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AGM to Lithium conversion questions


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We're considering pulling out six year old FullRiver 400AH 6 volt AG batteries and replacing with BattleBorn 100AH Lithium's.  Any input on the below questions is appreciated:

1.  My current 6 AGMs give us 1200AH (600 usable).  I'm thinking six 100AH Lithium's will give us the same usable amps, right?  

2.  Should be plug and play, after adjusting the charging data in the controller, right?

3.  Any thoughts on how much the six year old batteries have degraded, they haven't been used hard except the last year.

Thanks in advance for any feedback!

Brad

 

 

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Have you verified that all of your “charging” sources can be adjusted to the needed BB lithium settings? Some reworking of the battery interconnect cables will probably be needed going from 6volt in series/parallel to 12 volt in parallel. Will you be able to mount the BB’s in a area that you can control the low/high extreme temps?

(BB’s are a bit discounted for “Black Friday” and “Cyber Monday” on their website.)

Edited by DesertMiner
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IDesert Miner, I've got a good programable charge controller that can be adjusted to the BB's.  The cable connections will be no problem.  Temp control is something I'll have to work on but we usually head south when it gets real cold.

I saw the BB discount today, that's why I want to pull the trigger ASAP.

 

 

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About temperature control of the lithium batteries.  Keep in mind it is the internal battery temperature of the battery, NOT the outside air temp that dictates the charging of the batteries.   Additionally there is some heat generated when discharging (using) the battery and charging the battery.  This helps keep the battery internal temp above freezing.  

If the batteries are installed in a compartment protected from the outside air it has to get pretty darn cold outside for quite a while to get the battery internal temp below freezing.   Install a remote temperature thermometer in the battery compartment to monitor the temp.

 

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To replace 1200AH of lead acid battery with lithium, I would recommend 700-800AH of lithium.   Some of this depends on how you use your lead acid batteries.  If you most always take them down to 50% before charging, then the 700-800AH is best.  If you only discharge to 25-40% then 600AH of lithium should work fine. 

Yes you can take lithium down to 10% SOC, however you will get longer battery life if you only take the battery down to 30% or 20% SOC.  I equate this to, yes I can drive my truck at max acceleration, RPM's, braking, etc, but I will get longer life by not pushing it so hard.

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4 hours ago, Al F said:

To replace 1200AH of lead acid battery with lithium, I would recommend 700-800AH of lithium.   Some of this depends on how you use your lead acid batteries.  If you most always take them down to 50% before charging, then the 700-800AH is best.  If you only discharge to 25-40% then 600AH of lithium should work fine. 

Yes you can take lithium down to 10% SOC, however you will get longer battery life if you only take the battery down to 30% or 20% SOC.  I equate this to, yes I can drive my truck at max acceleration, RPM's, braking, etc, but I will get longer life by not pushing it so hard.

I also am trying to figure how much my new lithium phosphate battery pack will provide.  It seems when figuring in the Puekert effect and the inefficient solar charging of lead acid batteries it seems as if less capacity is needed for lithium phosphate.  I am wondering if others have experience with this?  Additionally, my experience is that lead acid batteries years old will have lost a significant amount of capacity.

Edited by Randyretired
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6 hours ago, Al F said:

To replace 1200AH of lead acid battery with lithium, I would recommend 700-800AH of lithium.   Some of this depends on how you use your lead acid batteries.  If you most always take them down to 50% before charging, then the 700-800AH is best.  If you only discharge to 25-40% then 600AH of lithium should work fine. 

Yes you can take lithium down to 10% SOC, however you will get longer battery life if you only take the battery down to 30% or 20% SOC.  I equate this to, yes I can drive my truck at max acceleration, RPM's, braking, etc, but I will get longer life by not pushing it so hard.

Al, Simply put and I agree with the idea of setting a goal of only discharging to 20-30 SOC.  I think the 600AH will work, as our six year old 1200AH batter bank is only delivering 375-425AH, depending on how fully jammed they are.  That has been sufficient for extended 30 days boondocking but we've had to augment the 1200W solar with generator, which we're trying to avoid.

