Question: Mixing Lithium Battery Brands in my Bank

pinchio · 07-10-2020, 07:41 AM

Hello,

Does anyone have experience mixing different lithium battery brands (lifepo4 based) in their house banks.

My current setup is a single Battle Born 12v 100ah. I want to add additional batteries as the price is lowering. Battle Born is great but still a premium price. I would like to add more 12v 100ah batteries but not sure what if any performance issues I may have or incompatibility. I suspect there will be no incompatibility if I keep the specs similar to each other such as rate of charge, discharge, high/low temp cutoff, etc.

It would open up options when Battle Born is out of my price range. Trust me if I could afford more BB I would but since the price is dropping let's be a little creative.

Thanks

AJMike · 07-10-2020, 08:14 AM

Quote:

Originally Posted by pinchio

Hello,

Does anyone have experience mixing different lithium battery brands (lifepo4 based) in their house banks.

My current setup is a single Battle Born 12v 100ah. I want to add additional batteries as the price is lowering. Battle Born is great but still a premium price. I would like to add more 12v 100ah batteries but not sure what if any performance issues I may have or incompatibility. I suspect there will be no incompatibility if I keep the specs similar to each other such as rate of charge, discharge, high/low temp cutoff, etc.

It would open up options when Battle Born is out of my price range. Trust me if I could afford more BB I would but since the price is dropping let's be a little creative.

Thanks

What other LiFePO4 batteries did you find that are 100AH and are less expensive than Battle Born? When I was looking BB seemed to be the lowest priced batteries that I could find.

I checked ReLion and Lion (apparently different companies) and they were more expensive than Battle Born when I checked, so perhaps the market has changed. I am interested because I have been thinking about adding a 3rd battery to the 2 BB I currently have and so I am also interested in responses to your post.

Winterbagoal · 07-10-2020, 08:32 AM

No experience, but here's a discussion I found on the internet, via a keyword search, on a fairly reputable solar/off grid website about battery bank mixing.
I take no responsibility for the opinions expressed therein, but they sound sensible/logical. The brand mixing part is near the end of the thread.
https://forum.solar-electric.com/dis...epo4-batteries

There are other hits, but this one was the only answer that covered your questions.
I guess not many people do it?

Goodspike · 07-10-2020, 08:39 AM

I would question whether it's okay to add batteries of the same brand, significantly different age. You shouldn't do that with ordinary flooded lead acid batteries, but I don't know about lithium-ion. Interesting question I don't know the answer to.

Here's my fun battery story. I have a wireless alarm system at home where the batteries in the sensors have a 10 year life. At about the 9 year mark I ordered new batteries through Amazon. When I tested the new batteries against the old batteries they were practically the same voltage, within a couple hundredths of a volt. I thought I had been shipped old batteries. Then I researched the battery type (which I don't recall) and the voltage drop on that type of battery is very shallow, but then once it starts it quickly drops off a cliff. My old batteries had simply not reached that point yet since they were "only" 9 years old.

Winterbagoal · 07-10-2020, 08:50 AM

Quote:

Originally Posted by Goodspike

I would question whether it's okay to add batteries of the same brand, significantly different age. You shouldn't do that with ordinary flooded lead acid batteries, but I don't know about lithium-ion. Interesting question I don't know the answer to.

Here's my fun battery story. I have a wireless alarm system at home where the batteries in the sensors have a 10 year life. At about the 9 year mark I ordered new batteries through Amazon. When I tested the new batteries against the old batteries they were practically the same voltage, within a couple hundredths of a volt. I thought I had been shipped old batteries. Then I researched the battery type (which I don't recall) and the voltage drop on that type of battery is very shallow, but then once it starts it quickly drops off a cliff. My old batteries had simply not reached that point yet since they were "only" 9 years old.

The "old with new" LiFePO4 question is answered in posts #2 and #5.

pinchio · 07-10-2020, 09:07 AM

Quote:

Originally Posted by Winterbagoal

The "old with new" LiFePO4 question is answered in posts #2 and #5.

