Charge with generator when lacking solar.

12VoltInstalls

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12v charging on the generators
Usually doesn’t put out much charging at all
This is just a temporary setup
have a small 12 volt setup to just run a small refrigerator and it has been working very well so far. I currently use the generator to charge the 12 volt 200 amp hour battery once every 3 or 4 days. I am using an inverter going from the 12 volt battery to the 120 side to the cabin. I also have a 12-volt charger that I run off of my generator to charge the battery when I need to.

Just back to the beginning here…
Since this is temporary a thing I have done may be of interest to you.

I have not over-wintered with my current RV setup nor have I had a running heater. Didn’t need it for the 7+ warm months I’ve used it for the past 3 years.
This winter, however, I am overwintering (to not spend the $5000+ cost of renting for the winter) but the issue I’ve had is with multiple cloudy days as both the fridge and furnace cycling as expected.

I was at 12.1 volts a few weeks back just after dark but two days of little solar. I thought I’d try charging with a vehicle. My 2021 Nissan Rogue wouldn’t charge (barely 12.4/12.4V at idle!!) but I discovered my 1987 jeep was 13.1 at idle. I hooked up the jumper cables and within about 45minutes at idle the readout on the inverter was displaying14+ volts. Other than a couple milliwatt lights I turned everything off for a half hour and it settled to typical (in summer) summer 12.8V. It was still 12.4 the next morning after running furnace and fridge all night long.
I’ve boosted a few times with the jeep now. Quieter than a generator, fairly effective, and I don’t think I burned that much gasoline. I’m still surprised. I’m rethinking my backup power situation (do nothing option) as 40 days from now cloudiness resides, days get longer, and in 90 days March arrives which is usually the last gasp of 0*F or -10F anyway.

A lot of words to basically set the stage:
If you have a vehicle that actually makes volts at idle, you might get all the amps you need with less trouble and fuss with just jumper cables. Bigger systems don’t have that option.
 

jbatx

Ok, what's next?
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Austin, TX
Get a old powersupply from a router or so. Lot of them can be adjusted (48V adjust to 52V or so)

They also do have a remote on/off switch. If you install a decent shunt you can interface with an ESP or Arduino and eg autostart when SOC <20%, stop charging when SOC >40%.

Charging with high amps is no issue for LFP, and it limits the runtime of the generator (Which usually make a shitload of noise). By not charging to 100% you always leave room for any available sun. In the end, its useless to spend $$ on fuel and noise, while the sun might do the same job for free.

Good options are eg Meanwell chargers (new), but cheaper DIY options include Eltek Flatpacks or old APC rectifiers like https://www.ebay.com/itm/392753355836
(I have three of these - they are massive beasts - Charges at 50 amps and voltage can be adjusted)
Installed in the chassis (3 pieces) they provide 50V / 150A and require 3-phase powerfeed.. They used to power our Foundry MG8 routers in the past. Those went to a scrapyard but I took the PSU to my place..)


For cheap 12V charging look eg at HP 1200W powersupplies. Those can be modified to output >12V (approx 14.2V would be ideal for LFP) and provide 100A current for cheap.
I love this forum. So many ideas and people smarter than me. I'm definitely going to add on to my existing esp32 monitors to start/stop the gene based on SOC or over all bank voltage

my Overkill/JBD eps32 monitor thread: https://diysolarforum.com/threads/anyone-working-with-the-overkill-solar-arduino-lib.27811/

I won't be using the 12v on the gene to charge anything - clearly, that's a lame idea. Instead I'll get an AC->DC charger or power supplies as folks here have suggested to charge the batteries. Connecting the charger output to the buses where all three batteries are connected in parallel. That is, unless you smarter folks have a better/safer/correct/etc way to do that.

I'm chatting with a small company that makes remote start/stop modules for the predator generators. One of their module uses a automotive door lock actuator to engage/disengage the choke - pretty clever. ...I'd rather not reinvent this if it can be had inexpensively. Should be able to easily wire that into relays that are opened/closed by the esp32.
 

