Microwave off Inverter. Volt drop with 3 batts parallel

pianotuna wrote:
Doubling the cell count makes a 100% difference.

lawrosa wrote:
Yes You guys have 4. May make a bit of a difference..

agreed pianogtuna. TWO GC shut down around 75-80% SOC in my case. FOUR GC still running at 50% SOC, even lower. goes from almost adequate to not to worry. in the first case microwave wouldn't ru after a long cold night with furnace discharge and increased internal resistance and reduced capacity due to low temp.

In the second case, never had had to worry about needing to start the genny to run the microwave.

I think that is similar to experiences you have posted as well.

lawrosa wrote:
Yes You guys have 4. May make a bit of a difference..

But if you look at my test and my 70 amp draw I ran this for about an hour.

I technically have 220 AH's. Although I didnt pull from the truck batt as expected, with inverter losses I pulled the batts down to some 60% per hydro readings.

AH's are AH's. It would seem if I kept going a bit after alarm I would have successfully pulled the 100 ah's /50% from the batts.

70 amp draw x 1 hour should equate to 70 + ah's out of battery with losses. But Peukerts law comes into play.

https://en.wikipedia.org/wiki/Peukert%27s_law

Two 6 volts @ 225 ah's im sure would perform the same discharge wise but with a more pronounced voltage drop.

But I cant prove this unless someone out there in internet land either trys it, or I buy 6 volts myself and try it.

Its a secret the 6 volts guys are not talking about....LOL

But not too repeat myself I can easily get rid of my high amp draw items and live a happy life with 6 volters I am sure.

From what I read a 70 amp draw on 6 volts for say 10 minutes and I would assume your inverter will be beeping away.. ( 2- 6 ers, not 4...)

a key component to success (or failure) is the inverter shut down voltage. One poster mentioned his shut down near 10v and worked fine on a pair of 6V, not suprising, but that low of a shutdown risks damaging batteries by drawing them down near 0% SOC.

By contrast mine alarms near 11.5V and shuts down around 11.2. all the difference in the world when hooked to a PAIR of GC. 1000W draw drops them down do 11.2 @ around 80%SOC. Pianotuner has had similar experience. now with a 10V shutdown, no problem.

with Four GC, load is shared, and I can run the inverter at less than 50% SOC without an issue.

crosscheck wrote:

ktmrfs wrote:
Hint: If you want to run a microwave on batteries or genny, I'd suggest you toss out the microwave in the RV and replace it with a panasonic true inverter microwave. Why? well it is the only microwave that when you drop the power level for cooking it drops the input power as well instead of just cycling between 0% and 100% power.

So...... as an example, I an EASILY run my panasonic on a 1000VA PSW inverter even though it draws 1500VA at 100% power. I just drop the power to 5, and it draws 800VA. yes it takes about 25% longer to heat a cup of water or warm some veggies, or defrost some meat, but it runs fine on a smaller inverter, doesn't sag the batteries as much.

When on shore power or generator I can run it however I want, and when on the genny it doesn't make the genny rev, idle, rev, idle like a regular microwave does.

We have a Panasonic inverter micro in the house. If it wasn't,t so big I would swap it with the RV one. Win/win. Good idea.

Dave

they make them in smaller sizes, need to search a little but amazon and sometimes costco sells one very close to the size of the typical TT microwave. One of the best changes I've done.

lawrosa wrote:
Two 6 volts @ 225 ah's im sure would perform the same discharge wise but with a more pronounced voltage drop.


Its a secret the 6 volts guys are not talking about....LOL

Exactly. :p

Doubling the cell count makes a 100% difference.

lawrosa wrote:
Yes You guys have 4. May make a bit of a difference..

Yes You guys have 4. May make a bit of a difference..

But if you look at my test and my 70 amp draw I ran this for about an hour.

I technically have 220 AH's. Although I didnt pull from the truck batt as expected, with inverter losses I pulled the batts down to some 60% per hydro readings.

AH's are AH's. It would seem if I kept going a bit after alarm I would have successfully pulled the 100 ah's /50% from the batts.

70 amp draw x 1 hour should equate to 70 + ah's out of battery with losses. But Peukerts law comes into play.

https://en.wikipedia.org/wiki/Peukert%27s_law

Two 6 volts @ 225 ah's im sure would perform the same discharge wise but with a more pronounced voltage drop.

But I cant prove this unless someone out there in internet land either trys it, or I buy 6 volts myself and try it.

Its a secret the 6 volts guys are not talking about....LOL

But not too repeat myself I can easily get rid of my high amp draw items and live a happy life with 6 volters I am sure.

From what I read a 70 amp draw on 6 volts for say 10 minutes and I would assume your inverter will be beeping away.. ( 2- 6 ers, not 4...)

ktmrfs wrote:
Hint: If you want to run a microwave on batteries or genny, I'd suggest you toss out the microwave in the RV and replace it with a panasonic true inverter microwave. Why? well it is the only microwave that when you drop the power level for cooking it drops the input power as well instead of just cycling between 0% and 100% power.

So...... as an example, I an EASILY run my panasonic on a 1000VA PSW inverter even though it draws 1500VA at 100% power. I just drop the power to 5, and it draws 800VA. yes it takes about 25% longer to heat a cup of water or warm some veggies, or defrost some meat, but it runs fine on a smaller inverter, doesn't sag the batteries as much.

When on shore power or generator I can run it however I want, and when on the genny it doesn't make the genny rev, idle, rev, idle like a regular microwave does.

We have a Panasonic inverter micro in the house. If it wasn't,t so big I would swap it with the RV one. Win/win. Good idea.

Dave

Below is an interesting thread on 6v and 12v Batteries in an RV.

Dave



http://www.rvforum.net/SMF_forum/index.php?topic=103699.0

crosscheck wrote:
Now for the real world experience of dry/boondocking camping. Since 2011, we have used 4 6v AGM or GC-2 batteries. Inverter is 2000w. 98% dry camping, almost no genny time.

Micro, used 2.5minutes at a time at least once a day, hair dryer, 4 minutes once a day, toaster 3 minutes every other day. Various low watt 120v appliances like magic bullet, battery charging for electronics, coffee grinder etc. run off inverter. Never had a problem with low voltage shut off on the inverter.

I am sure You can use true12v deep cycle batteries in place of the 6v batteries but as is stated in the link and by the author in another presentation, 6v GC-2's or AGM,s are the recommended batteries for RV boondocking/ high inverter loads.

Dave


http://www.rvforum.net/miscfiles/Choosing_right_battery.pdf

One key to your success, is like me. Use FOUR GC. using only two often leads to quick shutdown of the inverter unless the batteries are nearly fully charged. with four GC you are load sharing which helps a lot. And you and I only use the big loads for a few minutes at a time.

Now for the real world experience of dry/boondocking camping. Since 2011, we have used 4 6v AGM or GC-2 batteries. Inverter is 2000w. 98% dry camping, almost no genny time.

Micro, used 2.5minutes at a time at least once a day, hair dryer, 4 minutes once a day, toaster 3 minutes every other day. Various low watt 120v appliances like magic bullet, battery charging for electronics, coffee grinder etc. run off inverter. Never had a problem with low voltage shut off on the inverter.

I am sure You can use true12v deep cycle batteries in place of the 6v batteries but as is stated in the link and by the author in another presentation, 6v GC-2's or AGM,s are the recommended batteries for RV boondocking/ high inverter loads.

Dave


http://www.rvforum.net/miscfiles/Choosing_right_battery.pdf