Lithium Upgrade - Converter charger

[pvelit]

Hello, I have a question: Can I use a "voltage Booster" after my smart convert/charger (3 stage charging - 45 amp) to boost the 13.6V to 14.4V needed by my new Lithium battery?

I just updated to new Lithium batteries, and a 300W solar panels. However. I would like to also be able to charge my batteries using the original converter/charger when plugged into AC power.

The "voltage booster" I have... I can set up the:
- Max output voltage from 12 to 60. I will set it to 14.4 or 14.6
- Constant current regulator. I will set it up to 30 max.

Looks like it should work. However, I am confuse on how the converter charger will behave since it has the 3 stage automatic charging.

If anyone has any insight please share.

Thank you,

[craz_z]

ScottG wrote:
So you could drop any BMS equiped LI battery into a common, converter charger designed system for standard wet-cell batteries and it would do fine on its own?

With a drop in lead acid replacement lifep04 battery the short answer is yes the bms will take care of the rest.

Ideally solar is the best way and only turn on the converter as needed.

With any solar charger that is programmed to not absorb or float and cut-off at 14.4 ideally 13.7 I see NO advantage whatsoever in investing in a lithium specific charger.

Without solar I would not just leave the converter on 24/7 plugged in 365 days a year. then i would consider a lithium charger but if your a rv park person lithium was kind of a waste of money.

[2oldman]

ScottG wrote:
So you could drop any BMS equiped LI battery into a common, converter charger designed system for standard wet-cell batteries and it would do fine on its own?

Not from what I've seen. Li's need a charger rated for their needs. Now, whether an acid charger would actually damage an Li, that I do not know.

A BMS does a lot of things, as pointed out in the OP's batteries' spec sheet, but it does not change the input charging voltage to what it requires.. if that's your question.

[ScottG]

So you could drop any BMS equiped LI battery into a common, converter charger designed system for standard wet-cell batteries and it would do fine on its own?

[2oldman]

pvelit wrote:
I have two AIMS lifepo4 100AH each.

Looks like a good choice.

[pvelit]

I have two AIMS lifepo4 100AH each... Very happy with them. they have all the BMS functions of a battleborn, except the Temp management. No problem for me...I don't use the RV Trailer in the Winter. I store the Batts at home during winter.

[2oldman]

pvelit wrote:
Yes, my batteries should have a BMS... So, i should be fine.

You should already know that, but you haven't told us what batteries you have.

[pvelit]

Thank you for explaining all that! Yes, my batteries should have a BMS... So, i should be fine.

[craz_z]

This question depends on what batteries you have?
drop in replacements or home built lithium cells.

Drop ins you can use anything you want to charge them. BMS controls all functions as to how they are charged LVD HVD LTD especially if we are talking about battleborns. Other brands do not have low temp disconnect. NEVER charge below freezing.

Since you have solar let the solar do its job on the highend and you can monitor any charger for the "bulk" for fast charging.

If you want to maximize cycle life end the charge at 13.6-13.7 for LIFEPO4 Lithiums don't like to be at 100% at all times they live much longer at 80% SOC even Tesla recommends this on their NMC batteries.


They don't mind 100% but not forever cell degradation happens at very low cell voltage and at very high cell voltage of their charge curve.

The advantage of Lithium specific chargers are high amps for fast charging and complete cutoff at the 14.4 level. You wont find this in a regular charger as the absorb, float and equalize are all functions lithium does not want or care about.

Again if its a battleborn the BMS will take care of everything for you without a thought of damaging the cells.

Also if you are hooking up to utilize the charging off your alternator disconnect the battery or buy the battery isolation manager. You will toast the alternator eventually as they weren't designed to run wide open all the time. you start your car alt is asked to replace the amps then goes to a sleep mode where as if lithium is involved it will ask for anything the alternator can put out amp wise. dramatically shortening its life.


Now if its a home built system without BMS you need to monitor the voltages per cell and don't go over 3.65v per cell. Victron LVD with bluetooth will handle the low voltage and you can cut the power anytime you like with the phone app. Solar charger must be programmed if you can't program your solar charger dont use with lithium. without a bms Morningstar is harder but works, victron is the easiest with a lithium charge alogorithium built in plug n play.

BMS's are coming online with ebay and aliexpress, battery hookup if you don't want to monitor your batteries basically turning it into a battleborn.


If you look at the charge curve of lithium they live happily between 12.0v and 13.3 once you go outside of that they either charge rapidly or fall rapidly if you go past 14.4 or under 10.6 those are the only times you risk doing damage to a lifepo4 cell whether its prismatic or cylindrical.

[pianotuna]

ScottG,

Li are finicky about how they are charged. For example, they prefer to not be float charged. Lead acid on the hand love to be floated.

ScottG wrote:
I'm not up on this stuff but I wonder why the booster wouldn't work.

[phemens]

I echo the sentiment. Get a charger that can be programmed appropriately. The LIFePO4's don't like float/absorb charges

[ScottG]

I'm not up on this stuff but I wonder why the booster wouldn't work.

[pvelit]

Ha,ha,ha...I am a curious guy and I like to see if things work... if they do, then, why not. However, I guess you guys are correct. I may just go and buy a new charging system... but I may buy the booster and try it anyway 🙂

Thank you all!

[pianotuna]

I echo what 2oldman says. Expensive batteries need a proper charging system. This is not the time to be cheap.

[2oldman]

pvelit wrote:
Instead, if this works, I will spend only $15 for the Voltage Booster... just trying to save some money.

You just spent a lot of money on those very nice batteries. Now is not the time to get cheap.