The Canal du Rhône au Rhin: The Return to Montreux-Château and on to Besançon, a New Battery Challenge Emerges

Wanderlust leaving Mulhouse: I can still feel the heat.

On Wanderlust’s return journey from Rhine terminus of the Canal du Rhône au Rhin was quite different than the outbound cruise. The weather and river had changed. Gone were the cool rainy days and clear fresh flowing water of spring. In the height of summer the days were baking hot. The now murky languid water reluctantly flowed. In recent years France has suffered a batch of hot dry summers, perhaps a sign of things to come. It’s a future reality that could create difficulties for waterway transport.

For our cruising itinerary the biggest issue was indeed the lack of rain. The reservoirs supplying the canals were low; a reality that negatively impacted our cruising plans for the season. The drought did ultimately cut short our season, a particular disappointment after having lost the prior season for repair work.

The hottest of the days often have little breeze.

The heat had other consequences. Boats, though they sit on water, are modestly insulated at best. When it is hot outside it is hot inside. In the past we’ve seen temps inside Wanderlust approaching 100°F, a serious sweat fest. Fortunately during the 2018 repair extravaganza we upgraded our air conditioning with a portable unit. It was a great relief in the heat, even if it does require us to run the main engine, the generator, or be hooked up to a decent shore power feed. So unlike many other suffering boaters we passed we were very fortunate in that respect.

The heat plays havoc on the equipment too, a particular issue for equipment in Wanderlust’s engine compartment. On hot days, after the engine has been running for hours, it is not uncommon to see temperatures in the confined space near 150°F.

As we departed Mulhouse a little after noon at the end of June northeastern France was in the midst of a serious heat wave. Ideally we would have delayed our departure and waited out the heat. But how long would that take? It had been hot for the prior week.

It was a two fan day.

With the baking heat we opened up the wheelhouse as much as possible. We moved our two fans to the wheelhouse table and directed their flow at the wheel. Keeping the hot air moving was the best we could do. Outside in the 97 °F heat the decks radiated the sun’s heat. It was tolerable for only short stints. There was no lingering up top to enjoy the countryside after working the ropes in a lock. This day our dog Gigi, whose preferred station was at the bow on lookout for herons, wisely preferred cooler covered areas.

As we did on the way to Mulhouse, Wanderlust stopped again in Heidwiller. With no shore power we committed to running the air conditioning off the generator well into the night to stay cool. The heavy rains from our earlier stay in Heidwiller would have been very welcome now.

The next day the intense heat faded slightly with the high temperature merely reaching the low nineties. With an earlier start Wanderlust continued on to the port in Dannemarie, repeating the steps she made on the way out. In Dannemarie there was shore power for the air conditioning, eliminating the need for the generator.

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Gigi loved to bark at the herons, which would always fly off.

Earlier in the season rain and high water defined out cruising plans. Now it was the heat and declining water levels. As we continued along our starting time became progressively earlier as we attempted to miss the blast furnace heat of the afternoons as much as possible. It didn’t help much, as it never really cooled off that much at night. It got hot early and stayed hot late.

Departing the port in Dannemarie the next morning the temps were already in the high 70’s. It would be a cooler day, with the highs “only” reaching the high 80’s. It was still hot inside the boat without AC but it was a little more tolerable while cruising. Before the hottest part of the day, just after the lunch hour, Wanderlust pulled to the bank again in Montreux-Château and tied up for the night.

At end of cruising on hot days, we generally open up the engine compartment access as soon as we stop. The idea is that the engine draws in a considerable amount of outside air when it’s running, helping its compartment stay cooler. But when the engine is turned off there’s no air being drawn in and the engine just radiates its heat into the confined space. This heat bakes the equipment in the compartment, including the batteries. Putting the hatch up when we stop is intended to let some of this heat escape. I’m not sure it works. It seems marginally helpful at best. Nevertheless it was the best we could do.

San Francisco seems an appropriate neighbor for Wanderlust in Dannemarie.

Wanderlust in Montreux-Château: The service moorings on the opposite bank were occupied.

When Wanderlust arrived in Montreux-Château we stopped her engine and raised the hatch. Up from below came an unfortunately familiar smell, an odor somewhere between rotten eggs and melting crayons.

