What the max size inverter

I have a 3kw inverter with a built in transfer switch. My main incoming power cable goes to a 8 breaker sub panel, 2 for the ac's, 2 for the Inverter / Charger (I/C), 1 for the electric water heater, 1 for the factory 100 amp converter. The other 2 are spare at the moment, 1 will be a garage AC at some point.
The 2 going to the I/C charges at up to 150 amps, as well as powers the factory main breaker panel. This means when I have either shore power or generator power I have everything working, running off batteries I loose both AC's and the electric water heater - everything else works as normal. I am installing a 15 amp transfer switch so I can run the main AC off the inverter, for now using a Costco 2000 generator to top off the batteries (55 amp charger about maxes it out) but soon solar..

Vintage465 wrote:
So I have 2 six volt interstate golf cart batteries, 300w solar and a Samlex Controller. What is the max size sine wave inverter that could be installed? We don't watch TV, use microwave or really anything that uses 110v. I just would like to have some availability for 110v if absolutely necessary. To describe absolutely necessary:(if my wife needs to use the 110v grinder to make a special grind of coffee for her latte). Meaning, it would be a pretty short blast of usage.

thanks,

It doesn't matter what giant sized inverter you install per battery AH capacity. What matters is what the draw is of whatever you plug into the inverter.

First you have to look at the info on that grinder and tell us what input watts it wants, and whether a grinder is an inductive (like a motor with a surge start) or just a resistive load.

Given that info, your input supply in 120v needs will be known. Then your question can be answered, taken as, "What size inverter do I need for this job?"

I too got a good deal on a 1000W psw inverter. Works well with two 6V golf carts, although we rarely push the inverter's limits. And it was primarily for grinding beans too. Works well for that. Ended up using it with a lot of electronics as well when we couldn't find the right 12V adapters.

Wired it into the trailer's 110VAC circuits with a 110VAC sensing relay.

If I ever double my battery bank, I'll swap it for a 2000W inverter (and increase the 12V wire sizes). But till then, we're happy campers.

Vintage465 wrote:
We don't watch TV, use microwave or really anything that uses 110v. I just would like to have some availability for 110v if absolutely necessary.

JMO, but you'd enjoy greatest convenience by wiring an inverter to power the trailer "whole house", meaning set it up so you can plug the trailer's main service cable into the inverter's 120 vac output receptacle. Within the limits of whatever size inverter you choose the trailer then will behave just as it would when plugged into shore power. I probably would have chosen a 600 watt pure sine wave inverter but took advantage of a sale on a 1000 watt version that serves the purpose just fine, will even power a toaster or coffee machine, but most important of all - my wife's hair dryer, albeit on it's low heat setting.

Whole House Inverter Installation - 7 pics

MrWizard wrote:
My go power 300w, runs my coffee grinder no problem
I ground some this morning

What brand and model coffee grinder are you using, for reference purposes, in relationship to your Go Power 300? Obviously, these two paired together work well.

My go power 300w, runs my coffee grinder no problem
I ground some this morning

RoyB wrote:
. . .

I ended up using a 600WATT PSW Inverter ($259 AMAZON) for my duty work horse inverter to run my home entertainment items. battery chargers for cell phones, computers etc, NOAH WX radio, a couple of small electric fans, an ocassional electric lap blanket, and a few 120VAC lights when needed

. . .

+1 on the 600 watt PSW. It'll run our small 4a Oreck vacuum cleaner and 5-cup coffee maker. Very important to stay clean and caffeinated :)

My Mr Coffee grinder just barely works on a 300WATT PSW Inverter... It will try to start the motor and if I turn it off and on a few times I can get it to work... We too must have our fresh ground bean coffee brews for the day...

I would not even think about using a modified type Inverter if electronics or transformers is involved. Those items will get get very hot... It is just a few dollars more for the PSW type inverters and then you would not have to worry about what your family may accidentally plug into them... having said this I know alot of others use the modified type inverters and have good success... Its just me that won't go there...

I ended up using a 600WATT PSW Inverter ($259 AMAZON) for my duty work horse inverter to run my home entertainment items. battery chargers for cell phones, computers etc, NOAH WX radio, a couple of small electric fans, an ocassional electric lap blanket, and a few 120VAC lights when needed...

Our largest current drain during the typical day/evening run shows around 20AMPS DC current on my BATTERY MONITOR PANEL from 6PM to 11PM with our normal AC and DC items all drawing from the batteries. This includes a good strong 1A parasitic drain on-going all the time when running off the batteries... Our battery bank was planned to be large enough to cover this mode of operations. We get by very well with our 255AH 12VDC Battery setup...

This is installed very close to the battery main switch and then I run a couple of 120VAc multitap extension cords from it with one going to the home entertainment center area and the other one going back to the bedroom nite table...

These are my two emergency power stations for when we are camping off the power grid.

My game plan is to run down my batteries to their 50% charge state by 8AM the next morning. Then I use my 2KW Generator to run the on-board converter/charger to re-charge my battery bank back up to its 90% charge state in a three hour generator run time.

Normally when we are running the generator for its three hour run each morning this is the time we grind and brew our fresh made bean coffee for the day - then store it is a thermos...

If I had solar panels this would be used to reduce the amount of time I would be running the generator. My battery bank wants to see around 52-53AMPS DC current available when the converter hits them with 14.4VDC... A typical 120WATT SOLAR PANEL will only produce 5-6AMPS of DC Current in high SUN so this means it will take alot longer than three hours to get my battery bank back up to their 90% charge state... I will not start my run off the batteries unless I have at least a 90% charge state otherwise it gets dark on me around 10PM at night...

My camping off the power grid experiences... Been doing this since 2009 and have had great success running our emergency power needs in the one day/night run off our battery bank. in our OFF-ROAD POPUP camper. We don't even think about it anymore...

I still keep a close watchful eye on my Battery bank Monitor panel to see how it is doing through the evening. If it evers gets below the 12.0VDC VOLTAGE level which is around the 50% charge state then I will shut it down until we can run our generator the next morning to get them back up to their 50% charge state.

Roy Ken

Hi,

I'd lean towards a Samlex inverter. I'd probably go pure sine wave because some battery chargers don't 'like' modified sine wave, nor do electric blankets in general.

If you do go msw there are lots of el cheapo inverters.

It really does come down to what you wish to run. I don't think that 1000 watts is a good size--it is too small for the microwave--and too large for small loads.

So go small at 300 watts, or go large at 2000 watts.

I used a Cobra MSW 2500 watt for five years with great results but have replaced that with a 3000 watt Magnum pure sine wave hybrid unit.

I read this as minimalist requirements.

A 300-watt inverter would do quite nicely. Those small motors have brushes therefore 120 volts AC or DC it doesn't make any difference, certainly not demanding pure sine wave. It all depends on the future. Unplanned expansions. I would check Amazon dot com to see which brand of inexpensive modified sine wave inverter has the most stars, then read the reviews and try and glean info regarding long-term reliability. This could be a very inexpensive purchase.