far north as Luzon in the Philippines, east to Palau, south to the Solomons and west to Singapore. Once the pandemic is over, they plan to head further west to the Mediterranean.

Ocean Navigator: What type of batteries do you have installed on your boat? (i.e., lead-acid flooded cell, gel cell, AGM, or Li-ion or other)?

Dave & Sherry McCampbell: We are currently using Sonnenschein 6-volt Solarbloc Gel SB-6 200-amp hour batteries. These are premium gel batteries. They were purchased new in 2007, and so are now more than 13 years old. They still have plenty of capacity and rest at 12.9v while we are full-time cruising. Based on their current performance, we think they still have several more years of use available. Our previous batteries were well cared for, high end, Rolls Battery L-16 flooded lead-acid. They lasted nearly a decade. Our earlier Trojan 6v golf cart batteries typically lasted three to five years and Trojan L-16s five to seven years, even with good care and solar charging in the tropics. 


ON: How satisfied are you with your battery setup?

D&SM: We are very well satisfied! Although the gels are a bit more expensive than flooded lead-acid, we believe not having to keep up with watering and equalizing and the significant added cycle life is worth the added price. They require no maintenance other than being kept in a cool, dry location — not the engine room — and use of a temperature-compensated, three-stage charging source with acceptance set at no more than 14.1 volts. Their cycle life is extraordinary.


Mccampbell new lithium iron phosphate batteries

Dave McCampbell tests new lithium iron phosphate batteries purchased to replace Soggy Paws’ current gel cells.

ON: What is your usual recharging routine?

D&SM: We are mainly using 800 watts of monocrystalline solar panels and a 60-amp Morningstar TS-60 MPPT controller while cruising full time in the tropics. Since we are on a catamaran and the panels are mounted horizontally well aft, there is only minimal occasional mast shading. Our daily energy usage is approximately 150-amp hours, with half that overnight, so we are normally done with the acceptance charge by mid-day, leaving the rest of the day to float to full charge. We rarely use our backup charging sources, which include two small, externally-regulated alternators and a Sterling 60-amp shore charger. We have switches in the alternator field wires so we can keep them off and turn them on only if needed. And we have yet to use the shore charger since purchase four years ago. Even sitting at the dock, we don’t plug shore power into the charger, as the solar handles our normal loads.


ON: What are your future battery plans?

D&SM: We are amazed at the gel batteries we inherited with our catamaran five years ago. Here in the Philippines, they are actually harder to get and more expensive than the quality lithium we just received directly from China. Because we know our gels won’t last forever, and we plan to continue further west from our current location in the Philippines, we have decided to purchase new batteries now while it is convenient. After considerable study and lengthy discussion with other cruisers who have upgraded to lithium iron phosphate (LiFePO4) cell batteries, we have decided to do likewise. However, installing a quality, reliable lithium system involves considerable study, charging system modifications and additional maintenance equipment purchase. But ordering them directly from the manufacturer in nearby China now saves us a considerable amount of money. There are many advantages for full-time cruisers with modern lithium batteries, but they are not for everyone. Others in the U.S. might do better with gels. It sure would be simpler!


Alchemy underway

Dick and Ginger Stevenson’s Valiant 42, Alchemy, underway.

Dick and Ginger Stevenson
Dick Stevenson retired with his wife, Ginger, in 2002 and sold their house and cars to move aboard their cutter, Alchemy, a Valiant 42. They already had 25 years of cruising the Northeastern U.S. (Bermuda to Maine) with their three children, and since 2002 have wandered the Northwest Caribbean, Bahamas and parts of the eastern Caribbean. Then there were five years in the Mediterranean and six years in Northern Europe which led to a return to North America via the Viking Route: Scotland to the Faroe Islands, Iceland, Greenland, and into Newfoundland, Canada.

Ocean Navigator: What type of batteries do you have installed on your boat? (i.e., lead-acid flooded cell, gel cell, AGM, or Li-ion or other)?

