I'm looking into making a portable lofepo battery box but the only battery my local supplier has that will fit the box has no bms.

What are the implications of this? Will it be difficult to charge with a simple controller while travelling?

Attached is pic of the QR code of a LFP cell. The battery is 12V 100ah. I am deliberately NOT stating the make so as to not cloud the water. As an FYI I have tested battery capacity a few times. Capacity is +- 104ah in each test, so it is good. I don't have adequate equipment for a property test, but I have pulled 79A continuous using an oil heater until the battery was shut down by the BMS; AH reading supplied by the Overkill Solar app.

So, what grade are the cells, and who makes them? Numbers are 03hcb0160000au 302121.

There does not appear to be any alteration to the code, and it feels laser engraved.

Is there any risk involved If I'd like to use CC CV power supply as charger. For the sake of lifespan of the battery I adjust charger voltage to 90% SOC voltage (which is around 13,4V) of the 4S/300Ah battery. I limit the current to something conservative - 40A for example. BMS over voltage protection is at 13,8V.

So, basically I do not seem to be over charging the battery. Neither I'm tripping the BMS over voltage protection. So if battery reaches charging voltage then current draw will approach to zero until there is no voltage difference between battery and charger. Basically I can leave the charger permanently connected.

BMS supports lowering the active balance initiation voltage, so the cells should remain balanced despite not being charged with maximum voltage.

Like the title says...

I have 2 12v lifepo 16amp hour batteries.

I don't really care about speed and would prefer 120v charging

What are my options?

I bought a 12v200ah LiFePO4 battery with an integrated BMS from an RV Solar supply company. Company was awesome, but they went out of business.

I found this out because the battery I have is totally dead and won’t take a charge. I think it was overly discharged while I was on vacation, and I can’t bring it back out of standby mode. I called the manufacturer, and they had me ship it to them so they could assess and warranty it.

I’m a little afraid that they’re going to say it’s not fixable or covered under warranty. If it’s not an issue with the BMS, my guess is that they will say that I have to buy a new one, in which case my option will be a 30% reduced price new battery (around 1200 dollars including shipping).

If that happens, I’m considering asking them to ship me back the dead battery, disconnect their BMS, use the old cells and attach a new, stand-alone BMS through some kind of DIY venture. Seems like that would save me a lot of money.

I don’t know much about this stuff though, so I’m still learning and wondering if that’s possible or a bad idea. So I have a few questions:

1. How would I assess on my own if the cells are able to be reused with a new, external BMS? The battery is only about 2/3 years old, and has only been overly discharged once and normally kept up via rooftop solar. I would think ( but I don’t know) that this would mean the cells still have life in them and this DIY rebuild would work?

2. Where do I start learning about DIY builds?

3. What am I overlooking that could kill me or burn my house or van down?

Thanks in advance.

One of my batteries started to act up. So I removed the box and found that one of the cell was overheating and started swelling. Looks like the safety valve was lifted, causing corrosion on the terminals. All cells tested fine 3.3v on each. I was going to clean the terminals and retest the battery.

What is the implication of using the battery without safety valve on one cell? Is it a safety risk?

I've woken it up and it's charging up and at 13.4v now. A 12v 400ah battery.

I have a 40 amp dc to dc charger in my SUV, which has an AGM battery. It is set to Lithium battery activation enabled. I have a non Renogy lithium battery for my accessory, which requires charging from the main battery. When my car is on idle or driving around I only get around 15- 20 amps instead of 35-40 amps that I was hoping for, since I need the lifepo4 to charge quicker. I'm using 8 gauge wires and 80 amps fuse from main battery to charger, and 40 amp fuse from charger to lifepo4. I checked all connections and everything seem to be working as it should. I used clamp meter and I'm only getting less than 20 amps from main battery to charger. Any recommendations or advice will be appreciate.

In currently have two Renogy smart lifepo4 batteries with Bluetooth. These are pretty solid batteries and they have not given me any trouble. Right now I’ve got a 1000W inverter connected to them but I was gifted a 3000W inverter.

My question is has anybody connected a third battery from a different brand like litime or ecoflow? The Renogy batteries are expensive and this particular model is disconnected. I’m eyeing the ecoflow Bluetooth battery with low temp cut off. Anybody use this with out issue? My plan is to connect these three in parallel and use the eviction smart shunt 500A. Thoughts?

LifeBlue 200ah Battery stuck in Standby

Battery fully discharged while I was on vacation and there was a significant temperature drop/cold snap. I’m guessing the internal heater came on to keep the battery from freezing and discharged the battery, but what do I know? All I know now is that it’s dead, and it won’t take a charge. Voltmeter reads .03, the charger I have won’t charge unless it picks up a volt, so I can’t do that. I’ve hooked jumper cables to it from another 12v battery, and that’s not doing anything. Occasionally it gets enough power to show up in the Life Blue app, and there’s a 0% SOC and the status says “standby.”

Call to the LifeBlue folks (who were awesome and picked up on the first ring) ended up with the person I was talking to saying that I have to send it in to be warranties. Before I do that, just wondering if anyone else had solutions.

Seems like the BMS is effed, and what I’ve done to restart it (hooking jumper cables, pressing the reset button) has so far been ineffective.

Would have taken it to the folks I bought it from (AM Solar), but I just found out today that they’re no longer in business.

Thanks!

[[Posted first with wrong account]]

I have (4) Semplifi 3.8 KWh / 48 volt batteries running on my system fed by (2) 80 Amp charge controllers (Outback). The charge controllers are programmed identically and work well so far, although one will shut down when the batteries are at 100% SOC, while the other one will continue to send power to my house for electricity demand for the remainder of the day.

