Upgrading Golf Cart Batteries to Lithium Batteries.

DMS1

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May 8, 2021
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I am going to upgrade the Golf Cart Batteries in my RV to Lithium. Will I need to change out the RVs built in battery charger? If yes, what do you all recommend?

2nd question. If I were to get 2 - 12 volt lithium batteries now, is it OK to add 2 more in 6 to 12 months? Or do they all need to be purchased at the same time like Lead Acid and AGM batteries?

TIA
 

snoobler

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If the converter outputs a bulk/absorption less than 14.6V and a float less than 13.6V, it may work.

The biggest issue is usually the crap wiring between the converter and the battery causing a voltage drop. The charger may be supplying 14.6V, but the battery only sees 13.8V due to a mega drop between the two.

The official answer is no, you can't do that for the same reasons as lead-acid. In reality, you can add them as you describe as long as you understand that it's not optimal. It is less severe for LFP since they will degrade less in 6-12 months vs. lead-acid.
 

DMS1

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I think I am going to upgrade the converter charger to a Progressive Dynamics for Lithium batteries, the next question will be what Amperage should I get for say 4 - reBel or SOK 100ah batteries in parallel? They offer 25a, 30a, 40a, 45a and 60 amp versions.
 

snoobler

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The batteries have a charge rating. Select the converter on that basis.

Consider that the new PD converter may not be able to fully charge your battery if you have excessive voltage drop between converter/battery.
 

DMS1

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The batteries have a charge rating. Select the converter on that basis.

So, If I had 4 batteries in parallel and the recommended amps for charging is 30 amps, I would still charge them ALL at 30 amps?
 

DMS1

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Thinking outside the box here, it seems the RV Converter Chargers settings are all fixed, or only changeable from Lithium to Lead Acid or AGM. What If I put a Victron Orion DC to DC charger between my RVs Charger and the Lithium batteries so I can fine tune the battery charge settings to be the same as my Solar charge controllers settings (also a victron)?
 

time2roll

Photon Sorcerer
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Mar 20, 2021
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What is the existing converter? Most are not bad, none are perfect.

If you add that DC-DC charger you also need to have a method for power to return to the 12v panel. Seems overly complex.
 

DMS1

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May 8, 2021
Messages
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What is the existing converter? Most are not bad, none are perfect.

If you add that DC-DC charger you also need to have a method for power to return to the 12v panel. Seems overly complex.
I am not sure what I have right now, I need to find it and see what it supports.
 

DMS1

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May 8, 2021
Messages
43
What is the existing converter? Most are not bad, none are perfect.

If you add that DC-DC charger you also need to have a method for power to return to the 12v panel. Seems overly complex.
Yea, I thought about that a couple of hours I posted that.
 

DMS1

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I finally was able to get the specifications for the onboard charger, it only has one charging mode and charges as follows;

"Automatic three-stage charging extends the life of your battery with output voltage modes of 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode."
 
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