Do I have this right?

[Catmandu]

I have been reading and watching and trying to reactivate long dead scientific brain cells and my head hurts. But it is time to actually start buying some things as I'm on a timeline, so I need a little oversight, please.

I will be charging this 48v 105Ah LifPo4 battery on a golf cart by adding a single panel to the roof. The cart will get minimal use, should never get below 50% charge, and live outdoors always. I will purchase this Victron 100/20 48v capable MPPT controller, and use it with an appropriately dimensioned panel of ~400w that has a Voc of 48 + 10% = 53 volts.

Is my thinking correct, am I missing something?

Thanks!

 

[Zapper77]

I have been reading and watching and trying to reactivate long dead scientific brain cells and my head hurts. But it is time to actually start buying some things as I'm on a timeline, so I need a little oversight, please.

I will be charging this 48v 105Ah LifPo4 battery on a golf cart by adding a single panel to the roof. The cart will get minimal use, should never get below 50% charge, and live outdoors always. I will purchase this Victron 100/20 48v capable MPPT controller, and use it with an appropriately dimensioned panel of ~400w that has a Voc of 48 + 10% = 53 volts.

Is my thinking correct, am I missing something?

Thanks!

Panel voltage maybe too low to charge a 51.2v (nominal) battery

 

[Zapper77]

Assuming battery is 50% SOC, (52+5) you would need 57v for the MPPT to start.

 

[Catmandu]

Thanks for that thought. So that got me pointed to a datasheet for the battery which shows 53v as the flat part of the voltage curve. I would lose charging capability above, say, 93% SOC, which is fine. But once it drops to 53v, and if I had a panel putting out 58v, the controller would automatically kick in.

Not sure I've seen a golf cart sized panel putting out 58v, this may be tougher than I thought.

 

[Zapper77]

Thanks for that thought. So that got me pointed to a datasheet for the battery which shows 53v as the flat part of the voltage curve. I would lose charging capability above, say, 93% SOC, which is fine. But once it drops to 53v, and if I had a panel putting out 58v, the controller would automatically kick in.

Not sure I've seen a golf cart sized panel putting out 58v, this may be tougher than I thought.

Two in series?

 

[MisterSandals]

long dead scientific brain cells

this 48v 105Ah LifPo4 battery

I'm ruling out that you're a chemist :*)

Li (lithium)
Fe (iron, err ferrous)
P (phosphorous)
O (oxygen)
4 (4 oxygens) to make a common compound PO4 (phosphate)

LiFePO4 lithium iron phosphate

Po (polonium, bad unless poisoning a Russian double spy)

 

[chrisski]

Not sure I've seen a golf cart sized panel putting out 58v, this may be tougher than I thought.

Two in series?

2 X two hundred watt panels in series would make the required voltage would be much easier to find than a single 400 watt panel with voltage in excess of 60 VDC.

Also, I'd be interested in seeing how much power 400 watts of panels could put into a 5 kWh battery pack. Might get 1 - 2 kWh a day parked in the sun with the panel flat to the horizon.

 

[mikefitz]

Your panel volts needed to be over 60 volts, suggest two or more panels in series, example,

MEGA 200 Watt Monocrystalline Solar Panel | Best 24V Panel for RVs and

The RICH SOLAR Mega 200 Watt 24 Volt Solar Pane is a key component to any solar power (PV) system. Feautures a 9 buss bar solar cell configuration and mono PERC Technology. Each solar panel includes standard solar connectors that extend from the junction box affixed to the back of each panel.

richsolar.com

An alternative would be 3 or 4 100 watt panels in series.

 

[Catmandu]

I'm ruling out that you're a chemist :*)

Li (lithium)
Fe (iron, err ferrous)
P (phosphorous)
O (oxygen)
4 (4 oxygens) to make a common compound PO4 (phosphate)

LiFePO4 lithium iron phosphate

Po (polonium, bad unless poisoning a Russian double spy)

I am shocked, SHOCKED that you would call a new guy to the forum out on something like details!

My late grandfather-in-law was the DuPont Chemist, and he would have done the same.

I will work on coming up with a set of panels in series that will fit the footprint, thank you all for the help;