The last time we experienced this smell was three years prior in Ancy-le-Franc. In Ancy we nosed around the engine compartment after detecting the odor trying to find its source. We couldn’t identify where it was coming from and wrote it off as a quirk. At the time we were more focused and frustrated by the slick of diesel fuel that had appeared in the forward cabin bilge from a fuel tank leak that the owner of a workshop in Migennes had just pronounced a “weep”, suggesting it was something most would ignore. It was only the next morning when the engine failed to turn over that the source of the odor become clear: The starter batteries had failed. In the process of massively overheating and dying the batteries emitted the odor of hydrogen sulfide combined the smell of outgas released when the battery’s shell melted.

Had a starter battery just gone off again? It didn’t seem possible for one to go bad so soon. The engine starter battery had never gone flat before and there was never even a hint of hesitation when starting the engine. In fact the engine’s battery had hardly been used, having started the engine well less than 100 times. And when Wanderlust wasn’t cruising the starter battery was kept on a maintenance charger with a storage mode. Still, the familiar smell was troubling.

The generator battery at the left has liquid on this top but it is the bulging engine battery at the right that is the bigger problem.

I went below into the baking hot engine compartment and opened the battery box. It was obvious immediately that there was in fact a big problem with at least one of the batteries. One of the AGM batteries, the one used for the generator, had visible liquid on its top. Inside the confined box the only source of liquid was the batteries themselves. Though the generator battery looked to be in bad shape it turned out that it wasn’t the one with the biggest issue. The real problem was the engine starter battery to generator battery’s immediate right.

Looking closer revealed the main engine’s starter battery was in the midst of a nasty thermal runaway, a process where a battery rapidly exchanges its stored charge into heat in an uncontrolled fashion. The consequence was an extraordinarily hot battery at risk of starting a fire or exploding. There was nothing we could practically do to cool it; the battery stayed hot even when completely disconnected. On closer examination we could see the case of the engine starter battery was bulging and damaged, similar to what happened to the batteries in Ancy. Indeed this battery became so hot it caused significant visible heat damage to the outside of its generator starter battery neighbor held close together in the same battery box. It was clear now that the liquid on the top of the generator’s battery came from its neighbor in meltdown.

For the time being there was nothing to do but wait for the thermal runaway to end and the battery to cool. Chances seemed slim it would start the engine the next morning. But you never know.

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The following morning the keeper arrived to operate the day’s locks. I went to start the main engine, hoping for the best and expecting the worst. This time the expectations beat hope: The starter battery was indeed stone cold dead.

Unlike in 2016 in Ancy-le-Franc, we had a relatively straightforward way to get the engine started. In Wanderlust’s original configuration the starter batteries for both the generator and the engine were wired in parallel. This meant if one battery failed it would inevitably take down its wired partner. After Ancy I changed the set-up, splitting the function of the two batteries so that one battery started the engine and the other started the generator. And in theory to get Wanderlust going again all that would be needed was a quick swap of the leads so that the engine started from the generator’s battery.

Wanderlust’s new configuration of the batteries seemed like a good idea. But in practice it did not work out as expected. I hadn’t anticipated that the intense heat generated by one battery in thermal runaway could damage another independently wired battery installed with it in the same box. When the engine starter battery melted down it was basically like putting the generator battery in a hot oven. Did the high heat matter for a battery that was not being used? On visual inspection I could see that the generator battery suffered significant heat damage to its case. There was no way to tell what was going on inside.

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After telling the keeper that there would be a brief delay I went down below to swap the battery leads. Back in the wheelhouse there was a mental crossing of the fingers as the main engine ignition key was turned again. The engine fired up. But was there a hint of hesitation before the engine started or was I just imagining that? For the moment the question did not matter. We needed to get moving. Lifting the ropes we moved into the adjacent lock and were on our way for the day.

The engine ran continuously and the battery wasn’t tested the rest of the day as Wanderlust worked her way from Montreau to Montbéliard. We had planned to stay four nights in Montbéliard’s port as we arranged reservations for a tour of the Peugeot assembly line in nearby Sochaux. While in the commune’s port with a shore power feed Wanderlust’s remaining starter battery would be kept charged by its maintenance charger.

As time passed in Montbéliard my concern over the fidelity of our remaining starter battery increased. I experimented a bit with the battery, seeing its voltage drop at a rate that seemed a little too quick when it was pulled off the charger. Voltage always drops when the charging charger is removed. It can be a deceptive way to assess the condition of a battery. The bad sign wasn’t necessarily a bad sign. Nevertheless memories of being stranded in Ancy-le-France made getting replacement batteries as soon as possible a priority. Until we had replacement batteries I would only feel the comfortable if the remaining starter battery were on a charger overnight. In practice this meant it would be best to be on shore power as much as possible.

