Community Forums

Mkaye · 03-22-2020, 10:28 AM

researching to see if switching to Lithium is feasible
i have 1 size 31 lead acid at the moment

i installed a 3000W Xantrex inverter - short uwave use and milk frother

was looking at https://www.rj-lithium.com/supplier-...ifepo4-battery
or battleborn for comparison https://battlebornbatteries.com/shop...cycle-battery/

looking at the specs i see that 100A continuous is max - that's only 1200W
my uwave is 1500W i believe, so i would be in trouble if i ran it for 5 min
Li batteries have a max higher than 100A, but only for seconds - not minutes

i don't have the physical space for (2) 100ah batteries

anyone looked at this in more detail?

mark

pasdad1 · 03-22-2020, 10:34 AM

Quote:

Originally Posted by Mkaye

researching to see if switching to Lithium is feasible

i have 1 size 31 lead acid at the moment

i installed a 3000W Xantrex inverter - short uwave use and milk frother

was looking at https://www.rj-lithium.com/supplier-...ifepo4-battery

or battleborn for comparison https://battlebornbatteries.com/shop...cycle-battery/

looking at the specs i see that 100A continuous is max - that's only 1200W

my uwave is 1500W i believe, so i would be in trouble if i ran it for 5 min

Li batteries have a max higher than 100A, but only for seconds - not minutes

i don't have the physical space for (2) 100ah batteries

anyone looked at this in more detail?

mark

I think you would have trouble pulling 125 amps from just one group 31 lead/acid battery for 5 minutes without the voltage dropping below the LVCO (low voltage cutoff off) of the inverter.

twinboat · 03-22-2020, 10:36 AM

1500 watts at 12.5 volts is 120 amps.

One battery I looked at will shut down in 3 seconds at over 100 amps.

You could run the appliance thru a Kill A Watt meter and see actual watt draw. The meter is about $20.

Winterbagoal · 03-22-2020, 01:43 PM

Along the same lines, some lithium batteries do have a lower max amp draw cutoff, and so aren't necessarily the best option if you have a lot of short or long duration high amp draw devices, like power tools and generator starter motors.

mchero · 03-22-2020, 01:48 PM

What MODEL of inverter? Xantrex manufactures many 3K inverters.

powercat_ras · 03-22-2020, 02:29 PM

Yes, typical LiFe 12 volt batteries have a continuous rated output of 100 amps , roughly speaking that's about 1000 watts AC factoring in inverter conversion loss.

For example if you want to drive a 3,000 watt inverter at full output from 12 volt lithium batteries you would need 3 in parallel, to deliver the required current.

Mkaye · 03-23-2020, 05:53 AM

Quote:

Originally Posted by powercat_ras

Yes, typical LiFe 12 volt batteries have a continuous rated output of 100 amps , roughly speaking that's about 1000 watts AC factoring in inverter conversion loss.

For example if you want to drive a 3,000 watt inverter at full output from 12 volt lithium batteries you would need 3 in parallel, to deliver the required current.

that's pretty much the realization that i came to

Xantrex Freedom X inverter - 2000W (sorry not 3000W - brain isn't what it used to be), but i would still need 2 lithium batteries

mark

PbdBlue · 03-23-2020, 07:48 AM

Quote:

Originally Posted by Mkaye

that's pretty much the realization that i came to

Xantrex Freedom X inverter - 2000W (sorry not 3000W - brain isn't what it used to be), but i would still need 2 lithium batteries

mark

To be fair you would need more than two LA batteries to run a 2000 watt load for any length of time. Once you factor in Peukert's Law you're only going to get about 50AH usable out of a pair of GC2's. That's about 15 minutes with a 200 amp load.

Mkaye · 03-23-2020, 07:56 AM

as i said, i'm not trying to run my microwave for a long time, but occasionally we forget to defrost something, and i use the microwave for that on the inverter (when i can't use the generator)
the defrost cycle is duty-cycling full power, probably ~30% & my LA battery is OK
the LI battery would not be, as the BMS would step in & limit the max current to 100A and i'm sure my microwave would not be happy

mark

Smitty77 · 03-23-2020, 09:09 AM

You might give BatteryPro a call at Starlight Solar. Get your actual battery compartment space measurements. And see what might possibly be able to be kitted together for you to fit with a GBS built kit? Larry might also be able to help you with some ideas of where else in your RV you could locate the batteries too... Never hurts to ask those with lots of experience for their input - and Larry has the experience...

Best of luck to you,
Smitty

https://www.starlightsolar.com/elite...ery/index.html

SLOweather · 03-23-2020, 09:41 AM

In real world experience, yes, our first, single BB would shut down in 30 seconds with the inverter/MW load. with a second BB, it runs fine.

astrocamper · 03-23-2020, 03:31 PM

The Lithiums like to be inside. Is there another location inside that could handle more than 1 battery.

I have 4 battle born batteries in a row between my sit and sleep sofa and the pass through storage near the head of our bed. It made use of previous unused space.

mchero · 03-23-2020, 06:14 PM

Under the bed a good idea if you can find the space.

astrnmrtom · 04-01-2020, 09:24 AM

Looking at the issue from a completely different angle you could look into an inverter microwave. Since you mentioned defrosting, an inverter microwave works differently from a standard one. When you set the "power" level to 50% it runs continuous at 50% power so your 1000 watt microwave is running at 500 watts.

The easiest solution is to run the generator for those few minutes.