How to make a cheap isolated dual-battery setup for $50

[dwh]

Would you buy a new vehicle where the OEM used landscape wire.

Since it's a hell of a lot better than most of the wire that manufacturers actually do use in vehicles, I wouldn't get my panties in a twist over it.

Especially for a dinky little <10a circuit. Have you actually seen the crap that OEMs use for 10a cigar lighter circuits? Landscape wire would constitute a MAJOR upgrade over that crap.





(Unless you've logged the same 24,000 hours as a working electrician that I have, do me favor and don't try to teach your grandmother to suck eggs.)

 

[Hillbilly Heaven]

How about 30lus years as an electrician and electronics tech plus owned my own automotive electric business till I retired at 50. Yes I do know just a wee bit of knowledge about automotive wiring.

Since the early 90s the amount of wiring within a vehicle has increased drastically. Increased so much that it required electrical engineers to go to the chemical engineers to have them create new tougher polymers so that the thickness of the insulation could be decreased. They couldn't reduce the wire gage size so the used a thinner insulation. I know for a fact this has been done at least 3 times since the 90s. So yes if you compared what you found in a cigarette lighter wiring in the 80s to current day from outside it appears smaller but it is not. It is the same gage.

Also lighter circuits use to be rated 20amps so yes they would have used larger gage wire back then.

Residential wiring belongs in house not vehicles. You would not put 60 volt rated general purpose automotive wire on a 230 volt circuit. Get the inspector would love that crap.

For the same reason I can not recommend doing anything that might put himself or property in danger. You recommend landscape wiring. It is going into ground that will anywhere from dry to soaking wet from freezing to maybe 90 degree F. It is not subjected to vibrations, abrasion, chemicals and solvents, temps from freezing to in excess of 200F.

 

[Hillbilly Heaven]

How about 30 plus years as an electrician and electronics tech plus owned my own automotive electric business till I retired at 50. Yes I do know just a wee bit about automotive wiring.

Since the early 90s the amount of wiring within a vehicle has increased drastically. Increased so much that it required electrical engineers to go to the chemical engineers to have them create new tougher polymers so that the thickness of the insulation could be decreased. They couldn't reduce the wire gage size so the used a thinner insulation. I know for a fact this has been done at least 3 times since the 90s. So yes if you compared what you found in a cigarette lighter wiring in the 80s to current day from outside it appears smaller but it is not. It is the same gage.

Also lighter circuits use to be rated 20amps so yes they would have used larger gage wire back then.

Residential wiring belongs in house not vehicles. You would not put 60 volt rated general purpose automotive wire on a 230 volt circuit. Get the inspector would love that crap.

For the same reason I can not recommend doing anything that might put himself or property in danger. You recommend landscape wiring. It is going into ground that will anywhere from dry to soaking wet from freezing to maybe 90 degree F. It is not subjected to vibrations, abrasion, chemicals and solvents, temps from freezing to in excess of 200F.

 

[dwh]

How about 30 plus years as an electrician and electronics tech plus owned my own automotive electric business till I retired at 50. Yes I do know just a wee bit about automotive wiring.

Great.

So then you know as well as I do that either one of those wires will work perfectly well to feed a 100w solar panel to a 12v battery.

One is rated 300v, the other 150v.
That probably means either one can handle 15v.

One is rated -40C to +80C , the other -20C to +60C. If his battery is over 140F then he's got bigger problems anyway.
( http://support.rollsbattery.com/support/solutions/articles/4345-agm-charging
)
And it's not like the insulation will just magically fall apart outside the rated temp range.

Both are PVC insulation.
One claims oil resistance, the other UV resistance. Both are lying. PVC can handle oil or UV for a while. Can't handle either long term.





I think you just didn't like my flippant reference to lamp cord. Offended your professional sensibilities. But if you actually read what I wrote, I did not recommend lamp cord - you misinterpreted it and went reactionary.

So pull the stick out. Re-read the first post in this thread - evldave set the tone, and the tone is flippant.






(And please don't patronize me with any more crap about the difference between house wiring and vehicle wiring. I used to pick up side money wiring baja and rally racing vehicles. I too know a wee bit about automotive wiring.)

 

[MagicMtnDan]

 

[DiploStrat]

Peace!

PAX! You can both yell at me. I'm a history major who never, ever worked as an electrician or a mechanic!

And I don't have a yardstick.

 

[DiploStrat]

A meme picture like this one needs music included.
https://m.youtube.com/watch?t=0h0m0s&list=RDmdCUFyv48Mw&v=mdCUFyv48Mw

Got a beat and you can dance to it, and I'd like one too! For the purposes of this thread, it would have to long, multi-stranded, and well insulated. ;-)

And, for the record, every Swedish guitarist I've ever played with was great.