Wanderlust exits a lock.

The Do Littles really got around.

It doesn’t seem like a questionable starter battery should be a source of much angst. And in truth we had been conditioned by our lost week in Ancy-le-Franc. But the situation is not the same as it is with a car. If one wakes up in the morning and finds their starter battery has died it’s a relatively quick problem to solve: Get the jumper cables out, get a jumpstart, and then drive directly to a shop to get a replacement battery. On a boat on a canal in rural France, with the equivalent of a convenient service station can be several days cruising away, a dead battery can be a big challenge to deal with.

When we left Mulhouse we had contemplated a lazy paced trip back to the Saône. Now Wanderlust’s starter battery issue prompted a faster retreat. For the time being we would minimize staying in places where we would be off the shore power feed. If shore power weren’t an option we’d plan on running the generator more than normally would to keep the starter battery charged, something that worked out with our desire to run the air conditioner. Were we over reacting? The visually heat-damaged battery was still functional. It may be perfectly fine. Nevertheless it seemed advisable to be safe rather than risk being sorry.

Wanderlust moored in both l’Isle-sur-le-Doubs and Baume-les-Dames.  These were both one night stays despite power and water being available.

Wanderlust in Baume-les-Dames: A cold beer was conveniently located steps away.

The Doubs River sections are the real attraction of the waterway.

At this point in the season the region’s drought was becoming more severe. Fears of dwindling water supply for the regions canals were creeping in and pushed us forward. The rest of our season’s itinerary was at risk. It was a motivation to keep moving.

From Baume-les-Dames we retraced our route to the pontoon in Besançon. Besançon has an established port office. It seemed a good place for a battery delivery. After confirming that the capitaine de port could accept our package we placed an order online with the company that we used in Ancy-le-Franc. Delivery was promised in two days. It was France so we automatically added two more days. It didn’t seem a hardship for us to stay longer in Besançon.

Four days came and went and the batteries had not arrived. I contacted the battery company and was told that they had tried to deliver to the port office but the capitainerie was closed at the time. Somehow the opening times we had provided had been lost in translation between the battery store’s UK and France offices.

A few days later the delivery was attempted again. This time the delivery driver refused to drop off the batteries saying that the trees on the port office’s driveway prevented him from getting his truck in.   Odd, as this complaint wasn’t registered on the first attempt. Besides the trees along the straight 90-meter long gravel road to the capitainerie were not that low. It looked like an 18-wheeler could get in easily, not that a truck that large should be delivering two batteries.

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You can’t fight city hall, or French trucking companies, it seems. The trucking company now completely refused to deliver to the port office. We needed another delivery location.

After another round with the now very apologetic battery store we made arrangements to meet the delivery truck just off the road near the port. When the time came we made ourselves available and provided our cell number. But again the truck never showed. Eventually word trickled back from the battery store that the trucking company would not make a delivery to a road.

Time has taught us that with time we can eventually accomplish what we need to get done in France. It may not go smoothly and it may take a lot more time than it should, but when there’s a will there’s a way. This time we were beginning to doubt whether our belief was true.

The waterway gets fly fishing stream narrow at times.

Becky working the ropes:  The bandage is from a late night trip to a BMX course she attempted on her mountain bike for reasons I don’t fully understand….

Having finally reached a point where we were less fine being stuck in Besançon we developed a Plan C. Instead of trying to find a creative drop off place in battery the delivery-free zone of Besançon we would arrange instead with the battery store to deliver to H2O’s port office in Saint Jean de Losne. It wasn’t ideal for us, as it was out of our way and would take a few days of cruising to get to. But H2O’s port office in Saint Jean had received batteries for us earlier in the season. It seemed a sure bet.

All told Wanderlust spent 12 days in Besançon waiting for batteries. The extended stay did clarify one point: The lack of water was indeed going to soon shut down canals all around us. Our preseason cruising plans, which had us going north after we returned to the Saône, were toast. It would not be possible even if we tried to blast ahead as the canals would close by the time we got there. The timing had been close. We might have even made it if we hadn’t had the last round of battery issues. But now it was impossible.