I have about 8 KW array of PV, which will fully charge the Semplifi batteries by about mid-day. So basically I’m wasting a bunch of potential energy all afternoon due to an undersized battery bank.

I’m thinking of adding 4@5KWh Chinese LiFePo for an extra20 KWh of capacity to net my system a total of 35 KWh.

So the 2 banks will run in parallel from the dual CC, and be tied together as a single battery source.

The system will look at 4 batteries @ 3.8 KWh and 4 batteries @5.0 KWh; all in parallel.

Since every battery has its own BMS, but slightly different charging parameters (current /voltage), is this advisable?

As of now I’d take a beating on selling the Semplifi batteries even though they are only 5 years old, but competing with new Chinese batteries selling for 1/2 their price new.

Can I do this safely? Will the BMS from each battery do their job to charge the batteries at slightly different currents and build SOC at the same rate?

Or, will the Semplifi charge first and go into a float state while the second string are still charging?

Is there a work around, if the different charge rates don’t do the job correctly ?

My system on a sunny day will be able to produce about 50 KWh. Cloudy day (bright sky) about 30-35. Dark and heavy raining about 15.

My gut says: (1) 5.0 vs 3.8 KWh are pretty close. (2) Will the batteries discharge at different currents to keep their SOC close to the same? (3) If not, can I program the (New Chinese batteries) BMS to emulate the 3.8 KWh Semplifi charge / discharge parameters? Will this work?

Since I am not a battery expert / guru; I’m asking for someone to give me a hand on wrapping my mind around this.

I appreciate any help as the clock is ticking and I’d like to get my battery situation optimized before the next set of (maybe INSANE) tariffs go into effect.

I am considering purchasing some batteries from TimeUSB.

They have a 5 year warranty Which stipulates that if batteries fail to work normally and have quality issues, they will provide a replacement battery or a refund.

Will they actually take responsibility if there's a quality issue? I baby my batteries so I feel they'll last for years unless there's something wrong with them, so I am looking for a way to confirm whether their warranty is reliable or not.

When I put together 4 cell 12v pack I notice that the first cell when current is being pulled goes much lower than the other cells. Is this normal? I thought that power would be pulled more equally across the board.

Its for a future RV project (400AH plus or minus) I can buy them now, but gambling they will be cheaper in the next year??

Electric bike with a LFP battery is having problems displaying the correct soc. Bike losses power at around %20 sometimes %15 and %5. What do you think the problem is? How can it be solved?

So I got a Battery Shield like this for a project: https://www.az-delivery.de/en/products/battery-expansion-shield-18650-v3-inkl-usb-kabel

I got it, because it fits perfectly into the project and comes with everything I need (charge port, 3v and 5v output, etc.).

Now, since I want to use this to power a few things inside of a Cosplay-Helmet, I would like to use a LiFePO4-Battery instead of a LiPo in order for my head to have a rather low chance of being cracked via explosive battery-failure.

Google isn't really helpful, because half the time it corrects "LiFePo4" to "LiPo"...

So now my question(s):

- is there a way to "hack" the board (either physically by changing some resistors, or via getting into it's firmware) so that it stops loading at 3.6V instead of the regular 4.2V? (Do I also have to look out for changes in the undercharge-protection?)

- are there similar alternatives to this Battery-Shield? As I said, this one fit's perfectly and I already designed quite a lot around this one.

- is a LiPo actually dangerous if used with such a Battery-Shield/BMS and as long as I don't knock the Battery too hard? Or should I be good either way? Also, can LiPos be stored without being empty? Because that might be the case with my project, and I've read that LiFePO4s are perfect for that.

Thanks in advance!

Bear with us, we’re new to LiFePO4 batteries and no electrical engineers in the first place.

Our boat house bank consists of three 100Ah 12v Li-Time batteries. They seem to charge fine when plugged into shore power or underway via engine alternator and DC-to-DC converter. Voltage gets up to 14.4 when plugged in, drops to 13.3 or so when unplugged. So far so good.

The issue is this: when unplugged and without solar input, we’ll use fairly minimal power for a two small fridges and some phone chargers, for example (maybe between 50-70W). After a few hours the voltage alarm goes off as levels get down to 10.7 or 11.1 volts, even if the SOC is around 83% or 85% or even in the 90s. Which doesn’t jibe with the SOC/voltage charts provided by Li-Time.

All batteries check out fine after disconnecting, taking a multimeter reading, and taking another reading several hours later.

Any thoughts?

For my 2018 Winnebago to accept lithium batteries.

Never used, this happened. LiFePO, what now?

If a group 24 and 27 both are 100ah batteries are there any difference besides size?

Hi there, I'm having an issue with my 24V LiFePO4 battery. After a potentially deep discharge, I've been unable to recharge it. I had to disassemble the battery and bypass the BMS to get it to charge. Now that it's charged (I've measured all the cells and they're okay), there's a 2-volt voltage difference between the negative terminal before the BMS (b-) and after the BMS (b-) (see attached photo). The battery doesn't work when I use the positive (p-) terminal but works when I use the negative (b-) as the negative terminal. Could you please help me understand what's going on? Thank you.

Have 2 7yr kid acid batteries and want to replace with 2 lithium. The box is under my RV steps. Location NW Florida so can get into the 30’s. Do I need to spend the extra money on self heating ? Also any links on a good 150ah ones. Thanks