New lithium house batteries (2)

[JWH11550]

I just replaced my lead acid batteries with new power queen lithium batteries. (the converter is supposed to recognize the switch over)

Will plugging the shore power into my home 120v power charge the new batteries?

 

[Boat Bum]

Did it before?

 

[JWH11550]

Did it before?

It had dead batts in it when I brought it home. They never charged significantly even after staying at a campground with 30a shorepower and driving 10 hours. That's why I got the new batts.

 

[Kevin D Pem]

If your system is working yes. If it has a lithium setting fully. If it doesn't less than fully.

 

[T’sOVR&Explore]

The LiFePo4 battery internal battery management system (BMS) is designed to charge the internal cell groups from a converter or charger that provides constant voltage of 14.4 volts dc to the battery terminals. After the BMS in each battery has brought the internal cell groups up to full charge, that battery will stop taking current from the charger or converter until the BMS decides to do a little more internal cell group charging.

A just installed Lithium battery may take several hours of charge current before the BMS ends the charge current demand. If you simply leave it connected to the converter / charger for a full day, then voltmeter-read the battery terminals with the converter / charger still powered and connected, you will read approximately 14.4 vdc if the converter charger has auto-detected or been set for Lithium battery service.

If you read only 13.8 vdc or similar coming out of the converter / charger (as might be the case if only flooded lead acid battery charging is supported), it is likely not set up properly for Lithium charging.

A battery monitoring system designed for LiFePo4 service, consisting of a negative terminal shunt and a small display, will show you exactly what is going on and is well worth the modest cost and simple installation effort.

Happy travels!

 

[AbdRahim]

Is your BMS capable of dealing with Li batteries. When I had mine done, they had to replace the BMS to prevent burning out the alternator. At least that was how I understood it. There are many here who understand such things far better than I. Perhaps someone will chime in here.

 

[T’sOVR&Explore]

To AbdRahim - The battery management system circuitry inside the case/housing of each LiFePo4 battery is capable of taking large charging currents. The current demand on a alternator serving a discharged LiFePo4 battery can be excessive if the wire gauge and length of the wire path between the altermator and the battery is such that the conductor is capable of carrying high current without significant voltage drop.

In typical factory trailer tow vehicle wiring bringing current to the battery + terminal on the 7 pin connector at the rear of the tow vehicle, the conductor can be as small as 14 AWG, and in a length of nearly 20 feet. On a motorhome, the conductor size between the alternator and house battery can be much larger and the conductor length can be much shorter, enabling high current delivery.

One solution that can be utilized to manage Lithium bsttery charging current demand on an alternator is to place a DC to DC converter between the alternator and the LiFePo4 battery so that the DC to DC converter's current regulating circuitry limits the current delivery to what the DC to DC converter is rated to deliver. The chosen amperage delivery rating of the DC to DC converter may be 20, 30 or even 60 amps, depending on wire path conductor sizing and current delivery capability available from the alternator (in excess of the chassis current demands that the alternator also has to support).

Hope that this info was helpful!

 

[Kevin D Pem]

The LiFePo4 battery internal battery management system (BMS) is designed to charge the internal cell groups from a converter or charger that provides constant voltage of 14.4 volts dc to the battery terminals. After the BMS in each battery has brought the internal cell groups up to full charge, that battery will stop taking current from the charger or converter until the BMS decides to do a little more internal cell group charging.

A just installed Lithium battery may take several hours of charge current before the BMS ends the charge current demand. If you simply leave it connected to the converter / charger for a full day, then voltmeter-read the battery terminals with the converter / charger still powered and connected, you will read approximately 14.4 vdc if the converter charger has auto-detected or been set for Lithium battery service.

If you read only 13.8 vdc or similar coming out of the converter / charger (as might be the case if only flooded lead acid battery charging is supported), it is likely not set up properly for Lithium charging.

A battery monitoring system designed for LiFePo4 service, consisting of a negative terminal shunt and a small display, will show you exactly what is going on and is well worth the modest cost and simple installation effort.

Happy travels!

This is not exactly correct! CCCV works as stated, however.

One of the parameters of lower priced BMS units shuts down the battery terminals (typically ground), forcing a delay that will effect inverters. Most controllers (solar and others), maintain at 13.8-6 volts because of this issue with BMSs. You are correct that lithium asks for CCCV, however your battery manufacturers require something else. The spec. Is printed on your batteries.

 

[JWH11550]

The LiFePo4 battery internal battery management system (BMS) is designed to charge the internal cell groups from a converter or charger that provides constant voltage of 14.4 volts dc to the battery terminals. After the BMS in each battery has brought the internal cell groups up to full charge, that battery will stop taking current from the charger or converter until the BMS decides to do a little more internal cell group charging.

A just installed Lithium battery may take several hours of charge current before the BMS ends the charge current demand. If you simply leave it connected to the converter / charger for a full day, then voltmeter-read the battery terminals with the converter / charger still powered and connected, you will read approximately 14.4 vdc if the converter charger has auto-detected or been set for Lithium battery service.

If you read only 13.8 vdc or similar coming out of the converter / charger (as might be the case if only flooded lead acid battery charging is supported), it is likely not set up properly for Lithium charging.

A battery monitoring system designed for LiFePo4 service, consisting of a negative terminal shunt and a small display, will show you exactly what is going on and is well worth the modest cost and simple installation effort.

Happy travels!

Thanks, the converter on this RV is supposed to auto detect a change from lead acid to lithium. I just hope that's really true. I just took it back to storage after having the shore power plugged into my house 15a, 110v plug overnight.