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When we knew that Wanderlust would not be able to reach her planned winter mooring in Toul we quickly booked a spot in Auxonne. With cruising being disrupted it looked like boats finding moorings might quickly turn into a game of musical chairs. We were careful to not let Wanderlust be left without a mooring place.

Our 2019 season was a continuation of a trend. When Wanderlust was launched in 2013 we had grand cruising plans. Now it seems the plans were an aspirational goal: Not since 2014 had our desired route generated at the start of the season resembled the actual route. Our luck would not change anytime soon.


Battery follow-up:

Wanderlust had bad luck with batteries in 2019; losing both her bow thruster batteries at the beginning of the season are her engine starter on the return leg to Montreux-Château. Both battery failures were pre-ordained when Wanderlust was launched.

Wanderlust, and Gigi, back in Besançon.

At launch the thruster batteries were set up so that they would only charge when the main engine is running. It’s a configuration that creates several issues and tends to maintain the thruster batteries at a lower state of charge than is desirable. Adding a dedicated maintenance charger later for these batteries is complicated by a feedback charging loop that ends up with the thruster maintenance charger trying to charge the domestic battery bank with power drawn from the domestic batteries. But we needed to do something or else problems were inevitable whenever there was a long layover. Thus we did ultimately add a maintenance charger for the thruster batteries and are careful to make sure the charger is turned off prior to turning the main engine on.

The engine compartment high temperatures are a big issue for the starter and domestic batteries. On hot days the temps inside reach 65 to 70˚C. Such high temperatures are well outside of the operating window of many lead acid-based batteries. As we had painfully learned, such high heat can be fatal to batteries.

We did two things to address the heat issue. First we took the time to find batteries advertised as having higher heat tolerance and ended up with a pair of Odyssey PC2150 Extreme Series, advertised as having a working range up to 80˚C.

Wanderlust entertains the locals.

The starter batteries aren’t the only issue with such high temperatures in the engine compartment. Our expensive bank of 2V traction-style batteries used for domestic electricity off of shore power are also at risk, though their thermal mass kept their maximum temperatures in the 50’s. It’s hot high enough to reduce their life span of these batteries and to trigger the charger to shut off. With that it is not as high as internal temperatures experienced by Wanderlust’s starter batteries with their much smaller thermal mass. Also at risk from the heat are the domestic power electronics and many other parts of the boat’s systems that are held in the compartment. Such high heat in the engine compartment was a general problem that we needed to address.

At the end of the season careful examination revealed that the air inlets for the engine compartment were partially obstructed during the build. This meant that the air inlets were 10 to 20 percent deficient for the size of the engine. Since these vents are sized for running the engine at full throttle, something we rarely happens for extended times, we aren’t too concerned. It wasn’t clear that enlarging the air inlet vents alone would necessarily resolve the temperature issue. A bigger problem seemed to be relying only on the engine intake for air circulation.

Thus to address the cooling issue at the end of the 2019 season I decided to add a squirrel cage exhaust fan. This fan can be turned on and off with a switch at the dash. Along with the fan I also purchased a multi-channel remote thermometer. The senders for the thermometer were placed in various locations, including the engine compartment and the top of the starter batteries, to let us better monitor the situation. I’m hopeful that these additions will resolve the heat issue, but it remains untested at the moment. If must we will expand the vents too.

Wanderlust engine compartment blower installed at the end of the season: It blows into a deck storage compartment with drain slots to pass the air outside. The compartment doesn’t drain properly so the fan can help us dry it out if water collects.



The logbook says that from Mulhouse to Besançon is 146 kilometers with 84 locks and five lifting bridges. This distance was covered in seven cruising days, with stops in between in Heidwiller, Dannemarie, Montreux-Château, Montbéliard, l’Isle-sur-le-Doubs, and Baume-les-Dames. Wanderlust’s engine ran for a total of 34.7 hours during this stretch.

The map of the route:

3 thoughts on “The Canal du Rhône au Rhin: The Return to Montreux-Château and on to Besançon, a New Battery Challenge Emerges

  1. We had two full seasons, 2015 and 2016 when the actual cruise was close to the plan. Since then – no resemblance at all. I guess we have to learn to be light on our feet. Plans in jelly for sure.

    • I think you are winning, though. We’ve had a total of maybe 9 months in total on the water since 2015. Completely lost seasons in 2018 and 2020.

  2. Pingback: The Canal du Rhône au Rhin and the Saône: A Return to Saint Jean de Losne | Wanderlust

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