Need advice on a switch

pods8

pods8

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Okay I've been beating this battery setup thing to death but think I've finally decided on a compromise in my head. However I need some input/suggestions on an aspect I'm not too familiar with which is how to switch a higher amp load on/off remotely. IE I want to have a switch in my truck cab that can kill the charge line going to the axillary batteries. What is a reasonable and affordable method of doing this simply? Would something like a starter solenoid be correct in this type of application?

For anyone that cares I'm more or less decided on using a battery isolator off my alternator and then installing an switched disconnect in the line going to the aux batteries. Then I'd like to install a volt meter which will monitor the axillary batteries in the cab of the truck with a switch to this disconnect. This way I can see what state the batteries are in and give them a bulk charge if they need it but they won't be connected full time in case whatever batteries I use aren't completely in sync with the alternator for float voltage. Then when I get home I'll connect up an appropriate smart charger to bring things up to a fully charged level.
 
Since I use just a simple solenoid my kill switch is the ignition key. I've used the same method through 5 trucks and various types of campers and it works just fine (KISS) for me.
 
Since I use just a simple solenoid my kill switch is the ignition key. I've used the same method through 5 trucks and various types of campers and it works just fine (KISS) for me.

Jay how do you shut off the charge while driving ?Do you have another switch for this?
do you install a breaker or fuse anywhere just in case?
 
SnowMan
Actually I dont worry about it. I've never burned out a battery by over charging it. My Optima Blue tops typically last 5+ years and when they stop taking a charge I replace them. Perhaps ignorance is bliss in my case.
 
Since I use just a simple solenoid my kill switch is the ignition key. I've used the same method through 5 trucks and various types of campers and it works just fine (KISS) for me.

What is the "simple solenoid" you are using? That is the part I don't have a lot of experience with and was looking for recommendations. I can handle the switch for turning the solenoid on/off alright once I know how much juice it needs.
 
Yes, I always liked having a way to isolate the camper battery from the charging circuit. I did mine two ways......

1. 70 amp circuit breaker with resettable fuse. That way to isolate the positive side, just tripped the circuit breaker.

2. big knife switch on the negative side. Undo the knife switch and totally isolated from the camper batter.

Not very automatic, but I did not do it often. If I were solar charging the camper battery, this worked nice.

Good luck.

Dave/ seattle
 
(KISS) for me.

Me too.

I would skip the battery isolator and use a switch in its place.

You would need a continuous duty solenoid to control the circuit.
 
Me too.

I would skip the battery isolator and use a switch in its place.

You would need a continuous duty solenoid to control the circuit.

I'm planning for both, the isolator is insurance to make sure I am only pulling amps off the alt and not my starter battery such that if I'm drained down quite a bit and start up my starter battery won't dump its charge into the aux batteries (not good for the starter battery anyways) and then if something happens an I have to shut off the truck right after I'm not sitting with a drained starter battery.

Looking online for "continuous duty solenoid" it looks like I should be able to get something like a cole-hersee or such rather affordable for specialty places. I'm mainly wondering if the autoparts store will carry some sort of continuous duty solenoid or such that is used in a normal vehicle. This would be helpful for replacement parts down the road if something happened. Forgive the ignorance as I'm not too familiar with solenoids.
 
Check your local trailer or rv supply store. They should have one. It looks just like the solenoids on the fenders of 90s fords. Around $35.

Here is one from ev parts.
SL1911.jpg


http://www.evparts.com/cat-12+Volt+Coil+Marine+-+RV+Solenoids+&+Contactors.htm
 
Those are fine but they have a magnet and spring inside. When you have the key off the batteries don’t see each other. When the key on then the two batteries see each other. When they fail sometimes the lock open and both batteries see each other.

I just use a dual battery isolator that has a diode so the two batteries will never see each other. Sold at Napa, Kragen, etc… Not hard to hook up and cost around $40 to $60.

http://shop.oreillyauto.com/ProductList.aspx?CategoryCode=3018
 
Those are fine but they have a magnet and spring inside. When you have the key off the batteries don’t see each other. When the key on then the two batteries see each other. When they fail sometimes the lock open and both batteries see each other.

I just use a dual battery isolator that has a diode so the two batteries will never see each other. Sold at Napa, Kragen, etc… Not hard to hook up and cost around $40 to $60.

http://shop.oreillyauto.com/ProductList.aspx?CategoryCode=3018

Right. I desire to have both, the isolator so the batteries never see each other and I want some sort of solenoid/relay with a switch in the cab so I can manually cut off the juice to the axillary batteries as well.

