How to set AC charger to let LiFePO4 battery cycle?

[Tomthumb62]

Pardon me if this is a dead horse, searching didn't find an answer.

I have a standalone AC charger that only operates when our camp trailer is connected to shore power. Originally I expected this to work great, as we would likely only plug into shore power maybe once a week or less for overnight.

But my wife is now in a stationary location for several weeks. And it's raining, so not much for solar production. So she's plugged into shore power and the AC charger is charging. I can see remotely that the charger is likely in float (I can see system voltage but that's all I can see.)

The charger is a Victron IP22 12/30 single output. I'm not sure if this is Victron specific question, since many chargers have the ability to be programmed. How can I program the charger to let the battery cycle? I mean, can I ask the charger to charge up to bulk voltage, then absorb then float but not stay at float? To let the battery drain down to something like 13.1 or 13.2v before a bulk charge starts up again? I'd like it to cycle daily similar to what happens on solar and not to be in 99-100% SOC 24/7.

"Why don't you just unplug the charger and plug it in again when you're ready for a charge?" you might ask. Good idea, except unfortunately the plug is not in an easy to access location AND it would be just nice to not have to think about it and let the charger do this all automatically (wife is NOT happy about having something else electrical to have to mentally keep track of.) But I'm not sure I fully understand how this charger works (there are a LOT of options to change in the advanced/expert settings) or if it's even possible to let it do what I want it to.

If the first idea isn't possible, what would the pros/cons be of setting the bulk at 14.2 and float at 13.2? Is that a bad idea (mfr recommends 14.4 and 13.6)?

Thank you for any advice or experience you have to share.

 

[DIYrich]

Supposedly, a recharge cycle starts when the battery hits float or storage voltage. If that is so, set the voltages to say 20%, and it should discharge to 20% before starting another charge session.

Might want to set charge rate to 0.1c to go easy on the battery.

 

[LakeHouse]

Pardon me if this is a dead horse, searching didn't find an answer.

I have a standalone AC charger that only operates when our camp trailer is connected to shore power. Originally I expected this to work great, as we would likely only plug into shore power maybe once a week or less for overnight.

But my wife is now in a stationary location for several weeks. And it's raining, so not much for solar production. So she's plugged into shore power and the AC charger is charging. I can see remotely that the charger is likely in float (I can see system voltage but that's all I can see.)

The charger is a Victron IP22 12/30 single output. I'm not sure if this is Victron specific question, since many chargers have the ability to be programmed. How can I program the charger to let the battery cycle? I mean, can I ask the charger to charge up to bulk voltage, then absorb then float but not stay at float? To let the battery drain down to something like 13.1 or 13.2v before a bulk charge starts up again? I'd like it to cycle daily similar to what happens on solar and not to be in 99-100% SOC 24/7.

"Why don't you just unplug the charger and plug it in again when you're ready for a charge?" you might ask. Good idea, except unfortunately the plug is not in an easy to access location AND it would be just nice to not have to think about it and let the charger do this all automatically (wife is NOT happy about having something else electrical to have to mentally keep track of.) But I'm not sure I fully understand how this charger works (there are a LOT of options to change in the advanced/expert settings) or if it's even possible to let it do what I want it to.

If the first idea isn't possible, what would the pros/cons be of setting the bulk at 14.2 and float at 13.2? Is that a bad idea (mfr recommends 14.4 and 13.6)?

Thank you for any advice or experience you have to share.

Unless there’s some reason why you want to cycle the battery, just set the float voltage lower than the battery’s resting voltage when it’s charged. 13.0 or 13.2 (as you suggest) should do fine. The SCC should just sit there doing nothing unless the battery voltage drops below the float, which shouldn’t happen when you’re on shore power.

 

[Tomthumb62]

Supposedly, a recharge cycle starts when the battery hits float or storage voltage. If that is so, set the voltages to say 20%, and it should discharge to 20% before starting another charge session.

Might want to set charge rate to 0.1c to go easy on the battery.

Thanks, I appreciate that. Still learning exactly how charging works. Max the charger can do is 30A, which is 0.15C for the 200Ah 12v battery.

 

[Tomthumb62]

Unless there’s some reason why you want to cycle the battery, just set the float voltage lower than the battery’s resting voltage when it’s charged. 13.0 or 13.2 (as you suggest) should do fine. The SCC should just sit there doing nothing unless the battery voltage drops below the float, which shouldn’t happen when you’re on shore power.

Ok, that makes sense. And I just had an a-ha moment, I think! If I set float to say 13.0v, it isn't actually charging the battery anymore and simply will be passing (more or less, using the battery as a buffer) current onto the house loads. My desire was to just have the battery be basically charged, but not doing a high cycle thing where it drops to 92% and then back up to 100%, on a daily basis.

Anyways, thanks for helping me better understand this and I'll set the float to lower than what it is now.