Suburban - Sorry, yet another dual battery thread

[C.I.TR3]

My son and I are sleeping in the back of our (new to us) 2004 Suburban on our outings. Went to eastern Washington last weekend and it was COLD at night. Looking to augment our sleeping bags with an electric blanket for really cold nights. Additional power needs at this time are pretty minimal; 12v charging of electronics, lights, inverter for blanket (unless we get a 12v one) and laptop, maybe a fridge down the road. I would also like the ability to jump start off the second battery as a backup to the primary.

My plan was to do a KISS install ala the How to make a cheap isolated dual-battery setup for $50 thread. I tried to read all 100 pages, but got lost in some of the details so I am looking for some specific help. I understand that I need to run heavy duty wire from the starter battery hot to the isolator, from the isolator to the house battery hot and between the two negative terminals. I also understand that I need a 12ga wire from the isolator to a fuse that is key on and that I need to put fuses between the two batteries and the isolator.

My questions are:

1) Based on my needs above I am not sure how to size my components. For the isolator/relay, what amperage do I need. Happy to pay a little extra for the 500 amp model (https://www.amazon.com/dp/B001YIPXR2?tag=viglink20599-20) or is that overkill. Would the 200 amp Stinger (https://www.amazon.com/Stinger-SGP32-Battery-Relay-Isolator/dp/B001HBYXVS) be sufficient? Not sure what this is based on; what my alternator puts out or what my expected draw is going to be. Does wanting to jump start myself through the isolator affect this.

2) Based on the size of isolator, how do I size the fuses? Is there an advantage to fuses versus circuit breakers.

3) Also based on the isolator, what size wire do I need? Can I buy cables or do I need to make them myself?

4) I understand that with an isolated setup the batteries do not need to match. I currently have an AGM starting battery. What will give me the most capacity in a 34/78 battery at a reasonable cost? Will a deep cycle lead acid work or should I spend more for another AGM. The battery will be mounted in the factory second battery location under the hood.

5) Once all this is in place, how do I actually tie into it? I am assuming I put another fuse block somewhere then run any needed wires through the firewall and inside?

Sorry for all the questions, but help is greatly appreciated. My head starts spinning when reading through all the detailed electronics information and various options. Maybe it is because I do not drink beer only coffee. :coffeedrink:

 

[tbisaacs]

I still have my Amazon wishlist for adding a second battery to the Burb!

200 amp stinger and 2 gauge wire and a 150amp fuse.

200 amp should be more than fine. If you plan to add a winch then get something bigger.

You could also swap that agm into the aux tray and then buy a lead acid starting battery. It will be tight but will fit.

Once you get it in, add a distribution block and wire your accessories directly to it:

Blue Sea Systems 5025 ST Blade Fuse Block - 6 Circuits with Negative Bus and Cover https://www.amazon.com/dp/B000THQ0CQ/ref=cm_sw_r_cp_api_W-k7zbETD73B7


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[john61ct]

Look for the 12V heating pads that truckers use, go under not over.

A tiny propane portable for when you get up in the morning, get a CO alarm, crack a window to vent an never use while sleeping.

Get the 500A if jumpstarting, otherwise 200A fine.

Fridge needs a lot more charging input, solar or gennie, if you'll be doing that consider a proper ACR combiner.

For high amps use a fuse, 90% of wire capacity or 20% over max load expected.

Size wires using Blue Sea circuit wizard app.

Get custom wires made at genuinedealz.com

Best value deep-cycling battery is flooded Duracell 6v GC x2 from Batteries+ or Sam's Club.

Worth modding the tray if you can get them to fit.

Or give a list of BCI sizes e.g. G31, that will fit, but very hard to find and pricey to get 12V true deep cycling, basically only Crown, Trojan or US Battery.

Blue Sea for fuse blocks.

 

[Ducky's Dad]

Last time I looked, the highest capacity in a 34/78 dual purpose AGM was Odyssey or Northstar. My 34/78 Odysseys have been pretty good, my Odyssey G31s not so much. I have one Northstar G31 and I'm leaning in that direction for future purchases, but they are pricey. The current generation Optimas are fine (have four of them), but capacity is usually lower than Odyssey or Northstar.

An alternative on the 12V blanket might be a couple of heated work jackets from Milwaukee or Dewalt. Charge batteries during the day to heat the jackets at night. I know Dewalt makes a couple of dual port chargers that plug into the cig lighter socket, and Milwaukee probably has something similar. There are others.

 

[v_man]

My two cents...

-There are hundreds of step-by-step dual battery write ups online, including one in my build thread below :ylsmoke: They were of great help when I did my dual setup.
-Car batteries discharge more quickly in cold weather. I'd keep that in mind before trying to power a fridge and a heating blanket overnight.
-Add an auxiliary fuse box into your dual setup, I like the BluSea 12 slot.
-Budget more money and time for the dual setup than you think you'll need.
-A dual battery is a fun and engaging project, but you could probably save yourself a bunch of time and money by adding a few more blankets to your camping setup and a Coleman cooler filled with ice.

