LiFePo vs PB (Lead acid) ......

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I asked a pal who is in the business ......

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First as long as you use 4S LFP (LiFeP04), is completely compatible with Pb chargers and utilization equipment. LFP can be charged anywhere from 13.8 to 14.4 volts. One bit of advice Nigel is never ever fully charge any Lithium battery as that only shortens cycle life. Lithium does not require ever being fully charged like Pb. They work best in a Partial State of Charge. !3.8 to 14.2 is more than enough.

I build racing golf carts and use a lot of lithium batteries. Use to use a lot of Ch-Com LFP batteries like CALB or Synopoly not so much anymore because of they just do not last long and do not have the punch, or very high discharge rates of say a Nissan Leaf batteries most DIY EV builders like to use today. As for size it sounds like you have 180 AH today right with Pb? Equivalent size from Pb to LFP really depends on Discharge Rates and how deeply you need to discharge. Assuming just starting, lighting, and ignition you can easily get away with just 100 AH with 10C burst gives you 1000 MCA and sufficient capacity for some engine down time and running on battery. If on the other hand you turn off the motor and want to operate a day or two without the engine running, you will need to be at least 80% of the original Pb battery. So if you have 180 AH now will require 145 AH.

Since you are not in the USA or UK, finding quality LFP prismatic cells is going to be a challenge and you may have to buy Chi-Com POS LFP cells. Of the brands in China, CALB is the best junk they country sells (Chinese Aviation). In prismatic form factor you can get 40 to 200 AH cells. Just DO NOT USE any battery made from 18650 cells.. To get say a 100 AH battery in 18650 cells requires 200 cells to make a 4S25P battery. With Prismatic or coffee bag cells all it takes is 4 cells in series.

But Nigel remember this. A good Pb battery like those made by Rolls and Trojan are not only a lot less expensive, but will outlast any lithium. Rolls and Trojan offer models with 7 and 10 year warranties. Most you can get with Lithium is 1 year from China which you cannot file a claim for.

Good luck.

Your friend in the USA

Dereck

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End of story.
 
To put it bluntly .... the Marine world is a new boy on the Lithium circuit and you really have a lot to catch up on ....

Trouble is the 'snake oil boys ' are going to make a fortune out of you lot until you wise up .... Sorry to be blunt.

The RC Model world has been involved in Lithium battery use for many years ... the 'snake oil boys' have been shown the door ...

If you really want to know what to do with Li based batterys .... talk to REAL users !!
 
Judging by the posts I read about Li based batterys on boaty forums ..... I have to say there is a lot to be learned.

I have been using Li based batterys in high power RC model hobby that would make average boat owner eyes water ... for many years ....

I will help those who are open for help .... rest .......
 
Lots of people use batteries in different applications.
I have some contacts in the world of back-up power supplies, UPS etc.
I've other electronics acquaintances whose work with Li goes back to the days of pyrotechnic Sony laptops
The message I get from those corners of the industry is that the world is still changing quickly.
And you have to be very specific about your use-case to ask the right questions to get the right answers.
So someone's advice on what's ideal for a racing golf cart might be out of date next week and irrelevant to a weekend cruising yacht anyway.
 
Are you sure ? Do you know what 18650 cells are ?

Trouble is lay people get involved in 'arguments' they cannot support ...
Well Ii've not taken one apart personally, but the general word on the web is that most Teslas seem to have large numbers of of 18650 cells in them. But switching to a bigger 21700 format is in progress.
But these things are just cell sizes, Tesla don't AFAIK use LiFePO chemistry?
This is a bit dated perhaps now, but Maxim generally talk sense:
A Look at Tesla’s Latest Battery Technologies
 
Are you sure ? Do you know what 18650 cells are ?

Yes, I've got a fair few 18650's in various equipment on the boat.

Are YOU sure Tesla don't use 18650 batteries in their Model S and Model X vehicles? This from Wikipedia:

"As of June 2012, the battery pack used modified Panasonic cells with nickel-cobalt-aluminum cathodes.[116] Each cell was of the 18650 form factor (i.e., an 18 mm diameter, 65 mm height cylinder), similar to the Panasonic NCR18650B cell that has an energy density of 265 Wh/kg.[117]"
 
I find it interesting that people are using my post to refer to ... where in fact all the answers indicate they should be referring back to the one I posted in reply to.

As regards Tesla - I know that because of a number of fires involving Tesla cars - especially when involved in 'incidents' - that the batterys used are in question.
As another says - what was yesterday may not be tomorrow.

It may sound daft - but in fact RC World follows the world of battery evolution very closely - much closer than example would boaters ! Why ? Simple fact that weight vs power is a serious factor in RC and we all look for that golden egg of power over weight.

I'm sure there are a number of RC'rs who follow PBO RtR ..... and will verify that ...
 
For me it simply comes down to cost. I can get a 110 a/h lead acid battery for £80. So let’s call that, for arguments sake, 50 or so useable amp/hours for £80. How much can you buy 50 or so amp/hours of lithium/whatever power for? I’m guessing substantially more than £80. Not all yotties are wealthy. I’m not, and until lithium power gets cheaper I’ll stick with lead/acid.
 
There is an interesting U-tube blogger at:


He seems to know what he is talking about.

I believe the Tesla batteries have a higher energy density but don't last as long as LiFeP04, but could be wrong
 
For me it simply comes down to cost. I can get a 110 a/h lead acid battery for £80. So let’s call that, for arguments sake, 50 or so useable amp/hours for £80. How much can you buy 50 or so amp/hours of lithium/whatever power for? I’m guessing substantially more than £80. Not all yotties are wealthy. I’m not, and until lithium power gets cheaper I’ll stick with lead/acid.

I totally agree.

In fact I go even further than that ..... I just bought yesterday a 2nd user 78 A/hr HD Lead Acid that came out of a crashed Audi A6 ... battery is only just over a year old - load tester showed it to be in near perfect order ... 20 Euros. That will now go in my boat as its winter battery.
It will have a timer controlling a basic charger so it stays topped up ... in spring if it survives - it will get a 'sister' of similar price - but larger capacity ~90 - 100 A/hr. Same price.

I have used 2nd user batterys in my main boat for many years and all have performed excellently ... a couple I had when boat first came over from UK were good for 5 years ...

I thought this was PRACTICAL Boat Owner area ....
 
For me it simply comes down to cost. I can get a 110 a/h lead acid battery for £80. So let’s call that, for arguments sake, 50 or so useable amp/hours for £80. How much can you buy 50 or so amp/hours of lithium/whatever power for? I’m guessing substantially more than £80. Not all yotties are wealthy. I’m not, and until lithium power gets cheaper I’ll stick with lead/acid.

Wouldn't you also take into account expected life?

If your £80 110 Ah L/A battery is likely to last for 200, (or even 500) cycles, and a 110Ah Lithium is likely to last for 2000 cycles, how much could it be worth paying for the Lithium?
 
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