Dual Battery Setup Questions

[BugoutJeep]

Reading up on the description of https://www.amazon.ca/dp/B000MMFJH0/?tag=tjforum-20

I think it should be a pretty minimal way to run a dual battery. I don't think it's optimal, but from what I could tell, it should be fine. I still recommend a good charge controller, because batteries ultimately end up costing you a lot and add on the chance you get for a bad battery spoiling your food and/or recovery. I just worry a little about manual and my forgetfulness too. Having a switch like that on hand, would be a good backup eventually as well, but I still lean toward having a cheap Solar charge controller for my backup and can often be found much cheaper, though it's more complicated than the switch that was recommended above so more likely to fail than.

 

[ac_]

so about the switch:

No.1 position: normal - only main battery
No. 2 position: using Main & Aux - Charging Main & Aux
No. 3 position: connects Aux to Main to jump start.

Can I use only the second? for example when engine is off. to run accessories for camping.
But to isolate the second, so I can run everything without worry to drain the main.

So what I didn't mention is when the engine is off both batteries are separated. You will be fine in that aspect. Unless you flip the switch down to red, then they will be both together.

so typically when the Jeep is running I put it in the green position since they will both get charged while driving. If I am doing heavy winching I will put the switch in the middle and separate them so if I do use too much battery it doesn't spike the alternator or drain both batteries (with the car running) but it automatically puts it in the same mode as if the switch is in the middle when you shut the Jeep off. So your camping stuff will only drain your aux battery if the car is off. Unless you put it on the bottom or red mode then you will be on both regardless.

Mostly I just put it in green mode and leave it alone.
IN Green Mode driving both batteries are getting charged, but when you shut the car off the batteries are separated by default.

Green mode gets power from your ignition. Once the ignition turns off then the relay separates the batteries.

I hope that makes sense. I feel like I am rambling. I hope I am not making you more confused. but it looks like you have a pretty good understanding. I think you just want to know if when the car is shut off will both batteries die? And the answer is no as long as you don't manually have it in the red position. If it is in the middle or green position only the aux battery will be used by whatever is plugged into that battery.

I have the same things as you. I have a fridge and lights and a tent trailer I tow behind my Jeep and also use my aux battery for powering things when my jeep is off. I do bring a separate battery charger that I plug into my gen if I am going to be running a fridge for multiple days though. That is so I can charge my aux battery during the day. I can only get 7-8 hours of fridge off of the battery and I don't want to use the Jeep to recharge the aux battery from dead.

I hope that helps.

PS the painless wiring is kind of expensive but worth it in my mind. It came with spot on instructions, and is quality. I have the same dual batteries in my 3/4 Ton Chev as I do in my Jeep. Although in my Chevy I am running an Odyssey and a Yellow top optima where as in my Jeep I am running two Yellow tops. I went with the Yellow tops because they are full sized adult batteries and like others mentioned I didn't want to run two smaller batteries and the yellow tops fit nicely sideways. It has been a couple years and it is still going strong.

 

[TJim]

New question!!

How fast will my 124 amp alternator charge an aux AMG Battery 100AH? (deep cycle battery) (using an isolator)

 

[BugoutJeep]

As a guess, if you drained it to 0, which is bad but that would probably bulk charge 80% and maybe around 20 amp charge which would be about 4hrs and then maybe up around 2 hrs for the remainder.

Btw, this is the reason I don't suggest stuff like the yeti generator, jackery, etc, (unless they've changed) because those charge at like 2 amps, so an equivalent size would take roughly 2 days, which is rather hard on a trip. There's some differences in those systems but charging under 10 amps kinda stinks.

 

[ac_]

New question!!

How fast will my 124 amp alternator charge an aux AMG Battery 100AH? (deep cycle battery) (using an isolator)

I don't think anybody can answer that precisely. It will matter how drained it is. You don't really want to use your alternator to charge it anyway. I mean when you are driving it will keep it charged up, but you should put a charger on it and let it trickle over night if you drain it. Also if you use an isolator rather than a relay then it will drop a volt during charging from your alternator. I have tested this. That is why I use a relay vs isolator.

So when I go camping I will plug my fridge into my aux battery and let her run. During the day I will hook a battery charger to my gen and let it charge the battery all day. Then I will turn the gen off at night and let the battery drain, then I will charge it again the next day. Then I will let the Jeep top it off on the way home.

 

[BugoutJeep]

Btw, I was estimating that you had a charge controller. But I would still guess a similar time. Note that starting will require charging that battery and your alternator doesn't put out its max at lower rpms.

 

[BuildBreakRepeat]

I’m a big advocate for running both an isolater and a charge controller. The CTEK one I linked earlier does both very effectively.

 

[BugoutJeep]

I can't say it enough, batteries are expensive once you go this route, so try to take care of them and you don't want to get out and get stranded.

If you're out and have some time, solar can really help a bit without taking up much room with the folding styles.

 

[BuildBreakRepeat]

I can't say it enough, batteries are expensive once you go this route, so try to take care of them and you don't want to get out and get stranded.

If you're out and have some time, solar can really help a bit without taking up much room with the folding styles.

Having a hardtop will make my future solar integration easy, good advice.

 

[BugoutJeep]

Personally I don't permanently mount my mobile solar, but to each his own. I typically park in the shade and I've made extensions so I can lay stuff 20 ft or more from my Jeep.

That's better in the woods. In town that's tougher. I have a rack and nobody messes with my stuff at work and I leave it out during the day. You can get bike locks and stuff and maybe keep people honest.

 

[BuildBreakRepeat]

Personally I don't permanently mount my mobile solar, but to each his own. I typically park in the shade and I've made extensions so I can lay stuff 20 ft or more from my Jeep.

That's better in the woods. In town that's tougher. I have a rack and nobody messes with my stuff at work and I leave it out during the day. You can get bike locks and stuff and maybe keep people honest.

I like those super slim portable solar panels, I figure when the time comes I will make some brackets to attach it to the top for driving or in town, but be able to remove it for campsite shade. Your Jeep is pretty much setup as a great camping rig.