Can 12.06 volts charge a battery completely? (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

aamiggia

aamiggia

Joined
Nov 30, 2004
Threads
59
Messages
422
Location
Moncton, NB
I did the search on 24 to 12 vdc charging and I just finished the wiring, connections, terminations.

What I need to know is how a 12.06 VDC output of my 24/12 converter will charge my 3rd (12 volt system) battery?

The max charge on a batter is around 12.8 volts. my 110 AC to 12 VDc battery charger outputs 13.3 volts when it is charging. Is it possible for the battery to get a complete charge with a voltage of 12.06 out of the converter?

The converter is only on when the engine is running via a relay, so no worry about the 2 batteries equalizing into the 3rd stand alone.
 
No.
A 12 volt battery is made up (typically) of six cells each of which produce approx 2.1 volts when fully charged. So a 12 volt battery will typically be 12.6 volts at max charge.
A 12.06 volt supply cannot fully charge a 12 volt battery. To charge a battery the soure voltage has to be higher than the battery voltage.
Besides, why are you using a 24/12 volt voltage converter to charge your battery? Is the voltage converter always going to be active? ie. is it going to always be charging the battery whenever you have your Land Cruiser on and powering your 12 volt accesories at the same time?
Why not just supply your 12 volt accesories with the converter alone?
 
Yes, good clarification. The chart I posted above is for the sitting voltage of the battery. As you can see, 12.06V would not be near enough. You do want to make sure the charge voltage is what's needed for the type of battery you are running. One industry to look to if you are considering a 3rd battery system is the RV market. They deal with starting and house batteries all the time. Watercraft as well. Here is one link with some good info: RV Batteries, RV Battery Supply Denver, Colorado

hth's

gb
 
Some converters allow you to set the output voltage, usually with a potentiometer inside the unit. Check the manual that came with it and see what it says. Or if you know what a potentiometer looks like and have a bit of electrical knowledge, open up the converter and see if you can see any way of adjusting it. It seems strange to me that the converter can only output 12.06 volts... you should be able to pop it up to something that will actually charge a battery...
HTH
 
Freewheel said:
Some converters allow you to set the output voltage, usually with a potentiometer inside the unit. Check the manual that came with it and see what it says. Or if you know what a potentiometer looks like and have a bit of electrical knowledge, open up the converter and see if you can see any way of adjusting it. It seems strange to me that the converter can only output 12.06 volts... you should be able to pop it up to something that will actually charge a battery...
HTH
Click to expand...

12.06 volt output makes sense since inverters are used to run equipment, not charge batteries... for 12v equipment 12.06v current would be just about right...
 
Yes, at least 13.8 Volts is needed for an acid-lead battery, max 14.4 V

If your converter cannot be adjusted like Freewheel mentioned you can try to use the 'diode trick'.
Buy three or four diodes that each can handle the max current your converter can deliver.
Now put three diodes in series in the lead that runs from the converter to the negative pole of the battery you want to charge(the ring on the diodes should point towards the converter).
Just for clarification: "in series" means...connect the first diode to the second one and the second one to the third one.
Measure the voltage of the output. It should be around 13.8 V, because each diode should raise the voltage about 0.6 Volt when used this way. If the voltage is still too low, you can add one more diode. Be sure not to get a higher voltage than 14.4V.
 
Last edited:
blis said:
12.06 volt output makes sense since inverters are used to run equipment, not charge batteries... for 12v equipment 12.06v current would be just about right...
Click to expand...

Yes, many inverters will only output very close to 12V. However, we are not talking about converters not inverters. BTW, very few converters are designed to charge batteries. I know that the manual on mine says not to use it to charge batteries. After talking to the guys at Polar, I learned it is more of a question of liability as the converter does not have a charge controller/regulator. There are a few companies which make step-down battery charging converters. But most of us - me included - are too cheap to spend the extra money for one of these. IMO, the best solution (not the easiest) is to add a 12V alternator and a 12V deep cycle battery.
 
canucksafari said:
Yes, many inverters will only output very close to 12V. However, we are not talking about converters not inverters. BTW, very few converters are designed to charge batteries. I know that the manual on mine says not to use it to charge batteries. After talking to the guys at Polar, I learned it is more of a question of liability as the converter does not have a charge controller/regulator. There are a few companies which make step-down battery charging converters. But most of us - me included - are too cheap to spend the extra money for one of these. IMO, the best solution (not the easiest) is to add a 12V alternator and a 12V deep cycle battery.
Click to expand...

