battery/inverter recommendations

[jluke]

This is a topic that has been worked over pretty good, but I have a couple of questions. I have a 2000 Holiday Rambler with 2 6 volt batteries as house batts. We have a household refrigerator, not a large one, that, while on the road, I crank up the generator every couple of hours to keep cool. most of our trips are short ones, we do not boondock. End of this year, we are taking a long trip. I would like to install an inverter just for the fridge while driving, we will hook up to shore power every night. Can I add a 12v deep cycle for the additional juice needed or are 2 more 6v batts recommended. I am planning on a 2000 inverter, modified sine wave, do I need a pure sine wave for the fridge? Ideally, this would be a hookup where i don't have to unplug/plug, each night and morning. Does anyone have a schematic for this and or recommendations? Thanks to all

[wa8yxm]

First there is another thread here in one of the other forums about "WHy can I no longer find DEEP CYCLE batteries"

So the answer is both yes and no

12 volt DEEP CYCLE are made, but they tend to be expensive save perhaps for the GC-12 golf car battery

I would add another pair of GC-2 (Also golf car batteries) Like you have now.

GC-2 Pairs are around 220 amp hours (C/20 rate)
GC-12 about half that as I recall (like 125)
Group 31, also about 125=130
Group 27 and 29 just under/over 100
Group 24 75

Ang the "Group" batteries are MARINE/deep cycle, keep at least 75% full, V/s the DEEP CYCLE (Good down to 50% state of charge)

[jluke]

my thanks to everyone for their input, you've given me a lot of good information to work with and the installation should be simple. Saved me a lot of research time and time spent agonizing over the route I should take since you've all been there! Great site.

[kevden]

I have a peak inverter powering our mini fridge while traveling or boondocking. Very happy with it so far.
https://www.amazon.com/gp/aw/d/B0066IU9B0/ref=mp_s_a_1_1?ie=UTF8&qid=1498763222&sr=8-1&refinements=p...

[pianotuna]

I'd recommend a 1000 watt pure sine wave inverter.

It may be wise to upgrade the charging path from the alternator to the house battery bank.

[Sam_Spade]

horton333 wrote:

The tow vehicle should be able to provide enough 12 volt to the inverter while traveling down the road, so if you are 'always plugged in' at night there is no need for more battery. ..

That is an assumption which may or may not be true.

Need to know the wattage requirements of the fridge before a good answer can be given.

AND need to know for sure that the tow vehicle really DOES charge the house batteries when moving.

If the fridge were to use the ENTIRE capacity of a 15 amp, 120 volt circuit, that would be about 1800 watts. More likely that it uses half of that or less.......in which case a 1000 watt (continuous) inverter should be plenty.

But don't guess. Find out the power requirements for sure.

[Unyalli]

For less than $400 you can get 2000 watts of pure sine and a big honking fuse. Samlex SSW-2000-12A According to Samlexusa.com website these come with a remote meter.

[Matt_Colie]

jluke wrote:
This is a topic that has been worked over pretty good, but I have a couple of questions. I have a 2000 Holiday Rambler with 2 6 volt batteries as house batts. We have a household refrigerator, not a large one, that, while on the road, I crank up the generator every couple of hours to keep cool. most of our trips are short ones, we do not boondock. End of this year, we are taking a long trip. I would like to install an inverter just for the fridge while driving, we will hook up to shore power every night. Can I add a 12v deep cycle for the additional juice needed or are 2 more 6v batts recommended. I am planning on a 2000 inverter, modified sine wave, do I need a pure sine wave for the fridge? Ideally, this would be a hookup where i don't have to unplug/plug, each night and morning. Does anyone have a schematic for this and or recommendations? Thanks to all

John,

First, I am going to assume that this is the HR MH- Right?

If it is, your plan is good - I know it is working for me. (For about 10 years, 50 road days and about 60K miles.)

Now,
Do not add batteries to the house bank even if you are going to dry camp (like in a rest area or other) on occasions. Your 2 GC2s should hold the reefer over night. You can run the generator if needed during the day. (I hope you have a CO monitor.)

During a road day with stops, the main engine alternator should be able to manage the extra load, but if you do not have a system volt meter on the house bank, you should thing about adding one.

The reefer should run fine on an MSW inverter. It will run a little noisy (HUM), and the compressor may be warmer than usual, but we have been doing this for years. You 2K size should work, it does for most RV sized residential reefers.

There is no schematic to be had because it is too simple.
Find a place for the inverter that is close to but not in the same space as the house bank as the corrosive fumes from the house bank will kill it. You will want Gunga-Heavy wire to the inverter as the 12V to the inverter is 10 TIMES the current that the reefer draws. (We are talking about something that might be jumper cables here.) It also should be as short as you can make it.
Most inverters have 5-15 receptacles (normal household outlets). Just get a heavy duty extension cord to run from the inverter to the reefer. Do not do this in Romex (house wire) as that is solid and prone to vibration failures.

Even if you don't bother to move the plug when you are on shore power, the converter should be able to accommodate the load. Just get in the habit of opening the reefer down at departure to see if the light comes on.

There is a hidden benefit here....
Run another extension cord out into the living spaces to provide AC underway. This can run whatever your (or passenger's) want to run during the road day.

Matt

[kerrlakeRoo]

For what it's worth, I've used a Cobra 1500 watt MSW at home on several occasions for the fridge when power was out for a while. It did fine with maintaining a 24 cuft home side by side which was likely much larger than what your doing.

[jyrostng]

This is exactly what I did a couple of RV's ago. My inverter had a transfer switch build in as well as a battery charger. I found the breaker to the refrigerator outlet and spliced my inverter into it between the breaker and the fridge. at the same time I disconnected the dc converter because the inverter was a charger also, I didn't need 2 charging the batteries at the same time. I also added a battery. I had 24 hours of power for the refrigerator AFTER it was cold. so it wasn't required to run the generator while we weren't plugged in. without the transfer switch built in the inverter, it would have been much harder to do.
Modified sine wave worked fine for me, laptop, tv, fridge, I haven't found anything it won't work on yet.

[horton333]

jluke wrote:
This is a topic that has been worked over pretty good, but I have a couple of questions. I have a 2000 Holiday Rambler with 2 6 volt batteries as house batts. We have a household refrigerator, not a large one, that, while on the road, I crank up the generator every couple of hours to keep cool. most of our trips are short ones, we do not boondock. End of this year, we are taking a long trip. I would like to install an inverter just for the fridge while driving, we will hook up to shore power every night. Can I add a 12v deep cycle for the additional juice needed or are 2 more 6v batts recommended. I am planning on a 2000 inverter, modified sine wave, do I need a pure sine wave for the fridge? Ideally, this would be a hookup where i don't have to unplug/plug, each night and morning. Does anyone have a schematic for this and or recommendations? Thanks to all

The tow vehicle should be able to provide enough 12 volt to the inverter while traveling down the road, so if you are 'always plugged in' at night there is no need for more battery. Even if you pull over for an hour or two while on the road your existing battery will not be drained enough to care.
Pure sine wave will work better. Some fridges will not start with MSW and all will work more efficiently with pure sine wave. This is both the motor will run hotter, and more power is required for a given fridge than with PSW.
2kw of pure sine wave is expensive, you may want to consider something smaller if the fridge is the only use; but how much smaller is dependent on your fridge, but more like half that should do. That said once you have an inverter you may well find other uses .....