Boom Boom,
Thanks for the additional info. Let me ask if you would like to be able to run the microwave without the generator running, and do you intend to run the furnace overnight?
Scott,
I think LifeP0 are great, and I don't think there is as much fire risk as the absorption refrigerator (presuming a correct installation because any battery bank is a lot of stored power that can be dangerous). (There are numerous lithium variations and LifeP0 is not one of the more volatile ones.) BUT, I think the key is, do their advantages actually matter for your use? For me in a boat project I'm doing they absolutely do; in my Chinook not as much. Here are some of the main advantages as I see them:
1) Weight savings
As you mentioned above, this is not really a big deal in a 10,000# RV. (For my boat project it is a big thing.)
2) Space savings
Say two batteries instead of three. Under my Chinook couch, no big deal. In the boat I can only fit one Group 31-ish size battery, so it's a huge advantage.
3) Peukert loads
Lead acid (including AGM) batteries do not respond well to Peukert loads. The voltage gets dragged down. You probably know this but that's things that are huge/quick hits. A microwave is a great example. Unless you have a big lead-acid bank, running a microwave (and big inverter) is going to suck your voltage down. LiP0 shrugs that type of load off. I don't tend to run this type of load in my Chinook very often. Basically a shop vac or heat gun once in a blue moon. The way I handle that is to start my engine and combine the banks (or do it at high noon). Not something I'd want to do often but once every few months is fine.
In a nutshell, LiP0 don't care if your load is 50 amps for one minute, or 1 amp for 50 minutes. Lead acid do care. (You can somewhat overcome this by having a larger bank, but it's still a characteristic.)
4) Charging pattern
Lead acid batteries have an "absorption" charging stage. This is from about 85% charged to 100% charged. It's constant voltage diminishing current (untll they are full). In practical terms this means a couple of hours of pushing power slowly through the eye of a needle. LiP0 just go full out all the way to 100%. Does this matter? Depends. For me I'm able to get charged up almost every day even with the absorb cycle. It's a huge advantage, no question, BUT it may not actually matter depending on your charging setup and usage patterns.
Now, downsides:
1) Cost
Yes, they should last for more cycles, but you still have to buy them up front. And there is more to lose if something happens and you wreck one. There also may be added cost in associated equipment and wiring depending on how you are set up now.
2) Temperature
No batteries like heat, but LiP0 likes it even less than lead acid. So if you can't keep them out of a hot spot, their life will be shortened. They also can't be charged below freezing (although they can still supply loads).
3) Storage
IIRC, they can last a bit longer without charging in storage (although AGM already can go longer than flooded cells). There is perhaps a bit of fiddling before leaving them as they want to be at around 50% charge state in storage, whereas it's obvious and easy to charge lead acid to 100% and go.
4) System upgrades
This may or may not be a factor depending on what your setup is now. Yes, they need certain types of charging, but many of the good, customizable solar controllers or chargers can be reset to accomodate them. They don't really work with the "traditional" ACR type of combiner, because their voltage stays high and those combiners work by opening when one side is high and the other is low, and/or closing when both are low. Also they won't work with a Balmar Smartgauge (again, because their voltage is too consistent). They have a LOT of potential stored power, so OCP etc. has to accomodate that (AIC, etc.)
I'm probably forgetting a bunch of things, but in short, LiFeP0 are wonderful things, but their advantages may or may not pertain to you. If they don't, they're obviously rather expensive (hey, Lifeline AGM's finally look cheap
). If your setup takes advantage of their plusses, and you can accommodate the minuses, then their amazing qualities can be worth it.
My AGM bank is still going strong in the Chinook, so I don't need to decide for that. If I had to decide tomorrow I'd probably go AGM again because I don't take advantage of enough of the LiFeP0 plusses the way I use my Chinook. On the boat project, I am going LiP0 mostly due to space and weight concerns (still don't run big Peukert loads). And also because my charging sources are limited, so I don't have that two hours to "waste" in absorption.
), but I haven't talked to him since his install.
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