Talk to me about 2nd batteries (1 Viewer)

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Sorry, I know it’s been asked before. I don’t know if I’ve forgotten how to search, but I’ve tried to get relevant info through search and I keep getting bad results.

I’ve got an 02 LC. I installed the SLEE 2nd battery tray and the single ArB compressor. I have the redarc isolator wiring kit. I want to KISS and not do a DC to DC. So, if I’m not mistaken, my best option is to go with a deep cycle lead-acid battery, right? I don’t have a smart alternator, so AGM and LiPo batteries won’t be optimal….right?

If that’s the case, what is the best lead acid battery that’ll fit on the SLEE tray…group 35?

Thanks in advance for the input. Bonus if you can give me tips on what I can install downstream of my second battery to wire additional accessories to and where to mount. I think I have room on the slee tray next to the compressor.
 
What makes you think you don't have a "Smart Alternator"? If it's a stock '02 LC, it's a smart alternator.

I installed a very similar setup, but also installed the Redarc 25A DC-DC Battery charger. SLEE has the Redarc mount as well for the LC. Everything works extremely well including the solar input.
 
What makes you think you don't have a "Smart Alternator"? If it's a stock '02 LC, it's a smart alternator.

I installed a very similar setup, but also installed the Redarc 25A DC-DC Battery charger. SLEE has the Redarc mount as well for the LC. Everything works extremely well including the solar input.

Reading on interwebs I thought I had read the 02 was a dumb alternator.

So, you’re saying if I don’t get the DC to DC and just use the isolator, an AGM battery will charge just fine?
 
What makes you think you don't have a "Smart Alternator"? If it's a stock '02 LC, it's a smart alternator.

I installed a very similar setup, but also installed the Redarc 25A DC-DC Battery charger. SLEE has the Redarc mount as well for the LC. Everything works extremely well including the solar input.

Supranut says it ain’t smart. Which is what I thought I had read elsewhere.
 
Reading on interwebs I thought I had read the 02 was a dumb alternator.

So, you’re saying if I don’t get the DC to DC and just use the isolator, an AGM battery will charge just fine?
Actually, no. Without the correct DC-DC Charger, the Auxillary battery will never charge fully or correctly. Lead Acid, AGM, or Lithium won't matter. Here's a simple sheet from Redarc.
My only connection to them is I like their stuff and use it daily.
 
I may or may not have mine setup the best way possible, yet I haven't run into problems.

I run double lead acid batteries, separated with a voltage sensitive relay to isolate the aux battery.
While I have a bunch of low voltage incidental stuff (like lights, and other low current stuff) wired to the aux battery, my fridge is wired to a mppt controller of my solar panels on the load side, and the aux battery is on the battery side.

My logic is the fridge is basically going to be drawing power all the time, so there is value using the smarts of the mppt to manage that load. While the load from the lights, etc is negligible and will probably barely raise a blip on the battery side.

So far so good, with my aux battery always has enough charge. I am happy to sacrifice a few fractions of voltage from the alternator since the panels are always topping up the battery.
 
I have dual batteries with a simple battery isolator kit. I'm running AGM Group 49 batteries. You have to change out a 7.5 amp fuse with a GM diode and everything plays nice. Simple as that.
 
What makes you think you don't have a "Smart Alternator"? If it's a stock '02 LC, it's a smart alternator.
It’s a standard alternator because it only has three terminals on the connector: ignition, lamp and (S)-senses voltage at the battery. There’s are no wires to an ECU. The 200 has a smart alternator.
 
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Sorry, I know it’s been asked before. I don’t know if I’ve forgotten how to search, but I’ve tried to get relevant info through search and I keep getting bad results.

I’ve got an 02 LC. I installed the SLEE 2nd battery tray and the single ArB compressor. I have the redarc isolator wiring kit. I want to KISS and not do a DC to DC. So, if I’m not mistaken, my best option is to go with a deep cycle lead-acid battery, right? I don’t have a smart alternator, so AGM and LiPo batteries won’t be optimal….right?

If that’s the case, what is the best lead acid battery that’ll fit on the SLEE tray…group 35?

Thanks in advance for the input. Bonus if you can give me tips on what I can install downstream of my second battery to wire additional accessories to and where to mount. I think I have room on the slee tray next to the compressor.
FWIW, I think the DC-DC charger is the KISS option from the user perspective. There's no worry about diodes or isolators or battery types. Just plug it in and you can trust that a reputable DCDC charger is going to care for each battery appropriately.

It's a one time investment, but if you've already bought the 2nd battery and tray and compressor you're already beyond "budget build" territory. Finish it off right and throw in a DCDC charger. :) Plus, then when you add solar it's super simple plug and play.
 
