Dual Battery 24V to 12V third battery
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Yup...there's a few solutions from the marine industry for charging a 12V house battery from a 24V battery bank. Just make sure that the unit is an actual charger, not simply a step down converter. Usually costs a couple of hundred $ or so...
Lots of good info in this thread:
https://forum.ih8mud.com/diesel-tech-24-volts-systems/363689-charging-third-12v-battery-24v.html
I copied The Dude's set up and it has worked fine charging a Gel Tech deep cycle in my BJ74.
I have since acquired the 30 amp charger that Granite Grinder mentions and am going to swap over from using the Solar 24-12 converter.
It's mighty nice to have all the 12V accessories hooked up to their own power supply.
https://forum.ih8mud.com/diesel-tech-24-volts-systems/363689-charging-third-12v-battery-24v.html
I copied The Dude's set up and it has worked fine charging a Gel Tech deep cycle in my BJ74.
I have since acquired the 30 amp charger that Granite Grinder mentions and am going to swap over from using the Solar 24-12 converter.
It's mighty nice to have all the 12V accessories hooked up to their own power supply.
Most accessories can be had in 24 volts....my preferred route.
Tough if you want a good stereo (with amps + sub etc), cb, a ham radio or two...
If your 12V needs are fairly small a 20A 24-12 converter like the Solar will handle it nicely. I really like having the dedicated 12V system and not worrying about it.
I have a fix to hold the stereo memory, the rest I can deal with.
I'm adding a 12v alt to run my stuff on a completely seperate circuit. Keep my paws off of the stock wiring!
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Not that adding a 12 volt alt isn`t good but what needs are making you do this?
RufusTheDufus
SILVER Star
one of these or something similar is the easiest to wire up, IMO. It's not the cheapest route though. It will properly maintain a 12v house battery unlike a stock alternator.
The cheapest/easiest is a step down converter charging a 12V GM battery - confirmed by Polar Battery (our local battery gurus). Most step-down converters only put out 13.8V, which is enough to fully charge a GM battery. Lead Acid batteries require a minimum of 14.2V. I was told you can still use them, if you wire the 12V battery up with an electronic charger and plug it in a few times per month, so it gets fully charged. I've got both extra batteries and a couple electronic chargers and the step-down converters already wired in, so this is the route I will go for now.
Whaddauneed all that 12 volt power for?
Three major reasons.
1) I intend to add a fridge, offroad and camping/work lights, strong radio, inverter to charge a laptop (I have a 24v version as well if there are issues though), Racor heater, camp shower pump, possible h20 to air intercooler pump, and other chargers. I want to be able to drain the third battery fairly low if I am camping in the same spot for a few days without affecting the starting system
2) I already have a 12V alt from an FJ60 teardown so free parts!
3) I really want to leave the stock 24v system alone with the non-running draws I intend to use. On top of this, I really want to leave the stock circuitry alone and build a second circuit for all of the additional accessories. With how expensive it is to replace stock alts, and relays, why introduce more complexity to the system.
Oh, and here in the states, 12v accesories are MUCH cheaper than 24v.
1) I intend to add a fridge, offroad and camping/work lights, strong radio, inverter to charge a laptop (I have a 24v version as well if there are issues though), Racor heater, camp shower pump, possible h20 to air intercooler pump, and other chargers. I want to be able to drain the third battery fairly low if I am camping in the same spot for a few days without affecting the starting system
2) I already have a 12V alt from an FJ60 teardown so free parts!
3) I really want to leave the stock 24v system alone with the non-running draws I intend to use. On top of this, I really want to leave the stock circuitry alone and build a second circuit for all of the additional accessories. With how expensive it is to replace stock alts, and relays, why introduce more complexity to the system.
Oh, and here in the states, 12v accesories are MUCH cheaper than 24v.
I want to be able to drain the third battery fairly low if I am camping in the same spot for a few days without affecting the starting systemFair enough but all the rest can be 24 volt.
Haven't seen too many 24V Ham or CB radios. Ham radios are expensive to start with, can't imagine what a 24V model would cost or where you'd get one. How about a Warn PowerPlant? Combination 9500LB winch/ air compressor. Warn only sells a 12V model and this is a very handy unit, I used to run this off a dedicated 12V battery with a 30A 24-> 12V battery charger on my old HJ60. I understand that you can get a lot of stuff in 24V, just hard to walk into BestBuy and buy a stereo head unit and amps.
Exactly... I forgot the inevitable winch. 24V are great, but pricey, hard to replace, and again, I want to leave the stock 24V system alone.
Plus, take my list, add up the prices, and then add around 30 to 50% for the 24v upgrade. Then also bill my time for finding what I want in 24v at around 50-110 an hour which is my billable for my work... it ends up $$$. Not that i disagree with you about the fact that 24V can be found, it just would eb soooo much eaiser to just mount a second alt and fuse block instead of having a charger run the system.
K
Plus, take my list, add up the prices, and then add around 30 to 50% for the 24v upgrade. Then also bill my time for finding what I want in 24v at around 50-110 an hour which is my billable for my work... it ends up $$$. Not that i disagree with you about the fact that 24V can be found, it just would eb soooo much eaiser to just mount a second alt and fuse block instead of having a charger run the system.
K
Breckenridge, I am considering adding a second alt also on my 3B but have no idea how or where I would place it or support it... I have OEM power steering so that eats up that much more space. If you have any links or photos you could share that would be great.
Cheers
Cheers
Lots of heavy equipment electrics only come in 24-28 volt.
second alternator, is super easy to wire up, it only needs one wire to the battery, and you have so much more amps than a converter will give you, also it wouldn't tax your stock system.
Can you provide me with pictures of your second alternator setup, I would like to do the same and would like to seee where you installed it.
Thanks and have a good one!
Thanks and have a good one!
