H49/50 battery replacement

[Georgedoyle]

After conferring with an alternator expert, I disconnected the alternator positive cable that leads to the battery. The generator runs fine now with no error code and does not shut down. The alternator on the generator is now excluded from the charging routine. I reconnected the Dakota lithium starting battery. It will be charged by my main alternator when the engine is running or by the battery charger when the generator is running. The solar panels will also keep all of the batteries topped up. I think I have the system sorted out.

As I was dealing with all of the variables in my lithium installation, another problem popped up. My Yanmar 4jh4 HTE would not start. After a little bit of diagnostic work we figured out that the starter relay was bad. We think it stuck in the on position and kept the starter motor gear engaged with the flywheel after start up. This fried the motor and solenoid. New starter motor and relay fixed it. If you have this engine, it might be wise to change the relay before you get a catastrophic failure that ruins your starter motor. There was no warning in advance that there might be a problem with the relay. It came out of the blue. Luckily we were tied up to our mooring when we noticed that the motor wouldn't start.

 

[Zencra]

I fitted 6x100 a/h Battleborn LifePo4, they went in perfectly with room for 2 more if needed. Go Lithium, they're honestly life-changing. 5 years full time cruising with these and they're still performing like new.

 

[Georgedoyle]

Update on our lithium battery upgrade. We took our Hunter 49 to Catalina for the first test of our new lithium battery bank. Long story short, we stayed for 6 days and lost 10% of our capacity each day. We started with 1200 AH of storage. We used only our 400 watt solar array to charge. We ran 4 fridges, lights, pumps, and the microwave and charged several phones and iPads. We did not hold back on usage as we wanted to get a good idea of how long we could last without using the generator to charge. We also did not turn off the fridges at night like we did when we had AGM batteries. Turns out, we didn’t use the generator at all. One important point is that we maintained 13 volts the whole time. This was noticeable in the the way the fridges maintained temperature and in the way all of the other devices performed. overall, we were happy with the way the new batteries performed. It sure was nice not to worry about the batteries being in a prolonged state of discharge since lithiums are immune to damage from this common condition. It is possible that we will upgrade our panels and increase the wattage of the system in the future to try to improve on the 10% daily loss. But for now, we are pleased.

 

[SoSound]

Congrats!! I followed this thread for a long time, and did my own smaller installation this spring. We replaced two FLA house batteries with three 105 AH lithium batteries. Since then, we find that evening usage and overnight power needs consume about 10% of our capacity. During the day our 220 watt solar recharges us to 100%.

 

[Hayden Watson]

Update on our lithium battery upgrade. We took our Hunter 49 to Catalina for the first test of our new lithium battery bank. Long story short, we stayed for 6 days and lost 10% of our capacity each day. We started with 1200 AH of storage. We used only our 400 watt solar array to charge. We ran 4 fridges, lights, pumps, and the microwave and charged several phones and iPads. We did not hold back on usage as we wanted to get a good idea of how long we could last without using the generator to charge. We also did not turn off the fridges at night like we did when we had AGM batteries. Turns out, we didn’t use the generator at all. One important point is that we maintained 13 volts the whole time. This was noticeable in the the way the fridges maintained temperature and in the way all of the other devices performed. overall, we were happy with the way the new batteries performed. It sure was nice not to worry about the batteries being in a prolonged state of discharge since lithiums are immune to damage from this common condition. It is possible that we will upgrade our panels and increase the wattage of the system in the future to try to improve on the 10% daily loss. But for now, we are pleased.

I found the same with my LFP. You get an additional 10% boost in available power because of the voltage. All of our appliances use a relatively fixed amount of power when running and that fixed amount is in watts. Let's say an appliance uses 100W. Watts = volts x amps so... Your LFP batteries are at 13.2v 90%of the time regardless of SOC, so you are pulling 7.57A. Your FLA will range fairly linearly from 12.6v when full down to 12.0v at 50% SOC. That means you will be pulling between 7.9A and 8.33A. I know that on my boat, when cruising, I spent far more time at the 12.0v end of the scale if not below.