>>2977130
Needs to be a bit higher than 12 V to charge typically.
12 V lead acid car batteries are charged at around 14 V and the battery will drag the voltage down due to the low resistance of the battery and the limited current of the charger.
Which reminds me, you *may* also want to charge with your current limitations, a battery can deliver over 100 A which is nit what you want and may have explosive results.

Lifepo4 has around the same charge voltage as lead acid which is why those drop-in replacement batteries exist

Lead acid 2.4Vx6=14.4V
Lifepo4 3.7Vx4=14.8V
meanwhile other lithium aren't really comparable
Li-ion 4.2Vx3=12.6V or 4.2Vx4=16.8V

What really changes is the charge profile, a lead acid battery will keep absorbing power after fully charged while with lithium the voltage will rapidly increase

-lead acid: bulk charge to 14.4V to equalize the cells and then float charge to 13.8V
-lifepo4: charge to 3.7V per cell, around that number the voltage shoots up and charge needs to be stopped completely

The BMS will disconnect the battery once fully charged which will work but is not ideal as it is designed as a safety and not for breaking current regularly,
also once the battery is disconneted the voltage might be unstable if there's no other place to sink current on the load side.

A properly tuned charger will charge it to a voltage below the BMS cut-off threshold and then stop

>>2977130
BMS only does the following
>under voltage lock out
>over voltage lock out
>over temperature lock out
>gross over-current lock out (probably hundreds of amps)
>cell temperature monitoring
it doesn't limit current during charging.

>>2977130
you just need a current limited charger that puts out 14.6v at half the amps that the battery max charge ratings. if it says max amperage for charging use 10amps. only charge at max charge rate when you need to.

I've got a lifepo4 "drop in" engine bay/cranking battery in my car, no extra charging circuitry just connected directly to the alternator. It's been in there for 4 or 5 years at this point, still works fine. Don't know how it charges itself safely, all I know is if I've had it parked up for a couple of days with the car fridge running then that fucker will pull more than 90 amps out of the alternator at idle next time I start the engine kek.

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Can I use this kind of solar charge controller? It doesn't have a specific charge profile for lithium batteries.

>>2977175
Maybe.

>>2977175
These charge controllers are pieces of shit, they cannot deliver the rated current safely, even half of the rated current is sketchy. That aside, if you knew how the BMS is set up in the specific battery, you could use something like this. Without knowing the overvoltage trigger and overvoltage reset values in the BMS it's maybe less good an idea, but then again, LFP batteries aren't that sensitive, you will get many years out of the cells regardless (only the cells, because cheapo shit batteries can fail in other ways, mostly relating to the BMS).

>>2977154
Every typical solar battery BMS limits both charge and discharge current, only lemons from shit brands don't have the function, and those are considered dangerous.

>>2977175
those do support lithium ion and lifpo4 however. they are only capable of 10 amps max no matter what the specs say.

DO NOT try to use the USB ports. I do not remember why but under certain conditions they can fry your USB device or cause the controller to burn up.

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>>2977255
>>2977272
what is a good solar charge controller? i was looking at one or two of these things rated at 60a. cost about 100-110 aud.
and no victron nonsense, i'm not coughing up $500

>>2977276
I recommend this guys channel he actually test things and takes them apart, he verifies they do what they say or not.
https://www.youtube.com/@WillProwse

>>2977130
Your charger needs some form of current limiting because Lifepo4 batteries have an insanely low internal resistance compared to lead acid, which means the battery is more or less like a dead short across the charger. It will be right happy with pulling 150-300A at most charge levels which will absolutely kneecap your charger or alternator

Not op.
I have a 100mha lifepo4 battery that was replaced under warranty. The old one kept discharging and my charger wouldn't charge it back up.
That battery is dead. I'm getting like 0.05v out of it.
How can I get it to charge up and do a proper load test on it.

>>2977282
The battery is either in a protective state or it's fucked.
1. Open it and check it for signs of water ingress, corrosion, cell swelling, and any charring on the wires or connectors.
2 take any constant 12v supply like a wall wart you cut the end off and connect it to the terminals and plug it in for several hours and then see if it fixes it

>>2977276
Easun is fine on a budget. But generally it's better to buy an all-in-one device, an inverter-charger, unless you specifically only need low voltage DC.

>>2977154
>>2977256
Ackshally brainfarted, some BMS have current limiting, but (most) others only have overcurrent charge/discharge protection. Limits are usually 1C for both, some shittier batteries might have 0.5C. This is still mostly good enough as far as the battery cares, technically the charge controller in itself isn't important to manage the battery (you'd normally use way less than 1C worth of solar panels on any given battery), but the reason you use a charge controller is MPPT, direct DC connection would pull much less total energy out of the panels than an MPPT controller.

>>2977287
If the battery is for emergency purposes, you might want it trickle charged to keep it topped up at like 10 or 20 mA. Likewise, if it’s for nighttime lights you want it charged during the night at a rate that brings it to full charge just as the sun sets.

>>2977289
Dumb chargers aren't gonna have settings like that anyway. Most things on the charger side just run on voltage thresholds, unless you get a charger/inverter that can communicate with the BMS. Though voltage threshold is good enough for a UPS battery since it basically does that trickle charging.

>>2977283
Can I use another 12v battery and connect to it in series?

I tried 2 different charges. A car and one specific for lifeo. They don't detect it and will not output anything

>>2977286
Here, items over $1000 get import taxes. If I bought a combined unit it would be over $1000. If I buy an inverter and a charge controller separately then it doesn't get taxed. The tax is like 30%, which means it'd be like $400. I can buy an entire extra string of solar panels for that amount of money.

>>2977296
To use it and get 24 V? Yeah.
It’s better if the batteries are more or less identical.

To charge them? It’s better to charge them individually, however you can charge them in series. Also, it’s better that the batteries are identical.

>>2977397
https://www.aliexpress.com/w/wholesale-easun-solar-inverter.html
There is no mid-grade market for separate inverters and chargers. You either buy chinkshit for $300 (where for $300 you can buy a way better combined inverter/charger than the individual charger + inverter) or you buy the overpriced shit Victron. You should also have combo units on your own market. Like if you want something you don't have to worry too much about, then the cheapest is something like a single-phase GoodWe or Deye LV hybrid, those are about $1500. Conversely if it's for a low-risk application, like a shed or a small holiday home or RV, then buy the Easun combo inverter and fuse it well.

>>2977296
You mean in parallel?
Sure that will work but keep in mind if it isn't actually broken it will eventually come on and start pulling massive amps from the other battery, use proper big cabling between them

>>2977409
>>2978020
yes I mean use the good battery to forcefully charge the bad battery.
I tried 3 different battery chargers/tenders on it and all 3 say no batt detected and only output 0.50v.
I heard you can use a welder to bring back lead acid batteries back to life by forcing them a ton of amps.
Can you do something similar with lifepo?
I got 8 gauge cables and jumper cables.

>>2978074
Yeah, you can connect a welder to the lifepo and either ruin the battery, the welder, or both. Stop doing stupid shit and either learn how the battery works, or buy the right equipment.

>>2978074
>welder to bring back lead acid batteries back to life by forcing them a ton of amps.
That's more of a NiCd/ NiMh thing
Bad lead acid won't take any current, you need to push them to much higher voltages until they slowly start absorbing more current

Lithium is completely different and you would need to open the battery, locate the bad cell and try to charge it with a lab power supply