Battery

disgusted face

How’s everyone been out there? Hopefully, all are well and still kicking and screaming. I’m still lying low and pretty much operating under the radar, but I’ve been badgered lately to get fingers tapping on the keyboard again.

With winter approaching, and with the thought of storms and power outages energizing my little gray cells, I got to wondering just how long I could power up some essentials in the house using my Chevy Volt sitting in the driveway as a power plant.

Oh yes, it’s totally possible, there are tales from those who have done so on the internet, and there are even kits available.

power tower and elecric carMy Volt has a 17 kW-hr, 300v traction battery along with its DC generator plus a 12v battery for all the other normal loads. This 12v battery is charged by a DC-DC converter between the two batteries, so if I were to hook up an inverter to this battery I could supply 110v AC mains power to my household essentials during a power cut, or maybe power up an outdoor event, or fire up a blender and mini-fridge at a beach romp.

Possible? Yes, but for how long?

dead-batteryWe spend considerable time and effort trying to help boat operators understand how to look after their batteries, but we still hear of way too many premature deaths. So in an effort to get the message across from a different angle, we offer the following advice on how to inflict serious harm and punishment on expensive batteries without really trying.

Simply put, there are three main types of abuse you can employ to kill or maim your batteries:

  • Excessive heat
  • Physical damage (including vibration), and
  • Poor charging routines

The first two I hope to be self explanatory, but the third requires some detailed explanation.

Flooded lead acid batteries, including AGM's, don't like being left for extended periods in a partially charged state. Doing so allows some of the lead sulfate crystals that form naturally on the negative plate during the discharge process to harden to the point where they can't then be dissolved the next time the battery is charged. This is known as sulfation which leads to an increasing loss of useable capacity as more and more crystals harden.

Dave tilting hat with grin

OK, that’s not something you’ll hear every day, but it is very much a possibility, where thermal runaway can destroy Valve Regulated Lead Acid (VLRA) batteries like AGM’s (Absorbed Glass Mat). A Google search of “Thermal Runaway in AGM Batteries” will reveal enough technical papers on the subject to keep even the most techno-savvy occupied for a long while and will save me trying to explain the why’s and wherefore’s here.

The simple fact is that, given the right conditions, an AGM battery can, and will, start a self-perpetuating internal heating process (thermal runaway) which can end in catastrophic failure along with the possibility of fire and explosion, or at the very least leave you with a very sad-looking molten battery case.

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I've always wondered whether Firefly batteries really do charge faster than conventional lead-acid batteries, as the Firefly people tell us. There is oodles of information on the discharge characteristics in the Firefly blurb, but nothing much regarding this high-speed charging phenomenon. Well, now I know.

But let's first look at Lithium batteries because nothing can currently compare to their spectacular charging capabilities in their many forms.

These types of battery have the ability to suck in practically whatever amps the charging source can deliver, all the way through from start to finish, and such is their thirst that we really don't yet have charging sources powerful enough to satisfy their craving. Lithium batteries have an addiction: they're hooked on amps and all they want is more!

Those familiar with the now-standard 3-step Lead Acid charging routine of Bulk, Acceptance, and then Float stages will appreciate that, because Lithium batteries do not have to suffer through the painfully long, drawn-out Acceptance stage, they will recharge in a fraction of the time of Lead Acid equivalents.

Because of this, charging sources for Lithium batteries, especially alternators, need to be specially adapted and/or controlled in anticipation of them being forced to deliver their maximum amps output for the entire length of time of the charge. Ignoring this little nugget may well end in a debilitating melt-down, and I mean that quite literally!

Apart from the zippy charging, lithium battery systems will also last several thousands of cycles longer than conventional Lead Acid batteries, do not have to be fully recharged each cycle, can be discharged to deep levels, and are about half the weight. But they are also expensive, complicated, can't be charged when temperatures are at/below freezing, and for some they carry a scarily high fear-factor.

But wait a minute .... the Firefly is not a conventional Lead Acid battery, so let's compare its attributes to Lithium.

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