iRV2 Forums

iRV2 Forums (https://www.irv2.com/forums/)
-   Class A Motorhome Discussions (https://www.irv2.com/forums/f258/)
-   -   Replacing new Li-Ion batteries in Class A Motorhome (https://www.irv2.com/forums/f258/replacing-new-li-ion-batteries-in-class-a-motorhome-540270.html)

RichardE 06-09-2021 12:15 PM

To MoHo,

I recently worked with another Newell owner who installed a well known LiOn battery bank and used their CC/CV recommendations to the letter.

This setup was not treating his batteries kindly at all. When he challenged the CC/CV numbers from the battery maker, they quickly said that other setups may work better.

When you have a chance, please post your setup parameters. All of them. There are a few folks following this thread that can help you fine tune them to get the most out of that setup.

Specifically:
Charge current
Charge current time or trigger point to change to CV
CV voltage
CV trigger to turn off. Is it time, returned amps, or something else
What is your low battery cutoff for the inverter?

Are you using an external battery management system or depending upon the BMS internal to the batteries to protect them?

And lastly, how do you plan on using the battery bank? The reason I ask is that if you are a serious boondocker and need all the power available, then that will require a more aggressive charge and discharge setup. If you are a pedestal to pedestal traveler, then a less aggressive setup will work that should give much longer battery life.

And up front, I am not an alternator charge the LiOn guy. I know others are successful with it, but my bank is 1000 AHr, and would fry my alt in about an hour if it were trying to charge a low SOC situation.

757driver 06-09-2021 01:17 PM

Quote:

Originally Posted by vsheetz (Post 5783188)
Here's a pretty good article on the care and feeding of Lithium batteries.

https://www.solacity.com/how-to-keep...tteries-happy/

Overall a great article but I have issue with one paragraph.

“There is no sulphating, there is no equalizing, the absorb time does not really matter, you cannot really overcharge the battery, and the BMS takes care of keeping things within reasonable boundaries.”

Absorb time does matter…..a lot. Yes, you can overcharge a lithium battery and at a much lower voltage than one would think. A BMS should not be relied upon for controlling charging and discharging it should be used as a safe guard if your user settable parameters fail.

mohospinner 06-09-2021 05:57 PM

Quote:

Originally Posted by RichardE (Post 5784808)
To MoHo,

I recently worked with another Newell owner who installed a well known LiOn battery bank and used their CC/CV recommendations to the letter.

This setup was not treating his batteries kindly at all. When he challenged the CC/CV numbers from the battery maker, they quickly said that other setups may work better.

When you have a chance, please post your setup parameters. All of them. There are a few folks following this thread that can help you fine tune them to get the most out of that setup.

Specifically:
Charge current
Charge current time or trigger point to change to CV
CV voltage
CV trigger to turn off. Is it time, returned amps, or something else
What is your low battery cutoff for the inverter?

Are you using an external battery management system or depending upon the BMS internal to the batteries to protect them?

And lastly, how do you plan on using the battery bank? The reason I ask is that if you are a serious boondocker and need all the power available, then that will require a more aggressive charge and discharge setup. If you are a pedestal to pedestal traveler, then a less aggressive setup will work that should give much longer battery life.

And up front, I am not an alternator charge the LiOn guy. I know others are successful with it, but my bank is 1000 AHr, and would fry my alt in about an hour if it were trying to charge a low SOC situation.

Hi RichardE,

My batteries have a built in BMS and I'm controlling them with the Magnum ME-ARC controller to specify the charge settings.

I want to be flexible with my situation. We BoonDock from time to time and plug into park power also. So I'm guessing we are 70% park power and 30% BoonDocking.

Thanks,

Matt

mohospinner 06-09-2021 06:12 PM

1 Attachment(s)
Hi everyone. Thanks for your help so far. I have drawn up a diagram of my "proposed" install. Please take a look and let me know if I have designed this correctly. I am open to your input and looking forward to seeing your comments. Thanks-Moho

Attachment 331560

nvs4602 06-09-2021 06:29 PM

DC TO DC charger
 
Since my converter is not compatible with lifepo4 batteries.
I going to us a DC to DC charger to charge the battery from the alternator and the converter both. To do this I will install a SPDT relay with the converter connected to the normally closed pole. And the alternator connected to the normally open contact.


https://smile.amazon.com/dp/B08F2G1J...ing=UTF8&psc=1

mohospinner 06-09-2021 07:38 PM

Quote:

Originally Posted by mohospinner (Post 5785234)
Hi RichardE,

My batteries have a built in BMS and I'm controlling them with the Magnum ME-ARC controller to specify the charge settings.

I want to be flexible with my situation. We BoonDock from time to time and plug into park power also. So I'm guessing we are 70% park power and 30% BoonDocking.

Thanks,

Matt

RichardE,

I will post initial parameters tomorrow and see how it works. I still don't have the DC-DC charger or Smart Shunt. Placing order soon.

153stars 06-09-2021 09:02 PM

Wrong post

Caymanedge 06-10-2021 10:12 AM

I installed LifePO4 is a similar set-up, same Magnum MS2812 and utilized the ARC control. Set-up is easy and everything is working great. I wouldn't hesitate to do it again.
I also replaced my existing battery isolator with the Battle Born LI-BIM unit to protect my alternator. Connections were simple, but getting everything positioned properly to connect was a challenge. I had to make a bracket to mount it and a few extension cables.

mohospinner 06-10-2021 05:06 PM

Hi Richard,

Here are my parameters:

AC IN: 50A
VAC Dropout: 80A
Battery Type: CC/CV
Max Charge Rate: 100%
Max Charge Amps: 200
CV Charge Volts: 14.6
CV Done Time: 1.3 Hours (20 min per battery x 4 batteries)
Recharge Volts: 13.8
Low Battery cutoff: 11 Volts (manufacturer says 10.8, but I opted for the .2 buffer)

It looks like everything is controlled by the CC/CV settings and cannot be altered unless I'm missing something. The parameters were set by "Ampere Time" on a printed card that was included with each battery.

