Rigging up a house battery

[Theadyn]

I've decided to put a deep cycle battery in the spot under the hood and rig it up to have the alternator charge it while driving, with a continuous duty solenoid so as to not drain the starting battery when not driving. 

My question is, how hard is it to rig up?  Obviously, I won't be doing it as I have zero mechanical/electrical experience.  My question, though, is it so difficult I'll be needing to find a professional?  Or, ask someone with some skills and knowledge, like my dad for instance, to help with it?

It'll be a few weeks before this will take place so I have some time to plan and read up on it.   Any advice appreciated, thanks!!.

 

[GotSmart]

Dad can do anything.

 

[Seraphim]

I can't answer the solenoid question, - I know the theory but haven't used one - but the installation shouldn't be difficult if you have some basic tools and room for the battery. No reason you couldn't do it yourself. First objective is to find a spot to mount a battery, and determine what size battery you can fit in that spot: then mount a battery tray. Probably as close to the alternator as possible, but I'll let someone like Sternwake offer details. I'm just providing encouragement *grin*

 

[WheelEstate USA]

Really not a complicated system. The solenoid just needs to be connected to a wire which has no power when the key is off.

On our Dodge, the ciggy lighter is that point, as it only works with key on. I disconnected that wire and ran a fused wire from the house system to that port so it can be used while parked.

If Dad is a handy guy he will most likely be able to handle the job.

 

[ZoNiE]

Really not a complicated system. The solenoid just needs to be connected to a wire which has no power when the key is off.

On our Dodge, the ciggy lighter is that point, as it only works with key on. I disconnected that wire and ran a fused wire from the house system to that port so it can be used while parked.

If Dad is a handy guy he will most likely be able to handle the job.

X2. But be sure you put an appropriately sized fuse on the wire to the solenoid coil. Some of them draw a bit of current.

Also, You really should use two identically sized and aged batteries, as if one is old and weak, the other one will only charge up to the capacity of the old one. Also, use an isolator. You can google that.

Marine batteries will be the best bet here, as they are a hybrid of starting and deep cycle. Many people do this in truck campers.

 

[Optimistic Paranoid]

Also, You really should use two identically sized and aged batteries, as if one is old and weak, the other one will only charge up to the capacity of the old one.   Also, use an isolator. You can google that.

OK. that's just confusing.  The solenoid isolates the two batteries when the engine is off.  Why would you also need a diode type isolator too?

Also, if you wire an old and a new battery together permanently into one bank, the old, weak battery will drain power from the new, strong battery.  But if they're only connected when the alternator is charging them, the charging current, being a higher voltage than either, should flow into both of them.  Unless I'm completely missing something . . .

Regards
John

 

[SternWake]

The Simple solenoid is quite simple to wire up, Dad should have no issues.


Let him look through this for a bit


http://www.expeditionportal.com/for...tup-for-50?s=3d10e1b192c35468e06358538a09195e

Batteries that remain in parallel always really need to be the same make/design and age or at least very close.  Different batteries should not be Discharged together, or left paralleled when there is no load on them.

However there is little danger of issues occurring by having the batteries paralleled by the Solenoid when the engine is running.  One battery cannot feed the other when the alternator has the voltage up above 13.  Which ever battery is more discharged is going to demand more of the alternator current.  Since the engine battery should technically not be discharged by any house devices, 90%+ of the alternator current should flow into house battery anyway.  There is Little danger of overcharging the engine battery either, but long drives in super hot conditions might, but most vehicle's maximum allowed voltage drops in such conditions. and with less voltage(electrical pressure) less current flows.

I personally have an AGM battery, and a Flooded battery, and will parallel them most every time I drive, if the house battery is low, and these two have much different charging profiles.  I do NOT however discharge these batteries in parallel.  The AGM would be worked much harder than the flooded as it has a much higher resting fully charged voltage..

In the Expo diagrams in the link above, I usually recommend that instead of taking power from the engine battery(+) one takes power from the alternator(+) as the circuit is usually shorter and requires less copper, it also bypasses the too thin original alternator charging circuit.  It helps the alternator to better 'see' the depleted house battery and the voltage regulator is more likely to allow higher voltages for longer which will recharge the house battery much faster.