Dick Stevenson: I have used gel cell batteries for more than two decades now. I buy the best I can find (Sonnenshein in Europe and East Penn in the U.S.). They last six to eight seasons (full-time live-aboard or, over the last few years, six months on, six off — seems not to matter).

ON: How satisfied are you with your battery setup?

Gel cell house bank

Alchemy‘s gel cell house bank.

DS: Quite satisfied. I have been tempted by AGMs off and on since sailing back in North America, but AGM’s need for a regular full charge (very hard to accomplish at anchor), as well as their somewhat greater sensitivity to the charging algorithm, and the benefit of equalizing (Lifeline product) has put me off. AGMs also seem less forgiving of mistakes/abuse. I have stayed with gels for those reasons, and the fact that my gels have suffered occasional terrible abuse — ­­boat watch person in the Shetland Islands got confused and the batteries were down to 10+v all winter. Although hurt, the gels bounced back enough to be usable for another season and a half until I got somewhere where I could get new batteries at all, and at a reasonable price where I didn’t have to ship them in.

ON: What is your usual recharging routine?

DS: At anchor: charge when ~50 percent depleted and bring to ~80 to 85 percent with a 12v DC diesel generator.

ON: What are your future battery plans?

DS: Probably buy a new set of gels in the next year or so as mine are now in their sixth season. AGMs are still a possibility.


Sargo, at anchor

The Lees’ Garcia Passoa 46, Sargo, at anchor.

Bjorn and Jayme Lee
Bjorn and Jayme Lee bought Sargo, their Garcia Passoa 46 (2005 build) in the spring of 2018. They sailed Maine for the summer, then did an extensive winter refit themselves. This included replacing all core battery cables, bus bars and the 120V AC system. They replaced the previous 450Ah battery bank with the Firefly batteries. They also added solar, MPPTs, isolation transformer, MultiPlus charger, Venus control, BMV monitor, watermaker and generator. Their system was designed around the power need of the watermaker and how to charge the Fireflies. They cruised Maine during the summer of 2019 then worked south to the USVI before getting stuck with COVID travel restrictions. They decided to sail back to Maine for the summer of 2020. 

Ocean Navigator: What type of batteries do you have installed on your boat? (i.e., lead-acid flooded cell, gel cell, AGM, or Li-ion or other)?

Bjorn Lee: We have 900 amp hours of Firefly Carbon-Foam AGM batteries. Bank is six 4V L15 batteries wired in series to create two 12V that are then in parallel for the 900Ah capacity.

ON: How satisfied are you with your battery setup?

BL: Very satisfied. Ample power and depth for our needs, even when sailing offshore. Can charge and discharge quickly, and with the carbon foams, partial state of charge is not concerning. 

ON: What is your usual recharging routine?

Sargo Battery Bank

Sargo’s 900 am hours of carbon-foam AGM batteries.

BL: Most of our charging is via solar. 660W of solar (two 330W Panasonic panels) with separate (2) Victron 100-30 MPPTs into a Victron MultiPlus 3k Inverter Charger with Venus GX control and BMV 712 monitor. This takes care of 90 percent of our charging needs while cruising Maine and the Caribbean in the summer. We did need to augment some generator charging in December/January in the Bahamas due to the shortness of the days. 

We augment solar with a Honda 2200 generator run on deck through a Victron Isolation Transformer into the Multi. We use this when making water as our Cruise RO Seamaker 30 120V watermaker pulls 900W, which would drain the batteries quickly. The generator allows us to meet the 900W watermaker load and put up to 800W into charging the batteries if needed. A few times we have used the generator alone for charging, able to put 120 amps in for bulk charging. 

We really don’t use our engine for charging. We have a dedicated 115V alternator with a Balmar MC-614 charge controller for the house bank, which is small for our charging needs. It will obviously charge when we motor, but this is not something we depend on. 

ON: What are your future battery plans? 

BL: To use the current setup as long as possible. Install was spring of 2019 for the above.

Categories: Marine Technology, Offshore Sailing