Also curious as to what 757Driver says about the parameters I set. I installed the battery disconnect and am heading on a 5 hour drive tomorrow. I think I will just shut the house batteries off while I drive unless you all think otherwise? This is to avoid any conflicts with the alternator and I'm also still waiting for my Victron DC-DC charger and smart shunt to arrive. Thoughts?

mohospinner 06-10-2021 05:08 PM

Caymanedge,

Thank you.

Could you post your controller parameters for us to see? Also include the information about your battery bank. Thanks!

Caymanedge 06-11-2021 04:48 AM

4x170ah LifePO4
I am not near it to get the charging parameters right now. The only thing that jumps out at me from your list is the recharge volts. I believe mine settle at 13.4.

757driver 06-11-2021 08:52 AM

Quote:

Originally Posted by mohospinner (Post 5786471)
Hi Richard,

Here are my parameters:

AC IN: 50A
VAC Dropout: 80A
Battery Type: CC/CV
Max Charge Rate: 100%
Max Charge Amps: 200
CV Charge Volts: 14.6
CV Done Time: 1.3 Hours (20 min per battery x 4 batteries)
Recharge Volts: 13.8
Low Battery cutoff: 11 Volts (manufacturer says 10.8, but I opted for the .2 buffer)

It looks like everything is controlled by the CC/CV settings and cannot be altered unless I'm missing something. The parameters were set by "Ampere Time" on a printed card that was included with each battery.

Also curious as to what 757Driver says about the parameters I set. I installed the battery disconnect and am heading on a 5 hour drive tomorrow. I think I will just shut the house batteries off while I drive unless you all think otherwise? This is to avoid any conflicts with the alternator and I'm also still waiting for my Victron DC-DC charger and smart shunt to arrive. Thoughts?

Here are my thoughts.

CV charge volts- for normal day to day charging I would set this at 14.2v. This voltage will fully charge your lithium battery bank. Since your batteries have balance boards about once a month set this to 14.6v and let the balance boards do their thing. I have read where the more lithium batteries are balanced the more they go out of balance and need balancing.

CV done time- this goes hand in hand with balancing. The only reason for done time is to let the balance boards do their thing. Set this to the 1.3 hours when you put the CV voltage up to 14.6v, otherwise set it to 0.1-0.2 hours.

Recharge volts- once again it shows that the battery manufacturers don’t have a clue as to what they are talking about. A recharge voltage of 13.8v will keep your lithium battery at 100% SOC which is harmful. Once the charger switches off at 14.2v or 14.6v (as programmed) it will switch back on within seconds as the voltage drops to 13.8v and start the charge cycle all over again. For the thousands of cycles you will get out of your lithium bank let it cycle and set this to 13.0v.

Low battery cutoff- 10.8v or 11.0v is a good LBCO for lead acid batteries but is too low for lithium. Once a lithium battery hits about 12.0v it is at a very low SOC. I would set the inverter’s LBCO to 12.2v and make sure the inverter is taken off line prior to the lithium BMS activating.

mohospinner 06-11-2021 06:35 PM

Don,

Very Helpful! Thanks so much. I just changed the settings (as per your suggestions) and will see how it works out.

I had the batteries plugged in to shore power last night with no issues, so I guess I can scratch the DC cut-off problem off the list. Now I'm just waiting for the Victron DC-DC charger and the smart shunt to arrive in the mail. Everything seems to be good so far and I'm happy with converting to Lithium. Yesterday, I had the DC system and inverter system running off the Li-Ion batteries (without the shore power plugged in) and the voltage was very stable (even with getting the fridge down to temp and drawing up to 12 amps AC). Today we traveled 6 hours to our destination. I kept the house battery disconnect switch off (just to avoid alternator issues until the Victron system is installed).

Once I get the Victron equipment installed, I will post pictures and summary. Thanks again for your advice.

Best,

Matt

757driver 06-11-2021 10:30 PM

Quote:

Originally Posted by mohospinner (Post 5787902)
Don,

Very Helpful! Thanks so much. I just changed the settings (as per your suggestions) and will see how it works out.

I had the batteries plugged in to shore power last night with no issues, so I guess I can scratch the DC cut-off problem off the list. Now I'm just waiting for the Victron DC-DC charger and the smart shunt to arrive in the mail. Everything seems to be good so far and I'm happy with converting to Lithium. Yesterday, I had the DC system and inverter system running off the Li-Ion batteries (without the shore power plugged in) and the voltage was very stable (even with getting the fridge down to temp and drawing up to 12 amps AC). Today we traveled 6 hours to our destination. I kept the house battery disconnect switch off (just to avoid alternator issues until the Victron system is installed).

Once I get the Victron equipment installed, I will post pictures and summary. Thanks again for your advice.

Best,

Matt

Matt,

You are welcome. Once I got home to look at my settings (memory not as good as I thought) you could bring your LBCO down to 12.0v instead of 12.2v and have plenty of protection.

Enjoy your new batteries. :thumb:


All times are GMT -6. The time now is 11:55 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.