Swapping my leisure battery to LiFePO4

[TallPaul_S]

Nice! Get the app downloaded, then you'll be able to check the state of charge - I think fogstar are normally delivered at 30% charge. If you'll be installing it anytime soon then get it on charge with a mains charger with a lithium profile. It might take a day if it's only a 5a charger.

You could just use some terminal covers if you're strapping down the battery another way.

 

[wallport]

It'll be charged with the victron which is 15a when I connect it.

Tell me I'm wrong but terminal covers won't cover the fuse?

This is what it all looks like at the moment.
BTW those covers on the joining boxes are a pig to get open hence I'm not shutting them till last minute.

 

[wallport]

I'm seeing mention of rubber covers for under seat fittings. Could I just knock something up from a sheet of rubber to go over the top of the battery and a few cm down each side?

One other question - is my bm2 superceded by the BMS in the fogstar or should I connect it too?

 

[ginkster]

I'm seeing mention of rubber covers for under seat fittings. Could I just knock something up from a sheet of rubber to go over the top of the battery and a few cm down each side?

One other question - is my bm2 superceded by the BMS in the fogstar or should I connect it too?

Yep, no need for the BM2.

All you need is something non-conductive on top to stop anything accidentally bridging across the connections or positive to a ground. You could possibly modify the foam packing sheet that was on top of the battery from Fogstar and tape it to the battery for now. I used these for mine:


Similar things are available in loads of different sizes/shapes so you could get some to fit your setup.

 

[roadtripper]

For a new LiFePo battery I'd always recommend a few charge cycles similar to the forming charge that the cells go through when manufactured if you have the time.

See my post here:

Battery shelf mode

When you say fully charge a couple of times should I look to completely deplete it after the first full charge? My (yet to be installed) appliances consist of 12v sockets and usb chargers so it might take a while! :laugh:

www.t6forum.com

 

[wallport]

For a new LiFePo battery I'd always recommend a few charge cycles similar to the forming charge that the cells go through when manufactured if you have the time.

Well, was planning a trip away but the weather has put paid to that for a few days at least so might be an opportunity for a cycle or two.

I can see that the Victron IP22 does have a low current setting with a custom value - is this how to do it? At say 35%? Any other settings need changing?

Not sure how to discharge as I don't have any 12v appliances like you suggest? A usb fan but I think thats only about 5w, leave the fridge on? Is it worth doing this if I can't manage the discharge?

 

[wallport]

You could possibly modify the foam packing sheet that was on top of the battery from Fogstar and tape it to the battery for now.

Believe it or not I had thought of this and discounted it but you have made me reconsider - at least as a temporary measure. When I get my hands on this fuse assembly, we'll see how it sits.

 

[roadtripper]

Well, was planning a trip away but the weather has put paid to that for a few days at least so might be an opportunity for a cycle or two.

I can see that the Victron IP22 does have a low current setting with a custom value - is this how to do it? At say 35%? Any other settings need changing?

Not sure how to discharge as I don't have any 12v appliances like you suggest? A usb fan but I think thats only about 5w, leave the fridge on? Is it worth doing this if I can't manage the discharge?

You want to charge and discharge around 5A or 50w region - so leaving the fridge on sounds like a reasonable load in that area.

Not sure which IP22 you went for but on the assumption it was the 15A the simplest way is to enable the low current (50%) mode straight from the charger (you can probably do it in the app too) rather than setting up custom charging



Knowing where night mode is will be useful for when you use the van BTW - means the charger will take it easy for 8 hours and be less noisy

Main thing is to just keep on eye on it on the discharge side - the idea is to gently cycle the battery with a moderate load between full and pretty empty - not to run it till it cuts off and leave it flat.

 

[wallport]

OK given up waiting for fuse and strap which Royal mail seem to have mislaid and put the battery on charge.
I've set the victron ip22 to lion and 50% as suggested and here's some screens showing what is going on.
According to fogstar charging info, they say bulk charge at 14.2v but I'm only seeing 13.8. Is this right?

 

[TallPaul_S]

The default Victron lithium profile is fine, it should be 14.2v absorption and 13.8v float.





