Charge house battery from aux socket Conversion van?

[Tomcor]

I have been working on my 2002 ford conversion van.  Have built a bed frame with storage underneath. And new carpet installed. I was wondering if I bought a single Walmart marine battery could I charge while driving through the rear power socket? The socket is wired with 14 guage wire i notice. I will just be running some led lighting and charging phone and a tablet for now. I have a 30 watt renogy panel bought and a 5 watt pwm charge controller i got for a dollar on ebay. I will slowly be upgrading the solar system.

How long would i need run the van to recharge through the socket if the battery was say 60% charge?
Is the socket usable if I am driving every day. The socket only has power with ignition turned on.

I will posting some pictures of my van build soon.

Thanks

 

[Optimistic Paranoid]

Let's run the numbers.

The ampacity of 14 gauge wire used for steady power transmission is 5.9amps.  Lets round that up and call it 6 amps.

Lets say that your house battery has a capacity of 100 amp hours.  At 60% charge, you would need to put 40 amp hours back in.  40 divided by 6 is 6 point something - round it off to 7.

So you'd have to run your van for 7 hours a day to recharge your house batteries via 14 gauge wire.

People who use their engine to recharge their house battery usually end up running really fat wire - 4 gauge, even 2 gauge.  You need to tie the two systems together with a fire hose, not a drinking straw.

Regards
John

 

[Reverse Engineer]

Let's run the numbers.

The ampacity of 14 gauge wire used for steady power transmission is 5.9amps.  Lets round that up and call it 6 amps.

Lets say that your house battery has a capacity of 100 amp hours.  At 60% charge, you would need to put 40 amp hours back in.  40 divided by 6 is 6 point something - round it off to 7.

So you'd have to run your van for 7 hours a day to recharge your house batteries via 14 gauge wire.

People who use their engine to recharge their house battery usually end up running really fat wire - 4 gauge, even 2 gauge.  You need to tie the two systems together with a fire hose, not a drinking straw.

Regards
John

What are you running in terms of electrics to need 100AH every day?

My E-wheelz (an electric scooter which will give me ~12 miles of range at 15mph to go shopping with) stores up 10AH at 36V (3 x 12v deep cycle batts wired in series). That is the biggest draw. My portable electronics, cell phone, diode lights etc are all rated in milliamperes.  The portable ice maker, maybe 5AH for enough ice for the cooler.  The laptop if I run it 5 hours a day, maybe another 5AH?  Unless you are trying to run A/C cooling, I can't see how or why you would use more than 30 AH every day.  You still want storage of 100 AH of course, but you don't drain it down to zero every day.  Good battery maintenance with a Deep Cycle, you should drain no more than around 30% of the total storage each day.  Full discharges every day will kill a battery in no time.  Li-I Batts do better with full discharges than SLA, but those suckers are EXPENSIVE.  I can buy 4-5  SLAs for every Li-I Batt.  They are smaller and lighter, but not economic.

Besides that, you definitely should not depend on your vehicle engine as sole charging source.  It's way more efficient to have a small portable backup generator if you need some extra juice in a day.  I use a Yamaha 2000W model which is way overpriced but the smallest and quietest in its class for this.

 

[ccbreder]

No one said 100 amp hours every day. 40 amp hours or 30 amp hours, it will still take a long time to charge using the "power plug". If the lead acid battery is not fully charged it will gradually deteriorate. For such a small 100 AH battery, a Honda 1000 with a separate charger is the smallest quietest in it's class. Upgrade the solar as what you have is worth less than you paid. I recommend two 6 volt golf cart batteries wired in series for 12 volts. Only wish we all could afford LiFePo.

 

[Reverse Engineer]

No one said 100 amp hours every day. 40 amp hours or 30 amp hours, it will still take a long time to charge using the "power plug". If the lead acid battery is not fully charged it will gradually deteriorate. For such a small 100 AH battery, a Honda 1000 with a separate charger is the smallest quietest in it's class. Upgrade the solar as what you have is worth less than you paid. I recommend two 6 volt golf cart batteries wired in series for 12 volts. Only wish we all could afford LiFePo.

If you are not using 100AH/day, you don't need such a big pipe for charging.  You just need a little bigger pipe than how much you use each day.  The more you can conserve, the less the stress on the whole system.

Also, if you maintain a Storage Unit ($40/mo) as I do and/or your RV has decent space, you don't have to go with new batts to have a good storage bank.  I have about a half dozen batts scavenged at junkyards at around $15 each.  I wire them in parallel and storage capacity is plenty. I charge them whenever I drop in at the storage unit for exchanging items. There's always plenty of power this way.

