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Old 11-28-2022, 02:02 PM   #1
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1640 ESP battery questions

Hello, I currently have two 12v batteries in parallel, but only giving me 130ah total.
I have a 1000w inverter.

I am looking to upgrade to potentially a 2000w or higher invertor for things like a hair drier every now and then.. (and some other small plug in items).

Would i need more batteries? or upgrade to lithium batteries with like say 120ah each handle a 2000kw invertor.

Im struggling to know what i should and shouldnt do. My system is a dc system..so would use the Ac for powering my laptop etc.

thanks in advance.
Lesley
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Old 11-28-2022, 03:46 PM   #2
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It's not just the amps, it's the time, too

Quote:
Originally Posted by Lpaine1331 View Post
Hello, I currently have two 12v batteries in parallel, but only giving me 130ah total.
I have a 1000w inverter.

I am looking to upgrade to potentially a 2000w or higher invertor for things like a hair drier every now and then.. (and some other small plug in items).

Would i need more batteries? or upgrade to lithium batteries with like say 120ah each handle a 2000kw invertor.

Im struggling to know what i should and shouldn't do. My system is a dc system..so would use the Ac for powering my laptop etc.

thanks in advance.
Lesley
Lesley, it's not only the amps, it's also the amps over time that matters.

Looking at Amazon, I've seen hair dryers that consume 1100 watts and hair dryers that consume 1875 watts. These correspond to 9.17 amps and 15.6 amps at 120 volts.

Your 1000 watt inverter is clearly undersized for either one. So let's assume you replace it with a 2000 watt inverter.

The current draw (amps) from the batteries will be 10 times the 120 volt currents I listed above. Technical reason: watts = volts x amps. Watts consumed doesn't change (assuming perfect inverter). So the draw from the batteries would be 92 amps from the smaller dryer or 156 amps from the large one.

The small dryer would drain the batteries in 1.4 hours 130/92); the larger one in 0.83 hours (130/156). BUT you surely don't dry your hair for an hour. Let's assume you only dry your hair for five minutes.

92 amps x 5/60 = 7.7 amp-hours (small dryer for 5 minutes)
156 amps x 5/60 = 13 amp-hours (large dyer for 5 minutes)

So the answer is [B]Either of these won't drain your current batteries, but they WILL take a good chunk of your capacity.

Also, you never want to take lead acid batteries below 50% of their charge. You start to damage them when you do so. You stated that you have 130 AH capacity. Is that total, or for usage down to the 50% point. I suspect it's the total, and that you really only have 65 amp-hours safely usable. In that case, each 5-minute use of the small dryer would 7.7 of the 65 amp-hours, and each 5-minute use of the large dryer would consume 13 of the 65 amp-hours.

Does that help?
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Old 11-28-2022, 05:20 PM   #3
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Hi larry! that does help alot.

the 65amps is per battery (I'm assuming full charge) . i have two batteries in parallel.

would i need to upgrade the batteries if I go to a larger inverter? Or would i be ok with what i have now.

Im toying with upgrading my batteries to more amp-hours...and increasing the size of the inverter. I just didnt know if i could increase the size of the inverter without upgrading the batteries.

and yes..i would only be hairdrying to five-ten minutes or so.

Also, i have a 100w solar panel now which with my current setup charges to full in a day or so. (rarely use stuff during the day..mostly at night). would a 200w solar panel charge faster?
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Old 11-28-2022, 06:03 PM   #4
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Clarifications

Quote:
Originally Posted by Lpaine1331 View Post
Hi larry! that does help a lot.

the 65amps is per battery (I'm assuming full charge) . i have two batteries in parallel.

would i need to upgrade the batteries if I go to a larger inverter? Or would i be ok with what i have now.

Im toying with upgrading my batteries to more amp-hours...and increasing the size of the inverter. I just didnt know if i could increase the size of the inverter without upgrading the batteries.

and yes..i would only be hairdrying to five-ten minutes or so.

Also, i have a 100w solar panel now which with my current setup charges to full in a day or so. (rarely use stuff during the day..mostly at night). would a 200w solar panel charge faster?
Hi Lesley,

You currently have 130 amp-hours capacity, but you only have 65 amp-hours USABLE. Flooded Lead Acid batteries start to be damaged if they are drawn down below 50% state of charge.

There are two different questions you are pondering:
  1. Do I have to upgrade my inverter? Yes. The present inverter can only provide 1000 watts. It's circuit breaker will trip if you use an 1100 watt or 1875 watt appliance. (How many watts does your present hair dryer consume?)
  2. Will my current battery set work with a 2000 watt inverter? Yes, but each usage will take a good chunk of the available charge.
Now that we've concluded that you have 65 amp-hours available, remember these 5-minute statements:
92 amps x 5/60 = 7.7 amp-hours (small dryer for 5 minutes)
156 amps x 5/60 = 13 amp-hours (large dyer for 5 minutes)
If you don't use anything else, you can use the small dryer for 8.5 times or the large dryer for 5 times AND NOTHING ELSE. That's okay if you boondock for 2- or 3-day weekends and don't use a coffeepot, toaster, or microwave oven.
Quote:
Originally Posted by Lpaine1331 View Post
and yes..i would only be hairdrying to five-ten minutes or so.
Umm...ten minute drying halves the number of uses to 4-1/4 or 2-1/2 uses.
[QUOTE=Lpaine1331;2805521Im toying with upgrading my batteries to more amp-hours...and increasing the size of the inverter. I just didn't know if i could increase the size of the inverter without upgrading the batteries.[/QUOTE]
If you have the moolah, your needs would be well-met by replacing the Flooded Lead Acid batteries with Lithium (LiFePO) batteries. They have much greater capacity (amp-hours) and can be drawn down much lower without damage.