If one wants to take power from engine battery, which can make good sense when house battery is inside engine compartment, then another parallel cable, properly fused, from alternator(+) to engine battery(+) or engine battery(+) side of the solenoid, can greatly increase amps into depleted house battery and get it upto 80% charged, much faster.

 

[anewbiewannabe]

OK. that's just confusing.  The solenoid isolates the two batteries when the engine is off.  Why would you also need a diode type isolator too?

Also, if you wire an old and a new battery together permanently into one bank, the old, weak battery will drain power from the new, strong battery.  But if they're only connected when the alternator is charging them, the charging current, being a higher voltage than either, should flow into both of them.  Unless I'm completely missing something . . .

Regards
John

This. This shows me there's no wonder why lil newbies like me get confused even when our eyes aren't glazed over from lack of comprehension.

Would be kinda neat to set up a section on instructionables so that each particular repeating topic was wrangled into one area so we could study more or get confused more before asking questions of the kind caring people who must be getting tired of answering for the bizillionth time. I don't know about doing that kind of stuff so it may be some kind of pain or not doable---if so just ignore me. See, it's already been done. I shoulda quit while I was behind. I've read about everything posted in this category already...I think my lightswitch for my lightbulb moments is busted. ROFL

Oh this just made me chortle! Thanks!

 

[Almost There]

Finally - a wiring diagram and instructions that my brain can cope with...

The only problem I'm having is whether or not I can skip the steps that involve beer...

I may just have to find a beer drinker to do the install for me so that the instructions can be followed exactly...

Saved for future needs!! Thanks

 

[Optimistic Paranoid]

That's a terrific diagram from Sternwake.  But I do want to clarify one point I didn't see him cover.

All Solenoids have two large posts.  Some have one small post, some have two small posts.  The one Sternwake shows has only one.

The thing is, the one post solenoids rely on being mounted on chassis ground to complete the circuit. 

If instead of doing everything under the hood, you had your house batteries back in the van, and you mounted the solenoid near the house battery, MOUNTED ON THE PLYWOOD WALL, the solenoid Stern showed wouldn't work.

IF the Solenoid isn't mounted on the vehicles metal, you would need one of the two small post solenoids - one would be the hot wire, as shown in Stern's Diagram, and the other would be a ground wire run to vehicle ground to complete the circuit.

I hope I've explained that fairly clearly . . .

Regards
John

 

[anewbiewannabe]

Finally - a wiring diagram and instructions that my brain can cope with...

The only problem I'm having is whether or not I can skip the steps that involve beer...

I may just have to find a beer drinker to do the install for me so that the instructions can be followed exactly...

Saved for future needs!! Thanks

I finally found the beer. LOL Wonder if tequila would work as well cause since I don't drink beer my brain still can't cope with all of it? I love the writing style and the word directions make sense, sort of :angel: but the picture diagram I just wasn't up to follow right now.

*Makes note to ask for cheat sheet from Almost There when she's done.*

 

[Almost There]

*Makes note to ask for cheat sheet from Almost There when she's done.*

Oh Lord, don't try following me! My middle names should be 'dazed' and 'confused'!

 

[SternWake]

Hey, That link is not my work, just a link to somebody elses work.

One thing to be aware of, in addition to the single/dual post solenoid options, is that the trigger circuit also needs to NOT be live if the ignition key is turned back to ACCESSORY. If the solenoid is live when on ACC, then the solenoid is drawing about an Amp from the batteries, just to hold the batteries in parallel.

Also, the circuit that triggers the solenoid should not be live during engine cranking. If it is live, then the house battery is assisting the engine battery in cranking the engine. This is undesirable as any delicate electronics hooked to the house battery, can see voltage spikes when the starter is disengaged, and also the Solenoid contacts briefly have to pass very high amps, which wears out the contacts faster.

On Dodges, the Hvac Blower motor circuit is disengaged when the starter is cranking the engine, and as such makes a good trigger solenoid circuit to tap into. I am not sure about other makes.

One can also put a lighted manual switch on the solenoid trigger circuit, and choose when to allow paralleling of the batteries, but this can introduce some Human error factor when the switch is not thrown and the house battery is starving.

