These charge times seem crazy

[Bsheffer]

What I was told…..

The 100Ah Lead Acid (LA) battery has a usable 50Ah when brand new and due to internal resistance, they push back at chargers.
This means that if you are filling the 100Ah LA battery from a 20A charging source it will still take the same 5 hours to fill because that battery is only accepting 10A of charge due to the resistance pushback.

The 100Ah Lithium (LI) battery has a usable 100Ah when brand new and due to little to no internal resistance it can accept the full 20A from the charger.
This means you still have a 5 hour recharge time, however, you are charging twice the amount of amp hours back into the battery.


Now that I re-read, I am not sure my reasoning makes sense but I do know that once my lead acid battery got to 40%, I could no longer power things like the coffee pot supposedly due to low voltage. I confused the issues.

[SafariBen]

Yes, the low voltage cut out will protect the lead acid battery based only on voltage, and below 11V the battery would be nearly dead at rest, but under significant load it will cut out while the battery is still 40% in your case, or maybe 20% for a bank of four large 6V, but still at a higher capacity than the voltage indicates.



Yes, the lead will take longer to charge, but it can be pushed to a voltage higher than 14v also. According to this:https://batteryuniversity.com/articl...ging-lead-acid lead acid can be charged up to 1.5C or 150A for a 100A hour battery, hard for me to believe, but a 4 hour rate, or .25C is a conservative rate, that doesn't mean the battery will be FULLY charged in 4 hours, but it may go 0-75% in 3 hours.

[KD4UPL]

It's not so much that LI DOES charge faster but that it CAN be charged faster if the charging equipment is set up right.
If your 100 Ah battery is down to 10% you need to put 90 Ah back into it. If your charger is a 30 amp charger it will take 3.3 hours (more or less) to do that. A LI battery will accept the full output of the charger basically right up until the time it is full. Lead Acid batteries will accept less and less charge as they get full. They might start off taking 30 amps but it will tapper down to almost nothing as the battery is charged. This lengthens the process because the current going into the battery is dropping.
Also, a lead acid battery should only be charged at roughly a C/5 rate for good long life. For a 100 Ah battery that would be 20 amps. A LI battery is not nearly so limited. You could theoretically charge up to about C/2 if you wanted but off course that requires you to have a charger capable of that many amps. You can't just get more amps out of the same charger even if the battery will handle it.
Many chargers that are designed for LA batteries only charge around 13.6 volts. According to post #12 your charger is like this. If you can find a way thru programming or an add on "charge wizard" type device to make the charge voltage more like 14.2 it will charge faster. However, you don't want to just leave it at 14.2 volts across the battery indefinitely as a "float charge". LI batteries don't need nor like to be floated.

[Charlesland]

What converter are using? What guage wire to connect to battery?

[VKSheridan]

We replaced our 400 Ah FLA batteries with 800 Ah LifePo4. We recharge the Lithiums at 150 amps which is more than twice what the lead acid could receive without exploding.

If we are charging using just our 60 amp MPPT controller, we’re restoring the lithiums at just a notch higher than we were charging the FLA’s.

TLDR: Charge time is contingent on your maximum continuous charger output and state of charge PLUS what the battery’s BMS will allow. If the battery is hot, the BMS will limit input amperage to a trickle to protect the battery. Ditto if too cold.

[Loggenrock]

I believe you said your present charging voltage is in the 13.3 -13.6 range. That's fine for a FLA acid battery, but I believe too low to top off a LiPo battery. I'm NOT a Lithium guru, but I believe most Li batteries need a voltage over 14 volts output from your converter/charger to reach maximum capacity in a reasonable length of time. When you swapped the lead-acid out, did you upgrade your converter/charger, too? Some just need to have a setting changed for lithium cells, older ones (like mine..) would need to be replaced to adequtely charge lithium cells. ST

[Visionquest2]

13.6v is WAY too low to charge LifePo quickly and efficiently. That is a good target end point for a full charge with no load, but using it to charge means that it will get there very slowly (i.e. asymptotically). I leave my solar controller at 13.6 basically to just maintain a full charge when in storage and only using 1% or so of capacity daily. (so essentially using it as a daily top-off)


To charge quickly your converter should be set to 14.2 or 14.4 (at LEAST 14), with a "tail current" of 1 amp or so. Does your converter have a "boost" capability? With a higher voltage you will strictly be limited by the current output capability of the converter and wiring. That's also assuming that the BMS in the Battelborn doesn't limit charge current.