 

[ohiobenz]

http://www.ebay.com/itm/Universal-W...ution-Cooper-Bussmann-Off-Road-/322542703630?

Something cheaper than the SPOD... with relays as well as fuses.

 

[BSK]

Couple of questions that I'm sure have been answered a million times. I have a single battery system with solar already in place. I'm thinking about adding another battery. I have a group 27 agm under my hood, a mounted 100w panel on the roof, and a mppt charge controller in the back of my van. The battery is connected to the charge controller with 6 wire and a 40 amp fuse right next to the battery. I would like to add another battery back next to the charge controller. I think I'm going to use a blue sea acr to connect the batteries. I might also add another 100w panel. If I'm not self jumping is the 6 wire and 40 amp fuse adequate to use so I don't have to rewire all the way back? What size model acr would I need? Also I have a flooded starting battery, could I use that under the hood and move the agm back into the van or should I buy another agm? Thanks for any replys, as I read through this thread things tend to get lost in the head every 5 pages or so.

 

[BSK]

Thanks for the response. Another question for anyone familiar with the blue sea acr. If I use the blue sea 120 amp acr and I have solar on the house battery side the batteries will be connected when starting while I am in the sun correct? Would this mean that the 120 amp acr with my existing 6 awg wire between batteries would be insufficient and I would have to use the start isolation feature?

 

[scott7022]

I love seeing (reading) people who know their stuff go at it in such an informative and interesting way. Anyone that took the time to read this from the start, and did the directed readings homework, got an edumacation (sp intentionally done for effect for those pedantic editor types). I enjoyed this and while not a great deal was new my ability to express terms and concepts was greatly improved. You know the old saying; I know how it works, because I've done it for years but I can't tell you how to do it. "Some do, others teach."
Great, why I like this forum, information! My lunch break is finished so it is back to color correcting 5k video footage. But before I go a story, to make the electric types laugh, and to say thanks.

Back in the day, I think it was 1992/3 I was helping with an IASCA (International Auto Sound Challenge Association) pro level competitive demo car. Demo cars had to achieve X amount of points before being invited to the World Finals. We didn't think we had achieved this and so had gutted the car of the 20 grand of audio parts loaned by the companies and were designing a new one for next year. Mail came and we made the cut. This had been CC to the companies. They expected to see their demo car in Tulsa. We had a huge problem. 13 days to repair the car and get it from California to Tulsa Oklahoma. Luckily we had been careful with most of the speaker pods and sub enclosures and after a few shots of tequila, for nerves, two of us (I won't drop names) cracked a couple of cold ones and started putting the Toyota GTS back together again. The car was in the 501 to 1000watt class of competition. At the time that meant that the amplifiers could not be rated higher than 1000 watts at 4ohms. The fact we were running at 1ohm wasn't taken into account. Suffice to say we were pulling a ton of power rearward.
The transport container truck arrived in the morning and we were tuning the car for sound quality, using a power supply to run the stereo system (bypassing automotive), with a Melissa sound computer. It sounded beautiful, like a concert hall. A concert hall that could switch from London to Amsterdam, with Lemmy screaming Ace Of Spades as your fillings rattled. We had this in the bag. The truck backed up to our dock and I jumped in the car and started it.
HMMMMMMMMMMMMMMMMMMMMM
A ground loop! Magnified to Dorothy Chandler Pavilion acoustics. I killed the stereo power and yelled at my partner. We popped the hood and started looking. Debating, arguing and trying to articulate our opinions/positions with "I know how to do but not how it's done" lexicon. We were kids.
The driver interrupted our discussion with; "I got to get this rig moving."
My partner pushed the car into the container and the driver secured it to the floor as I grabbed 4,8,10 gauge black cable spools and assorted tools. I grabbed a 12 volt shop light and two new fancy Gell Sealed Car Audio batteries that were on the charger and tossed them into the back along with the contents of the fridge and two mop buckets.
The driver watched, confused.
We both, without talking, got into the back of the truck and said; "Let's go!"
A discussion about state laws, safety requirements, and various other totally appropriate words of protest was ended by.
"Do you wanna get paid?"
A so began the 30 hour odyssey group loop hunt. The first eight hours of looking for resistance differences in the usual places was a failure. This tossed aside and with a single light, and quickly diminishing supply of beer, every audio component got a 10 gauge wire, the same length as the longest run. Then these wires were torch weld soldered into a 4 gauge main bus grounded at one point. Being too drunk to argue anymore we spent the rest of the time between the buckets and hiding black wires so the judges wouldn't see.
We arrived at the Tulsa Arena loading dock and the driver opened the door to find us hung over and in our underwear.
I started the Toyota, turned on the stereo and smiled, no ground loop.

Thanks to those that added to my vocabulary with this forum post so that now I can articulate why I want to do X or Y coherently to a professional!

