Reading about dual batteries
Posted by havoc_penguin@reddit | overlanding | View on Reddit | 26 comments
afternoon,
I've been reading up on dual battery setups, pros and cons with solenoids vs dctodc chargers and the myriad of options.
ideally, id like to run a full time inverter for tools, fridge, lights and basically, whatever else I need while camping, overlanding, 4x4 riding or just general day to day use. main things will be camp lights, fridge, power tool battery chargers and laptop/camera battery charging.
I would like 2 batteries, I'll keep my lead acid and use an agm or lithium(I'll mount it in my truck cab) so I'd need a smart charger, a 2k, ish, watt pure sine wave inverter and a dctodc smart charger with isolator. plus wiring, fuses and the misc stuff.
I'm not worried about solar charging, yet, but I do want the ability to be able to run different types of batteries. I've read a dctodc smart charger allows that. I also don't have room in the engine bay unless I reroute my air box so an agm or lithium in the cab would be ideal. I do have a tool box so that's also an option.
my budget isn't huge but I'm prepared to spend 500-1k USD on the setup. less if I can manage.
this will be going into a single cab dodge ram pickup.
thoughts?
baconpizzaman@reddit
I would pick up a DC-DC charger off of Marketplace, or on sale. There's a ton of models to choose from in the 20-50A range and that would allow you to charge while driving. A lot will offer solar inputs as well. In my area you can regularly find Renogy DC-DC chargers in the 100-200$ range. Solenoids are way cheaper but only work if the batteries are the same chemistry, which could get you going but I think you would quickly outgrow. Then grab whatever size Lithium battery you can fit in your vehicle (100-200Ah) with good reviews for 400-600$ and some wires and you're pretty well started!
havoc_penguin@reddit (OP)
There is a renogy 20a for $60 2 hours away.
211logos@reddit
Look at /r/vanlife and /r/vandwellers. Renogy isn't well regarded, and that may explain the price.
havoc_penguin@reddit (OP)
And there's a 60a for $100 3 hours away.
baconpizzaman@reddit
All depends on what battery size you'd like to charge, as well as your stock alternator capacity. I'm running a 50A DC-DC charger off my stock Tacoma alternator, but I have the tow package which gas a 130A Alternator vs the regular 110A
havoc_penguin@reddit (OP)
Mine is 140a I believe.
baconpizzaman@reddit
What vehicle? 140A comes out to about 1650 Watts of charging capacity, but if your vehicle needs 135A it doesn't leave much head room. Usually, the more modern the vehicle the more power intensive they are and they'll have a little less head room than older ones.
Most DC-DC chargers are smart enough to adapt to whatever amperage you'll give them, but obviously it's best to stress the stock system as little as possible
havoc_penguin@reddit (OP)
2008 ram 1500 with the 5.7l hemi
havoc_penguin@reddit (OP)
My local area is full of trash but I'll check marketplace too. Id rather but new since I won't have everything together all at once and I'll know it works or at least has a warranty
zpollack34@reddit
I have a Renogy lithium system that I just rebuilt in my Tacoma. The first iteration had the battery and equipment in the back seat. Recently I moved it to the bed under a topper.
Firstly, inverter should only be used when absolutely necessary. The majority of what you listed is available in native 12v DC variants and those should be used. Converting from 12v DC to 120 AC is extremely wasteful. You may need it for charging power tool batteries but that's about it. I charge a 15 inch MacBook from an Anker 12v charger. I power a Starlink from 12v. All my lighting, fridge, compressor, hot water. All 12v. I don't even have an inverter aside from the one built into the Tacoma.
As for battery chemistry, I would highly recommend lithium. They can be mounted anywhere, have better density, no gassing or venting needed. Just buy quality. I went with Renogy a few years ago because it was the basically the safe choice. I have heard LiTime or some other amazon brands are just as good now. Just read up on them since lithium can melt down if the BMS is junk.
You're on the right track with needing a DCDC charger. Your alternator likely is not going to charge the lithium properly so you'll want to go with DCDC over a solenoid isolator. My Renogy properly cuts off when the ignition is off so I don't have a separate isolator for that. It can do a max of 30a between alternator and solar. that's like 400w of solar panels it can handle.
One change from my first iteration to this one is considering how much I drive and keeping the system topped up. I drive maybe 20 mins a day but like to keep my fridge running all the time. I added a 10a NOCO AC charger this time so I can keep the system topped up in the garage.
As for wiring, fusing, etc, buy quality parts, put fuses everywhere that makes sense. Don't cut corners on wire terminations. Do it right or you could be buying a new truck.
havoc_penguin@reddit (OP)
I'll keep the 12v to 120v in mind. You are correct though, the only thing I'd need a house plug for is the Ridgid/Milwaukee battery charger. I could probably step the inverter down to what.... 200watts or something small like that?
I like the idea of shore power too like what you did with the AC charger. My mom and dad has a 30ft bumper pull and I tag along with them when they are in town so it would be cool to be able to charge it from one of their outdoor plugs lol
Lithium scares me lol. I don't want to buy a new truck. I might try to somehow isolate it into the toolbox if I go lithium, in case of worse case scenario.
When I started reading about dual batteries forever ago, I remember they had to be the exact same kind and I didn't want to have to upgrade one and buy another so I'm happy about the dctodc charger.
Id like the option to go solar charging but as of right now, it's not a need I'm looking for.
