Help with dual battery setup for 95 FZJ80 (1 Viewer)
- Thread starter WheelDrivenADV
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I'm doing the LCPhil thing and just hooking both batteries together in parallel. I don't have any refrigerators, but I do have a big snowplow that pulls as much amperage as a heavy winch during use. I just needed more capacity so as not to run the battery down too much when plowing, the stock alternator and battery just can't keep up when the snow's really coming down. A bigger battery would probably have been a cheaper option but I like the idea of having two- just like the dual fan belts. And a little extra cranking power will come in handy when it's good and cold out!
I went very overkill and used 1/0 cables to hook the batteries together too- basically making it one big battery. No point in having a hot spot in the wiring somewhere. If it turns out later on that I need some kind of disconnect or something between the two I'll see about adding one then. For now this should do the trick, but we'll only know for sure about 2-3 snowstorms in!
I went very overkill and used 1/0 cables to hook the batteries together too- basically making it one big battery. No point in having a hot spot in the wiring somewhere. If it turns out later on that I need some kind of disconnect or something between the two I'll see about adding one then. For now this should do the trick, but we'll only know for sure about 2-3 snowstorms in!
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Why not make it longer?
same here, i also cut a length of heater hose and then cut a slit down the side of the HHose so it slipped over the A/C hose to insulate it against the battery tray, that was over 20 years ago and hasnt had any ill effect to the operation of the A/C
So you can run an AGM (main battery) and a lithium (accessories) in parallel off an OEM alternator with no problems?? Love the KISS. But may want to hook up solar option for the lithium just because I already have the fold up panel from Bluetti.My 40 years as an Electrical contractor told me to do it.I also run a 100ah Lifepo4 lithium and a group 31 AGM the same way in another rig.
BillyGoatMTB
SILVER Star
First question I would ask myself is, do you need a lithium? To each their own, I went Costco group 27 start and marine, added solar and a RedArc isolator
Easy and pure KISS
Unless lithium technology has changed under the hood isn't ideal for them and they have a different charging profile compared to flooded, I suppose if you went RedArc bcdc you could select the profile but I'm not super familiar with the bcdc.
I went flooded (1 cca starter and 1 Marine deep) for my system because it's way more than I need for my fridge and accessories my RedArc isolator back floats from the victron mppt solar controller to the starter battery once the marine "house" battery is charged and anywhere on the continent I can get distilled water or a replacement group 27, or 24 deep or regular for cheap.
KISS is the key, and for my needs I built what made sense.
Good luck and whatever way you go, hope you enjoy the journey
Cool. Yes, intent was to locate the lithium inside since the engine heat not good for them. My agm house battery does not sustain enough volts to run fridge, lights, heater and my Bluetti does not have the amps for the start up demand on the diesel heaters. Lithium will put out the continued amps and volts to run the accessories. Just can't see spending the $$ to buy a name brand set up when you can piece meal it for tons less. When I have half of the kit already.First question I would ask myself is, do you need a lithium? To each their own, I went Costco group 27 start and marine, added solar and a RedArc isolator
Easy and pure KISS
Unless lithium technology has changed under the hood isn't ideal for them and they have a different charging profile compared to flooded, I suppose if you went RedArc bcdc you could select the profile but I'm not super familiar with the bcdc.
I went flooded (1 cca starter and 1 Marine deep) for my system because it's way more than I need for my fridge and accessories my RedArc isolator back floats from the victron mppt solar controller to the starter battery once the marine "house" battery is charged and anywhere on the continent I can get distilled water or a replacement group 27, or 24 deep or regular for cheap.
KISS is the key, and for my needs I built what made sense.
Good luck and whatever way you go, hope you enjoy the journey
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BillyGoatMTB
SILVER Star
Perfect, sounds like you have a plan.
I got all my made in USA cable and connectors from Quality Copper Battery Cables Made in the USA! - BatteryCablesUSA - https://www.batterycablesusa.com/?gad_source=1&gclid=CjwKCAiAvJarBhA1EiwAGgZl0DRDYln1wk6BjsEhhUx7HGOUwX9t1NKCq8cbB--3TGlU421XYzYSYRoCObwQAvD_BwE
I used their extreme cable, they also make custom lengths.
Measure, cut, crimp, heat shrink, repeat
If you charge the lithium battery with a DC-DC charger then it won't be an issue. The DC-DC chargers come in different outputs so you could go with something like an 18A or a 30A. This inherently limits the amount of current the lithium battery can pull from the alternator/charging system. This would be a great case for a manual throttle control where you could run a high idle to charge things up while camping.
