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How do you charge those Lithium Ion Batteries?

Updated: Dec 7, 2021

Calypso is pretty high tech when compared to a lot of the boats cruising around. She’s been designed well and we’ve upgraded quite a few items such as new solar, a wind generator, new Lithium Iron batteries and such. She’s pretty much on point!

There has been one issue, however. Calypso hasn’t been able to charge her house bank from the engine alternators. This means that the only source of charging the house bank (which everything runs off of) is the solar, wind generator and diesel genset. While we haven’t gone on an overnight passage with the new Lithiums, we have with the old battery bank. While sailing overnight, the house bank required charging from time to time. That may not be the case anymore thanks to the shiny new Lithium Iron batteries snuggled in her battery compartment but we wanted to add a little more redundancy.

All of the sailing equipment such as power throttles, chart plotters, auto pilots, radar, etc draw power from the house bank. So while you’re sailing overnight with no solar, the old bank would get low. We’d simply start the generator and charge it up from time to time and that was fine…But what if the generator stops running? A issue that we’ve had a couple of times including right now as it’s popping an oil pressure low warning. No parts are available due to shipping issues so it’s not running and probably won’t until this whole virus thing settles down, that fact has caused us to move into the next upgrade.

The main photo you see here is of a Balmar 614, it’s now wired into the starboard engine’s alternator on Calypso. This thing is awesome!

The original design for the charging system was simply a regular engine alternator with a wire coming off of it, it ran to the starting battery for that engine and that was it. Here’s what we’ve done.

We’ve replaced that wire with some seriously thick cable and it’s now running from the alternator to the house battery bank. The original wire was too small to charge Lithiums and could have caught fire if used. We’ve also bypassed the internal regulator on the alternator itself and now the Balmar 614 regulates it. Not only does it regulate the alternators current, it allows the alternator to produce more power than before, it monitors alternator/battery temp and it acts as a multi stage charger…So the alternator DC current is provided in Bulk, Absorb and Float directly to the house bank.

Long story short, when we run the starboard engine we will be properly charging the house bank right up to the 14.4 volts they need! They’ll charge, absorb and then float. So we’ve essentially added a back up…Actually more of a primary charging system and the genset is a back up…Which is great!

I (Jeremiah) am far from an electrician so we had a professional come do the install which was really helpful. He installed it, programmed it and gave us a lesson on all of the above. Now, the starting battery isn’t hooked directly to alternator anymore…So how’s that getting charged? Calypso was already fitted with a system that will allow cross charging (see second photo). So the house bank will now (when the system is in auto mode) charge the starting batts from the house bank. This also provides a way to charge a dead starting battery...Charging from batteries that have multiple sources of charging...So a dead starting battery can get charge from solar if needed, as an example. It’s all fire and forget at this point.

We would’ve done this to the port engine as well but there was only one Balmar 614 on the island. That’s ok though, we don’t mind getting some sea time on this component before installing it on both engines. As long as it performs as well as it has so far and as well as all the reviews on it say, we will absolutely install it on the port side as well. The Balmar unit was around $330 US.

Another item we’ve upgraded in the process is installing a Victron Battery Monitor (third photo). We mounted this right on the nav station, it’s hooked directly to the house bank and it provides battery capacity, amps used or provided, percentage full, hours until empty and more. It’s a great piece of gear to get an accurate picture of the battery bank and it’s right at the navigation station! That’s a great thing when on passage because you can just glance in at it. Otherwise we’d have to go down below and click through the menu on the original battery monitor…Which isn’t as accurate as this.

So we’re very happy with all the upgrades! Calypso is the most upgraded Antares 44i we’ve ever seen. Maybe we’ll even run out of upgrades to do one day…But I doubt it.

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