Edit: And the failure potential is why I'm looking for an automotive type solenoid if possible so I could readily get the same size replacement from an auto parts store while on the road if need be. What I'm having a hard time finding any information on is whether those 4 pole remote mount starter solenoids are rated for continuous duty or not and what amp. Looks like standard motor products makes a lot of stuff but I'm yet to find the specs.
 
Check your local trailer or rv supply store. They should have one. It looks just like the solenoids on the fenders of 90s fords. Around $35.

Here is one from ev parts.
SL1911.jpg


http://www.evparts.com/cat-12+Volt+Coil+Marine+-+RV+Solenoids+&+Contactors.htm

That's exactly what I'm running in my rig with no probs. My blue top is always charged and I've never seen it read anything less than a full charge even after multiple days of camping so i'm guessing it's not getting overcharged. KISS indeed.
 
Like I said I've use this system for many years and its simple so I'm sticking with it but good luck.

Oh I'm not trying to convince anyone otherwise, I was just stating that I desired to A: have them fully isolated and B: have the ability to manually switch off the feed to the aux bank. I was just looking for help on the solenoid part but the more I read it sounds like all the solenoids that would be for automotive use are intermediate duty, looks like the continuous is more of a marine application so those would be the stores to check out if I ever needed something on the fly.
 
Even if a solenoid fails it's easy to test and bypass if you needed to. :thumb:
 
skip the soloniod

Just thinking out loud here..... Could you simply switch the charge wire? Is your desire for a soloniod because you don't want to run the charge wire through the cab, and you want the switch inside the cab? But then you want to monitor voltage anyhow, so why not just run the charge wire through the cab? That would make it simple to throw on a volt meter on the RV side of the switch. It's been a while, but it seems i remember the charge wire being a 12ga w/a 20A fuse? A simple 20A switch would work - then you could skip the solonoid.

I was thinking on this same line last year when I took a 6000 mile journey from AK to America and back. I was concerned about overcharging (cooking) the RV battery since all I have is the factory isolator on my 03 Grandby model and would be spending many hours driving (charging). I remember reading about marine alternators that are capable of "smart charging" the "house" battery banks. I'm pretty sure the typical automotive voltage regulators are not the "best" way to maintain a RV deep cycle battery, but do an adequate job for most folks most of the time. I'm all ears if anyone has experiences / tips to share.

As was mentioned, another reason for adding means to disconnect the charge wire might be if you have/add solar charging for the RV battery. I'm havn't yet figured out how the alternator and solar charge controller would interact. Anybody have solar AND an isolator?

Good topic pods8. And I also shop at West Marine for items like you are interested in. They have an excellent catalog I often reference.
 
Just thinking out loud here..... Could you simply switch the charge wire? Is your desire for a soloniod because you don't want to run the charge wire through the cab, and you want the switch inside the cab? But then you want to monitor voltage anyhow, so why not just run the charge wire through the cab? That would make it simple to throw on a volt meter on the RV side of the switch. It's been a while, but it seems i remember the charge wire being a 12ga w/a 20A fuse? A simple 20A switch would work - then you could skip the solonoid.


Mainly trying to avoid the larger switch in the cab that would be required for this, much easier to find a place for a small toggle or rocker switch than one rated for full amps and then also fish that wire up into the truck. I was figuring I'd size the wire/fuse for somewhere in the 30-60amp range.
 
Wiring a solenoid

That's exactly what I'm running in my rig with no probs. My blue top is always charged and I've never seen it read anything less than a full charge even after multiple days of camping so i'm guessing it's not getting overcharged. KISS indeed.

I'm pretty clueless about 12vdc stuff and want to use a solenoid as you do for the aux battery. My local store sold me the Cole Hersee 24117 saying it is what I need, but they don't know how it should be wired up. I've looked thru the CH website but still am unclear how the wiring to and from the solenoid should be set up. Anyone have a simple to read schematic of what wire goes to which pole on the solenoid? Thanks
 
I'm pretty clueless about 12vdc stuff and want to use a solenoid as you do for the aux battery. My local store sold me the Cole Hersee 24117 saying it is what I need, but they don't know how it should be wired up. I've looked thru the CH website but still am unclear how the wiring to and from the solenoid should be set up. Anyone have a simple to read schematic of what wire goes to which pole on the solenoid? Thanks

Well the bigger posts on the sides that are inline should be the ones for your main power run (ie to the battery) I believe it bidirectional so it shouldn't matter which you hook to source verse battery. The posts on the top of the unit are for engaging the solenoid. Not sure which is for positive verse negative or if its universal but you could just use some jumpers to test each way and see if one or both "make" the solenoid circuit.
 
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