| Author |
Message |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 151
Registered: 7-2005
Posted From: 152.20.216.103
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 22, 2007 - 4:48 pm: | |
I'm working on the DC system in my MC-8. I'm unsure as to what size cable to use for my 12 volt fuse panel. I'd like to plan for 100 amps, just so I won't have to run these cables again if I need to upgrade. I've got about 15' max. between the batteries and the panel. Also, can the 12 volt converter be wired to the panel directly (it has two lugs), can the panel be wired to the converter (it also has two lugs), or should both be connected directly to the battery. I'll be running a 24 volt system for ease of charging from the bus alternator and for a nice inverter in the future. I have a Vanner 60 (or 80... I can't remember at the moment) Eq. so I'll be pulling 12 volts off the center tap. I've had no luck in finding a chart with current ratings for given wire sizes over a specified distance. If anybody has any suggestions, or can provide a link to such a chart, I'd really appreciate it. Thanks.
David |
joe padberg (Joemc7ab)
Registered Member
Username: Joemc7ab
Post Number: 73
Registered: 6-2004
Posted From: 66.38.159.33
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 22, 2007 - 11:18 pm: | |
David
Jock A. Fugitt wrote an excellent brief www.purplebear.com/busnuts/bus_elec.html it has various tables for calculating voltage drop for cable size and run . 100 Amps with a run of 30 ft ( to and fro) would require 0000 for a voltage drop of 0.2 volts and size # 1 wire for a voltage drop of 0.5 volts. Hope this is of some help
Joe. |
Chris Martin (Cjmiam)
Registered Member
Username: Cjmiam
Post Number: 2
Registered: 1-2007
Posted From: 69.4.115.238
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 23, 2007 - 4:08 am: | |
David,
I hope I understand your question. You got me confused when you interchange inverter with converter and hooking up a 12v converter.
That's a lot of amperage to be running. And you have a 60 or 80 equalizer? Well as Joe stated, 1 awg would be allowable or 0 even better. I don't think you need 000. The 1awg wire will be big enough, but if you run 100 amps through your 60 or 80 balancer, you'll heat it up and it will fail or trip.
How many amps is the "Inverter"? (Note: a "converter" goes the other way, ie 120 to 12.) And will it be 12 or 24v?
Using the balancer will keep one battery from draining more than the other, but if you hook up a 12v inverter directly to the battery it will not be "balanced" and your alternator will charge both batteries the same causing an eventual battery failure. So you would want to hook your inverter to the panel if possible, but that will figure in to your total amperage consumption. Also, you state a "nice inverter" when you are talking about 24v. If you purchase a 24v inverter you can and should go directly to the batteries. You will not be able to use the panel because it is only 12v right?
I'd go with 1 or 0 awg to the panel through the balancer and purchase a 24v inverter for a direct connection to the battery. Keep it close by the batteries. Also remember to protect the wire running to the panel from vibration. You may want to run it through a hose or else just make sure it is well attached. It would be wise to install a breaker if the the balancer doesn't feature overload protection. Hope this helps.
Chris |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 152
Registered: 7-2005
Posted From: 152.20.216.103
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 23, 2007 - 8:04 am: | |
Right now, I'm using a 12 volt converter to charge the 24 volt house batts. The Vanner will do its thing by equalizing the charge between the two 12 volt (actually, each pair of 6 volt) batteries. It is an 80 amp converter, which will charge 12 volts at 80 amps. Actually, the Vanner eq. will charge at 60 amps total (its a 60 amp eq) which is 30 amps to each battery. This will allow me to run my present 1000 watt (24 volt) inverter to power a small 'fridge. This is attached directly (with a fused disconnect) to the house batteries. No inverter will connect to my 12 volt panel. Eventually, I'll look into one of the large 3600 or larger inverter/ chargers, but at the moment, that's not in the budget.
The loads that the panel will handle are 12 volt lights, water pump, exhaust fans, a few relays, GPS, sat. radio, stereo, CB, a couple of dash fans, etc. Since the converter will be mounted very close to the panel, so I'd like to run one cable from that location to the batteries. I hope that clarifies things a bit! Thanks for the input and link. |
Tom Caffrey (Pvcces)
Registered Member
Username: Pvcces
Post Number: 1035
Registered: 5-2001
Posted From: 65.74.69.234
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 23, 2007 - 10:20 pm: | |
David, I have a feeling that you have the wrong idea about the Vanner. AFAIK, it will equalize batteries where the charge is applied to the 24 volt point, not the 12 volt point.
You should check this out to be sure of your hookup.
Good luck.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
David (Davidinwilmnc)
Registered Member
Username: Davidinwilmnc
Post Number: 153
Registered: 7-2005
Posted From: 75.178.86.198
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 24, 2007 - 6:14 am: | |
Hi Tom,
No, I don't have the wrong idea about the Vanner. I've just had it so long waiting to use it that I forgot some of the finer details! The 'high' battery (center tap and 24V connection) are what get charged. It then balances (equalizes) with the 'low' battery, which is having 12V pulled from it for the lights, etc. It's coming back to me now. I had to go out and take a look at it last night to make sure which model I have; it's actually an 80 amp. eq.... not bad for $130 new on eBay. Thanks for the reminder on how to hook up this thing.
David |
Tom Caffrey (Pvcces)
Registered Member
Username: Pvcces
Post Number: 1037
Registered: 5-2001
Posted From: 65.74.69.234
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 24, 2007 - 11:47 pm: | |
You're welcome, David.
Tom Caffrey PD4106-2576
Suncatcher
Ketchikan, Alaska |
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