Need help hooking up house batts and conveter to Distr. Panel

[ski43]

I am hooking up my house batteries and conveter to a 12 v distrubution panel and have some questions.

1. should I have a switch to turn off power from house batteries to the panel when using the converter, should I also have a switch between the converter and the panel

2. what size wire should I use from house batteries and panel and from converter to panel

3. should I take the ground to the panel from the bus body or go to the negative of the house batteries.


thanks for any help

[bowmaga]

slightly confused about the converter to the 12 volt panel.  are you converting 110 to 12 volt or something?

but I'll explain what i just did.

we have a 110 panel and a 12 volt panel

we also have a 2500 watt xantrex inverter to convert the 12 volt power to 110.

we have 8 - group 27 100 amp batteries, wired in parallel, for the house.

your inverter should give you some wire sizes in the manual.  Ours told us to use 4-0 gauge, which is huge and expensive for any run over 5'.  It depends on the size of your inverter.  Our old inverter only had 1 gauge ran to it, and it was a 1000 watt. but we wired all our batteries together with 4-0 gauge and then ran from the batteries to the inverter w/ 4-0 and placed a 300amp fuse between in the hot wire going from battery positive to inverter positive.  The bigger the wire the less amprage you lose. 

If you can get a hold of some nice big welding cable, that would be a good deal.  But be prepared....the 4-0 gauge wire cost us over $8 per foot.

we used 8 gauge wire to run both from our inverter to the 110 panel.  then we used another run of 8 gauge to run from our 12 volt panel to our house batteries.

We took our negatives to the batteries.

the inverter is grounded to the the bus.

[H3Jim]

Converter makes low voltage DC from AC
Inverter makes AC from low voltage DC

Most folks use an Inverter in their conversions, thats why we are confused.

[Marcus]

Ski, If you have a marine surplus store around you can buy 4/0 for less money. Don't skimp on wire size to save a few dollars. In the end it will cost you more. Most good inverters will have a built-in transfer switch. Just my 2 cents worth. marc

[ski43]

The conveter converts 110 to 12 v, incase of dead batteries, I can run 12 v off the generator

[HighTechRedneck]

The chart at this site can help you determine the necessary wire sizes:

http://www.engineeringtoolbox.com/amps-wire-gauge-d_730.html

[Sean]

As I also wrote on the "other board,"

We need to know the make and model of converter and inverter, the voltage, size (in amp-hours), and type (AGM, Gel, or flooded) of the battery bank, and the total expected load on the system in order to answer any of your questions except #3, where the answer is to wire directly from the load center to the battery negative, and also tie the battery negative to the frame at the closest possible point.

BTW, Jim -- not all inverters have built-in chargers.  I am guessing from the questions that this one does not.  I am not a fan of RV-style converters myself, but to each his own.

HTH,

-Sean
http://ourodyssey.blogspot.com

[ski43]

I have a RV Dimensions Unlimited inverter. Model number WIN-12X20B3RT.

Specifications:

Millennium Series Standby Power Systems (SPS)
Output Voltage (VAC) 120 RMS ±5%
Output Frequency: 60 Hz ± 0.05%
Output Waveform: Quasi-sine wave, with waveform stabilizer
Input Voltage: (VDC) 11 to 14
Operating Temperature: -20° to 40° C (0° to 104° F)
Efficiency: Up to 93%

Other Design Features:

Thermally controlled cooling fan. Enclosed AC and DC cable connections with strain relief. Built-in battery charger and transfer relay


Remote Control Panel:

LCD Display - Blue background, 16 white characters by two lines. User-friendly messages. Dimensions W x H x D: 5.75 x 3.75 x 1.25


Unit Protection:

Automatic electronic short circuit/overload protection Automatic high temperature shutdown Automatic low battery shutdown at 10.5 VDC (with in-rush delay)


Detailed Specs:

