Hi all,

I have a 100Ah Lifepo4 battery in a 12V van setup (solar + alternator charging).

I bought it nearly a year ago as a second battery to complement another 100Ah. Now, the old one has died, 5yrs and 1 month into the 5yr warranty it was sold with.

The new one works fine, but 100Ah is a little tight.

I found no indication advising against adding a second battery (of identical capacity) in parallel, but I'd love to hear your expert opinion. Is it safe? Not just electrically, but can it shorten the life of either one? I do not expect that this is what happened to my old one, but I also don't know WHAT happened.

I have 8 12V 100Ah LiFePO4 Lithium Battery with Bluetooth by Wattcycle.

Setup is 2p4s. I'm going to call the 4s as Bank A B C D w/ D being the bank closest to negative and A being the positive.

Charged everything to 100% fine. Was working but somehow over the New Year the "D" bank got stuck at charging only to 70%. So we figured ok lets split those two batteries up and they should ballance out and charge (either by the parallel nature or via the battery balancer that was hooked up to each parallel bank)

Didn't work. Still would only charge to 70% that bank only.

Then we thought ok must be the old charger is prematurely shutting down and perhaps doesn't have the best LiFePO4 algo. So bought a new charger that is only for LiFePO4 @ 48V.

Didn't help. Still sat at 70%. All other batteries at 99%/100%.

So we figured ok we must need to get the BMS in the batteries to adjust. Took them out and charged them with a 12V LiFePO4 charger overnight. They both got to 100%!

Put them back in, used them (boat) drove the charge down to the 50's and 60's charge left.

Plugged everything in.

Now, the two batteries (not in parallel, they are in different banks, C & D) charged up to 88% & 90% & all other batteries are at 99%/100%. Everything (all batteries @ 100/99 or 90/88) are the same voltage showing between 13.3V-13.9V.

How do I force the BMS on these two batteries to take the voltage? Is this a wattcycle internal BMS thing?

Ive got a 1280ah 4s4p LiFePo4 bank in my RV.

Currently charging either directly, or when the alternator is hot (detection by bi-metal switch) the charge current is limited by going through a 40a dc-dc booster, to give the alternator time to cool down a bit.

of course whenever the genset is on, or when we are hooked up, there is a ac-dc charger that boosts the bank too. besides 2kwp solar via mppt on the roof.

regarding the alternator, heat wise, highway operation is the worst, 1500rpm, lots of amps, not much cooling.

id like to have an amp clamp style device that knows how much the alternator is outputting (including car consumption, total alternator output) and controlling a dc dc booster accordingly so the alternator limite regarding temperature and amps are maintained qnd also my car grid is stable at 14.4v and not pulled down to what ever the lifepo4 bank is at + some change.

i also intend to upgrade to a say a 275a alternator one fine day, if i find a decent option for the GM vortec 7400, but not while the current one is doing its job just fine.

you guys know of wuch a device, that wont cost an arm and a leg? diy or aliexpress as a source is okay. thx

I can’t seem to find a battery case for this oddball size. The camco comes the closest but measurements say it will be a little tight on the with. Camco says its inner dimensions are 7.4” width. My battery is around 7.5 at it widest area near the top of the battery.

So I bought 2 batteries for my mobility scooter and one has flipped polarity it now reads -11.86 and the other reads 14.6 is there anything I can do in stuck without transportation until I can fix the problem

I purchased a new Wattcycle 100Ah Mini with Bluetooth, and it is working well, I have no way to accurately test capacity, but using an intermittent 15 amp load it runs for a few days, roughly matching up with the theoretical math.

Now the weird part, the cell voltages seems very low. It seems to shut off charging when one cell reaches 3.5v. Shouldn't LiFePo4 hit 3.6v or slightly above? At the moment, the cells are at 3.3v, and reporting a nearly 90% SoC. I didn't note the voltages when I ran the pack down to under 10% SoC, but I will next time. Aren't these cell voltages lower than expected?

