Charging deep cycle battery?

[Fritz]

I'm not up with batteries and charging. (almost clueless)   Can you recharge a deep cycle battery by running a 10 amp charger from your cigarette lighter and than to the battery while driving?

 

[highdesertranger]

yes and no. what 10 amp charger? what battery? highdesertranger

 

[Fritz]

yes and no.  what 10 amp charger?  what battery?  highdesertranger

It's a Shumacher 10 amp charger with 2 amp trickle for 12 volt batteries, and an Interstate deep cycle battery I use for a trolling motor and to run my CPAP machine at night to sleep. Oh I forgot to mention I'm running a AC/DC converter from the lighter to the charger and then the battery. Thats a big leave out.

 

[B and C]

It would help if you can provide all the parts you plan on using, including battery (size in Ah not CCA (car battery)) and how far you intend to discharge it. Car power port to what inverter to what battery charger charging what battery. Since this is all new to you, you probably have no idea of how heavy a load you're going to put on it. You need to list out each device with how much power it consumes (@12V Ah's) and for how long you plan on having it consume that power. This is called a power audit. When all added up, you can (rule of thumb) only use 50% of the batteries Ah capacity without adversely (greatly shortening) affecting battery life which relates to replacing the battery sooner than it needed to be. Don't spend big bucks on your first battery as that is what is called here as the learning battery.

Depending on how deeply you discharge a big battery it could take a day or two of driving to get it back to full at that low rate. I can already say a continuous duty solenoid tied to you alternator and the other side tied to you deep cycle with a large AWG cable (4 AWG) would be much better. Fuse both ends of the cable, no fires allowed. Bad practice to try to idle your engine to charge it also as the alternator needs air flow to keep from burning itself out.

Good luck.

 

[B and C]

@HDR. I'm slow. What can I say but my reply was longer.

 

[Fritz]

@HDR.  I'm slow.  What can I say but my reply was longer.

Sorry for delay, my AC/DC converter says on back, Input 12V DC, output 115VAC 60 Hz.
My charger is [font=Tahoma,Verdana,Arial,Sans-Serif]0.6 A continuous and 0.3A[/font][font=Tahoma,Verdana,Arial,Sans-Serif] intermediate input and vica-[/font][font=Tahoma,Verdana,Arial,Sans-Serif]versa output.  [/font]
[font=Tahoma,Verdana,Arial,Sans-Serif]My battery says 750 MCA, that's all I can find. Its a Marine/RV deep cycle. I'm new to this lingo so don't know really what you need.[/font]
My breathing machine say 0.5 - 0.3 A
I've use the battery and machine for years, but was wondering if I could charge it will driving this way.

 

[highdesertranger]

I would forget running it through that charger, it would work but is very inefficient. it would be much better to charge it straight off the alternator. that way there are no conversion, with every conversion you loose 10% minimum.

however if you run it straight of the alternator you must run it though some type of isolator that only makes the connection when the engine is running. to easiest and cheapest way to do this is run it through a solenoid. Blue Sea makes an excellent ACR(automatic charge relay). I would stay away from the solid state isolators.

remember like B and C said it could take several hours of driving at highway speed to recharge a depleted battery. idling doesn't cut it. this is why solar is so popular.

highdesertranger

 

[Fritz]

I would forget running it through that charger,  it would work but is very inefficient.  it would be much better to charge it straight off the alternator.  that way there are no conversion,  with every conversion you loose 10% minimum.

however if you run it straight of the alternator you must run it though some type of isolator that only makes the connection when the engine is running.  to easiest and cheapest way to do this is run it through a solenoid.  Blue Sea makes an excellent ACR(automatic charge relay).  I would stay away from the solid state isolators.

remember like B and C said it could take several hours of driving at highway speed to recharge a depleted battery.  idling doesn't cut it.  this is why solar is so popular.

highdesertranger

Thanks a lot.

 

[tx2sturgis]

Can you recharge a deep cycle battery by running a 10 amp charger from your cigarette lighter and than to the battery while driving?

{snip}

Oh I forgot to mention I'm running a AC/DC converter from the lighter to the charger and then the battery.

Sometimes ease of use and convienience are more important than 'efficiency'. If you already have those items give it a try.

Alternators themselves are around 50% efficient, gasoline engines can be as low as 25% efficient. So very small efficiency losses in your equipment while driving don't really matter much. It won't cost you any noticeable amount of extra fuel.