Not sure I understand your response? Are you referencing another thread? Since post #2 and #5 in this thread don't answer any questions.

AJMike · 07-10-2020, 09:16 AM

Quote:

Originally Posted by pinchio

Not sure I understand your response? Are you referencing another thread? Since post #2 and #5 in this thread don't answer any questions.

He is referring to the posts in the thread he referenced. Posts 2 and 5 do address your question but like @Winterbagoal I have no idea if they are correct or not.

You might want to contact support at the company that made your current battery to ask.

Goodspike · 07-10-2020, 10:29 AM

Quote:

Originally Posted by Winterbagoal

The "old with new" LiFePO4 question is answered in posts #2 and #5.

Huh? Post 2 didn't answer that question and your post is post 5.

Edit: I get it now, but answers from a user forum are hardly authoritative, as even you seem to note.

Winterbagoal · 07-10-2020, 11:03 AM

Quote:

Originally Posted by Goodspike

Huh? Post 2 didn't answer that question and your post is post 5.

Edit: I get it now, but answers from a user forum are hardly authoritative, as even you seem to note.

Which also applies on this forum, no? People answer questions based on their own knowledge, and anecdotal experience, and the OP can take it or leave it. It's the "I read somewhere" stuff that I take with salt grains, unless there's a link provided. I can do my own analysis, and vetting, then.

I say again, that website does have an excellent reputation, as does the company that is it's parent. Over the years, I've gotten some fairly sound info from AZ Wind/Sun, and have actually participated in their forum, many years ago, when I started researching off grid technology. Between them and AM Solar, you couldn't go far wrong posing questions to their forum members. I would trust most opinions rendered, with the caveat I mentioned.
The alternative is contact BB and ask them, but they will likely say "no", you shouldn't do that, buy some more of our stuff. Contacting the less expensive battery provider will likely get the opposite response, "sure, no problem, how many do you want?".
Lastly, the link suggested some logical reasons why you can mix lithium iron phosphate, related to the differences in how they age, the more consistent output discharge voltage between charges, and so on. Applied to both battery age and brands, unlike their FLA counterparts. Another reason to go lithium?

BobC · 07-11-2020, 07:51 AM

One solution would be to create two separate battery banks, one new and one old. That way you could switch between them as one got low. You'll also need a system for independently charging them. This all could be as simple as a Battery 1/Battery 2 switch. You wouldn't want a 1/2/All switch.

There may be a way of accomplishing this with some form of battery isolating technology so both banks can be used and charged simultaneously without the problems of mixing new and old. I'm not an expert in this so maybe someone else will chime in.

Winterbagoal · 07-11-2020, 09:12 AM

Another option might be to join the iRV2.com forum, and throw this question out in their "Going Green" forum. Lots of off grid knowledge and experience over there.

pinchio · 07-11-2020, 09:27 AM

My current charge setup is as follows so I'm doubtful I would setup a separate charge circuit with the same benefits due to cost.

Victron Multiplus 3000/120v
Victron Smartsolar MPPT 100v/30a

Both the products are connected directly to the bank for charging and don't have the option of a second circuit. The multiplus does have a trickle charge connection which I have tied into the chassis battery.

Cheers

BobC · 07-11-2020, 10:49 AM

Quote:

Originally Posted by pinchio

My current charge setup is as follows so I'm doubtful I would setup a separate charge circuit with the same benefits due to cost.

Victron Multiplus 3000/120v
Victron Smartsolar MPPT 100v/30a

Both the products are connected directly to the bank for charging and don't have the option of a second circuit. The multiplus does have a trickle charge connection which I have tied into the chassis battery.

Cheers

It wouldn't need to be separate, just switchable. Each bank should have it's own BMS.

Another source to consult would be Will Prowse and his DIY solar forum and Youtube channel. Neither is limited to solar, despite the names, and both address pretty much everything about LiFePO4 batteries:

https://diysolarforum.com/members/will-prowse.1/

https://www.youtube.com/channel/UCoj...q8kmJme-5dnN0Q

And, from what I've read, Battle Born has a good reputation for customer service. They may be able to advise you. This can't be the first time this has come up.

