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help connecting auxiliary battery (or batteries)


Les

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I just bought a 1986 Toyota Slumber Queen. I need help in setting up my auxiliary battery (or batteries if I need to go get one more 12 volt deep cycle).

I think I need to connect the 3 wires that are tied together with a faded flagging tape to a positive, and the 2 short white wires connected to the negative. 

Now there are still some wires that are longer (and have splices in them) and look like they should be connected to another battery (I have an empty spare battery box).

There is a 50 watt solar panel on the roof (and I think that is why there is that big silver metal box .. inverter???? maybe???). I don't know if the solar panel works as I seen records of it being bought in 1997.

I have photos attached to help depict what I am talking about.

Thank you for any/all help. I honestly don't know much about this electrical stuff. There is also a light switch connected to this silver metal box. Not sure what is supposed to do (help in explaining this too, if you can).

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That’s some scary looking wiring. Personally, I’d gut all the 12v wires and start fresh. 120v should be easier to determine if it’s hooked up correctly. A good multimeter with continuity capabilities is a must. Also a good understanding of 12V automotive circuits.

Edited by fred heath
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Hi Fred. Thank you for  your quick response.

Is this is HUGE expense, gutting all 12V wiring and replacing? I am on an extremely tight budget at the moment. I was hoping just to connect a couple of batteries according to how they all fit between the sunken battery (and the other battery I need to buy to fit into the spare black battery container).

All the stuff I have been reading is talking about parallel and series multi battery connections. This seems confusing to a beginner, as it seems the youtube videos have wrong or misleading information (looking at the comments people make on the videos).

If the 12V wiring is all replaced, does this mean I would only need 1 deep cycle 12V battery?

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Start your truck and test to see which wires have a charge. With truck running isolator is sending a charge to your house battery. Those wires connect to the positive terminal on the battery. Ones with no power go to negative. 

Linda S

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Oh and wires from solar need to come through a charge controller. You need to find it and follow the wires

Linda S

Don't know what the 70 amp circuit breaker is. Nothing in your camper needs that high of a rating. Maybe they had a generator in the past?

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Hello Linda. Thank you for your information. I will do this tomorrow and see what's up with my wiring. My further investigation on multi batteries cleared my confusion. Now I know why I would like more than one battery (I do want to do more boondocking than campsites). I really appreciate how quick you all have jumped to my dilemma. Thank you all so so much. 

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Now you know why previous owners are so disliked.

1. GET A VOLATMETER. Harbor Freight has a cheap $5 digital that is very good.

2. The 70 amp box only has a 20 amp breaker in it. That's about normal for a main feed. Do you have A/C, micro wave, electric booster for your water heater??

3. Before you power things up, follow the wires and see where they go. Label the battery end of wires. Where do the wires from the 70 amp gray box go? s there a 110v AC sub panel somewhere?, it should have  1 or 2 circuit breakers. Do any of the battery wires go to a 12v fuse panel?

After you verify that all the wires go someplace and you don't have any dangles, sparkies anywhere then you can start things up and do voltage checks.

 

This is a way simplified diagram for a motorhome...12-volt-rv-wiring-diagram-2003-newmar-ko

 

How about 1 big battery instead of 2 little ones??https://www.renogy.com/deep-cycle-agm-battery-12-volt-200ah/. Remember measure 2x

Edited by WME
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Hello WME. Thank you for your detailed info. I have to say again, you all are so amazing with such quick responses and information. Thank you, thank you thank you!!!

First off to quote some unknown person who seems to be knowledgeable AND humours ... "Now you know why previous owners are so disliked." I find this to be more true each passing day that I work on my new-to-me Toyota.

1. I do have one of these meters.

2. I do have an A/C (looks to be newer). No microwave (and never will have one). I haven't looked at my water heater yet (I will do that today)

3. I started to follow wires last night (and will continue now that I have a good guideline to work with .. thank you!)

My new battery is a 12 volt deep cycle. I was wanting more capacity due to the desire to boondock more than visiting campsites. My research shows that I should be using 2 batteries with the same measurements AND also the same age (don't mix older battery with a new one). I don't think the testing that I would be doing with the new battery will effect things once I get my 2nd battery. They should still both be considered new and of equal value (but please do correct me if I am wrong with this thought).

Regards and have an awesome day,

Leslie

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What group size is your deep cycle battery or Amp Hours? For the very best power the batteries should be the same size and same maker. AND with a build date within 6 months. Variations to this will result in less power, BUT things will still work 

Boondock rthoughts, some are in the Duh catagory😁

A smaller load is the same as a bigger battery, replace all your light bulbs with LED bulbs. 10 new led bulbs use less power than 1 old style incandescent bulb.

A propane RV heater is a marvelous thing, but they are a power hog. So cool/cold weather requires more more battery.

Example my setup is 280w of solar, Mppt controller and 230ah of battery. In 50 deg weather and my wife using her CPAP machine at night I use 30% of battery capacity. My batteries are fully recharged before 4 pm the next day

50w solar is an extend a stay thing. Instead of batteries being dead after 3 days boondocking, you can go 5 or 6 days. Being frugal with your power use a 100w panel will do. If your a power guy (computers, TV, cell phone games, CPAP machine) 200w of solar and 200ah of batteries is needed for perpetual motion. Old Skool rule 1AH of battery  will need 1w of solar. 

With a normal lead acid deep cycle cell battery max safe discharge level is 50%. Here's a chart... vertical side is life cycles, bottom line is % of discharge. This chart is for lead acid batteries. Other types (AGM, Gel, Lipo) have different charts

cyclelife2.gif

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