 

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Nice thing about Battleborn's is they will take a big charge until they are full, so if charging from solar, they will take advantage of your max solar output. without the solar derating current for absorption and float. Same with charging from generator through converter or inverter/charger, Much shorter gen run time. I swapped my four 8D's at 500 usable a/h's to 6 battleborn's and freed up space and dropped 460 lbs.

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4 hours ago, Randyretired said:

I also am trying to figure how much my new lithium phosphate battery pack will provide.  It seems when figuring in the Puekert effect and the inefficient solar charging of lead acid batteries it seems as if less capacity is needed for lithium phosphate.  I am wondering if others have experience with this?  Additionally, my experience is that lead acid batteries years old will have lost a significant amount of capacity.

I guess you could say that with LiFePO4 you could get by with less capacity.  I have not thought about it that way.

We use about 75-150AH in a day.  In Jan 2016 I bought a 400AH lithium battery kit from Starlight Solar and built our battery pack.  At the same time I installed 650 watts of solar.  This has served us very well and is continuing to work well.  The 650 watts is from a pair of 325 watt residential solar panels that maxed out the roof space on our then 29' Class A.  I have since moved the system to our 36' Class A and have room for a 3rd large panel.  If I ever install a residential fridge I'll add the panel and install another 200AH of lithium.  

One of the great benefits of lithium is that they never need to be charged to 100% for long life.  When I had golf cart batteries there was always the need to get them back to 100% every 5-7 days to keep them from sulfating.  

I feel the lithium batteries paid for themselves on our 2016 trip to Alaska.  We spend 138 days from the time we crossed into Canada and then back into the lower 48.  We only had elect hookups for 2 nights and only ran the generator for about 2 hours one day because of multiple days of heavy cloud cover.  Our batteries did not charge from the engine alternator.   No need for RV Parks at $35-$50/night.  I figured we saved over $3000 in RV Park fees. 

 

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1 hour ago, Al F said:

I guess you could say that with LiFePO4 you could get by with less capacity.  I have not thought about it that way.

We use about 75-150AH in a day.  In Jan 2016 I bought a 400AH lithium battery kit from Starlight Solar and built our battery pack.  At the same time I installed 650 watts of solar.  This has served us very well and is continuing to work well.  The 650 watts is from a pair of 325 watt residential solar panels that maxed out the roof space on our then 29' Class A.  I have since moved the system to our 36' Class A and have room for a 3rd large panel.  If I ever install a residential fridge I'll add the panel and install another 200AH of lithium.  

One of the great benefits of lithium is that they never need to be charged to 100% for long life.  When I had golf cart batteries there was always the need to get them back to 100% every 5-7 days to keep them from sulfating.  

I feel the lithium batteries paid for themselves on our 2016 trip to Alaska.  We spend 138 days from the time we crossed into Canada and then back into the lower 48.  We only had elect hookups for 2 nights and only ran the generator for about 2 hours one day because of multiple days of heavy cloud cover.  Our batteries did not charge from the engine alternator.   No need for RV Parks at $35-$50/night.  I figured we saved over $3000 in RV Park fees. 

 

I like your setup.  It sounds like it fits your use.  I just ordered 16 200 amp hr cells and we have 2,000 watts of solar.  I installed a 18 cu ft residential refrigerator last winter when our RV fridge quit.  I was pleasantly surprised to see it only uses about a thousand watt hours a day.  Right now we have 6 golf cart batteries but I wanted more capacity.  The solar kept up with our mini split during the day and easily charged the batteries but by morning our batteries would be 50% soc  or less  if we weren't careful.  Looking around yesterday I found Aliexpress had a special on the 16 new grade A cells for $1437.  That seemed like a good price so I bought it.  Hopefully that will meet our storage needs.

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28 minutes ago, Randyretired said:

I like your setup.  It sounds like it fits your use.  I just ordered 16 200 amp hr cells and we have 2,000 watts of solar.  I installed a 18 cu ft residential refrigerator last winter when our RV fridge quit.  I was pleasantly surprised to see it only uses about a thousand watt hours a day.  Right now we have 6 golf cart batteries but I wanted more capacity.  The solar kept up with our mini split during the day and easily charged the batteries but by morning our batteries would be 50% soc  or less  if we weren't careful.  Looking around yesterday I found Aliexpress had a special on the 16 new grade A cells for $1437.  That seemed like a good price so I bought it.  Hopefully that will meet our storage needs.