Wellbuilt

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Messages
777
Just back to the beginning here…
Since this is temporary a thing I have done may be of interest to you.

I have not over-wintered with my current RV setup nor have I had a running heater. Didn’t need it for the 7+ warm months I’ve used it for the past 3 years.
This winter, however, I am overwintering (to not spend the $5000+ cost of renting for the winter) but the issue I’ve had is with multiple cloudy days as both the fridge and furnace cycling as expected.

I was at 12.1 volts a few weeks back just after dark but two days of little solar. I thought I’d try charging with a vehicle. My 2021 Nissan Rogue wouldn’t charge (barely 12.4/12.4V at idle!!) but I discovered my 1987 jeep was 13.1 at idle. I hooked up the jumper cables and within about 45minutes at idle the readout on the inverter was displaying14+ volts. Other than a couple milliwatt lights I turned everything off for a half hour and it settled to typical (in summer) summer 12.8V. It was still 12.4 the next morning after running furnace and fridge all night long.
I’ve boosted a few times with the jeep now. Quieter than a generator, fairly effective, and I don’t think I burned that much gasoline. I’m still surprised. I’m rethinking my backup power situation (do nothing option) as 40 days from now cloudiness resides, days get longer, and in 90 days March arrives which is usually the last gasp of 0*F or -10F anyway.

A lot of words to basically set the stage:
If you have a vehicle that actually makes volts at idle, you might get all the amps you need with less trouble and fuss with just jumper cables. Bigger systems don’t have that option.
😜 charging with your Jeep’s alternator is a terrible idea you are running a 6cly/8cyl motor for hours to charge a RV system , that altanator is not mentioned to charge like that it will burn up in short order
i allso think you are burning way more fuel then you think , then there is the where in tear just idling there
 

Wellbuilt

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Jbatx
Your genarator is really to large to be efficient , you could run a charger on a champion inverter generator 3500 watts and save a lot of fuel .
It depends on How much you run the generator to charge the battery but it won’t take long to get the cost of the generator back in fuel and I think they come with electric Remote start🤗
 

12VoltInstalls

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😜 charging with your Jeep’s alternator is a terrible idea you are running a 6cly/8cyl motor for hours to charge a RV system , that altanator is not mentioned to charge like that it will burn up in short order
i allso think you are burning way more fuel then you think , then there is the where in tear just idling there
I agree, but it did get me by the couple of times I needed it. Which was the point.

It didn’t take hours, surprisingly quick, actually.

Mennonites own the local starter/alternator shop. This is one of theirs and they have rebuild parts in stock. While daily charging like that wouldn’t make sense it did get me by and gives me some security without buying a generator. I’m ok with it.
 

Wellbuilt

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I don’t know what battery’s you have but LA battery’s require a long absorb charge so hours ?
I guess if you have a few battery’s to charge it mite get you some power for a day or 2 in a pinch .
are use a bolmar marine 100 amp alt on my deisel sail boat motor and it gives me a quick charge when motoring in and out of the marina but the 1000 watts of solar really kept the battery’s charged .
I’m in NY 50mils west of Kingston and it’s hard to keep charged with out a generator and using it every day or 2 .
I’m sure you have plenty of snow and clouds in VT and I think you battery capacity will get walked down buy under charge ing by spring . I like to get 6/7 years out of them I use 16 la battery’s
 

12VoltInstalls

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think you battery capacity will get walked down buy under charge ing by spring . I like to get 6/7 years out of them I use 16 la battery’s
That is more truth than fiction for sure. It’s been on my mind.
I still get plenty of charge and recovery on a sunny day but as you point out, not a lot of sunny days.

I have a solution in mind- a 10 or 15A 12V power supply which exceeds my standby static load. That should carry me over the next few months. By The Ides Of March it won’t matter any more!
 

