solenoid

[Blacktank]

is this what i am looking for? cole hersee 200 amp
anyone know of a cheap just as good version ? 

do i need a fuse? where and how big?

quickest,easiest route to charging and any charging is better than no charging
still would like to go 2 alternators but still have plenty of wrenching to go and fighting burnout so save that for another time

[Optimistic Paranoid]

is this what i am looking for? cole hersee 200 amp
anyone know of a cheap just as good version ? 

do i need a fuse? where and how big?

quickest,easiest route to charging and any charging is better than no charging
still would like to go 2 alternators but still have plenty of wrenching to go and fighting burnout so save that for another time

Cole-Hersee is a good brand.  Normally open is what you want, so yeah, this is what you are looking for. 

It's unlikely that you can expect to move more than 100 amps between batteries, so if you could find a 100 amp version for less money, you could save a few bucks that way.

On the other hand, if you want the capability of jump starting the engine from your house batteries, 200 amp is a good choice.

If you are going battery to battery, you need TWO fuses, one at each end, each as close to the batteries as you can get. 

If you are going directly from the alternator to the house battery, you only need one at the house battery end.

As for what size fuse, what size wire are you planning on running?

[sternwake]

One can find solenoids rated for 90 amps as cheap as 15$.

Usually when solenoids fail they fail with the contacts seized together, meaning NO battery isolation.

When the starter battery gets cycled in parallel with the house battery, it might not be noticed, until one cannot start the vehicle and finds their starting battery has basically shit the bed and needs replacement.

I will be hooking up a solenoid in a 95' chevy g20 later this week. The 200 amp colehersee silver tungsten contact solenoid was 41$ on Amazon, but that price could not be brought up on the guy's phone, had to be on the laptop.

Now I see it is back upto 54$

https://www.amazon.com/Cole-Hersee-24213..._5?ie=UTF8&qid=1515637901&sr=8-5&keywords=cole+hersee+solenoid

You could always buy cheap now. If you have a voltmeter with voltage sense leads on engine battery, and on house battery terminals visible from drivers seat, it will be easy to see if/when the solenoid fails. The dual voltmeter is a good idea anyway. If the solenoid fails with contacts seized the engine battery and house battery voltage will always be the same or very very close.

With a voltmeter on engine battery one can see when it when it is becoming weak when starting. ...When voltage regualrly falls below 10v whilst cranking. Depending on the trigger circuit origin the house battery might contribute to starter current. Better to not have house battery assisting engine battery. Better for solenoid, better for electronics hooked to house battery. Best to finsd a circuit live only after engine starts for the trigger, or put an illuminated switch on the solenoid trigger circuit.

With a voltmeter on the house battery one can see just how ineffective the vehicle's Voltage Regulator/alternator is at recharging a battery to full. When the VR seeks only 13.6, about 1/3 the amps will flow into a battery, compared to 14.7v.

So one is basically at the mercy of the vehicles voltage regulator, but a thick low resistance circuit will make the most of what voltage is allowed, and a cheapo solenoid can/might/will introduce a lot of resistance.

So the solenoid can be a buy once cry once thing, but a cheapo solenoid might not only require another solenoid be bought, but a new engine starting battery too. Not included is the hassle of when and where the system fails.

[Putts]

Is there any reason to not just use a manual battery switch to parallel the two banks after starting the vehicle?

Something like this.



I'd probably be a dummy and forget to turn it on or off at times, but it would seem to me a better way to be in control of what's happening.

[sternwake]

The manual switch is all about the human error factor.

I actually use switches, but I only have one battery a tthe moment so the switch need not ever be moved. but when I did have a house battery, i would prefer to start engine on engine battery, turn switch to BOTH while engine is trunning and switch ignition circuit back to Engine battery when OFF.

It is one reason I do not want to go back to a dual battery system. It would be different if my switch was easier to reach, but it is basically behind my drivers seat in the cabinet, and turning the switch to OFF, might blow out the diodes in my alternator.

There are many dozens of ways to isolate a house battery from engine battery with engine off, and many dozens of products. The simple solenoid is one of the most effective and cheapest. The only issue is finding the ideal trigger circuit, and tapping it cleanly.

