LiFePO4 Battery ?

[KevinWI]

I have 2 12v deep cycle lead marine batteries in my boat. One in the back runs my starter and a few electronics. The one in the front runs the trolling motor and a few electronics.
Been pretty happy with the setup overall....never run out of juice while fishing....I generally charge up between trips.....
But these LiFePO4 batteries have me intrigued due to their weight..... (their price has me less intrigued)....
It got me to wondering if I could buy one and wire my 12v deep cycle marine battery to one of these in parallel. My onboard charger will charge either battery type, but I'm curious how it would work with two different battery types. I've heard manufactures don't necessarily recommend it, but technically, it should work.

 

[Still Afloat]

I don’t think it’s a good idea to wire different battery types in parallel. There are a lot of reasons but, one is that LiFe batteries are higher voltage than lead acid.

The LiFePO prices are running about 30 to 50% more than lead acid. However, they outlast lead acid by a few times so you are coming out ahead in the long run.

I don’t think you will look back and wish that still had lead acid batteries for your TM.

 

[Zum]

Like the above post id say no... atleast I wouldnt,he batteries are too different.
Ive done a bunch of reading and havnt heard of anyone trying it and everyone saying its not a good idea.
A 100aH lifepo4 is going to outlast(time wise) the deep cycle battery your probably running now.(probably even less aHs)

 

[InSaneFisherMan]

I would not connect different chemistry batteries in series or parallel.

In parallel, when charging, the voltage is the same to both batteries. At 14.6v it would overcharge the lead acid battery and eventually damage it.

When discharging, current flows from the battery with lowest internal resistance (lifepo4). Not sure the lead acid battery would be used much, until the bms shuts down the lithium battery.

Lots of risk, for little or no reward.

 

[Still Afloat]

I have 2 12v deep cycle lead marine batteries in my boat. One in the back runs my starter and a few electronics. The one in the front runs the trolling motor and a few electronics.
Been pretty happy with the setup overall....never run out of juice while fishing....I generally charge up between trips.....
But these LiFePO4 batteries have me intrigued due to their weight..... (their price has me less intrigued)....
It got me to wondering if I could buy one and wire my 12v deep cycle marine battery to one of these in parallel. My onboard charger will charge either battery type, but I'm curious how it would work with two different battery types. I've heard manufactures don't necessarily recommend it, but technically, it should work.

You were just pulling our legs, right?

 

[KevinWI]

You were just pulling our legs, right?

Not a bit

 

[InSaneFisherMan]

Not a bit

Video results are very simular to my previous post.

I still would not recommend connecting them in parallel, but if you really need the extra battery, i would install a battery switch between batteries that would only alow one battery at a time.

Charge and discharge each one individually.

 

[thill]

I don't think you said that you were going to wire them together.

You were asking about charging correct?

Just get a separate charger for the LiFeP04. I purchased one from Amazon for $25, and have been very happy with it. I actually recently bought a second one since I'm now up to three lithiums.

 

[thill]

Go on Amazon and search for TimeUSB and you will see a quality lithium battery for about $200 depending on the current sale.

They come with a good 5 year warranty and customer service is excellent, even for dumb questions like the ones I had.

 

[KevinWI]

I don't think you said that you were going to wire them together.

You were asking about charging correct?

nope....the question was about wiring them in parallel.....charging wasn't the issue.

 

[airshot]

Never connect batteries of different types together period !

 

[Still Afloat]

Just because it worked short term for a YouTube knucklehead doesn’t make it good science.

Fully discharging a Lithium battery repeatedly will greatly reduce its usable life. This is exactly what the guy demonstrated, the Lithium was dead and the AGM kept operating at a lower voltage.

This is just asking for trouble. I’m dropping off this thread, don’t even want to discuss this topic.

 

[MDCrappie]

I would not connect different chemistry batteries in series or parallel.

In parallel, when charging, the voltage is the same to both batteries. At 14.6v it would overcharge the lead acid battery and eventually damage it.

When discharging, current flows from the battery with lowest internal resistance (lifepo4). Not sure the lead acid battery would be used much, until the bms shuts down the lithium battery.

Lots of risk, for little or no reward.

What would be the issue with connecting in series? Inquiring mind wants to know....

 

[airshot]

Lipos do not play well with other type batteries or chargers!! When used exactly like they should be, they are great!!! But, if missused even slightly they burn white hot fast !! They will also burn anything near them !! So fast it will be ashes before you realize it !! They can also explode like a grenade...never try to cheat a lipo !!

 

[InSaneFisherMan]

What would be the issue with connecting in series? Inquiring mind wants to know....

Not a battery expert, I would not connect different chemistry batteries in series.

Series, not familar/sure if any multi-bank charger supports charging with different chemistry when connected in series. If not you would have to isolate each battery and charge separately.

When discharging, current flows from each battery fairly eavenly (total current is equall to current of lowest capicty ah battery). Since damage occurs to lead acid battery at 50% debt of discharge, you would still have to stop using the battery at 50%, losing the remaining capacity in the lifepo4 battery.

Lots of risk, for little or no reward.

 

[LDUBS]

Not a battery expert, I would not connect different chemistry batteries in series.

It is all witchcraft to me. That ABYC video you posted in the other thread was pretty good. Here is a screenshot from that video about mixing battery chemistries.

 

[jethro]

I didn't even think you were supposed to connect two different ages of batteries, even of the same type, because the more worn one will reduce the performance of the new one. That's just what I have been told- probably by a guy selling batteries to be fair.

 

[flatheadsteve]

I didn't even think you were supposed to connect two different ages of batteries, even of the same type, because the more worn one will reduce the performance of the new one. That's just what I have been told- probably by a guy selling batteries to be fair.

I dont think you are. My new battery came with instructions on how to balance it with others before using in a parallel or series connection. A blues seas switch will keep batteries separate while allowing you to select which one or both for starting purposes. They make multiple applications to fit any setup you could think of.

 

[MDCrappie]

Not a battery expert, I would not connect different chemistry batteries in series.

Series, not familar/sure if any multi-bank charger supports charging with different chemistry when connected in series. If not you would have to isolate each battery and charge separately.

When discharging, current flows from each battery fairly eavenly (total current is equall to current of lowest capicty ah battery). Since damage occurs to lead acid battery at 50% debt of discharge, you would still have to stop using the battery at 50%, losing the remaining capacity in the lifepo4 battery.

Lots of risk, for little or no reward.

Ok, I thought maybe it was that you knew something that I didn't. I would not charge them while in series. Using them? Sure. I don't see any issue at all.

 

[MrGiggles]

Not a battery expert, I would not connect different chemistry batteries in series.

Series, not familar/sure if any multi-bank charger supports charging with different chemistry when connected in series. If not you would have to isolate each battery and charge separately.

When discharging, current flows from each battery fairly eavenly (total current is equall to current of lowest capicty ah battery). Since damage occurs to lead acid battery at 50% debt of discharge, you would still have to stop using the battery at 50%, losing the remaining capacity in the lifepo4 battery.

Lots of risk, for little or no reward.

In series you are only as strong as the weakest battery, and it's possible to discharge the weaker battery past the point of damage without knowing it.

Otherwise there is little risk as the batteries cannot equalize like they will in parallel.

It's not recommended to charge them in series (aside from needing a charger capable of charging at 24 volts) for the same reason it's not recommended to charge in parallel.