Blue sea 7622. That’s the simple option. Lead acid batteries are perfectly happy being charged directly from the alternator. The blue sea will allow you to combine batteries for hard starting. I don’t think the redarc dc-dc can do that. Obviously you can add your own battery switch to combine, but it’s simpler when integrated and packaged with the ACR.
 
Blue sea 7622. That’s the simple option. Lead acid batteries are perfectly happy being charged directly from the alternator. The blue sea will allow you to combine batteries for hard starting. I don’t think the redarc dc-dc can do that. Obviously you can add your own battery switch to combine, but it’s simpler when integrated and packaged with the ACR.
Redarc can jumpstart a dead main with the Aux batt if using a DCDC charger with a SB112 solenoid. I went this route and can “jump start” my main from the driver seat with push of a button. Came in pretty handy and worked perfect when my main batt was on its last leg.

Its not the simplest setup, but works great, and leaves the door open for varieties of batt types and solar, etc.

8642203F-483C-417E-BC96-E9908875EAB9.jpeg


AF31DF80-3B0D-4F29-8D69-F9B16D1469B7.jpeg
 
Redarc can jumpstart a dead main with the Aux batt if using a DCDC charger with a SB112 solenoid. I went this route and can “jump start” my main from the driver seat with push of a button. Came in pretty handy and worked perfect when my main batt was on its last leg.

Its not the simplest setup, but works great, and leaves the door open for varieties of batt types and solar, etc.

View attachment 3095471

View attachment 3095472
With that arrangement, how big are those fuses running from the Aux to solenoid to main batt? I've wanted to setup mine in a similar fashion, but fusing it to any functional degree seemed likely to also prevent the current needed to jump start. 🤷
 
Redarc can jumpstart a dead main with the Aux batt if using a DCDC charger with a SB112 solenoid. I went this route and can “jump start” my main from the driver seat with push of a button. Came in pretty handy and worked perfect when my main batt was on its last leg.

Its not the simplest setup, but works great, and leaves the door open for varieties of batt types and solar, etc.

View attachment 3095471

View attachment 3095472
This is a seriously clean set-up. Any more pics of it? You've done good work. I see how small the DCDC Charger is, makes me consider going to AGM despite the simplicity of the 7622.
 
Redarc can jumpstart a dead main with the Aux batt if using a DCDC charger with a SB112 solenoid. I went this route and can “jump start” my main from the driver seat with push of a button. Came in pretty handy and worked perfect when my main batt was on its last leg.

Its not the simplest setup, but works great, and leaves the door open for varieties of batt types and solar, etc.

View attachment 3095471

View attachment 3095472
This makes a lot of sense. And I already have the SBI12. So I’ll order the DC to DC, baddest ass group 35 battery and call it a day then? I can keep my factory lead acid battery and not worry about battery comparability?

Also, to @suprarx7nut ’s point, is the fuse size a concern? Can’t I just use the one it comes with?

As many details as you can give me/us about your build would be great. Like what are those two octopi looking things attached to your terminals?

Going this route I’m able to add solar later, right?
 
I agree that using the DC/DC charger is the easiest way to keep it simple, you just hook it up and forget about it and let it do all the calculating and work.

I made a video that may be helpful and answer some questions.

 
This makes a lot of sense. And I already have the SBI12. So I’ll order the DC to DC, baddest ass group 35 battery and call it a day then? I can keep my factory lead acid battery and not worry about battery comparability?

Also, to @suprarx7nut ’s point, is the fuse size a concern? Can’t I just use the one it comes with?

As many details as you can give me/us about your build would be great. Like what are those two octopi looking things attached to your terminals?

Going this route I’m able to add solar later, right?
I think group 34 is the largest you can fit in the Slee tray. I have a 31 in my starter tray and a 34 in my homemade tray.
 
I approached dual batteries (both AGM) in my 100 a bit different using a simple 500a solenoid as an isolator.

The isolator is triggered by a two pole (on-off-on) switch inside. On one pole the relay is triggered via 'ignition on'. This is pretty much a set it and leave it setting. The batteries are separated when the vehicle is off. The 2nd pole is connected to the 2nd battery so that I am able to manually activate the solenoid to self jump start. The self jump start worked great one day in the shop when I managed to drain the starting battery. Not only is the system simple and dumb, it would be very easy to repair it in the field if necessary. It's been working for the past 3-4 years.

A couple of years ago I also added 100w of solar to the roof and use a basic solar charge controller to help keep the 2nd battery topped off when parked.
 

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