I don't know much about lithium batteries (or hair dryers either) so I'm using https://www.amazon.com/LiFePO4-Lithi...2-8997e41410bb (like the hair dryers). Others can tell you whether it's a good choice. It's a 100 Amp-hour battery with 100% discharge limit. That means that two of these raises your capacity from 65 AH to 200 AH! They cost $329 each (!) and if your current converter (battery charger in the RV) isn't lithium-capable, you may want to change that, too. With these you could go several days without worrying.
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Also, i have a 100w solar panel now which with my current setup charges to full in a day or so. (rarely use stuff during the day..mostly at night). would a 200w solar panel charge faster?
Hmm... Yes, of course 200 watts of solar will charge the batteries faster and more completely than 100 watts.

You only get 100 watts from the panel for an hour or two around noon, and then only on clear skies, sun high overhead (summer), and in an unshadowed (tree-free) campsite. Maybe the dawn to dusk average is closer to 40-50 or lower.

Flooded Lead Acid batteries don't charge at a linear rate. The closer they get to full-charge, the slower they accept additional charge. (Lithium batteries don't have this annoying characteristic--they accept a fast charge rate throughout the charging cycle.)

I don't have the numbers to work with, but I'm pretty sure that neither 100 nor 200 watts of solar can keep up with the hair dryer. With lithium batteries you might be able to charge at home and camp for several days.

Or you could simply get a generator and use it when you are using the hair dryer.
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Old 11-28-2022, 07:05 PM   #5
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I agree, get an inverter generator with at least 2000w of power. Then you can run the hair dryer and recharge your existing batteries. Way cheaper than buying a bigger inverter, expensive lithium batteries and upgraded converter.
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Old 11-29-2022, 09:28 AM   #6
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I agree, get an inverter generator with at least 2000w of power. Then you can run the hair dryer and recharge your existing batteries. Way cheaper than buying a bigger inverter, expensive lithium batteries and upgraded converter.
^what he said.


don't forget ... whenever you plug in the 120v AC from the pedestal
if you have a converter (most trailers will have one)
The converter will also charge your battery.

If the battery is no longer connected for any reason, the converter will power your 12v stuff...



and learn to live with wet hair
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Old 11-29-2022, 10:22 AM   #7
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thank you!

I think im looking to move to the Lithium battery. You mentioned i will need to upgrade my converter to accomodate lithium..is there anything else i need to think about for this conversion?

and i found this hair dryer..https://www.amazon.com/Wireless-Rech...56790848&psc=1

HA its the little things!
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Old 11-29-2022, 11:07 AM   #8
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cordless hair dryers were invented centuries ago
sit in sun and use a towel.

what you need to do is ask yourself..
How often will you be on battery power only
do you intend to do a lot of boondocking

How much power do I use each day.
can my existing battery supply that usage... + a little bit more
can my charging system replace that battery usage
how long will it take to replace the power.

once you worked out the above you can look at you upgrades

For just a few $$$
add some more solar
Look at better lead acid GC2 batteries more storage no other upgrade
Small GAS generator ....


More $$$
Lithium Batteries + solar
if no solar, you'll more than likely need a converter upgrade.

Cost goes up considerably with consumption... try to limit usage is the better idea
------------------------------------------------------------------------

The cordless dryer ... read the reviews

if you have long thick hair I doubt it would work well.
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Old 11-29-2022, 03:09 PM   #9
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Hmm...

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Originally Posted by Lpaine1331 View Post
thank you!

I think I'm looking to move to the Lithium battery. You mentioned i will need to upgrade my converter to accommodate lithium..is there anything else i need to think about for this conversion?
May also have to adjust or replace the controller for the solar panel(s).

Since the lithium batteries are more costly (and don't emit dangerous fumes), some people move them from the trailer tongue to an inside location.

If the batteries are a long distance from the converter, most people replace the interconnecting cables with a heavier grade.
Quote:
Originally Posted by Lpaine1331 View Post
thank you!
=and i found this hair dryer..https://www.amazon.com/Wireless-Rech...56790848&psc=1

HA its the little things!
It is indeed the "little" things. That hair dryer you identified is only 400 watts! Pretty small! It will take quite a few minutes to dry your hair.

"The Law of Conservation of Energy" (a principle of physics) suggests that it will take so much time that you will wind up using the same number of amp-hours to achieve the same dryness. (And that's not counting the time in the middle where you stop--with wet hair--to recharge that dryer so you can continue.)
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