Wellbuilt

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How are you going to power the power supply ?
They are not power factor corrected and need a good size generator to power it .
I like the IOTA chargers I think you will need to run a 3500 watt generator to power it .
I’m still buried in snow in March at my place .
The best way to charge is with a inverter / charger it seamless .
 

12VoltInstalls

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How are you going to power the power supply ?
Due to recent changes at the property I’m located on 120/240 is hundred fifty feet away.
I’m waiting for the ‘converter charger’ (15A) to arrive and I’ve been testing an adjustable 10A electronically adjustable output battery charger. Of course the charger isn’t intended to be a power supply. But it’s doing about .75- 1.3A at 120V set at ~8A 14.2V so it should neither tax the long cord nor does it create any heat. Not even warm. This tiny bit seems to be more than sufficient for the need. Plus right now I’m at 12.3V battery and the SCC is putting out 14.1V at 7.3A and the sun’s not even really up yet.

So that’s my low-buck low-effort solution to the next few months. Once it gets warmer it will probably not even be needed until next year. And at 1A, my buddy’s $0.16/kWh puts me at max $12- or $14/ month expense and it isn’t needed every day. It was yesterday, but it won’t be needed at all today.

I can either use the generator trigger on the epever or a voltage controller board (I have it in hand) to trigger a 120V relay that will turn on and off whichever charger I choose to use - automatically. I also bought a small inductive digital monitor to record kWh and display in the moment demand.

Once I implement to 800W it should become less necessary. (At 800W, 8 months of the year I’m way, way oversized. 50A charging possibility is almost too much! Even at 600W in summer it has been more than I can use)

(just realized this isn’t my thread though!)
 

Wellbuilt

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🤣 ooops
That sound good I’ve been thinking about some thing similar .
I’ve bought all the land around me so now I could drop a power pole 100feet closer to the house .
I’m wondering if I could just run a 10g wire 700 feet to my cabin to run a power supply ?
I have the wire ?
Maybe boost the voltage at the pole .
I don’t need much power 300watt a hour adds up fast .
The poc wants 60 bucks a month to be hooked up .
It’s a rate for part time use ? Seams like a lot .
 

12VoltInstalls

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10ga for 700’ … I’d do some math! You need your max amps load PLUS about 30% headroom snd I’m not sure you’d have the volts at 700 feet?
EDIT- that could work! The ‘cost’ of course - as you probably know - will be higher than than your “usage” because the voltage drop goes away as consumption mostly as heat .
 

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Wellbuilt

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It’s just a thought , I have enough 10g to make the run .
My system is 120 vac and I only have 10/2 with ground Direct burial cable .
It’s a spool that has been in my shop since the 90s I mostly use 12g .
 

Wellbuilt

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maybe some thing like this could work ?
It’s says it can take 108 to 124v ?
I’m sure this will drive the inspectors crazy .
I have to dig thru the woods working around a lot of rock ledge
In one area I need to go up a 15’ vertical ledge , so maybe conduit in that area .
For now I’m up there for long weekends 3/4 days every 2 weeks or so I can just run my Honda .
2 years ago we did not get a lot of snow I plowed 3 times , last year I plowed every week some times days in a row .
When we live there full time I mite need more power in the winter 🥶
B4A266D7-BE9D-4220-8949-1DB3F76F7665.jpeg
 

12VoltInstalls

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maybe some thing like this could work ?
That could work fine. Didn’t realize you were 48V. 12V10A is 120V/120W whereas you’d be like 750W. Just need a meter box with a breaker and earth stake. It seems like a good idea if the clouds hold you back.
 

Wellbuilt

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Yup, 48 volt Go big or go home .
I used 12v on my sail boat or RV but for a cabin house 48v makes more sense to me.
I have 3 vacant 7 acre building lots and I’m thinking about building a house/cabin on the first one
in a year or so , I could use that power .
So far this year it not so snowy just cold .
 
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