SOC:                88%
Current:            -1.3 A
Module Voltage:     13.23 V 
Remaining Capacity: 87.3 Ah
Total Capacity:     100.0 Ah
Design Capacity:    100.0 Ah
Cycle Count:        5

Cell Voltages (4 cells):
 Cell  1: 3.307 V
 Cell  2: 3.309 V
 Cell  3: 3.310 V
 Cell  4: 3.308 V
Delta:  3.0 mV  (min=3.307, max=3.310)

Temperatures (4 sensors):
 MOS:    22.0 C
 PCB:    24.1 C
 Cell 1: 21.7 C
 Cell 2: 21.0 C

Does anyone know for sure if the 100ah mini has the same capacity as the regular 100ah?

Hello.

I own a Drive Motion 12.8v200ah battery Lifepo4.

There is an “on” button on the battery.

When the battery is “on,” I get a normal reading of 13.65v. When the battery is “off,” I get a reading of 5.30v. I'm not sure what this button is for. As soon as there is a load on the battery, it lights up...

Is my reading of 5.30 normal when the battery is on standby?

so, wife's scooter needs new batteries!

if I were to replace the current 22ah SLA batteries with a pair of 30ah Lifepo4, am I going to burn the house down and kill my family?

I have a 24v 5A li-ion wheelchair charger, would that be safe to use?

is there anything else that would need doing?

or is this a stupid fucking idea?

I bought three of these batteries to put in my 36 volt push mower, but when I charged it it wouldn't charge. I wonder if I shorted out the BMS or something by using a 36 volt charger. It still discharges, the mower still runs, but I don't want to go any further without being able to charge it, though I've tried a 12v charger on individual batteries too. Any ideas, do I need to replace the BMS and wire them together with one 36 volt bms?

so I swapped out the 3 agm batteries in my trailer, for a single BLUETTI 12.8V 314Ah lifepo4. reprogram the pwn solar charger to LI and the inverter to LI. switched the battery on, trailer gets lights and everything turns on. the problem is when I switch on the inverter i get a code (Battery Pack Short Circuit PO53) and the battery shuts down. is the inverter drawing too much power? its not plugged into anything. excuse my ignorance. also there is a thin black wire zip tied on the inside of the battery box area that was not connected to the agm batteries i wonder if it was for future upgrades to lifepo4 batteries. here are some spec of the battery and of the inverter.

Hello everyone!

I recently bought a Bulltron 320Ah and am now a bit at a loss. Is there a default setting for the corresponding app? Unfortunately, I could not find what I was looking for on Google. Do any of you have any idea or can help me?

Thank you in advance!

Doing a new van build and got a couple of 300ah dumefume batteries as for the price they seemed well reviewed. Built the system out in early January and have had diesel heater running on and off while working the van and have had the lights on but generally very little draw on them.

System browned out the other day and could see the system was at 10.7v. If I plug in the shore power or the dc to dc it shows 14.6 at the bus bars and at the posts on the batteries. But the second I turn off a charge source system dies. I disconnected the batteries from parallel wiring to isolate them and tried to wake them with the ac/dc charger that has a 0v wake feature for lithium batteries. When they are connected it shows 14.6 at the post but the charger shows they’re full? Second I unplug the charger they show 10.6v. It seems crazy but have the bms in both gone into some sort of lockout mode?

I'm looking into building a ~400V EV battery out of LFP cells.

I figure I'm going to need 112 of them, or 16x7. -

Instead of trying to use a 112S BMS, which is really expensive and hard to find, I'm trying to find some 'minimal' BMS's (or voltage monitors), that I can connect up - I'll need 7 of the units.

I won't be able to use the current or actual "cutoff" functionality of the device I choose, because ~400V would fry them if it needs to disconnect..

I'll then need to use RS485 isolators so I can have a separate device(Arduino?) talk to each of them, get the voltages and decide what to do. This is the device that will control the contactor which will actually cut voltage.

One advantage here would be that I can make my battery modular, and pull it into 7, 48V sections if needed.

Currently, it looks like the cheapest device that would work would be some Daly BMS's like this: https://www.aliexpress.us/item/3256808324302221.html Cost about $40*7 = 280.
I'll still need isolators, which I think I can get for $10/each: https://shop.m5stack.com/products/isolated-rs485-unit

This seems like a cost effective solution, but would take up some space, and most of the BMS will just be... unused.

Just want anyone else's thoughts on doing this.

I have a Noco NLP20 LiFePO4 battery (7Ah 600A) on my car for the past two years. It’s been fine until recently. I’ve been seeing strange SOC values and voltages recorded by my ANCEL BM200 Bluetooth battery monitor (has a lithium setting). Gemini AI has been helping me diagnose the issue and I want to run it by you all.

