Cable size does matter when it comes to working with it and finding the best connectors that do not us a crimp for an electrical connection. I am in the process of replacing two Group 31 flooded batteries with two lithium phosphate ones and it took some needle nose vise grips to get the connectors on the ends of the 3/0 welding wire into place inside the battery compartment.
If it takes 3% longer to charge a battery bank the difference is trivial. I can recharge from 50% SOC in 60 minutes with the Onan running and if that is increased by 3% to 61.8 minutes who really cares?
I see a great many installations with very heavy gauge wire with connectors that are crimped onto the wires which is mechanically unsound and causes more than a 5% current loss with reduced wire to connector contact surface. Connectors that use the solder slugs are much better for RV and marine use than crimped on connectors. If you are not familiar with the solder connectors then check them out on the delcity.net website.
To fully charge the LiFePO4 batteries you need 14.5-14.6V at the battery. Not going to happen when your charger is set to put out 14.6V and you have a 3% loss. Now you are only getting 14.2V at your lithium batteries.
The Lithionics batteries that I am using have a recommended charge voltage of 14.4V to 14.6V and anyone who thinks that battery chargers are accurate to 0.1 volt is misinformed. I can also adjust the output voltage from the Xantrex to provide the voltage needed at the batteries with their internal BIM and accomodate any voltage loss with the cable run.
It is also worth noting that Lithionics states in their documentation that charger equalization and temperature compenation should be disabled. Adding a separate external battery temperature monitor is of no use with these lithium phosphate batteries.
2ft of 1/0 wire from battery to bus = 0.56% drop
Then 1ft 1/0 wire from inverter charger to bus = 0.28% drop
So there shouldn’t be a problem charging at 14.6v correct?
Maybe little more loss across bus and through switch, but total loss should be less than 1%.
Thanks for advice.
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Jim. Former, 2021b Micro Minnie 2108DS
Medically grounded, but still lurking the Micro Minnie Discussions