Journey On's Li Battery install

[journey on]

Well, 3 mos to the day, that lithium battery is in Journey On and operating as expected, a glorious milestone.

First of all, I'd like to thank Bob/thataway for sharing his battery configurations with me. Just knowing that someone else had done it was invaluable. I also read various discussions of battery chargers and batteries, both on the C-Brats and elsewhere. Thanks to all, and I make no claims to originality, but appreciate all the insight.

OK, here we go. The prices of LIFePO4 batteries had me ignore the idea of using them. Then I saw the youtube by Will Prowse on the 100 ah Chins battery, where he gave it a good review: cells, packaging and BMS.

So, again I thought it through. 1 ea li battery and 1 ea battery charger would save me 100 lbs in the stern of the boat, since I would replace 2 golf cart batteries. But I would have to save the Group 31 flooded lead acid to both serve as a charger buffer and a starting battery. I also reviewed the house loads which were driven by the refrig at 3.5 amps at 50% duty cycle (need that cold beer.) So say that it's 50 ah/day.and a 100 ah li battery could handle that and more.

Amazon delivered a Chin 100 ah li battery for $390 (w/tax,) and a Renogy 12V 20A DC to DC On-Board Battery Charger for $120. I picked the charger because it's output was less than half of the Honda output and the cheapest decent one. And I sat and looked at them and read the manuals, several time. Also please note this wasn't the last of the costs, which I didn't add up but were probably ~$250 more.

The first step was to remove the old golf cart batteries. I'm as old as Bob, so when Pete, my son, came down, I asked his to help remove them. He got them out of there by himself, God bless him again. The next step was time consuming, such as removing all the spare wires and re-routing what was left. Then I mounted the li battery and the charger. The battery went as far inboard as possible. It was light, 1/2 the weight of a single golf cart battery, 38#. The charger was mounted up-side-down to the bottom of the coaming step. Next was the rewiring: battery switch, battery, charger, lead from the motor, control switches. Those damn control switches had to be purchased, mounted at the helm and wired. They were for turning on the charger (normally the motor ignition does this,) and a 1/2 rate charge. I feel both are needed when you're plugged in to shore power. Judy installed the under cabinet tie wraps, bless her.

So, now everything is wired, I turn on the battery switch and the cabin lights give a draw of 0.7 amp (led's.) Try charging, nothing. Well, I'm not totally devastated, I'll check it tomorrow. And I did: one wire not connected. Fixed that, it all works: charges when the D+ switch is thrown, goes to 1/2 rate when the LC switch is thrown, cabin lights are on as are the chart plotters, etc.

Now on to clean up the boat. Yes it's a mess. And I'll post if this works or if it doesn't.

Anyone need 2 ea Trojan golf cart batteries? In SoCal.

Boris

[thataway]

Great install Boris! You will love the Li batteries. Are you going to put in a 120V AC charger? It is nice to be able to top the battery off when you are at a dock or get home.

[croakz]

Nice job! Do you have pictures of the install? I'm trying to decide where to put my DC to DC charger. Thanks!

[journey on]

Well, yesterday was the culmination of all the stuff I've been working on for a long time. Today is a new day and I've got photos:Journey On Battery Album.

Bob asked if I'm going to get a battery charger and I assume that he means a shore power charger specifically for the Li battery. The answer is no. I'm using the starting FLA battery as a buffer to the DC-DC Li charger. As the start battery voltage drops, the regular charger starts charging the start battery. It works, but apparently the 20 amp charger is only good for 10 amps per battery, so I run it at 1/2 capacity when I'm on shore power (as in right now.)

Here is an overview of the installation. I admit there's some cleanup to be done. More pics in Journey On's album



Boris

[Csharpx]

Great job !

[journey on]

I added some schematics and a parts list, so I can remember. And I thought I'd throw them in here.

Bill of Materials


Functional Diagram


Wiring Diagram


Boris

[thataway]

Nice Job Boris. Where is the fuse? I would feel more comfortable with a direct fuse off the battery, then a single point after the fuse for all of the cables.

My installation was a bit different, since I used the 80 amp charger on the Victron Multiplus inverter. I had only one cable from the batteries (2 100 amp batteries) to the 300 amp fuse block. Then 2/0 cable to the inverter (about 3'), and the shunt for the Victron 702 monitor. I fused the lead from the Sterling 30 amp charger (DC To DC). from the engine start battery.

Are you able to monitor the total amps in/total amps out?

One of the advantages of the LiFe PO4 batteries is that they are a higher float voltage (about 13.4-13.6 volts, vs 12.6 to 12.8 Volts for FLA batteries. The battery does not get to 12 volts until 90% discharged.

I made a portable battery station of 100 amp LiFePO4 battery, a 10 amp AC charger and 18 amp Victron Battery to battery charger, all attached to a group 31 battery box, so even octogenarians could move it. In this case the fuse was a 60 amp breaker, since there was no inverter involved. --again one lead off the battery to the breaker--and then leads to the outputs.

[journey on]

Bob, each circuit has a fuse/breaker, which are not shown since they're outside the schematic. There is a main breaker for the house, and, as you know, the factory wired several circuits directly to the battery, such as the bilge pumps, Wallis and chargers. These individual circuits are fused. There are so many fuses I couldn't add more.

I ran the 3 cabin lights (0.8 amp) for 3 days and it took 8 hrs to recharge at 8 amps in.

Boris

[Knipet]

Very nice Boris, and thanks for the schematics.

Is the House Switch a 3-way and to keep the house battery circuits and starter batteries completely isolated except for when or if a situation arises when you either want to use the house battery to start the outboard, or the starter battery to run the house which in that case you will also want to make sure the DC to DC charger is turned off with the control switch?

[journey on]

The house switch just allows one to choose which battery powers the house circuits. It's a legacy switch, which I kept.

Note that one cannot start the Honda outboard with the Li battery. It has a max output current of 100 amps. The Honda starter needs >200 amps.

Boris