[Rufis]

I have a lower end (spelt cheap) Moseworth 100Ah LiFePO4 battery. They're charge instructions: 14.6V and a maximum charge current of 0.5C or 50 Amps. I could charge this fully depleted battery in under 2 hrs. Prefer a C/5 profile - 20A and charge when she's ~50% depleted, using my 2200W/1700W running generator. It powers my 0-15V/0-60A adjustable charger.
I'm doing a capacity test as I type this, the BMS will stop the load draw (a 30W AC bulb) at 10.5V, I'm planning to double the charge current to 40A and compare the times to full charge, hoping it will be around 2 1/2 hrs. Then at 50% DOD my generator run time should be ~ 1 hr.
In my experience the battery manufacturers provide their own specific charge profile, it's the Bible for longevity and efficient charging. I'd reach out to Battle
Born (spelt expensive) for guidance. My hunch is they will tell you 14.6V is mandatory.

[Duner]

Here's the data from the Battle Born 100ah 12 v manual:

How to Properly Charge Your Battle Born Batteries.

"To ensure optimal performance and longevity, it's crucial to charge your Battle Born batteries correctly. Please verify that any charging component in your system (such as converters, inverter chargers, solar charge controllers, or DC-to-DC chargers) are capable of being programmed to the following specifications:
- Charging Profile Bulk/Absorption 14.2V - 14.6V
- Absorption Time 1 hour for a 200Ah battery bank (two batteries in parallel)
- Float 13.4V - 13.8V"


Also, as one member stated above, make sure you have heavy enough gage wire between charger and bat terminals. Typically the manufacturers use minimal size wire. If you haven't beefed it up to larger size you may be getting a significant voltage drop. That will definitely increase the charging time.

When I'm dry camping, I set the charge rate to 50% so I only have to run the generator for 1-2 hrs. When I'm connected to shore power, I charge at 10% and I don't care if it takes all day or all night to fully charge. My goal is to extend the life of the batteries and minimum run time on the generator.

Consider this Victron BM-702 to know exactly what power is going in & out of your batteries. The app on your phone will tell you everything and let you set a SOC alarm so you'll know when to fire up the generator dry camping.

Good luck,
Bill

[SafariBen]

Originally Posted by Rufis

... I could charge this fully depleted battery in under 2 hrs...

Maybe, maybe not. It will charge at .5C for much of the range, but like lead, it will slow near full.


According to battery university, lead can be charged at faster rates during the bulk phase also. The HUGE difference, is Li is happy being charge from 10-60% in one hour and then cycle back to 10 or whatever, while lead wants to get to 100% ASAP and stay there any time it sits. Lead will also loose more power in the process, possibly many times the loss of what Li loses, so if Li is 98% then lead might be 90% at the same rate.

[Tilted Kilt]

Originally Posted by Bsheffer

Hey gang...new 2024 Thor Tiburon Sprinter 25 foot....

I recently had my 100 AH lead acid replaced with a 100 AH Battleborn Lithium. Not a cheap battery. Usage capacity and decreased charge time was the goal.

In the end, I am nowhere near the charge time decrease I expected. I ran a bunch of experiments and regardless if I charge the battery from the 3000 watt ONAN generator or plugged into 220 power, it would take at least 3 hours to fully charge the battery from 10%.

When I look at my power control panel, it shows the amount of power going in or out of the battery. Depending on the starting capacity of the battery(And I ran tests at 95%, 60%, 35%, The input wattage I saw was 77 to 477 watts.

From what I could tell, due to be very overcast, I was NOT getting any charge from the solar panels.

Obviously I could be missing something and maybe my exceptions are way out of line but I would have envision a full charge in for instance an hour.....at the most. The wildcard is I have a little bit of concern about the dealer install. A couple screws that held the LCD control panel were just laying out and when I went into the electric panel configuration, the charge profile of the battery was still set to AGM. Obviously I changed that to Lithium and is reflected in the tests as discussed above....

So I guess the question is.....if you have what seems to be a somewhat standard 100 Ah Lithium Battery, how long does it take to charge and from what source?

Lithium people can be zealots so be careful, but just dump a ton more money into it you'll be fine. I love my lead acid batts, cheap to buy and available everywhere

[David 70]

Charging at 100 to 150 amps seems like an awful high rate for any battery. That type of amps is close to what my charger puts out when I set it to start boost for starting an engine when the battery is dead. That charger has large cables and short, 2-3 feet.

[VKSheridan]

I hear ya David. My batteries are rated at 200 amps maximum charge rate. I can’t speak for other brands but that’s the maximum spec. for mine.

[JorgeS]

Bessemer, take a look at the specs on your charger. It may only put our 30A max.
The 3000W generator can provide enough energy, but if your charge current is 30A max, that's all you'll get.

Also check the voltage at which the charger can reach. Mine goes to 14.3V which is good for Li-Ion batteries.
If your rig came with one battery, 30A may be all the charger can put out.