I use manual switches and sometimes decide to let the engine warm for a bit before allowing the depleted battery into the alternator charging circuit, especially if it is damp out, as the alternator belt might slip and squeal above a certain rpm.

 

[Theadyn]

I think my eyes are glazing over, too, lol. Which is why I'm asking if I should seek a professional or just dad with some knowledge for the install.

Definitely want to try it under the hood. There is space, it would not take up much coveted space in my living quarters, and wouldn't have to worry about gassing. Here is the blog post I have pics showing the space available for what I am wanting to work with: http://adventuresofhulajohn.blogspot.com/2015/04/objective-house-battery.html

Will definitely keep that link handy Stern, ty!!!! Though, dad pretty much detests internet, lol, I doubt he would condescend to come read it. If I play my cards right, I can hit up both him and my uncle (who lives across from him) who both used to be able to make any engine fly, to get this accomplished. Many thanks!!

 

[highdesertranger]

almost there you must follow every step and not leave any out. ha ha ha just kidding. while I do enjoy my beer, I never drink and work or drive, the beer is for the end of the day relax time. highdesrtranger

 

[GotSmart]

I used this solenoid

http://www.amazon.com/dp/B008R1T5IM/ref=pe_385040_30332190_TE_M3T1_ST1_dp_3

This fuse box

http://www.amazon.com/Scoshe-EWFH-Single-Fuse-Holder/dp/B000KIR8M0/ref=pd_bxgy_auto_img_y

and these fuses.

 http://www.amazon.com/Absolute-ANL100-2-Pack-Fuses-Plated/dp/B005EUTA3E/ref=pd_bxgy_auto_img_z

These switches for controlling the solenoid

http://www.amazon.com/gp/product/B007B856YY/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

This fuse box for the house power

http://www.amazon.com/gp/product/B001P6FTHC/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

These for the 12v outlets

http://www.amazon.com/gp/product/B001U4ZZPK/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

and this on the back window for safety backing up.

http://www.amazon.com/gp/product/B000TCCWS2/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

I used 4 Gauge wire from the alternator to the solenoid and on to the battery. I found a wire under my dash that was only hot when the motor was on, and used that for the power to activate the solenoid.  The 4 G wire has a fuse on each side of the solenoid. 

I also have links for many other things I used, and will use again on my next build.

 

[flying kurbmaster]

I have a manual switch as well, Sternwake you mentioned turning yours on after the engine was warm, is it ok to switch over to both batteries after it is running, I was under the impression that was something I was not supposed to do. Surges??? I may be misinformed, but on my sailboat I thought I was told not to do that. ???cheers

 

[SternWake]

I have a manual switch as well, Sternwake you mentioned turning yours on after the engine was warm, is it ok to switch over to both batteries after it is running, I was under the impression that was something I was not supposed to do. Surges??? I may be misinformed, but on my sailboat I thought I was told not to do that. ???cheers

With a 'make before break' manual switch, one must make sure to not turn the switch to OFF while the engine is running, or POOF go the diodes in the alternator.  Well they might not go up in smoke, but the higher the load on the alternator when the switch is turned to OFF the higher the likelihood that they do.

Most manual switches are make before break, but there are some which break the contact before moving to both, then onto the other battery.

Some manual switches have an Alternator field disconnect option,  so that if the alternator is externally regulated, and the field wires are run through the switch, then one cannot destroy the alternator by turning the switch the wrong way.

My first Switch had the OFF position at the 6 oclock position.

I now use 3 different higher quality switches, one for the ignition, one for all loads, and one for the solar, and their OFF position is 12 oclock.

So I had to reteach my brain as to which was which.  My Switches are kind of hidden from view where they are located, unless I remove some storage boxes,  and there is no obvious difference as to which way the switch is pointing by feel alone, so i drilled a small hole and put a stainless screw in the indicator position and make doubly sure I move it in the correct direction, to BOTH, instead of OFF.

I do not want my house battery assisting the engine cranking, but sometimes it happens, and there have not yet been any consequences.  I worry about the fridge compressor controller, but apparently they have some capacitors to suppress surges.  Still, I don't want the voltage to drop by 1.5 volts nearly instantly wen the starter is cranking and while the compressor is running.

 

[MikeRuth]

ElDave on that thread is a total riot! I get a kick outta reading his stuff.