-All the other questions you asked have been asked and answered time and time again, an evening or two of research would probably yield a ton of info...

 

[Martinjmpr]

If you can find my dual battery thread it will answer all your questions. Since my 'burb is also a 2004 it should be identical.
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I searched and searched and the largest capacity battery I could find in a 34/78 was a 68ah X2 at Batteries Plus. Expensive (almost $300) but has worked well. You cannot get a bigger battery in the stock 2nd battery location by the firewall, though you MAY be able to get a bigger battery at the location of the starter battery behind the driver's side headlight.
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EDIT: Here's the thread. Let me know if you have questions. It's been just over a year now and except for one little glitch (had a wire pull off while I was on a very rough stretch of road) no problems or issues so far.
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http://forum.expeditionportal.com/t...stall-DONE!-Uh-Sort-of?highlight=dual+battery
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Unfortunately since Photobucket decided to say "screw you!" to its long time users, not all pictures are visible. Let me know if you need to see some.

 

[john61ct]

Optimas are robust starters, not proper deep cycling.

 

[john61ct]

For AGM Lifeline as well as Odyssey and Northstar.

Just check they are designed for deep cycling, chart should show 800+ cycles at 50% DoD and not give CCA rating.

Firefly G31 is excellent for PSOC, but $500+ per 100AH and currently backordered.

 

[Ducky's Dad]

Optimas are robust starters, not proper deep cycling.

As you noted, Optima makes both starting batteries (Red) and deep cycle (Yellow). The confusion comes with the Blue marine Optimas, because they offer both a starting and a deep cycle, both with blue tops. Optima told me that the Blue starting batteries (dark gray body) are identical to the Reds, with the addition of the marine studs, and the blue Dual Purpose Marine is identical to the Yellow plus the additional studs. The dual purpose marine has the lighter gray body, but some battery dealers don't seem to know the difference.

Re:

Firefly G31 is excellent for PSOC, but $500+ per 100AH and currently backordered.

, I think the Northstar G31 is 102ah, costs about $400-$425, and does not seem to be backordered. I think the Odyssey G31 is also 102ah, but I'd avoid that battery unless you get a really good deal (I'm on my third one).

 

[Mgyver1]

I think the Northstar G31 is 102ah, costs about $400-$425, and does not seem to be backordered. I think the Odyssey G31 is also 102ah, but I'd avoid that battery unless you get a really good deal (I'm on my third one).

The Batteries Plus X2 batteries are the same as Northstar batteries. Their 31M has a 4 year warranty where as Northstar’s warranty is 3 years. If you have a Batteries Plus near you it might be worth looking in to. They retail for right at $400 but they typically have a 10% coupon if you order online and pick it up at the store. When I called the store they said they could do the 10% off in the store without needing to mess with the online ordering. Give your local store a call & see what they say.

 

[LandCruiserPhil]

Optimas are robust starters, not proper deep cycling.

Good to know, should I of got more than 6.5 years out of my last set of dual Optima blue tops wired in parallel?

As for dual batteries with the introduction of jump boxes I now run all my dual battery set ups in parallel and dont separate. This works both batteries equally and doubles your capacity and extends your life.

I also run electric heat blankets, fridge, and charge accessories, last weekend ran the heat all night along with the other normal stuff and woke to 12.45V.

 

[Martinjmpr]

The Batteries Plus X2 batteries are the same as Northstar batteries. Their 31M has a 4 year warranty where as Northstar’s warranty is 3 years. If you have a Batteries Plus near you it might be worth looking in to. They retail for right at $400 but they typically have a 10% coupon if you order online and pick it up at the store. When I called the store they said they could do the 10% off in the store without needing to mess with the online ordering. Give your local store a call & see what they say.

31/78 X2 is under $300 here in CO, and you can always get 10% off if you ask for it. I think the warranty is 5 years.


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[rayra]

The first couple pages have a lot of doomsaying and bickering, but I think you'll find most of the info in my topic useful, starting around post #45.

http://forum.expeditionportal.com/t...on-my-inputs-and-ouputs?p=2156789#post2156789

eta I went with 'normal' Interstate batteries for cost and ease of availability / replacement if something goes wrong with one. I just recently replaced my Grp75 starter with a Grp 78 (bumped the 75 to my old pickup, whose 6yr-old battery finally bit it), so now both my starter and aux match. My dual setup has been installed for just over 1 year and working fine. Been making good use of the rear power ports and inverter and am soon to add solar on the roof and the charge-controller in the vehicle to feed / keep the Aux topped.
My current usage, I'm averaging sometimes as much as 0.3v less on my starter battery. But I think that's the parasitic load of all the USB charger ports I added to the factory wiring of the vehicle. They're always hot and it's sometimes a couple days between use of the vehicle. I might rig the rooftop solar to passively top off the Starter battery, instead. Or make it switchable in my rear power box. But most of my 'expedition' use would come from the Aux anyway, so I might as well leave the solar connected to it.

 

[tbisaacs]

Rayra with the combo breaker!

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[rayra]

KI-AAH!

/more of a Batman fan