Charging Deep Cycle

Dam2009

Seaman
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May 3, 2013
Messages
66
I recently heard about people recharging their deep cycle batteries with portable power packs. I have two sitting around, however, never attempted it before.

Just wondering if any of you heard or used power packs to recharge deep cycle batteries.
 

UncleWillie

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Oct 18, 2011
Messages
3,995
Re: Charging Deep Cycle

"Portable Power Pack" as in, a Battery in a box usually used start a motor when the primary battery fails the task?
If So, Think about it. You want to charge one Battery by using another Battery. :confused:
That is equivalent to to using one credit card to pay off another credit card and expecting to be out of debt soon. :facepalm:
 

Dam2009

Seaman
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Messages
66
Re: Charging Deep Cycle

Thanks for your two cents. Your belittling, however, is rather unnecessary.
 

UncleWillie

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Re: Charging Deep Cycle

I am sorry if you think I was belittling you.
It was not my intention. :upset:

I was only trying to illustrate the point that the circular logic of using a battery to charge another battery was unsound on the fundamental level.
Even on a one time basis, it would make more sense to just use the Power Packs directly, than to transfer the energy from one battery to another, and suffer the high losses involved in the transfer.
As I consider it further, unless the Voltage on the donor batteries were near or above 14 volts, which they never will be;
Little to nothing would be transfered at all.

I most certainly did not mean to imply that you would ever use credit to pay off credit.
It was only meant as a practical example that most everyone reading this thread would immediately understand.

Again, I apologize most sincerely for any misunderstanding. :embarassed:
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Charging Deep Cycle

Charging a partially discharged battery by paralleling it with another battery will result in a transfer of energy but only to the point where both batteries equalize. The battery will never reach a full charge however.
 

UncleWillie

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Re: Charging Deep Cycle

Charging a partially discharged battery by paralleling it with another battery will result in a transfer of energy but only to the point where both batteries equalize. The battery will never reach a full charge however.
I am reconsidering that age old logic.
Consider the Donor Battery as a simple 12.6 volt Voltage Source.

Raising a discharged battery up to the 12.6 volt level takes very little energy and would happed relatively quickly.
Unless you could get the discharged Battery's terminal voltage above its Float Voltage (~13.4v),
No charging will occur, as there is not enough potential difference to to bias the battery's chemistry to reverse itself.

The donor Battery would tend to warm the Discharged Battery slightly, but do no useful work of charging.
Consider how long you would have to charge a Battery at 12.6 volts to full charge it. Forever!
It will not just never reach a FULL Charge. It will not receive ANY Charge.

To charge the Deep Cycle battery from two Power packs would require connecting the Power Packs in Series to produce 24 volts.
You would then need a circuit that would limit the amount of current and Terminal voltage of the Deep Cycle Battery to nominal levels. Essentially a DC to DC Charger.
This only makes sense in very limited circumstances like charging a 5v cell phone battery from a 12v Car battery for convenience sake.
In the Primary example here, it would make more sense to just use the power packs as the batteries they are.
 

Silvertip

Supreme Mariner
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28,758
Re: Charging Deep Cycle

We are playing with semantics over the word "charging". "Boosted" might be a better term. Maybe that's why jumper cables are called "booster" cables and not "charging" cables. When jumpers are used between vehicles, the running engine is indeed "charging" the discharged battery. If another battery is simply used to "jump" another, the term "boosted" is more applicable. Left for a period of time both batteries will equalize at some level, neither of which will be fully charged. If that were not the case, dual battery switches, isolators, and ACR's, Add-A-Battery systems would not be necessary. That's certainly not the only reason they are used but it is one reason.
 

IraRat

Petty Officer 1st Class
Joined
Feb 9, 2013
Messages
248
Re: Charging Deep Cycle

Thanks for your two cents. Your belittling, however, is rather unnecessary.

You consider that post belittling? He responded in an as concise and informative way possible.
 

UncleWillie

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Re: Charging Deep Cycle

We are playing with semantics over the word "charging". "Boosted" might be a better term. Maybe that's why jumper cables are called "booster" cables and not "charging" cables. When jumpers are used between vehicles, the running engine is indeed "charging" the discharged battery. If another battery is simply used to "jump" another, the term "boosted" is more applicable. Left for a period of time both batteries will equalize at some level, neither of which will be fully charged. If that were not the case, dual battery switches, isolators, and ACR's, Add-A-Battery systems would not be necessary. That's certainly not the only reason they are used but it is one reason.

I agree that when paralleling two otherwise independent batteries, the additional battery adds A "Boost" to the Starter in the sense that it assists the Primary Battery in starting the engine.

As the system voltage in this situation will never exceed 12.6 volts, I propose that it does Nothing to "Boost" the actual charge level in the Primary Battery, Just to assist in cranking the Starter.
No Lead Dioxide will be generated in the Discharged Battery and so no "Charging" can be claimed.

If the two batteries were to remain paralleled for a long enough time the "Booster" Battery would give up its capacity to the Discharged battery (in the form of heat) until the the internal voltages became equal.
But the Discharged Battery would not gain ANY capacity in the process.

If the Engine in the "Booster" vehicle is running at the time, the system voltage will be above 14 volts and as such also above the "Float Voltage" necessary to bias the battery chemistry to convert the Lead Sulfate back into Lead Dioxide and and actual "Charging" of the battery could be claimed.

Battery Switches, Isolators, ACR's, and other Add-a-Battery devices all combine the Batteries when a charging device is also present.
They will/should separate the batteries when the system voltage fall below the Battery's Float Voltage.
 

Outsider

Lieutenant Junior Grade
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Apr 24, 2007
Messages
1,022
Re: Charging Deep Cycle

Your belittling, however, is rather unnecessary.

Sooo, you've not thought about it, which is what was suggested. But if you do, look at the amp hours available from your power pack v. the amp hour capacity of your deep cycle battery. If that's belittling, remember who asked the question ... :cold:
 

UncleWillie

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Oct 18, 2011
Messages
3,995
Re: Charging Deep Cycle

Gentlemen, let us ALL just stop and think about it for a moment! :joyous:

I have apologized to the [OP] quite sincerely and publicly for any misunderstanding between us.
The [OP] has a right to be upset if he wishes. You have a right to your opposing opinions. :)

All this belittlin' Talk serves absolutely no purpose to the subject at hand.
I am going to ask everyone very nicely that we end it here! Just Let it Die! :cool:

Let's stick to the subject of charging batteries and all behave like Big Girls! :eek: :facepalm: OK? :eagerness:


I included lots of smilies, so nobody thinks that I am upset!
 
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