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Brian I think you are overlooking some things. 24 and 48 volt super high efficiency air conditioners like Truckers, Off-Griders and Telecom use. I agree with your POV. If all you need is lighting, some entertainment like a TV/Radio/AV and low power devices 12 volts is just fine. But you have people who insist on electric cooking, refrigeration, and the impossible air conditioning requires a lot of power that a 12 volts is just not capable of doing safely, efficiently, and economically.
Some of the air conditioners for trucks run on 120 VAC anyway, and are installed with a dedicated inverter, so the only benefit of higher voltage is smaller cable. Of course in a 24 volt vehicle, 24 volt air conditioning would make sense. Similarly, in a facility where 48 volts is used for other purposes, 48 volts would make sense for air conditioning.

Lots of RV users cook electrically with 120 VAC appliances run by an inverter powered by a 12 volt battery bank.

I agree that if demand is huge, higher voltage is more appropriate. That demand would be unusual in an RV. If it isn't justified by huge demand it can still be used, but it's hard to see a net benefit. I would discuss what sportcoupe might need, but apparently that isn't allowed. :rolleyes:

Mobile compressor-based refrigerators normally operate on 12 VDC, which is no problem because their power demand is small compared to air conditioners and cooking appliances.
 

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There seems to be three choices for batteries. FLA, AGM, and flavors of lithium.

Automakers are already switching to AGM. Lithium isn’t readily available in high capacity cells.
When you say automakers and AGM, you mean Starter batts right? Totally separate market, little to do with deep cycling batts suitable for House bank usage

1000AH LFP cells are readily available, in fact cheaper than the 400AH other smaller sizes.

No other lithium type is suitable.

But add GEL, also a great choice, Sonnenschein and Deka. Very long lived if coddled, but persnickety about the charge profile.
 

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Discussion Starter · #90 · (Edited)
We could move this to a new thread titled "build me a camper van battery" if the mods prefer. ;)

Or continue to digress from the thread title that has the word lithium in it. :)

I need a battery that supports my future camper van electrical needs/requirements as follows.

  1. refrigerator (40 watts)
  2. hot water ??
  3. water pump (on demand)
  4. vent fan (12-30 watts)
  5. LED lights (<20 watts)
  6. device charging (60 watts)
  7. LED TV (40 watts)
  8. gasoline heater (14 watts)
  9. air conditioner (410 watts, occasionally)
 

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I need a battery that supports my future camper van electrical needs/requirements as follows...
1. refrigerator (40 watts)
2. hot water [unknown power, possibly as much as 1800 W]
3. water pump [minimal power, typically less than 100 W]
4. LED lights [likely a few tens of watts]
5. device charging [as much as a couple hundred watts if charging a laptop plus multiple mobile devices]
6. small tv [likely less than 100 W]
7. gasoline heater (14 watts)
8. air conditioner (410 watts, occasionally)

None of those loads appear to be high enough to require currents that would make cabling unreasonable at 12 volts (although the water heater could be significant if large). The air conditioner startup load could be substantial, but still not unreasonably large among RV 12 volt cabling practices. I don't see a reason to consider higher-voltage configurations, whether lead-acid or lithium.

400 Ah @ 12 V is 4.8 kWh . All of those loads together do not appear to be high enough for the discharge rate to be an issue for a battery of this size (regardless of voltage), so this looks like a straightforward energy storage issue, without a power capacity issue. If this were for propulsion power (it's not), this would be equivalent to a battery-electric scenario (energy priority) rather than a hybrid (power priority). That makes nearly any battery chemistry viable.

The use of an electric water heater in an RV with a fueled space heater seems a little unusual, but the vehicle is apparently not diesel, and gasoline-fueled water heaters are rare, if available at all.

I note that there are no cooking appliances listed. Assuming that this is correct, it removes most of the large loads often seen on RV electrical systems; however, there's also this:
I still have to source an efficient microwave that will still pop popcorn. :cool:
Even the smallest available microwave oven has power demand comparable to the air conditioner. As long as there are not multiple large appliances, or they are not run in combination with the water heater or air conditioner, current and power demands should still be non-issues for this size of battery at 12 volts.
 

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... And LFP will eliminate the need for solar.
In a thread of 90 posts, sportcoupe has not mentioned the endurance required, or how frequently driving or starting the van or other engine as a generator might be acceptable, so there is no way to determine whether another charging source such as solar is required. All we know is that 140 A @ 12 V (nominal) is available for charging (and a rational person might guess that's the van's alternator). Since the total capacity of the battery bank is a fixed requirement, and the charging source doesn't change the battery choice, I don't see any relevance to a discussion of a solar system or whether it is required.
 

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Discussion Starter · #94 ·
Hot water isn't figured out yet. I may even forego hot water if an efficient solution isn't available.


Heater might be a Webasto gasoline air top heater unless I find something more cost effective.
https://www.amazon.com/Webasto-Gasoline-Heater-install-9032227A/dp/B01M2ZCWTF


Cooking will primarily be outside van using camp stove. I will need a way to boil water for coffee though without setting up the camp stove 10 times a day.... Forgot to mention that.
 

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Discussion Starter · #95 ·
In a thread of 90 posts, sportcoupe has not mentioned the endurance required, or how frequently driving or starting the van or other engine as a generator might be acceptable, so there is no way to determine whether another charging source such as solar is required. All we know is that 140 A @ 12 V (nominal) is available for charging (and a rational person might guess that's the van's alternator). Since the total capacity of the battery bank is a fixed requirement, and the charging source doesn't change the battery choice, I don't see any relevance to a discussion of a solar system or why it is required.


Daily driving with occasional stops of 2-3 days. Starting ICE engine 220A alternator is perfectly acceptable to charge house battery. I have a 140A smart battery isolator to charge if it would be suitable to the house battery.
 

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Discussion Starter · #96 ·
Even the smallest available microwave oven has power demand comparable to the air conditioner. As long as there are not multiple large appliances, or they are not run in combination with the water heater or air conditioner, current and power demands should still be non-issues for this size of battery at 12 volts.

I may have to dump the microwave and make popcorn on camp stove :)
 
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