Dual Battery Setups! Let's see them! Multiple Batteries Thread!

that is correct.

 

How necessary is a battery to frame ground? Ive had a deep cycle group 24 in my bed for over a year, and no issues. Its not connected to the starting battery (yet). Just solar has been keeping it topped off

 

If you are going to use the alternator to charge it, the battery has to be connected to a common truck ground. IMO, best is connecting it to the negative post of the starting battery.

 

Im planning on using this DC-DC charger, because you can mix/match batteries.

$391 CTEK D250SE, 20A, 12V Battery Charger For Starter And Service Batteries In RV, Truck And Overlanding Vehicles, Solar Battery Maintainer, 12V Lithium Ion Battery Charger And Smart Alternator Compatible

https://www.amazon.com/dp/B07X4YTP1P/?coliid=I1AEM15MRZRX1W&colid=3FMYHVA2X45UO&ref_=lv_ov_lig_dp_it

I guess my question is, does the 2nd battery need to be connected to a frame ground in its current state? - not connected to the starting battery, just solar

 

I use a CTEK on my 2nd battery. I have both batteries connected to the frame.

With the CTEK, the batteries will need to share a common ground, since you only run a +12 from the starting battery to the charger.

 

My setup is the same as yours I think and my ground is to the frame. I've considered using the truck charging system and have decided not to go that route. Toasting a truck battery and alternator 125 miles into the mountains is not a thing I want to do. And for those who will say "these systems are tried and true" I know better. LMAO.
Zim

 

Would you not recommend the CTEK? I thought it was nicely priced compared to the Redarc

 

The truck charging system, as it sits, will not charge 2 batteries to their fullest. Once one battery hits full charge, the "smart" alternator reduces its output to "save fuel". At that point, the 2nd battery will no longer receive a charge. (Yes, this is a simplified explanation.)

 

I have talked to Redarc at the overlanding show in Springfield, and still did not have a warm and fuzzy. These systems have preformed flawlessly in Australia for decades with no problems. My issue is why use the truck system for anything "custom" or "accessory" to the truck. If it's not required to operate the truck, as designed by the big guy in the leather chair in Japan, why screw with it? I can have my refer, camera batteries, camp lights and other crap run off the solar. (I do need another 2 AGM battery tho). Off road lights can use the truck as they are low voltage. The only thing that is show stopper is a winch, which I do not have YET. If I do get one, I think the truck would handle it for as many times as I would use it, but I have another battery, and a

$100 NOCO GB40 : 1000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack, Portable Jump Box, Power Bank & Jumper Cables - for 6.0L Gas and 3.0L Diesel Engines

NOCO GB40 in a pinch if I need it.
I know this sounds anti-industry, but I've sold, installed, tested, blown up and actually had a heart attack working with batteries over two decades. FACT LOL. I'm not walking out 63 miles from 11,622 feet to get help because my Christmas Camp lights and super duper waffle iron ate my truck...Ahahahahahahaha.
Thanks for listening, and I'd get a portable panel, Jackery for a backup and leave the truck alone.
Zim

 

Yup, fact. And that is just one reason.
Zim

 

That was kind of my reasoning why i havent linked them together. My 100w solar panel and this group 24 (62ah) diehard battery have been doing just fine for bed lighting and fridge. I don't have much more charging requirements than that.

But i wanted a backup plan, because I've been parked in shade, battery drawn low, and fridge not cooled before. Wanted to be able to turn on truck while im getting ready to leave, and have my batteries both charged via alternator.

 

I just installed the CTEK D250SE with an SOK 100ah battery. From everything I could find, at least for the 2nd gens do not have a "smart" alternator. So I installed the CTEK without connecting the smart alternator wire. I have cycled my battery about 5 times so far with no issues. It goes through stages bulk charges at 20amps, I'm happy. Once you get the CTEK connected it just works.

With the CTEK, you are pulling power from your starter battery (20amps), the alternator is still only charging your starter battery.

 

Isnt that where the solar comes into topping off 2nd battery? Or am i not getting the DC-DC charging correct?

 

Well this is good to hear!

I consider myself a super novice when it comes to electrical - like eyes glaze over at wiring diagrams. But im not going to jump on the bandwagon with everyone else. I want to find another option that is equal or possibly better than mainstream, which is how I figured on the CTEK

 

What did you end up doing? I’ve got the option to go the ferrule route or ring terminals but it’s so cramped with my oversized batter that ground would work better for me with ferrules. Did you use these terminals + ferrules? Did things stay nice and tight?

 

I actually have not done anything other than ignore the problem. At some point I might figure something out, but its not on my list anymore.

 

For the record: Y'all don't kill me here, I'm a old guy. Y'all got lots more money too. LOL. Those systems are great, but I'm opting for safety first.
Rock on.
Zim

 

Yeah I have just the one battery, and in 90* heat it was almost cycled at 8pm (refer)...And you're right about the trees. That's why I'm getting a portable 100W panel so I can move it around in tree canopy situations. (I'm fixed on the roof) I'm loving my set up and testing for the Westward Trips is going well. We've been out at least 20 times in the last 45 days.
Zim

 

I'm not sure if I understand your question, so I will answer what I think you are intending to ask.

The CTEK can use 2 different power sources to charge the battery. The main power source is your alternator (obviously, only when the truck is running.) A secondary power source is a solar panel. As you mentioned, the solar panel will keep your battery charged (within reason) while your truck is not running.

I don't know what happens when the truck is running and the sun is out. I'm sure it is talked about in the manual (which you can download from their site). I currently do not have solar, so I never looked.

Does that answer your question?

Also, responding to something @Tacman19 said - when using a DC-DC charger for the 2nd battery (even with a common ground), if something runs amok and discharges the 2nd battery, you will still be able to start the truck, as the starting battery will not be affected. Keeping the batteries isolated is a good thing to do for safety and reliability.

As an aside, I run two of the same batteries as starting and house. That way, if my starting battery has a physical failure (I have had 2 over the past 30 years) I can physically swap batteries, and drive home. Sure, my fridge won't stay cold, but I won't have a tow truck bill to deal with.

 

You mentioned the trucks charging system.. does that mean no additional chargers? I kinda figured that the factory alternator wasn't designed to charge 2 batteries to full or even 2 at all.

My question is, will the alternator charge starting battery to full, and dc-dc charger charge 2nd battery to full? And if not, the solar will charge the second to full? (Depending on the kind of battery of course)