biggoolies
Adventurer
That is a very good idea. I may do the same add an insulated curtain.
2200 watts of solar on the roof?
- Thread starter MTVR
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biggoolies
Adventurer
Do you have any ideas of what material or a supplier of such? Re. Insulated curtain
rayra
Expedition Leader
well you touch on the genesis of AGM in the first place, their resistance to vibratory damage. which IIRC is the entire reason for the Odyssey line development for off road racing vehicles. Which has now spread as some sort of standard for anybody going off-pavement. Despite their charging requirements not matching most of the vehicles they are installed in.
I've never known a flooded / wet cell to last in a vehicle in very hot or freezing climes for much more than three years regardless, so I don't see that as a fault, more of a 'norm'. So call that $30/yr for my flooded grp78. Or more like double that as I'm deliberately buying a new one every 2yrs, installign it as Starter and bumping the prior Start to Aux and the Aux to an older idle vehicle and starting a home battery bank. So I keep my vehicle batteries 'fresher' that way.
An Odyssey (AGM) 78-790 equivalent is $260 locally. So it had better last that 9yrs for an equivalent cost / year. IF that matters to a person.
I drive some washboarded roads occasionally, don't enjoy it, and hardly ever drive fast off-road anymore. And my 'house' loads are minimal, so deep discharge isn't a concern either. And they're supplemented by rooftop solar and a high output alternator. So for me the AGM is neither necessary or economic. And before my alternator swap I'd have had the same insufficient charging issues. So I found other more affordable ways to do things.
rayra
Expedition Leader
bigger the bank, lower the comparative load, given the same draw. Couple that (figuratively and literally) with a low-volt limiting device and never draw down the bank deeply enough to damage it. And you arrange the wiring of your bank to equalize the load. These precepts are all over off-grid solar / prepper forums.
It seems in the 'overlanding' sphere this stuff is coming piecemeal, and getting distorted somewhat by new sechy expensive tech and faddish adoption, without a broader understanding or what or why.
/that's in part why I've been making noise about DC-DC charger implementations to make up for battery tech mismatches in vehicles, compounded by use models where the DC-DC charger becomes an obstacle to the far higher bulk charging available from the vehicle's factory DC charger. Which is more important, larger bulk charge while on an extended 'expedition' with a concomitant 'conditioning' charge back home, or always applying the 'correct' higher charge voltage to a mismatched battery solution every day, but at a far lower and probably insufficient amperage during a protracted trip? The former seems a better solution to me, for CONUS trips. Not being a 'true overlander' with plans to tour to the ends of continents.
It seems in the 'overlanding' sphere this stuff is coming piecemeal, and getting distorted somewhat by new sechy expensive tech and faddish adoption, without a broader understanding or what or why.
/that's in part why I've been making noise about DC-DC charger implementations to make up for battery tech mismatches in vehicles, compounded by use models where the DC-DC charger becomes an obstacle to the far higher bulk charging available from the vehicle's factory DC charger. Which is more important, larger bulk charge while on an extended 'expedition' with a concomitant 'conditioning' charge back home, or always applying the 'correct' higher charge voltage to a mismatched battery solution every day, but at a far lower and probably insufficient amperage during a protracted trip? The former seems a better solution to me, for CONUS trips. Not being a 'true overlander' with plans to tour to the ends of continents.
Peter_n_Margaret
Adventurer
I direct charge my 400Ah AGM house batteries from the alternator if the solar fails to do the job.
The alternator is 14.4V.
If the batteries are low (which is the only time I need to do it) the charge rate starts at 70A (from an 85A alternator). That charge rate drops off as the batteries come up due to the reducing difference between the alternator voltage and the battery voltage, but charging does continue until the batteries are full.
Getting them full is not a concern though, because the solar is also contributing at the same time and will top them up.
A DC-DC charger would be better at topping them up as it would hold a higher charge voltage for longer, but the alternator will slam more power in over the initial charge period and that is the important bit for me.
I have seen 70A charge from the alternator plus 30A from the solar at the same time.
There is no reason why you could not utilise a DC-DC charger AND direct alternator charging AND solar all at the same time if you wanted the best of all the options.
Cheers,
Peter
OKA196 motorhome
The alternator is 14.4V.
If the batteries are low (which is the only time I need to do it) the charge rate starts at 70A (from an 85A alternator). That charge rate drops off as the batteries come up due to the reducing difference between the alternator voltage and the battery voltage, but charging does continue until the batteries are full.
Getting them full is not a concern though, because the solar is also contributing at the same time and will top them up.
A DC-DC charger would be better at topping them up as it would hold a higher charge voltage for longer, but the alternator will slam more power in over the initial charge period and that is the important bit for me.
I have seen 70A charge from the alternator plus 30A from the solar at the same time.
There is no reason why you could not utilise a DC-DC charger AND direct alternator charging AND solar all at the same time if you wanted the best of all the options.
Cheers,
Peter
OKA196 motorhome
rayra
Expedition Leader
That's the sort of alternating charging I'm describing. But what you describe depends on your ALT not charging at a voltage which the solar controller or DC-DC would interpret as 'full'. The 14.4 you mention. Would those devices still work if the ALT is putting out 14.6-14.7? Maybe / probably go into float modes. (shrug)
Peter_n_Margaret
Adventurer
I have never seen an alternator that is 14.6 - 14.7V, seems very high, but that does not mean they don't exist.
Even if the alternator offered a higher voltage than the solar or DC-DC charger I can't see that it would be a problem.
In my case the solar offers a higher voltage than the alternator and when the battery gets to a tad over alternator output voltage, the alternator shuts down, the tacho drops to zero and the alternator light comes on, so I notice immediately. At that point I switch the alternator solenoid connection to the house batteries off and the solar finishes the top up as normal.
Cheers,
Peter
OKA196 motorhome
Could be something as simple as a rectangular sleeping bag unzipped.
Regarding our alternator and it's use with a DC to DC charger, our vehicle comes with a massive 24-volt 150-amp alternator, which would be the equivalent of 300 amps at 12 volts. Our vehicle also has a fast idle switch that raises the idle speed up to 1,500 rpm if needed, but we plan only to harness the alternator's power when the engine is already running for some other purpose, like driving- we have absolutely no intention of relying on our vehicle's 11.9 liter (730 cubic inch) engine as a 425-horsepower, 1,550 pound-foot generator.
That would work, although, you might want to avoid the zipper for the safety of a dog's eyes (or kid's) nosing by the curtain.
Maybe something like: https://www.amazon.com/AmazonBasics...ng,+Black&qid=1588842831&s=home-garden&sr=1-4
biggoolies
Adventurer
Good ideas. Thanks
You are welcome.
@MTVR, it night even be big enough to fold in half and still block off your planned loft bedroom.
Can you dumb that down for me just a little bit? I don't know what EU AC IO is, or why that wouldn't work for me?
Peter_n_Margaret
Adventurer
Personally I would choose stand alone solar controller (Victron MPPT) and inverter (whatever size and quality you choose to suit your usage requirements).
Likewise the (110/240V?) charger. Personally, we don't have a grid connect charger. If the solar can not do the job then the alternator will.
Cheers,
Peter
OKA196 motorhome
Likewise the (110/240V?) charger. Personally, we don't have a grid connect charger. If the solar can not do the job then the alternator will.
Cheers,
Peter
OKA196 motorhome
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