But most Unideal trigger circuits are also effective, they just cause the solenoid to cycle on and off more with the key turned to on and might allow the house to assist engine battery in starting. This might even seem beneficial with few detractions, at least until the contacts on the solenoid become worn and develop more resistance.

Here is the simple way to do it requiring no Trigger circuit. It simply connects the boatteries when the engine battery sees charging voltages.

https://www.amazon.com/Bussmann-RB-BS-13...oding=UTF8&pd_rd_i=B00KD0KC1E&pd_rd_r=R7HFXBVG13Y2M9KFCFFV&pd_rd_w=xdEGZ&pd_rd_wg=cx4Oo&psc=1&refRID=R7HFXBVG13Y2M9KFCFFV

Downside with this product, is with solar, when the engine is turned off, the solar can keep voltage above the threshold, and some solar wattage will be going to engine battery, instead of all wattage going into house battery. How much of a difference this makes depends on the depth of discharge of both batteries. Some of that solar wattage mig t also be used simply to hold the contacts in the solenoid together. This might be as high as 15 watts just to hold solenoid closed and even an fully charged engien battery might require 15 watts to be held at absorption voltage. So that could be 30 watts of solar going into house battery, that is not.

note above product is Unidirectional, meaning it parallels batteries when one side sees charging voltages. they sell bidirectional solenoids that parallel when either battery sees charging voltages.

Some might find the engine battery being charged by solar to be a good thing. I am not of that opinion, when the house battery is depleted. When depleted I want all Solar wattage getting the house battery to Absorption voltage ASAP, and for as long as required. Diverting any of this wattage to engine battery, or simply used to hold solenoid closed, might/can/will hinder the achieving of house battery full charge before sundown, and achieving full recharge before next discharge begins is the key to very good+ battery longevity.

Ocean is calling..........

Laptop off.

[Blacktank]

i found this site,they are in my neck of the woods and have a few things i need/want http://www.partdeal.com/cole-hersee-12v-200a-continuous-duty-solenoid-24213.html?zmam=74973193&zmas=1&zmac=4&zmap=77197098&gclid=EAIaIQobChMI2OaVoLfZ2AIV05N-Ch0fXQD4EAkYASABEgJJpfD_BwE

my rig came with a solenoid so i have the extra wire for the solenoid,size 10ish
so can i use size 10 wire from the solenoid to house battery?

if so i would want one of these?http://www.partdeal.com/ami-midi-fuse-30...stems.html



there are good deals and then there is cheap,cheap things tend to be cheap and will cost you in the long run so like stern said a $15 solenoid can and will fry your system costing way more than the $50 top of the line solenoid

[Putts]

The manual switch is all about the human error factor.

I actually use switches,

That's what I wanted to hear. I'm accustomed to dealing with my own stupidity...don't like it when things break or don't make good decisions.

Ocean is calling..........

Enjoy!

[Ballenxj]

Is there any reason to not just use a manual battery switch to parallel the two banks after starting the vehicle?

Something like this.



I'd probably be a dummy and forget to turn it on or off at times, but it would seem to me a better way to be in control of what's happening.

Had one similar in my old class A, but it had positions for battery 1, battery 2, both, and off I believe. Worked great. I went to start the 454 one day and found the start battery was dead. Uh oh, I thought I might be stranded. Switched it to the both position and fired it up.  

[Blacktank]

can i use size 10 wire from the solenoid to house battery?

if so i would want one of these?http://www.partdeal.com/ami-midi-fuse-30...stems.html

so alt to solenoid,solenoid to fuse at house battery,correct?

[sternwake]

You can use 28 gauge wire

The Thinner and longer the copper, the more voltage drop. The less will amps flow.

A 15' one way 10 awg circuit will allow perhaps 20 amps to flow into depleted when voltage regulator is seeking 14+ volts, initially. When wire heats and VR decides mid 13 volt pressure is fine and dandy you'd be lucky to see 8 amps.

plan to upgrade cabling if you want more effective alternator charging.
4awg would likely max out a cold alternator with depleted house@ ~ 50 amps. More at higher rpms.

Do't max out alternator for more than 10 15 minutes idling. without driving 35 mph+.