Adding a solar panel would help even more since it would keep the house battery topped off for the most part. I'd probably only do this if I had space on a rack and planned to park in one location for more than a day or two.
I highly recommend the Victron hardware for solar charge controllers, DC-DC chargers, etc.. It's what I used when I built out a solar system for my truck camper.
Just data points - I'm running the same Victron solar controller and a RedArc BCDC.
+1 - Lithium requires a charge profile, likely only provided by a BCDC. A "smart alternator" is less capable of charging lithium than a "dumb alternator".
+1 - Lithium is not ideal for underhood installs, and may even be dangerous on really hot days. Good plan to keep it inside.
+1 - A BCDC underhood is a waste of the tech to simply charge 2 engine room batts (lithium notwithstanding, but that's been discussed). The batts are close enough to each other that even straight-parallel wiring is sufficient for 99% of charge demands.
+1 The auto relay used by @BillyGoatMTB is ideal and even a dash-switched, dumb relay (what I use) works well to keep them isolated when desired.
+1 - As mentioned, AGMs or any SLA are much easier to source. Far less expensive too. If a single AGM is insufficient, add a second in parallel for still less the cost of a single lithium while probably outpacing said single lithium ouput at that point. Yeah there's the 'weight' cost, but still.
Generally speaking a BCDC's party trick is eliminating voltage drop over distance, which then too, greatly reduces the cabling cost to overcome said drop.
If that same BCDC also has charging profiles for diff batt chemistries AND a built-in MPPT solar controller (aka, redundant w/another controller), bonus - bonus - bonus.
And just a note that IME the Redarc BCDC charge profiles can be changed "on-the-fly" (remotely even) for greater flexibility/speed in charging regardless of chemistry. This tho requires some knowledge (and E/I monitoring) to safely do so.
Other BCDC makes may allow for similar control.
+1 - Lithium requires a charge profile, likely only provided by a BCDC. A "smart alternator" is less capable of charging lithium than a "dumb alternator".
+1 - Lithium is not ideal for underhood installs, and may even be dangerous on really hot days. Good plan to keep it inside.
+1 - A BCDC underhood is a waste of the tech to simply charge 2 engine room batts (lithium notwithstanding, but that's been discussed). The batts are close enough to each other that even straight-parallel wiring is sufficient for 99% of charge demands.
+1 The auto relay used by @BillyGoatMTB is ideal and even a dash-switched, dumb relay (what I use) works well to keep them isolated when desired.
+1 - As mentioned, AGMs or any SLA are much easier to source. Far less expensive too. If a single AGM is insufficient, add a second in parallel for still less the cost of a single lithium while probably outpacing said single lithium ouput at that point. Yeah there's the 'weight' cost, but still.
Generally speaking a BCDC's party trick is eliminating voltage drop over distance, which then too, greatly reduces the cabling cost to overcome said drop.
If that same BCDC also has charging profiles for diff batt chemistries AND a built-in MPPT solar controller (aka, redundant w/another controller), bonus - bonus - bonus.
And just a note that IME the Redarc BCDC charge profiles can be changed "on-the-fly" (remotely even) for greater flexibility/speed in charging regardless of chemistry. This tho requires some knowledge (and E/I monitoring) to safely do so.
Other BCDC makes may allow for similar control.
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BillyGoatMTB
SILVER Star
Made a duel battery video with more specifics on the RedArc / Victron system I planned out if anyone is interested or for future reference
Made a duel battery video with more specifics on the RedArc / Victron system I planned out if anyone is interested or for future reference
very nice. reminds me alot of my setup
I have heard about the MPPT controllers needing to be mounted vertically so may pay to check on that.
otherwise very clean & neat work !
BillyGoatMTB
SILVER Star
Thanks, I'll check on the MPPT being vertical, never heard of that it's solid state but maybe it's a heat flow through thing.
Perhaps for questionable-quality MPPTs.
And too for the amount of current running thru them.
My units are regularly stowed and run horizontal for the most part. But they have good airflow all the time as well.
The panel they are on is hinged and opens to a vertical alignment.
However no issues either way - going on 3 years or so.
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BillyGoatMTB
SILVER Star
I'm not charging unless I'm stationary, so engine bay head and electric components heat saturation was a consideration but not a concern for me.
I wanted to try something new and fresh on the 80 that fit my needs, I believe I achieved that. If I ever add a mounted solar panel I'll move the victron mppt.
Great conversation, info and tips!
Agreed.
I was responding to @robnicko.
Tho failed to highlight that my devices in question were mounted inside the cargo area.
Which is different from an engine bay environment...where even Redarc recommends a vertical mount solution.
