Charge controller question for lithium batteries.

[BGMAC]

Doing some research and admittedly I’m not very smart about this stuff, but I’m trying. I also looked at previous posts, but I didn’t see anything so here goes.
I have 4 lead acid 85AH batteries with a Progressive Dynamics converter/charger model PD9270 13.6 amps output.
I’ve read/heard you should change your controller to output 14.6 volts to completely charge the battery which I understand.
Now I have also have read that you can use one like I have, but it will only charge to 80%-85%, but may charge higher over a very long period of time. It also stated it would make the batter last even longer.

Looking for thoughts on this. Keep in mind, I’m not wanting to do major changes to the motorhome. Just wanting better batteries before my trip to Alaska. The 400AH lithium battery at 80% is far more then what I have now.

https://www.amazon.com/gp/product/B0CMQ8R747/?tag=rvf01-20

 

[Neal]

Take a look at SOK too. I've been impressed with what I've seen/read on them:

Amazon.com

 

[BGMAC]

Take a look at SOK too. I've been impressed with what I've seen/read on them:

Amazon.com

They maybe good or even better than what I’m looking at, but nearly 4 times the price, I can’t justify that. One thing I look at is not getting to carried away and be overpriced on the motorhome. Going lithium is a nice upgrade when reselling, but the price needs to reflect the type/age of the rv. Unless your keeping it forever.

 

[TheLooks]

It is true they will last longer. You just lose 15% of potential power. If this is more then you currently have as you can draw down much further, it is a win.

 

[Kevin D Pem]

Some real answers!
You say lead,then you say lithium!!!
For lead 13.6 is the second stage of a three stage charger. First stage is 14.4 this is ideal up to 80% charge. Second stage is 13.6 this is ideal to charge that last 20%. This 13.6 assures the battery does not overheat. The 3rd stage only maintains a full charge.

Lithium is different!!!

The charger voltage should be set at the battery manufacturers recommended voltage! This can vary by battery manufacturer and is based on. The BMS built into the battery bank. The majority of BMS units are passive equalizer types. They use resistor networks to equalize the cells, keeping them at an equal voltage. For this network to function the charge voltage must be at specified voltage!!!

You can use lower voltages to charge your bank, but they will not ever equalize. When lithium batteries are allowed to become unbalanced, they become a fire hazard. This is why it is recommended to allow your car to get a full charge occasionally.

Note: there are active balancing networks out there but the cost is high, and would make those batteries appear over priced.

 

[BGMAC]

Some real answers!
You say lead,then you say lithium!!!
For lead 13.6 is the second stage of a three stage charger. First stage is 14.4 this is ideal up to 80% charge. Second stage is 13.6 this is ideal to charge that last 20%. This 13.6 assures the battery does not overheat. The 3rd stage only maintains a full charge.

Lithium is different!!!

The charger voltage should be set at the battery manufacturers recommended voltage! This can vary by battery manufacturer and is based on. The BMS built into the battery bank. The majority of BMS units are passive equalizer types. They use resistor networks to equalize the cells, keeping them at an equal voltage. For this network to function the charge voltage must be at specified voltage!!!

You can use lower voltages to charge your bank, but they will not ever equalize. When lithium batteries are allowed to become unbalanced, they become a fire hazard. This is why it is recommended to allow your car to get a full charge occasionally.

Note: there are active balancing networks out there but the cost is high, and would make those batteries appear over priced.

Thanks for the info.

On the lead acid battery chargers I did know of the charging and floating functions, but that was about it.

On the Lithium, I did read about load balancing a bank of batteries was important. Avoiding that I was replacing my current 4 lead acid batteries with only one Lithium battery.

Side note: This is the one bad thing about the internet. There is so much information that is inconsistent. It’s hard to figure things out sometimes when very little about a subject.

 

[newmarokie]

I just put 3 SOK 206AH batteries in my coach. I did not charge/discharge properly and have spent the last four days getting them right. When I got them right, they settled in at 209, 215, and 218AH hours each. The only additional equipment change out was a Li-BIM. Some here say that won't work, we will see. I was about $2200 dollars all in.

 

[Kevin D Pem]

I just put 3 SOK 206AH batteries in my coach. I did not charge/discharge properly and have spent the last four days getting them right. When I got them right, they settled in at 209, 215, and 218AH hours each. The only additional equipment change out was a Li-BIM. Some here say that won't work, we will see. I was about $2200 dollars all in.

And the seller knew they were going in the same system?

Unbalanced from the get-go Hmmmm

 

[John Burke]

You may be able to turn off the smart charge (3 stage charging) and go to straight max charge which is your 14.6 volts. On my Jayco, not sure the model number of the convertor, but on mine I go to where the green trouble shoot light is, on the convertor, and there is a switch. A tiny, repeat, tiny switch which allows the smart charge to be disabled. On one side of the switch it says LA and the other says LI, for lead acid and lithium. I just moved the switch and my lithium batterys are charged like they should be.

 

[newmarokie]

That is where I failed in the initial charge/discharge cycles. It is common on the SOKs to see them come in with slightly higher capacity than they are marketed. I wasn't getting full discharge/charge to the point of BMS kicking in. Smart chargers or inverters are a problem on the initial cycling that SOK recommends. I have figured that out and am getting there.