**creativepart** · 07-11-2020, 11:42 AM

This is just my opinion, and it's based only on reading of other users experience and watching the Will Prouse YouTube channel... so it's basically worthless.

But I see no reason that you could not mix batteries of the same capacity and the same voltage even though some are older than others. The OP has stated the older batteries are not materially degraded or damaged in any way.

However, it if were me, I'd spend the extra money to buy the batteries from Battleborn. I think the difference in pricing is probably less than 15% and both the peace of mind and knowing the quality of the BB batteries it would be worth that upcharge. Also, to prevent any clouding of possible future warranty claims it would seem advantageous, as well.

https://www.youtube.com/watch?v=gOqQp2Xjr6U

AJMike · 07-11-2020, 12:57 PM

Quote:

Originally Posted by creativepart

However, it if were me, I'd spend the extra money to buy the batteries from Battleborn. I think the difference in pricing is probably less than 15% and both the peace of mind and knowing the quality of the BB batteries it would be worth that upcharge. Also, to prevent any clouding of possible future warranty claims it would seem advantageous, as well.

I agree as to the worth of spending the extra money. If someone had issues with mixed batteries they would never know if the problem was because they mixed the manufacturer or not and if it was me I would kick myself for saving a bit while possibly causing trouble that might end up being even more expensive than the savings.

As to mixing the batteries itself, I wonder if different BMS in the batteries might not cause a problem. As I understand it (perhaps "understand" is too strong a word) the BMS helps to control things like the charging and I would worry about too many cooks in the kitchen, so to speak.

But then I am talking from nearly complete ignorance on the subject ...

pinchio · 07-11-2020, 07:05 PM

Unfortunately being from north of the border the price difference is more like 1/3 more than what you are buying south of the border.

For instance your $949 USD for a 12v 100ah BB is $1315 CAD plus 13% tax here at the local BB dealer. Whereas I can get a Renogy (and others) equivalent 12v 100ah from Renogy Canada website shipped free for just over $1K. I'm not a fan of the limited warranties, too many conditions. Batteries are disposable commodities and should be priced as such.

Kbwitt · 07-15-2020, 08:23 PM

I know you can add more batteries at a latter date if needed of same brand , age has no barring. Different brand not sure. That's one of the good features if you find you need more or your needs changed just add more.

JoeC · 07-15-2020, 10:52 PM

My $.02. Spending money on more electronics to couple but isolate batteries certainly isn't the answer, you'd be spending even more money on a rube goldberg solution. Duh. Looking for cheap solutions to expensive technology issues is a great way of throwing good money at ill-conceived problematic solutions. Battery technology isn't rocket science, but it's close.

Sure, slapping together a bunch of mismatched batteries will work, for a while, with reduced performance but you probably wouldn't know that anyway, because you were too cheap to put in a decent battery monitoring system to see what kind of performance you are getting out of your battery bank and whether or not it is operating at published performance levels. Oh yeah, and make sure to use under-sized cables, you can save a few bucks there too. My recommendation and also a good rule to live by in general is this: Anything worth doing is worth doing right.

orangeminnie · 07-15-2020, 11:34 PM

In my observation, all the low-cost alternatives use prismatic cells, and are assembled in China. While manufacturing consistency has improved, in general cylindrical-cell-based batteries such as BB and Relion are said to be safer, more reliable, and longer-lasting - particularly in hot environments. Unless you can get 100aH with a BMS at less than $500, I'd stick with BB. Check out the sizeable BB discounts for Escapees RV Club members.

MrBill · 07-16-2020, 06:54 AM

I am a retired certified diesel mechanic on the semi trucks with the Apu system we used 4 group 31 gel batteries when we replaced 1 battery we replaced them all at the same time because of the voltage drop and age difference also used same brand across the board. Because of the experience I have had I am using 4 agm 100 ah batteries in my 81 winne. Next system is solar power.