A link to the batteries you chose? Thanks, Jay

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The Battleborn batteries the OP is looking at have BMS and low temperature no charge protection built in. 

If you have you toob capability take a look at the channel "DIY Solar with Will Prouse".  He tests and takes apart stuff. 

I haven't made a battery decision yet for my "long time" ( i.e. 2 nights to up to 6 months travel camper) but I am leaning toward good quality lithiums...  

but I am currently sidetracked investigating silicon dioxide (Si02) chemisty mainly because you can pummel them cold temperature and abuse wise at about 1/2 the 2000 charge cycle cost of lithium. 

But this is a lithium topic thread. 

 

 

Edited by noteven
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15 hours ago, Randyretired said:

I like your setup.  It sounds like it fits your use.  I just ordered 16 200 amp hr cells and we have 2,000 watts of solar.  I installed a 18 cu ft residential refrigerator last winter when our RV fridge quit.  I was pleasantly surprised to see it only uses about a thousand watt hours a day.  Right now we have 6 golf cart batteries but I wanted more capacity.  The solar kept up with our mini split during the day and easily charged the batteries but by morning our batteries would be 50% soc  or less  if we weren't careful.  Looking around yesterday I found Aliexpress had a special on the 16 new grade A cells for $1437.  That seemed like a good price so I bought it.  Hopefully that will meet our storage needs.

Scrolling down in the link you provided (copied below) I find a 200AH battery made up of 4 -- 200AH cells with busbars and screws included for $1427.  It does state that it is 16 pieces, but the image looks like 12 of the pieces are possibly the busbars and screws.   https://m.aliexpress.com/item/4001295281066.html?trace=wwwdetail2mobilesitedetail&spm=a2g0s.12269583.0.0.4e3471b5Z4GpVH

Do you see the same thing I see or is there another link with the 800AH for $1427? 

Additionally, scrolling down farther is a 200AH battery for $880.  The ad specifies 8 pieces, but it image looks like the 8 pieces are 8 CALB cells of 100AH each for a total of 200AH.

 

 

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28 minutes ago, Al F said:

Scrolling down in the link you provided (copied below) I find a 200AH battery made up of 4 -- 200AH cells with busbars and screws included for $1427.  It does state that it is 16 pieces, but the image looks like 12 of the pieces are possibly the busbars and screws.   https://m.aliexpress.com/item/4001295281066.html?trace=wwwdetail2mobilesitedetail&spm=a2g0s.12269583.0.0.4e3471b5Z4GpVH

Do you see the same thing I see or is there another link with the 800AH for $1427? 

Additionally, scrolling down farther is a 200AH battery for $880.  The ad specifies 8 pieces, but it image looks like the 8 pieces are 8 CALB cells of 100AH each for a total of 200AH.

 

 

I really believe that is 16 cells as another add for that stated 12v to 48v.  It appears that each add states the number of cells.  Maybe I am wrong.  I'll know in a few weeks.  I sure hope I am right.😶

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14 minutes ago, hemsteadc said:

Yeah, that's what I was asking.  Unless this is for an HDT, it surely isn't an HDT topic.

Maybe not directly, but we use these battery banks in our HDTs, as well. I have 500+ AHs in mine and am planning lithium at the end of this set. Not to stir the pot, but I would venture to guess many HDTers have similar projects and interests. Besides, I personally don't really care what department it's in. Good info is good info. Jay

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Just now, Jaydrvr said:

. Besides, I personally don't really care what department it's in. Good info is good info. Jay

I do. Possibly more good info could be gained if this were in the Technical section,, where it's much more likely people who know about this are browsing.  

Edited by hemsteadc
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In the interest of derailing even further, but bringing the HDT angle in.....Our truck batteries are 7 years old, and sometimes after sitting for a couple months, the truck cranks slowly.  No maintainer or charger of any kind is used.

So, if I determine these batteries have neared the end of their tenure here, should I consider flooded lead acid, AGM, or is there a better solution?

And I know, a solar charger would likely get me another year or two out of them, but at what price?

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