Lithium Stickies?

jacobconroy

Hillbilly of Leisure
Just wondering if a knowledgable, helpful, electronic Guru or group on the forum would be interested in creating and posting at least two stickies:

Lithium for beginners
Lithium-related-acronyms
And possibly a list of good (not too technical) reference material for newbies.

While trying to "get hip" about lithium batteries I've found that the charging systems, methods, hardware, and else are considerably more complicated than traditional 12 volt lead-acid setups. It's easy to get lost in the lithium lingo. Members have been very helpful when I ask questions, but some sort of starting point would be awesome.

Anyone else think this would be a great idea?

Beginners links

Charging:
LifePo4 Acronyms & glossary for this thread:
 
Last edited:

jacobconroy

Hillbilly of Leisure
Anyone feel free to quote / parse / extract from this https://sprinter-source.com/forum/showthread.php?p=766905

But note opinions vary widely among experts from different backgrounds, use cases and disciplines.

Published specs are not to be followed if longevity is your priority. . .

Wow...that is a very good link that answered a lot of my questions about charging and more importantly, pointed out a handful of things that I didn't know I didn't know. :)

Perhaps another good place to go would be "Choosing LFP capacity for your needs". Anyone have a good link for that?
 

john61ct

Adventurer
State your needs?

With lead, usually 50% Ah capacity is usable, most owners draw LFP down as low as 80%, so 400Ah of LFP can replace a 600Ah lead bank.

Less voltage sag, so if the lead was sized for high current loads like a microwave or electric induction cooker, the difference can be even greater.
 

jacobconroy

Hillbilly of Leisure
State your needs?

Good info, but I'm not asking about my own needs. Just looking for a reference or in-depth explanation of how one goes about choosing LFP battery capacity when beginning to plan a system according to the general consensus of "best practices"...if one exists.

For example, how would a person determine what is best for their needs concerning single/multiple banks, choosing the appropriate amount of available amp hours for your typical loads (with LFP longevity in mind),why do typical loads matter, what (if any) relationship is there between expected daily loads and capacity?

The end result being something such as, "I typically use X amp hours per day, and I want to be able to avoid shore power for X days and it may be as low as 40ºF each night, so I will need to buy a battery of X size, and will require solar input of X watts per day".

Or, maybe everything needs to be calculated in watts instead of amp hours? I have no idea.

I found this link about LifePo4 for beginners, but the forum is for electronic vehicles. I'm not sure if it is particularly relevant to what most of the forum members here might need. Per your link above, LFP maintenance seems to be very different when considering high or low amperage loads (electronic vehicles vs. fridge).
 

john61ct

Adventurer
Yes.

An energy budget in Ah per 24hrs @12V is required,

google for online calculators, spreadsheets, samples,

actually measuring device loads in average use with an Ah meter ideally, otherwise will have to make do with WAGs.

If ICE power on demand is available, size for 2 days, could round down.

If trying for mostly solar, size for 4+ days, round up.

Nice thing with LFP (out of many) is if you realize you need more, in the first few hundred cycles, if well treated is still "as new" can just add more.

With lead if you're halfway through lifespan, advice is to buy all new, don't want an unmatched set.

Also Peukert coefficient is so close to 1.0 with LFP, splitting banks into portable packs is NBD, with lead makes for lower total capacity, reduced lifespan.

Just make sure separate packs are at the same voltage before paralleling.
 

john61ct

Adventurer
wrt panels, basically as much as fits on top, really can't have too much

likely still want a little genset and tap into alt while driving
 

jacobconroy

Hillbilly of Leisure
What do the following acronyms stand for? I'm putting a glossary in the original post. I could Google them, but I don't want to link to inaccurate info.
  • WAGS
  • ICE
  • NBD
Is there such a thing as an inexpensive, effective amp hour meter?
 

jacobconroy

Hillbilly of Leisure
Ah, I figured those acronyms out. But this is part of the problem.

When trying to make sense of a post where every fifth word is an esoteric technical acronym, it's hard to filter out the slang from the tech.

I put all three in the glossary anyway. ;)
 

john61ct

Adventurer
ICE internal combustion engine, can be vehicle + alt, or a genset.

WAG is the acronym, WAGs is just the plural
 

john61ct

Adventurer
Has a bad rep these days, but if you're burning dino juice anyways for a couple hours 2-3 times a week, charge up quick while you're at it, that's the real beauty of LFP, super high CAR*

as opposed to lead minimum 6 hours to get back to Full, ideally daily, that's really what mandates solar.

With the former setup, solar is 100% optional, only need it if you want to reduce ICE runtime.

*Charge Acceptance Rate (you're welcome, there will be a surcharge 8-D)
 
Ill lay out the install I just did in my 80 series rear mounted 100AH lipo with low temp charging. coming soon. its all installed running thru a redarc and priority charging through a merlin solar panle. I did not F^%$ about. lots of help from the forums
 

dreadlocks

Well-known member
Lithium is going to become the norm here real fast..

Li = Lithium
Fe = Iron
Po4= Phosphate
LiFePo4 = Lithium Iron Phosphate aka LFP
 

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