Efficiency is important when charging or powering something with solar, but is not really important IF you are already driving and just want a way to keep that battery maintained OR recharge it from a slight depth of discharge.

But, speed of recharge does matter!

If the battery you intend to recharge is deeply discharged, it will take many hours of driving to recharge it with a 12v to 120v inverter to 12v battery charger configuration.

Speed of recharge matters, and of course a direct connection to the alternator would be best, but brings with it complications and cost.

Try your original idea...maybe it will work for you. If not, you can make changes as needed.

 

[Fritz]

Sometimes ease of use and convienience are more important than 'efficiency'. If you already have those items give it a try.

Alternators themselves are around 50% efficient, gasoline engines can be as low as 25% efficient. So very small efficiency losses in your equipment while driving don't really matter much. It won't cost you any noticeable amount of extra fuel.

Efficiency is important when charging or powering something with solar, but is not really important IF you are already driving and just want a way to keep that battery maintained OR recharge it from a slight depth of discharge.

But, speed of recharge does matter!

If the battery you intend to recharge is deeply discharged, it will take many hours of driving to recharge it with a 12v to 120v inverter to 12v battery charger configuration.

Speed of recharge matters, and of course a direct connection to the alternator would be best, but brings with it complications and cost.

Try your original idea...maybe it will work for you. If not, you can make changes as needed.

Thanks Tx2, I like your thoughts.

 

[WalkaboutTed]

Sorry, wrong thread. In hospital and not thinking too straight.
Ted

 

[Gr8ful]

tx2sturgis I agree but the ambo has a digital panel showing voltage, amps the alt is putting out (it takes 16-17 to run) temp, etc but if the batteries get much under full it locks into a mode at idle saying batteries charging. It also has a feature if you set the parking brake it doubles the idle speed of the engine to charge faster, I think all do & works well.

 

[terranaught]

I just installed a 12-14v converter 22$, I wired it into a switched fuse so it is on when the engine is and will charge the cabin bats at 10 amps . it says overload protected, I have less than an hour on it, we will see.
https://www.ebay.com/itm/WaterProof...780289?hash=item239e1129c1:g:tfcAAOSw-CpX98hF

 

[highdesertranger]

help me out here. a good working alternator outputs 14.2 volts. so when the engine is running the voltage should be up around 14 not 12 and the output should be greater then 10 amps. I can't see how this will work better than just hooking the house battery up to the alternator with a solenoid. highdesertranger

 

[Gr8ful]

I have a 120v 10 amp Deep cycle charger then this one that does it all & does it all right!
Stanley GBCPRO Brand New
Fully automatic multi-voltage smart golf cart and vehicle battery charger-6-48V automatic voltage detection-3 stage high efficiency automatic rapid/maintenance charging-Battery voltage tester-Microprocessor controlled-Lightweight portable design-Round & rectangular golf cart connectors included. (Fits most popular golf carts)-O-ring connectors allow for universal and permanent installation.-Battery clamps for 6-24V applications-Float mode monitoring

 

[terranaught]

help me out here.  a good working alternator outputs 14.2 volts.  so when the engine is running the voltage should be up around 14 not 12 and the output should be greater then 10 amps.  I can't see how this will work better than just hooking the house battery up to the alternator with a solenoid.  highdesertranger

it lets me use small wire (12ga) to go the 15-20 feet to the cabin battery, then 3' leads to the battery, and I still get 10 amps.
I have tried direct with a switch but couldn't get more than 2 amps even with 8 ga wire at that distance.
I've also tried the diode spliter with poor results.

 

[highdesertranger]

something is not right here. I hear you on the diode splitter though. highdesertranger

 

[Weight]

You are not doing something right. If you only parallel the starter and house battery the alternator will provide more than 10 amps and more than 14 volts. 8 awg is not heavy enough wire for a charging circuit except maybe from solar panel to controller.

 

[terranaught]

I burned up a 300w inverter charging with a normal 10a automatic charger, I think it was from back emf at the top of the wave, making differentiated spikes.
the converter was cheaper and easier to install than large gage wire.

 

[highdesertranger]

you know for years I tried everything rather then spend the money on a 12v refrigerator. in the end, if I would have just bought the 12v refrigerator I would have saved a boat load of money. enough to buy the 12v refrigerator and have money left over.

the moral of the story is you are wasting money by trying to save money. just like I was. just install a proper dual battery solenoid and wire and be done with it.

highdesertranger