LFP charger for standby application

[French_guy]

Hello,

Other than Victron, what chargers have a storage function (to maintain the battery at a reduced voltage once fully charged)

About Victron: other than the IP (22 vs 67 and the 15A vs 17A), are there any major differences between:

https://www.amazon.com/Victron-Energy-12-Volt-Battery-Bluetooth/dp/B07TJK3X71

and this:

https://www.amazon.com/Victron-Energy-12-Volt-Battery-Bluetooth/dp/B08TRP71QM

Thanks

 

[RCinFLA]

Battery Tender's charge to about 14.3v then drop to about 13.3 vdc which is fine for LFP 12v battery. It will hold the LFP cells to about 50% SoC.

You will get no balancing during the standby time so every few months you should perform a full charge balancing cycle.

Make sure any battery maintainer does not not have float voltage above 13.6vdc which is 3.40v per cell.

 

[French_guy]

Battery Tender's charge to about 14.3v then drop to about 13.3 vdc which is fine for LFP 12v battery. It will hold the LFP cells to about 50% SoC.

You will get no balancing during the standby time so every few months you should perform a full charge balancing cycle.

So better go with a Victron charger, right?

 

[French_guy]

Assuming I buy the Victron IP22 12v / 15A, it doesn't come with wires, so I will have to get some
1) I assume 10AWG are plenty enough for 15A?
2) I need to install a fuse, and it must be as close as possible to the positive battery terminal, correct?
3) What type of fuse / fuse holder should I use? I would like to find one with screw terminals, and not with the wire already "molded" into it...any suggestions?

 

[googdot]

Apart from the IP ratings and amps, the one big difference to keep in mind is the IP22 has an internal fan, while the IP65 and IP67 models do not.

 

[French_guy]

Apart from the IP ratings and amps, the one big difference to keep in mind is the IP22 has an internal fan, while the IP65 and IP67 models do not.

I think the 15A version does not.....

 

[DIYrich]

You don't want or need to "maintain" LiFePO4 batteries at full charge. Just let them sit at 80%.

 

[French_guy]

You don't want or need to "maintain" LiFePO4 batteries at full charge. Just let them sit at 80%.

Yes, this is why I mentioned the Victron...
What about the wire size and fuse holder type?

 

[DIYrich]

Yes, this is why I mentioned the Victron...
What about the wire size and fuse holder type?

What are you trying to accomplish? My inverter has a setpoint to charge from grid (like 30%). Anything higher, and it only charges from pv. If you don't have pv, it will sit forever until a power outtage drops the batteries below the setpoint, and then recharges them when the grid comes back up. You can then draw the batteries to 80% and let it sit again for months.

The victron comes with a wire and fuse.

 

[French_guy]

What are you trying to accomplish? My inverter has a setpoint to charge from grid (like 30%). Anything higher, and it only charges from pv. If you don't have pv, it will sit forever until a power outtage drops the batteries below the setpoint, and then recharges them when the grid comes back up. You can then draw the batteries to 80% and let it sit again for months.

The victron comes with a wire and fuse.

I'm not using an inverter nor pv..it's for a 12VDC backup sump pump
So I need a charger that will maintain it in storage mode. Thinking about the Victron IP22 12V / 15A
It doesn't come with wires, so I'm planning to use 10 AWG....
And I was asking for the fuse / fuse holder type. I know the fuse protects the wire and needs to be as close as possible to the battery....but what looking for recommendations
And I will also need a fuse between battery and pump controller, correct?

 

[DIYrich]

Assuming wire is NOT in conduit, 10 awg with 20a fuse is more than adequate.

In conduit. You need 8 awg wire for a 20a fuse. If you use 10 awg with a 15a fuse. You risk blowing the fuse.

This is for charger to battery. All that stuff about closest to battery, doesn't apply. It is the load wire that needs the protection you mentioned.

 

[French_guy]

Assuming wire is NOT in conduit, 10 awg with 20a fuse is more than adequate.

In conduit. You need 8 awg wire for a 20a fuse. If you use 10 awg with a 15a fuse. You risk blowing the fuse.

This is for charger to battery. All that stuff about closest to battery, doesn't apply. It is the load wire that needs the protection you mentioned.

Correct....not in conduit
Any fuse holder suggestions with screw terminals?

 

[DIYrich]

https://www.autozone.com/electrical-and-lighting/fuse-and-accessories/p/bussmann-atc-fuse-holder/32415_0_0

 

[French_guy]

About the wiring, should it be A or B?

 

[French_guy]

https://www.autozone.com/electrical-and-lighting/fuse-and-accessories/p/bussmann-atc-fuse-holder/32415_0_0

is 12 AWG enough?

 

[DIYrich]

If the startup amps of the pump are 15 amps or less, then either works. If more, then A, and a wire for pump that is sized for it.

 

[DIYrich]

14 awg is good for 32a chassis wiring.

 

[French_guy]

If the startup amps of the pump are 15 amps or less, then either works. If more, then A, and a wire for pump that is sized for it.

The pump's specs says 10A continuous and 18A in-rush...

 

[DIYrich]

The pump's specs says 10A continuous and 18A in-rush...

Same wire and fuse is fine. If needed for the pump, you can upsize fuse to 25a with 14 awg or larger wire.

 

[French_guy]

Would this be a good choice (I like the possibility to manually switch the circuit)

https://www.amazon.com/YOUNG-MARINE-Circuit-Trolling-Mount-50A/dp/B075KZTKDD

or this:

https://www.amazon.com/gp/product/B08ZXNZ3D3

with this:

https://www.amazon.com/Conext-Link-AFS25-10-Nickel-Fuse/dp/B01D9ISXW6