IMO you have 2 real choices:
1 go 24 volt with what you can, use 24-12 converter for the whatever you can't get in 24 volt.
2 install a 12 volt system if you really think you have to.

running a crapperload of 12 volt stuff off converters gets power hungry really fast.

To answer you question, No you cannot sufficiently charge a 12 volt battery off 12.06. Get a different converter if you have to do this or the 12 volt battery will be no good from undercharging in a very short time.

Why do you need this?
 
Thanks everyone. That's what I figured.

I forgot to mention that I have a 20 amp solar controller from the converter to the battery. I really wanted the 3rd battery as a backup to run accessories when the vehicle is off and not draw on the starting batteries.

I never stopped to think that the output of the converter was exactly 12 volts. I might try the diode trick or get an RV/Marine 24 to 12 volt battery charger.
 
aamiggia said:
Thanks everyone. That's what I figured.

I forgot to mention that I have a 20 amp solar controller from the converter to the battery. I really wanted the 3rd battery as a backup to run accessories when the vehicle is off and not draw on the starting batteries.

I never stopped to think that the output of the converter was exactly 12 volts. I might try the diode trick or get an RV/Marine 24 to 12 volt battery charger.
Click to expand...

The solar controller should be designed to take the input from the converter and manage it. Ie: Appropriate float and charge modes, self managed. As has been mentioned, check the insides of the converter (and manufacturer literature) to see if you can up the output. What are the brand and models of both the converter and solar controller?

Here is a great thread with good discussion and a few links to products: https://forum.ih8mud.com/diesel-tech-24-volts-systems/363689-charging-third-12v-battery-24v.html

gb
 
Last edited:
I'm sure the solar charger will manage the battery charging, but the input voltage is too low. The 24 to 12 VDC converter I bought is designed for running accessories, not charging batteries, which it does a great job at.

The 3rd battery was an afterthought. Since I can't increase the voltage of my converter I need to get a 24 to 12 charger with an output of 13.8 volts and run everything off the 3rd battery.

The good news is my wiring will not change much just swaping out the 24 to 12.
 
I know you've spend some money already, but there is an interesting thread in the Expedition section of Mud on charging a deep cycle house battery. While that conversation is specifically for 12V starting systems, there is a link to an interesting product which you hook up to your 24V system to charge a 12V house battery. Products :: Battery Chargers :: Digital Mobile Charge40 - 24V to 12V Battery to Battery Maybe not useful for your situation, but for someone searching for info in the future, it may help. An expensive, but all in one unit.

From this thread: https://forum.ih8mud.com/expedition-builds/453854-properly-charging-deep-cycle-battery.html

gb
 
Greg,

The ProMariner 5503 was what I would ideally like. It is a smart charger and I don't need the solar and the battery charger, but it's a little too costly. I've seen them online for as cheap as $429.

Funny thing is that there is a 12 to 24 version (5505) on Eba, new, for $100. If there was anyway I could convert it to 24 to 12 I'd buy it in a heartbeat.
 
Problem solved. Thanks to a DC to DC converter from powerstream that outputs 13.8 VDC and 12 VDC. I just added it to the mix. It actually simplified the wiring.

Now my soalr converter is actually doing something because the input voltage to it is 13.9 VDC. I'll try to put together a drawing of my system.
 
You must log in or register to reply here.

Similar threads

Ghostrider I
Dual post battery
Replies
13
Views
1K
Ghostrider I
Ghostrider I
LevinBR
Battery Equalizer Install
Replies
7
Views
2K
LevinBR
LevinBR
BrickRunner
Eaton Elockers on 24 Volts
Replies
4
Views
847
BrickRunner
BrickRunner
SkyfireCruzin
  • Question
Help identifying a leak.
Replies
4
Views
495
SkyfireCruzin
SkyfireCruzin

Users who are viewing this thread

Total: 2 (members: 0, guests: 2)

Share this page

Back
Top Bottom