Hybrid LifeP04 - FLA advice

[cookietx]

Here is a video I found of someone that has been running a hybrid system for 18 months

 

[iRondo]

This came across my radar a few days ago and has me intensely interested. Currently, I have two banks, both 400ah, 1 LFP and 1 FLA with a Stirling BB1260 between the two banks. Not happy with the Stirling. It just doesn't charge the LFPs adequately.
^ That video was the first I heard of the possibility. He talks about putting a resistor between the FLAs and the LFPs to bring them to balance but doesn't say how big the resistor has to be.

 

[grizzzman]

Well what he has described is exactly what I have observed in my Hybrid system.

 

[iRondo]

Well what he has described is exactly what I have observed in my Hybrid system.

How do you have your DC-DC charger connected into it? By the sounds of it, I may have all the components necessary already. Maybe I just need to reconfigure and rejigger?

 

[grizzzman]

How do you have your DC-DC charger connected into it? By the sounds of it, I may have all the components necessary already. Maybe I just need to reconfigure and rejigger?

The DC to DC is not used in the way you think. It is a backup charger. It is in a pelican case. 20 foot of 4AWG and is used when solar can't keep up.( rare in my case) the only thing between my banks is a 100 amp fuse.

 

[iRondo]

The DC to DC is not used in the way you think. It is a backup charger. It is in a pelican case. 20 foot of 4AWG and is used when solar can't keep up.( rare in my case) the only thing between my banks is a 100 amp fuse.

I always thought those guys in the Facebook LFP forums were exercising their credit cards more than necessary. I designed my system as bare-boned as I dared but this takes it to a new level. "How far can we go Mr Kramer?"

 

[grizzzman]

I always thought those guys in the Facebook LFP forums were exercising their credit cards more than necessary. I designed my system as bare-boned as I dared but this takes it to a new level. "How far can we go Mr Kramer?"

How will YOU ever know unless you try yourself?

 

[Popuptoaster]

I just killed two FLA batteries (I am 24v) in a set up like this, I noticed a drop in capacity (batteries were not lasting through the night, I was woken up twice by the inverter low voltage alarm at 4am) I put it down to the very grey days we had been having and my own fault for not keeping an eye on the state of charge of the batteries in the evening. I have an ATS that kicks in when the battery voltage is low for the 240v equipment but I have it set to switch early as i still have some 24v loads direct so need some battery capacity left for the night time.

Anyway, after investigating it turns out the FLAs were dead, not holding a charge and after the solar stopped charging they were slowly dragging all the power out of the Lithium battery until the MS shut it off and their voltage continued dropping until the various alarms sounded, neither were old or in bad condition at the start and had been fine when tested about 5 months previously.

I don't know exactly why they died, the SCC was set correctly for them, I'm not necessarily blaming the hybrid set up for killing them but it seems very odd they both died well within their expected lifetimes and under not particulary heavy loads or rapid charge/discharge. Luckily the lithium battery seems fine so far as I can tell, i still dont have enough solar to top it right up in the nasty grey weather we are having here in the UK but it is lasting through the night now that the FLAs are not in the system.

 

[grizzzman]

I just killed two FLA batteries (I am 24v) in a set up like this, I noticed a drop in capacity (batteries were not lasting through the night, I was woken up twice by the inverter low voltage alarm at 4am) I put it down to the very grey days we had been having and my own fault for not keeping an eye on the state of charge of the batteries in the evening. I have an ATS that kicks in when the battery voltage is low for the 240v equipment but I have it set to switch early as i still have some 24v loads direct so need some battery capacity left for the night time.

Anyway, after investigating it turns out the FLAs were dead, not holding a charge and after the solar stopped charging they were slowly dragging all the power out of the Lithium battery until the MS shut it off and their voltage continued dropping until the various alarms sounded, neither were old or in bad condition at the start and had been fine when tested about 5 months previously.

I don't know exactly why they died, the SCC was set correctly for them, I'm not necessarily blaming the hybrid set up for killing them but it seems very odd they both died well within their expected lifetimes and under not particulary heavy loads or rapid charge/discharge. Luckily the lithium battery seems fine so far as I can tell, i still dont have enough solar to top it right up in the nasty grey weather we are having here in the UK but it is lasting through the night now that the FLAs are not in the system.

If you don't mind my asking, How are you monitoring your FLA and LFP banks for state of charge?

 

[Popuptoaster]

If you don't mind my asking, How are you monitoring your FLA and LFP banks for state of charge?

I have the victron ap on my phone and an lcd power meter type display up on a bulkhhead that has voltage and amp draw etc although I have to admit I hadn't been monitoring either particularly closely.