 

[Reverse Engineer]

This is a "boondocking"(I think this is what you folks call this) method for keeping your electrics charged up for free, least as far as the power itself is concerned for you.

Do you go to a library or coffee shop or truckstop each day? Go to a laundromat to do laundry? If so, there are numerous electric outlets to plug into. In a backpack or briefcase ( I have used both for this) you have a 10-20AH Deep Cycle Batt (Werkers are OK, about $50) plus a 10A 12V AC/DC batt charger. While you eat lunch or do your laundry or chat on the internet in about an hour, you collect up enough juice to run all your electrics most of the time. Just driving around provides all the rest of the power you need. Its only if you do not drive much each day you have to start scarfing up free power. Laundromats are the best for this. You can sit in there for 4 hours while you do laundry, cruise the internet and charge 2 batts at the same time.

 

[Optimistic Paranoid]

If you are not using 100AH/day, you don't need such a big pipe for charging.  You just need a little bigger pipe than how much you use each day.

The thinner the wire, the greater the resistance.  The greater the resistance, the more the voltage drops.  Try to push 14.8 volts down a really thin wire, and you may only get 13.5 volts at the other end, the rest going up in heat.

Yes, it's possible to overdo it.  You get to the point where the expense isn't justified by the returns.  Best practice is to use a voltage drop chart, and limit the drop to under 3%.

Most people don't realize just how significant the difference between 14.8 volts and 14.4 volts is when you are recharging a battery.

Regards
John

 

[SternWake]

A ciggy plug is a horrible electrical connection. The contacts are spring steel which is a poor conductor. The quality ranges but most, at 7 amps, will start heating up greatly heasting that spring steel, weakening its spring, making for an even poorer connection.

It is probably some 20 feet of 14 awg to reach the rear ciggy plug from ciggy receptacle to whereever it hooks to the switched ignition source.

So Even IF the engine battery is up at 14.4v from the alternator, perhaps 13.4 to 13.5v would make it to the depleted house battery.

Long story short, getting a lead acid battery from 80% charged to 100% charged takes about 4 hours, NO MATTER THE CHARGING SOURCE.

But in the case of 14awg wire over a 20 foot run through a ciggy connector and multiple other connections, the actual amount of current which will flow will be very small. A full recharge from 60% is not going to happen in 4 hours, not 7 either.

Whether enough juice is returned to even keep the battery viable for 6 months with this method is up for debate depending on how much is actually used from the battery and how much it is driven.

If the ONLY recharging system is to be the alternator, AND the are regularly draining the battery below 80%, then thick copper between alternator and house battery is going to be quite effective at bringing a battery back upto 80%.

Once the battery starts limiting the amperage it can accept in the 80% charged range, then the thickness of the wire becomes less and less important, as less current flowing means less voltage drop.
But still, this 14awg ciggy plug plan to a house battery is a poor idea which will have the battery punch drunk in a few days, and it will never sober up
.

Yes, some charging will occur, if the fuse is not blown instantly, but it will only be a fraction of what the battery could accept and the alternator could deliver.

 

[Reverse Engineer]

Agreed the DC cig outlet is lousy for charging, except as a trickle charge method running maybe 2A through it.  I keep my car battery topped off this way plugging in my car overnight on real cold nights.  I have an outdoor outlet to do that.

If you want a bigger pipe, the best deal is to use A/C extension cords, they are cheapest by the foot for thick wire. Snip off the plugs at each end and strip the wire. Just make sure you use some red/black electrical tape at each end to identify your +/- wires!

 

[Tomcor]

Thanks for the info. I won't be living in the van till about March. I am just planning for my mobile retirement. Just wondered if the rear socket was good for anything except blowing up air mattresses. I have been reading alot on this forum. I am aware of thicker gauge wire is the best. And read alot about solar charing systems. I was just looking for a cheap way of just keeping a single battery topped off with just very minimal amp usage to start.

If i mounted the single battery near drivers seat and ran some 4 gauge wire from a solenoid near starting battery would be best. How much would i have to drive to charge with just minimal amp usasage?
I figure being a conversion van it would have a larger amp alternator.

 

[Reverse Engineer]

Thanks for the info. I won't be living in the van till about March. I am just planning for my mobile retirement. Just wondered if the rear socket was good for anything except blowing up air mattresses. I have been reading alot on this forum. I am aware of thicker gauge wire is the best. And read alot about solar charing systems. I was just looking for a cheap way of just keeping a single battery topped off with just very minimal amp usage to start.