Remember, in the bulk stage the voltage will rise as the battery charges. 14.2v is the 'full' voltage, which is what the end of the bulk and absorption stages is aiming to get to. Then once it's full it'll reduce the voltage to 13.5v.

 

[Bigsidavies]

When I swapped to LiFePo from AGM I took the black battery selector wire and just connected it to the battery input terminal on the ctek 250SE. That cable comes from the battery, so by my reckoning it a 12v battery feed.
It’s also the way Lee @Dellmassive did it in one of his how to threads.

 

[wallport]

Ah that's the alternator charger - I have also done that wiring change but am charging on hookup at the mo and will test that behaves as expected later.

 

[wallport]

So 100% charged and moved to absorption at 14.2v. Is this as expected? Want to understand for the future as want to just leave it really.

I will take it off charge now and turn fridge on.

 

[TallPaul_S]

Yeah that's it, as expected. It's still technically on absorption stage, once that's ended the charger will drop down to 13.5v.

As for state of charge, well the fogstar app is what you want to be checking, it won't be guessing based on voltage.

One thing to note - once you've gotten the first few charge cycles out the way you won't need to keep the van on hookup, there's literally zero reason. You can always just give the starter a charger every 2 weeks in winter if it's not being used. But there should be no need to keep the LB on charge.

 

[ginkster]

View attachment 242506View attachment 242507
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So 100% charged and moved to absorption at 14.2v. Is this as expected? Want to understand for the future as want to just leave it really.

I will take it off charge now and turn fridge on.

That's good. Leave it to go to float or storage then stop charging. Use the fridge to discharge to 20%ish and charge again - do this a couple of times. It'll take a few cycles for the Fogstar BMS to start reading accurately. If you are not going to use it in anger for a few months then discharge to about 50% for storage rather than leaving it full or constantly charging from the DC-DC.

 

[wallport]

OK it made it to the storage phase and I took it off hookup. Fridge is now on using about 43w or 3.1a but I guess this will become intermittent once the fridge gets down to temperature. Hence not sure how long it will take to get the battery down to the 20% you suggest but will presumably be more than 24 hours, probably more like 48 hours (in future I will of course want the battery to last days with the fridge on).

I think we will go away in the van on Monday so not sure how many cycles we will get in before then or how to play the amount of charge at the point we go. Also, do I keep the fuse out of the d250se so that we don't charge while driving?

To add to the complication I'm not sure if we will have hookup on the site or not as yet. If we do have it, should we only connect it when essential to try to keep the discharging going? Could also pull the fuse between the victron ip22 and the battery so that we would only have hookup (I presume this works)?

Perhaps someone could advise what's important and what's nice to have in the initial charging/discharging regime.

Many thanks again for this. I do want to treat this battery well given what happened to the last one so apologies if I am over thinking again.

 

[TallPaul_S]

The fridge should use about 1ah per hour, I'd whack it down to the lowest temp, you might get 2Ah per hour. So 50hrs or more.

 

[roadtripper]

You can always pop a light on as well?

Keep in mind the the early cycles are an ideal to continue forming the cells and to let the BMS calibrate, don't get too focused on it. If one of the cycles is you going away and having an enjoyable weekend then that's what it's all about!

Don't worry about pulling fuses, if you don't need mains devices maybe do without the EHU and spend the money saved on an enjoyable beverage.

When you get back get a couple more cycles in if you can then relax and enjoy the van.

 

[ginkster]

Mine took 6 days to get down to 25% with only the fridge running so you may want to help it out by putting some lights on and running the heater (good to do monthly anyhow). Roadtripper has it spot on. I’d do what you can over the weekend then charge it back up for your trip (DC-DC if the drive is long enough or ip22 at home) and then use the time away as your next discharge. Unless you need the 240v if not bother with EHU (that’s the great thing with lithium). If you do hook up and want to avoid the battery charging then you can turn the ip22 off via the app. Have a great trip.

 

[wallport]

Yeah I saw it was going to take too long and knew the heater was due 30mins on full so I did that and have turned the lights on (though I don't think I'll leave them on at night as they may attract attention).

Also, all fuses are back in except the d250se so if there is parasitic drain that can discharge it a bit too. Really a simulation of a trip with no hookup on the drive!

Currently at 80% 84ah.