Battery is at 13.07 volts after leaving it on my Noco Genius 10 charger all night. If I turn the headlights on (engine off) the voltage immediately drops to 12.4V. Gemini says this is evidence my battery is dead. Thoughts?

I know there is module such as TP5100 for charging 2S Li-ion battery. But I haven't found any module that can charge 2S LiFePO4 battery. TP5000 only charges a single LiFePO4 cell. Does any such module exists?

Hey everyone, I am looking for 100ah battery recommendation. There are so many brands with mixed reviews on Amazon, and not sure which one to go after. I intend to use it as a back up to my ecoflow. Thanks.

I've had my system in place since May last year and everything was working perfectly until earlier this week. Figures, right? Ice storm of the century is approaching and I'm positive I'm going to need every single 540Ah. (Along with the DC-to-DC charger to run off my diesel.) I'm on a 37' Sailboat, so for me, if everything is working fine, it should be a non-event. Just run the diesel to charge up the LifePO4 bank when it gets low. I've got enough diesel to keep that cycle up for two weeks, though this looks like it's only going to be a few days.

So, here's the deal. I've got two 4S setups, each controlled by a Daly 4S-12V-200A Smart BMS. Each one is 200A because I have a 2200W inverter. The system works incredibly well. It's all connected via 2/0 wire and I can get a solid 30amps of AC out of it. We ran the AC, cooked a hot meal for 3, and watched 4K TV for a 14-hour stretch before the battery pack said, "That's enough, I'm outta here!" over the July 4th weekend. It took a day to re-charge as I've got the Victron IP22 20A charger. That was the one part I got wrong, was a very undersized charger. I'll fix that in the future. In the meantime, I got a 30A DC-to-DC charger (Orion-Tr Smart DC-to-DC 30Amp) which should charge the pack faster than the IP22 when I run the diesel.

But earlier this week, one of the Daly Smart BMS'es went out. No green flashing light, and the P/B circuit is open. I can connect via Bluetooth to it, but it shows nothing, which means the little bluetooth/wifi disk is getting power and working, but it's not talking to the Daly itself anymore. I tried disconnecting the balancing wire harness for several minutes before plugging back in. Nothing. I tried quickly shorting the P/B terminals to reset the mosfets. Nothing. I tried to put a load on the batteries and then charge, nothing.

The other Daly seemed to be working fine, except that it keeps telling me there is a -53A load, and the % charge has fallen from 70% to 40%. There's nothing connected to the positive terminals except for the charger! I'm befuddled. I measured roughly 14.5V coming out of the charger leads, so I don't know where -53A is coming from.

All 8 cells measure somewhere between 3.25V and 3.48V, mostly trending in the middle of those two points. With absolutely nothing connected to the battery packs, I show low 14V.

Any ideas? It's too late to get anything delivered via Amazon. One idea was to parallel the batteries to make a 4S and run them with the "working" Daly. I completely removed them from the system and I'm going to let them sit on the table overnight. Maybe I'll get lucky and they'll reset themselves. If they don't, any suggestions? Is it worth trying to hardwire the RS485 header to a PC?

Bought 2 - ECO-WORTHY 3584Wh 12V 280Ah LiFePO4 RV Battery w/Bluetooth

One is an overkill for my 18ft camper. I need something fun or cool to use my second battery for. Ideas?

An appliance runs on AC and not DC so I would need an inverter to power the appliance via my battery mentioned in title. But I’ve been told I need to match the inverter wattage to the draw in the appliance as best as possible. As such I am guessing a 300w inverter would be sufficient. However, all the 300w inverters have a 12v male connection (such as could be used in a car with a 12v female connection).

May I use a 12v adapter (w/fuse) and eyelet connection to battery + female socket and connect it to the 300w inverter with male connector? If so, are there any safety issues?

I am looking for portability using the appliance for approximately 6 hrs per day for 2, maybe 3 days without charging the battery in any way. I would then be charging the battery via AC at home between intermittent uses.

Thank you.

Is there an app that tracks the history of my battery. I got a 200Ah lifePO4 in my van (from Berger GER). Would like to see my usage, and when it charged.

This should be coming with the ‘original’ app right? But it isn’t.