If i mounted the single battery near drivers seat and ran some 4 gauge wire from a solenoid near starting battery would be best. How much would i have to drive to charge with just minimal amp usasage?
I figure being a conversion van it would have a larger amp alternator.

There are just a ton of factors in here that make it hard to say exactly how long you have to run your engine each day to keep all your electrics going.  How much juice the alternator produces, what type of batt and what its internal resistance is, what your wiring is, are you supplementing with a solar panel (recommended), and of course how big an electric hog are you?  lol.  AKA, how many electric devices do you run each day and for how long?  I'm a medium size hog, I run my laptop most of the time I am awake.  When fishing, I run the ice maker.  If you buy ice and just use your cell phone, you'll have lower consumption.

In the truck, never a problem since I was running the engine 10 hours a day minimum and getting paid to do that.  In the RV (A 1983 Tioga), with my usage and JUST using the vehicle, I probably need 3-4 hours of engine time for that, but I have a solar panel and as mentioned will scarf up electricity with portable batts if I need to.  Then there is always the option of firing up the Yamaha if necessary while out fishing or otherwise not near sources of grid power.

Starting off, see how much power you are consuming.  If you find a shortfall, start adding charging methods.  You don't need to invest all at once here.  If parked a lot though, probably at least one PV panel to deploy would be good.

 

[highdesertranger]

Reverse Engineer got a link to that ice maker that makes enough ice for your cooler but only uses 5AH. highdesertranger

 

[Reverse Engineer]

Reverse Engineer got a link to that ice maker that makes enough ice for your cooler but only uses 5AH.  highdesertranger

Portable Ice Maker AB-ICE26S

I usually only have to run it through 3 cycles of ice making a day for enough ice, but I am in a relatively cool environment even in summer.  If you are in a hot environment, you will have to run more cycles for enough ice in your cooler for the day.

 

[SternWake]

That ice maker draws 230 watts.


That's 18 amps at 12.6vdc, lets call it 20.5amps with inverter inefficiency.

Disregarding peukert as your capacity is unknown, this ice maker can make enough ice in ~20 minutes to last you 24 hours?

 

[Reverse Engineer]

That ice maker draws 230 watts.


That's 18 amps at 12.6vdc, lets call it 20.5amps with inverter inefficiency.

Disregarding peukert as your capacity is unknown, this ice maker can make enough ice in ~20 minutes to last you 24 hours?

About 18 minutes (3 x 6 minute cycles) if the avg temp is around 70F or below and your cooler is well insulated.  If you have higher avg ambient temps than that, you will need to run more cycles.

 

[ccbreder]

You are running that ice-maker plugged into line voltage. Not really viable for van travel with an inverter from batteries.

 

[Reverse Engineer]

You are running that ice-maker plugged into line voltage. Not really viable for van travel with an inverter from batteries.

No, I run it off a 12V Deep Cycle Batt connected to a 1000W MSW Inverter.

 

[highdesertranger]

so 27 cubes(3 CYCLES) is enough for you? here 27 of those cubes with the holes in them wouldn't even chill a six pack. someone else posted up about using an ice maker. I would like to have ice but I did some research on them and didn't find one that was efficient enough to use. highdesertranger

 

[Reverse Engineer]

so 27 cubes(3 CYCLES) is enough for you?  here 27 of those cubes with the holes in them wouldn't even chill a six pack.  someone else posted up about using an ice maker.  I would like to have ice but I did some research on them and didn't find one that was efficient enough to use.  highdesertranger

Yah, this is enough for a day of fishing generally speaking.  There is usually still some ice left on Day 2, so next round I end up with more ice in the cooler.  By the end of the week, I don't need to make ice every day, only every other day or so. However, this is Alaska of course, so you rarely have temps above 70F even in the summer.  The cooler is well insulated and I throw a metallized emergency blanket over it.   Keeps both the fish and the beer cold.

Anytime from October to March refrigeration is of no concern at all in Alaska.  lol.

 

[Canine]

From what I've read, using the alternator as your primary recharging source is pretty inefficient unless you are a trucker on the road a lot. Better to get some solar up on the roof, even a basic Renogy 100A kit isn't very costly and should do you better than the alternator.

At least while you are stopped/parked the solar, given no shade and other optimal conditions, can give you 4-5 hours of charge a day, then follow your idea of the house/marine battery placed close to the front of the van for the short drives. Look up SternWakes posts from other threads and follow his advice.