Output Power (Watts Cont.) 2,000
Output Current (Amps AC) Up to 16.5 Peak
Output (Amps AC) 70
Output Rating: (hp) ½
Input Current (Amps DC) Up to 200
Weight (lbs.) 44
Dimensions LxWxH (Inches) 15¾ x 11½ x 7¾

BATTERY CHARGER

(Built-in) 3 step charger with automatic conditioning; Temperature compensated output voltage; selectable between wet and sealed lead acid batteries; selectable between small and large battery banks Output Current (Amps DC) 100 Input Current (Amps AC) Up to 21


TRANSFER RELAY

(Built-in) Fail-safe shore power Transfer Relay Current Rating (Amps AC) 30 Transfer Time (milliseconds) Less than 16 typical Usage: Any 120 VAC, 60 Hz single-phase products within the inverter's power rating that does not require a pure sine waveform.


I am using 6 - 6 volt golf cart batteries - wet cell


Do I need a conveter when I run off of AC or does the inverter supply 12 vdc when charging to power my 12 vdc stuff, like heat, water pump, lights.

[Sean]

John,

It looks like your inverter already has a built-in charger.  So, no, you do not necessarily need a converter.  In fact, I would say that most of us with charging inverters do not use converters.

A converter will, however, do two things for you:

1. It will provide a more regulated DC voltage to your DC appliances when you are plugged in.  The inverter's built-in charger will put out close to 15 volts when in the "bulk" charge phase, and, while most 12-volt accessories will run fine on this, you might find the lights to be a little bright, and it might shorten the life of the bulbs by a few percent.

2. It will handle all the DC loads, allowing all 100 amps of the charger's output to go into the batteries, for a slightly faster charge.  But most coaches have only a few amps of DC running at any time.  Also, you are still limited by the size of your shore power connection and/or generator output.

So the choice is yours.  Just remember that, in order for the converter to work at all, the batteries must be disconnected from the DC loads.  Most converters have internal relays to accomplish this.

-Sean
http://ourodyssey.blogspot.com

[TomC]

I have a Trace inverter that has up to a 130amp charger on it.  With my two 8D AGM Lifeline batteries, I have it set at 14.1 volts for charging and 13.2 volts for bulk or at rest.  The only appliance that makes a bit of noise when on the inverter charger is the Fantasic fans-they make a high pitch whistling sound when the inverter is charging-but no whistling sound when off.  The inverter/charger is a really nice feature that makes life a bit easier in that you don't really have to think about the house batteries once the inverter/charger's settings are set.  You should adjust for temperature though.
I have a separate circuit breaker box for my inverter run 120vac items.  When power is present, it runs through a 30 amp breaker from the main box, and when there is no power runs through the inverter-nice.  Good Luck, TomC

[Sean]

John,

Forgot, in my last response, to answer the other part of your question:

For an eight-foot cable run (my estimate based on you saying the inverter is in the coach somewhere above the batteries in the condenser bay), 00 ("two ought" or 2/0) is the minimum gauge you want to run.  That will cover your 200-amp max load, and will give you a 2.13% voltage drop, which is acceptable.  Bigger cable is always better, because it will run cooler, waste less energy (lower voltage drop), and allow you to add battery, charger, or inverter capacity later.  For the minimal difference in cost, I would run 0000 (four ought).  FWIW.

-Sean
http://ourodyssey.blogspot.com

[ski43]

The batteries are about 20 ft from the distr. panel, while the inverter is about 10 feet due to how I would have to run cable,  what size cable should I run to the panel, should I run direct from batteries to panel or can I run to the inverter and at the same attachment point on the inverter run cables to the panel

[ski43]

is 00 different than 2/0

[buddydawg]

00 and 2/0 are the same as is 0000 and 4/0 etc.  just don't confuse  #2 with 2/0 and so on.

[ski43]

so 2/0 is not 2 gauge, if I want 2/0 what do I ask for and where is the best place to get it.