Id also like to move my 4 light relays plus all fuses for this system to one box but I'm not really finding a solution. I've got 4 40amp relays for my lights already.
zpollack34@reddit
I doubt those lights need 40 amps. Read the specs on them and fuse just higher than peak. I've been using an Auxbeam controller which basically acts like a relay box. One control cable goes to a control pad and all the devices terminate to the main unit with individual fuses.
If you go with a DCDC charger that has PV inputs, you can always terminate those to like an MC4 and plug in a portable panel array. Those are a few hundred bucks and give you the flexibility to place it in the sun while your truck is parked in the shade.
As for the wattage required for an inverter, do the math. Check the specific charger you want to use. If you're ok with slower charging the cheaper chargers will generally draw less. But if you were wanting like a double or more charger that is fast, you might need 1000-2000w. 2000w is about the max you could pull from a single 100ah lithium. Then you'd need to either do two 100ah or a 200ah with higher output to drive the larger inverter plus other electronics.
I know Renogy's, and im sure others, inverters have AC input, too. So you could wire together the ac in for the charger and inverter and then when you plug in to shore power, you get both switching over to AC.
havoc_penguin@reddit (OP)
The dual battery charger from Ridgid is 240w.
Pinholio_Mf@reddit
Ultimately there is tons to consider and I for one am grateful for this community for helping us out. Pls make sure and post what you eventually decide is going to work best in your ride.
havoc_penguin@reddit (OP)
The Milwaukee M12 charger is 120v 750ma to 12v 3a and the Ridgid is 120v 60w to 18v. For the single Ridgid. For the double, it'll probably be 120v 120w to 18v.
You're correct, my lights are maybe 20 but my truck used to be a first responder truck and it had them in it. The lights have 3 modes and each mode has its own relay since each relay has its own switch. Felt it easier to control it like that.
I'll check out the auxbeam box but I'd still like the keep the light modes separate like I have them now. Smaller relays but still need 3 spots, plus all the other stuff.
Crafty-Farm-8470@reddit
I would not use a lead acid with an agm. It may not be dangerous (some people disagree) but agm requires a higher voltage to charge, so you'll need a voltage booster if you go the solenoid route or need to set the dctodc voltage higher.
I had a solenoid for a few years, but I could never get it to really work the way I wanted it to and went through several alternators (I think because a fuse was partially burned through so it made the alternator work hard, but that's a different story). I now have a Redarc dctodc charger and high output alternator that work well (fridge, winch, lights etc).
estunum@reddit
What kind of tools? Sounds like you need 200ah+ Technology with power stations is at a point where it’s way less hassle and perhaps cheaper to just go the all in one route. A BLUETTI Elite 200 V2 and an alternator charger will run you a little over $1k with minimal wiring.
The problem I’ve had with power stations is that they never have a great DC solution. You can’t run a distro block from the station to power all your dc loads for example. I think BLUETTI offers a hub, but it’s pricey. They also just came out with their Elite 300 which has a TT30 port that would solve that problem and you can run all your DC loads.
Otherwise you need to piece it all, and it won’t be drastically cheaper. What it does give you is scalability and serviceability. The two things a power station can’t give you. I made an amp rack style for my wiring. I still have to add the inverter, but I have definitely blown over your budget by sticking with REDARC and BlueSea components.
CW-Eight@reddit
I’d suggest starting with looking more into what needs DC vs AC. Fridge, lights, and charging can all be done with DC.
Don’t get me wrong, I’ve put inverters in both my van and my boat, but that is for running induction cooktops (avoid propane).
But without induction, I doubt I’d have inverters. They do make life easier, because then you can just use the charging stuff you already have for the house.
Just an idea for consideration.
Shmokesshweed@reddit
I would personally pick up a 500-800w alternator charger and a portable battery in the 1kwh capacity range with a 2000 watt inverter and call it a day. Doable for $500-700. Less wiring, less headache.
havoc_penguin@reddit (OP)
I don't mind the wiring honestly. Gives me something to do after work. I'm pretty set on dual batteries, charger and an inverter. Its more simple in my mind. Once it's all installed, I just plug whatever into the inverter and off I go.
tank19@reddit
I looked at dual batteries for a long time but recently needed to buy a power station for my small camper. The alternator charger and a power station seems infinitely more flexible. All the benefits of a dual battery system with the ability to take out the power station for home, camp, garage or other usage.
Shmokesshweed@reddit
The flexibility is awesome to have, in my opinion. I can't make it out at any time and charge it at home. I can also use it for power outages or where I need power where my vehicle can't or won't get to. I also use it with a 5 kwh external battery at home. It's a good setup for me.
havoc_penguin@reddit (OP)
I'll read up on them again. A buddy of mine has a big one for his deer camp and he loves the thing.
havoc_penguin@reddit (OP)
I've considered it. I've looked at the big Anker power stations and I do like them but this will be only for my truck so that's why I'm looking at dual batteries with an inverter.
bluehiro@reddit
Redarc for DC to DC and solar, they sell one unit that does both very very well. Keep you "house" battery inside the cab as planned, go for a Lithium Iron Phosphate or similar.
Overall your plan looks good. Just be sure to use the right size wires, fuses, etc. Personally, I am using a BlueSea SafetyHub 150 as an auxiliary fuse block under the hood, I have found it very helpful. (running Redarc DCtoDC, AuxBeam light controller, Weboost, Fridge, USB C, etc)
havoc_penguin@reddit (OP)
Id like to have an independent fuse block for everything too. I've got my relays for my 2 light bars already with my switches above my head but I'd like to move them and the new stuff to a dedicated box.