portable welder charging

[coachgeo]

Any engineer/chemist types in here?

My welder uses vehicle batteries. See http://www.weldingweb.com/showthread.php?t=6329

Ends up I got some bad ones I have to replace for around 200+ buks orrrr this:

http://www.batterylifesaver.com/car-auto-battery-life-saver.html

They will give me 30day money back gaurnetee if not satisfied.

What do you think?

He reccomends the B model.

Here is info on it from the website

About 80% of lead (sulfuric) acid car or auto batteries fail prematurely because of a buildup on the plates. This buildup causes the car battery to become unusable at approximately one-third of its natural life. BATTERY LIFE SAVER dissolves this buildup, restoring the battery to full capacity.

How does it work?
Battery Life Saver solves your car battery problem by dissolving the buildup!
Using breakthrough square wave technology, BATTERY LIFE SAVER sends a frequency signal to each crystal of the lead sulfate buildup, causing it to convert back into lead and sulfuric acid, dissolving the crystal.

This restores the battery to its original condition and allows the electrical charge to be drawn from the battery.

in another area on the website it does say it may take a few weeks to fully fix a battery.

[Rick V]

George,

I expect you batteries are not sulphated - that usually comes from lack of use over a long time. You have been a heavy-user over a short time.

It it more likely that you may have some collapsed plates because of the heavy loads you imposed on the batteries in a near-discharged condition. I don't think "Battery Life Saver: is going to save you. It's a lot of moey $200 when there are other sure alternatives open to you - see my post of a few minutes ago in "Trouble shooting 12 volt welder".

Rick

[awright]

Wow! You are getting some very competent, knowledgeable, thorough advice from Rick V. I'm hesitant to try to add to that information (but can't resist).

I agree with Rick V that your batteries probably failed from abuse, not lack of special "battery saving" technologies or from manufacturing defects.

Automotive batteries are made to start cars at very high current for a very short time - perhaps a second or two for a car in good condition. You probably learned at your father's knee NOT to crank your hard starting car for extended periods without letting the battery "rest," that is, dissipate the bubbles and localized heating due to the high current drain.

Your welding activity puts a very high current drain on your batteries for extended periods (at least, extended relative to car starting). That would be in the category of "criminal battery abuse." I'm not being critical here - I have a Ready-Welder myself, although like so many of my toys, I haven't actually cranked it up yet.

Lead-acid batteries are permanently damaged if they are drained down to too low a voltage, even if not abused by excessive current drain. While you can sometimes bring them up to normal voltage after excessive drain (and sometimes can't), as when your car recovers from a dead battery, the battery will have been permanently degraded. The fact that your welder has stopped performing is not a good method of detecting that you have drawn the battery down into the damaging zone.

You can buy "low battery monitors" at marine supply stores and alternative energy (solar) supply outlets. These will sound an alarm when you draw the battery voltage below a preset voltage at which damage begins to occur. These would normally be designed for a single 12 volt battery, so you might have to buy one for each battery. If you were into electronics, you could build such an item easily and cheaply. By the way, you want to monitor battery voltage under load, not at idle, since they will recover voltage at rest.

I think it is a BIG mistake to buy used batteries for such a demanding application. You don't know the history of used batteries and, in the absence of detailed capacity testing, your chances of getting a well-matched set of batteries is nil. Well-matched batteries are vital if you are charging them in series or draining them unmonitored in series because the weak battery will be repeatedly over-drained AND over-charged until failure, even if it could have provided reasonable service under ideal conditions. In any case, the entire string is limited to the capacity of the weak battery.

Parallel charging can be safe as long as all batteries are in good condition and accept charge up to the normal maximum safe voltage since the charging current will tend to go to the battery with the lowest voltage. Thus, as the various paralleled batteries accept charge and their terminal voltages increase, they distribute the current as required to keep all batteries at the same voltage. As long as the actual charging current going to the weakest battery is not excessive for that battery, things are fine. The problem occurs when a battery becomes degraded and draws most of the charging current or limits the voltage that the rest of the bank can charge to.

I think multiple chargers are a good idea, but rather than putting multiple chargers in parallel to charge multiple batteries in parallel, charge each battery individually with a separate charger. That way, if you have high quality, well-regulated chargers and monitor conditions (charging current, charging time, voltage), you not only get optimum charge in each battery, but you can continually monitor the condition of each battery. If you are sure that the charger outputs are floating with respect to the charger case (to avoid surprises if they make contact) and with respect to earth ground, you can charge the batteries individually without disconnecting them from the string.

Have fun.

awright

[coachgeo]

Im thinking this- Parallel charge the whole bank AND trickle charge indivdually all at once. Suposedly my little trickle chargers (one for each battery) will not see or be affected by any other input but the battery it is hooked to. thus Im thinking about hooking up trickle charger to each battery while also parallel charging the whole bank with an auto shut off larger charger (10a). The idea is when one battery is worse than the others, the whole bank charger will cut off at the level of that battery, then the trickle charger(s) will cary on to fill the better batteries to their full charge. The trickle chargers will keep going till their own auto shut off feature stops it.

. Does this sound wise?
. Am I correct that my little trickle chargers (one for each battery) will not see or be affected by the parallel charger?

[coachgeo]

After reviewing short term and long term cost, personal goals etc. I gave up on the idea of using my future truck's batteries to power the welder. I've decided to add shore power to the welder instead of batteries.

More HERE (http://www.weldingweb.com/showthread.php?t=6403)

[awright]

A wise choice, coachgeo.

There's a lot to chew on in your comments in the other thread, but just to finish here, NO. If I understand what you were proposing with the parallel heavy charging and individual float charging, "...all at once), it would not do what you expect unless you disconnect the batteries to float charge them individually after the heavy charge. I think that is the kind of scheme that sounds feasible, but after about the third time rewiring the whole thing you would get tired of the hassle and abandon it or go to an entirely different scheme.

awright

[coachgeo]

BTW- al the batteries I'm dealing with here are MARINE deep cycle's and NOT auto batteries.

two new ones are Gell Cell and old one is typical Wet Cell

[awright]

There you go, mixing battery technologies and conditions in a series string. That makes it all the more important to monitor terminal voltages on each individual battery so strong batteries don't allow overdischarging of the weaker battery without your noticing it. Same for the desirability of individual charging.

awright