Sunday, September 23, 2018


I put this information on Instagram (, but not everyone is on IG, so here is a regurg, starting with what I posted, upon which I will then expound in this blog post, because this is super-important.  For you guys who have a lithium system charged by a single engine alternator (plus or minus other charging options such as generator, shore power, or solar), if your alternator behaves as mine did, the outcome could be life-threatening.  DO NOT ASSUME THAT YOU ARE SAFE FROM THIS TYPE OF FAILURE IF YOU HAD A PROFESSIONAL INSTALL YOUR LITHIUM SYSTEM. 

My IG tile. 

Our 17-month-old 200 A Bosch alternator began failing last month when I was on the road between Houston and Nova Scotia. This was a particularly pernicious problem because my first sign of trouble had nothing to do with our camper van’s lithium system - instead what happened is that I started losing the chassis electrical system, which would have developed into a middle-of-the-freeway potentially catastrophic breakdown if I hadn’t caught it in time. There’s a #vanlife myth floating around out there that if you have a Sterling battery-to-battery charger in your system, it will protect against engine alternator damage. This is not true - it will protect against SOME types of alternator damage, but it will NOT prevent your alternator’s clutch from wearing out grossly prematurely, which is what happened to ours (we had it diagnosed by a repair shop today; I estimate that this alternator did perhaps 20 hours of heavy-load lithium recharging spread across the 17 short months of its life before failing). Those of you who have single-alternator lithium rigs might be sitting ducks if you haven’t hardened your electrical system against this kind of weak-link-in-the-chain breakdown scenario. See vids by YouTuber Alternatorman for more detail on alternator clutches. Thanks once again to @million_mile_sprinter for helping me out last month.

OK, now the expound.  When I said "I started losing the chassis electrical system", what I meant was that I began noticing that I could no longer crank my air conditioner fan up to its highest setting.  I was driving through Mississippi in August - trust me, under those conditions, it's noticeable if the a/c starts to wane.  I literally had a panic attack when I realized that there's basically only one thing that could bring about that result - a failed or failing alternator.  I opened up the OBD Fusion app on my iPhone which bluetooths to a reader that we have permanently mounted in the van's OBD socket.  Sure enough, the chassis battery was reading 12.8 V, which is way below what it should have been.  The alternator was not charging the chassis battery.  The van was about to stop dead in the middle of IH-59 between Hattiesburg and Meridian (i.e., middle of nowhere). 

I pulled off the road and sprang to the back of the van to look at the lithium charging status.  I had done my usual thing that day by driving from Houston to Laf Louisiana, stopping for lunch, and running our roof air conditioner off our 300 AH lithium battery for about an hour while I took a nap.  I then got back on the road with the alternator engaged to bring the lithium battery back up to full charge (a heavy-load scenario for the alternator because I'd run it down to about 50% state of charge (SOC)).

Cue additional horror when I got to the back of the van, which is where our electrical control system is located:  my lithium was reading about 90%, which means that the alternator had been, and perhaps still was, charging the house battery at the expense of the chassis battery.  That should never, ever, EVER happen, and I didn't understand how it was even physically possible given the way we had configured our system. 

Immediately I de-loaded the alternator by isolating the lithium charging circuit.  (Yes, we'd had the foresight to install a kill switch for that when we DIY'd our electrical system). 

I then got back on the road, praying that whatever was remaining of the alternator functionality could then put its full contribution into the chassis battery, which was dangerously low at that point.  I had planned to stop for the night in Toomsuba MS, but I kept driving straight through to Tuscaloosa AL to give the battery time to recover.  That's a 615 mile run on the day, more than I prefer to do when driving solo, but it was necessary.

I got to Tuscaloosa (excellent boondocking Cracker Barrel there BTW), pulled out my voltmeter and measured the chassis battery directly, terminal to terminal (we don't rely on the OBD exclusively because it seems to not have foolproof accuracy; story omitted for brevity).  It was reading not ideal but reasonable.  I knew I'd have enough juice to get the van running properly in the morning. 

No more deep lithium discharges from that point forward.  No more alternator charging, period.  I was in a rare pocket of cooler summer air (a cool front had passed through) such that I could live without a/c, and rather than bailing on the trip and returning to Houston, I continued heading north, hoping to intercept Joel Sell (Million Mile Sprinter) in Philadelphia.  I had my husband (who was still back in Houston) make contact with him to see if he could replace the alternator while I was en route, and he said yes.  A Philly detour would add only an hour or two to my total route.

Here's the maddening part:  Through no fault of his own, Joel couldn't determine conclusively on the spot what was wrong with the alternator.  Of course he could take it off site and get it diagnosed, but that takes time.  I arrived at his place around 2 p.m. on a Friday afternoon and I didn't necessarily want to hang around until Monday morning.  So we made the decision to just go ahead and replace the existing alternator, which clearly had something wrong with it, so that I could get back on the road.

The replacement deed in progress.
As for what was wrong with the alternator, that would have to be determined later.  Joel and I did some preliminary testing just so that my engineer husband could have data to noodle on.  It looked like this:
Tap to expand for clarity.  If you are a less-technical person, know that higher voltages indicate a better-performing alternator. 
I continued to Nova Scotia without further incident, carrying the half-dead alternator with me.  A 200 A alternator is big and heavy and a pain to tote around in a small van.  After I off-loaded my meal-encapsulating solid ice blocks at my father's place, I used our hitch-mounted Yeti to carry it.

These were my 2018 ice blocks, 35 pounds apiece with vacuum-packed home cooking embedded in them.  Many good meals were had by at least seven adults courtesy of these, which I prepared in Houston and took with me. 
Five weeks after I set out, my husband and I returned to Houston, never having resumed alternator charging.  We had the old alternator diagnosed yesterday.  The clutch was worn out and was slipping under high-load usage scenarios.  It's being repaired as I speak, and I'll follow up with a separate blog post on that process.  And BTW, who even knew that alternators have clutches?!?!  They did not used to have this failure-prone add-on.  I'll also discuss that subsequently. 

First moral of this storyNO MORE SINGLE ALTERNATOR OFF-GRIDDING.  We are going to reconfig our van for a second isolated alternator which will be dedicated to just the house lithium battery.  That way, even if we have another such failure, it won't kill the chassis battery and disable the Sprinter's native electrical system to boot. More on that later.

Second moral of this story:  This whole failure episode of mine is exactly why off-grid vans need as many redundant systems as they can support within their space limitations.  Many have asked why we'd go to all the trouble and expense to put solar on the roof when the alternator is going to outperform solar's recharging ability by a factor of somewhere between 3 to 4.  The answer is that STUFF BREAKS.  Sometimes it breaks in ways that nobody can predict.  Never before this had I heard about alternator clutches failing, and I've been following all of the vanning and off-gridding forums for four years now!!  Neither had my husband ever heard of this phenomenon, and he had done months of research on mobile lithium systems.

My boondocking property in Canada, where there was no crimp in our style.  We completed a 5-week off-grid trip even with this limitation of not being able to use our new alternator, because our solar alone took care of our lithium battery.  We had to be careful with our usage, because my property is surrounded by these high trees, limiting sun exposure.  But we spent 2 of our 5 weeks here without any recharging problems, running on solar alone. 
I'll close this post with this 3-minute video that describes alternator clutches.  Read it and weep.  Watch it and weep.  The manufacturers took a pretty good device (alternators have been around for a long, long time) and screwed it up by adding this failure-prone clutch part.  More on that later, too.