 

[dwh]

No, your car battery will carry the bulk of starting load.

Yup. The deep cycle battery + the wire feeding it will have a lot more resistance than the cranking battery direct to the starter, so most (if not all) of the power for the starter will come from the cranking battery.

Plus the ACR will auto-disconnect if the starter drags the voltage down too far too fast.

No worries.

Your 6awg will carry for duration of starting substantially higher than its 80-100ish amps its rated for.

We're still trying to teach Verkstad proper English. He means "CAN carry" (substantially higher than it is rated for), not "WILL carry".

 

[Stereo]

Request for installation specifics

I'm going to run 4 gauge wire from my truck battery back to my pop-top truck-bed camper to power a frig and charge my camper battery while driving. I have some specific questions I hope you can answer:

1. Everything's gotten a lot more expensive since this post was started so I'm investing more than I anticipated in the supplies and I don't even have a crimper yet. I'll be using Anderson quick connects which seem to require their own specialized crimper to make the crimp round rather than oval. What's the least expensive way to make these crimps? If I end up having to purchase a crimper, will this one that's linked to in previous posts work on the Anderson connections?

2. Do the fuses on the battery cable need to be screwed in place or can they float free on the cable as long as there's not too much slop in the cable? I'm using the holders suggested in the first post. (Incidentally, this company requires a minimum $25 purchase).

3. I'm hesitant to permanently terminate the truck side of the cable inside the bed of my truck 'cause when I don't have the pop-top truck camper on it, I'm often hauling stuff. I think the cable could be easily damaged. And I don't want to put a huge hole in my truck bed to accommodate the Anderson plug end when I connect the camper. So my draft plan is to terminate the truck-side cable on the frame close to the joint between the cab and the bed, then run the camper-side cable along the underside of the camper, then down the rigid Torklift Anchor Guard tie-down at the front of the camper, and then on to the truck-side connection on the frame. I'll house the portion of the cable that runs down the tie-down to help protect it and the cable won't stick out any further than any of the truck or camper parts. (I thought about running the cable between the narrow gap between the bed and the cab but I'm worried it may get pinched, and I'm not whether the cable will be flexible enough to do that anyway.) Any problems with my plan? If so, can you please offer a suggestion as to where to terminate the cables to allow for easy disconnection?

4. Are zip ties OK to use to secure the cable to various truck elements along the cable run path, or might their skinny width abrade the cable over time? If the latter, what's an alternative securement?

Thank you for your help.

 

[Paddler Ed]

So after reading many different forums, thoughts and ideas I did something like the $50 set up... but kind of blew the budget...

I knew what I wanted to achieve, which was a non-permanent set up that is movable between the car and the camper trailer, with a solar input for when it's in the camper.

So I worked out what I had and what I needed, found a circuit diagram drawing package and sketched up this:



From that I went shopping at eBay, local parts shops and the hardware store:



All of that got tested over a weekend away to make sure it worked, with it all resembling an IED:



And then tidied up once we got back, with all the bits attached to a piece of MDF, all connections heat shrunk and holes drilled in the box.



What I used:
-1x 130AH AGM Battery (AU$240)
-1x Projecta IDC25S DC/DC and Solar charger (with inbuilt MPPT solar doohickey) (AU$220)
-2x 50A manual reset circuit breakers (AU$10 ea)
-2x Red Anderson (Narva version) plugs for the solar lead input; the alternator input (which is not wired up yet, will run in via Grey plugs and a 50A circuit breaker under the bonnet) (AU$10ea)
-1x Bus Bar for the negatives (AU$20)
-1x 4 fuse fuse box for the pod on the top (AU$15 + $40)
-Lost track of how much cable - about 2 metres of 8B&S is in the box I reckon, and 10m of twin core 8B&S is on the solar feed cable (AU$90)
-1x small cable gland as a breather ($2)
-1x 26mm cable gland as the route in for the solar input ($2)
-1x Big toolbox (Tactix seem to be identical to a load of other ones that are available from a number of different manufactures) ($60)

I think that's the lot...

All up, including the battery and DC/DC charger, I think it came in at around AU$730... so a touch more then getting something off the shelf, but I knew what I was getting, how it works and what I need to do to fix it.

 

[dwh]

-1x 130AH AGM Battery (AU$240)
-1x Projecta IDC25S DC/DC and Solar charger (with inbuilt MPPT solar doohickey) (AU$220)

Nice job.

You might consider setting the Projecta to "wet" instead of "agm" to get a 14.7v bulk voltage instead of 14.4v.

14.4v is conservative for AGM, most of them can handle (and will stay in better shape) being bulk charged to a bit higher voltage.

It will also help the solar to harvest a few extra amp hours before the charger drops out of bulk mode.