|Topic Review (Newest First)|
|04-02-2008 03:00 PM|
|camaraderie||Bill...thanks much for the detail...great info!|
|04-02-2008 12:54 PM|
I forgot to add a simple "bottom-line" for most boaters:
While there is little if any scientific evidence to prove that the widely marketed "de-sulfating" devices actually work, there is reason to believe that high-amperage charging devices which use pulse-width modulation (PWM) technology actually do have some benefit in extending the life of lead-acid batteries of all types.
In other words, it probably makes sense to forget about the little de-sulfator devices but rather to invest in a good full-size smart battery charger which uses PWM technology. The good news is that some of these are not very expensive, i.e., even less than the better known "marine" battery chargers.
|04-02-2008 12:36 PM|
Originally Posted by btrayfors View Post
|04-02-2008 12:08 PM|
Yes, you're right. We did a study of some of the pulsing devices available for "reviving" batteries and for "preventing" sulfation.
Not sure we're gonna publish, although there's a writeup and a magazine has accepted the idea for publication. Basically, we've not too much to say other than we were unable to discern any useful benefit among the devices we tested and the batteries we used, despite trying for over a year.
This is a very murky area. While there are hordes of affectionados and even cult-like followers, some building and testing their own pulsing "desulfating" devices, and you can find lots of testimonials about their incredible performance, we were unable to find such benefit. And, we know of at least one other scientifically-based trial which also could not discern any serious benefits.
We first became suspicious when we began testing the output of the devices themselves, using a spectrum analyzer and other lab devices. We found that they were all different, i.e., the pulse characteristics differed markedly one from the other in terms of frequency, amplitude, power, pattern, timing, etc. Since the supposed mechanism of action was to inject a pulse which would be resonant with the PBSO4 crystals, thereby causing them to break up, we wondered how the very different pulses could have this effect. We were unable to demonstrate that they did.
I suppose our bottom line to the question, "do these really work, or are they just snake oil", is a decided "maybe". We're not saying that pulsing doesn't work or can't work in some situations. But what we are saying is that it hasn't been proven anywhere to our knowledge and we are recommending that a purposeful longitudinal study be done to find out under which circumstances the technology might work. This would have to be financed by some government entity to remove any manufacturer bias; it should be done by a recognized technical lab (Sandia???); and should be given enough time and funds to settle the issue.
Now, that said, the type of pulsing I was talking about above is different. Car manufacturers investigating battery technologies for hybrid cars have found that the most effective way of recharging is via pulse chargers. These are high-amperage, relatively high voltage devices.
The Iota chargers use PWM technology. They use a pretty high voltage spike during the charging cycle, but pulsed in such way that the batteries cannot be damaged through overheating. Note that there is no battery type setting on the Iotas...they can be used with any type battery. I have two of them, one on the boat which maintains my dedicated anchor windlass battery bank in the forward cabin (2 T-105s in series), and one at home which maintains the T-105 battery bank which powers all my radios. In both cases, the Iotas have kept these batteries healthy for several years -- as measured by a sophisticated internal resistance device -- while even top-of-the-line marine chargers like the Victron Multi-plus on my house batteries (6 T-105s) have not done as well.
Sorry for the long post, Cam.
|04-02-2008 10:49 AM|
|camaraderie||Bill...As I recall, you were investigating "pulsers" and your comment on the IOTA pulse charges reminded me of that. Have you reached any conclusion about the aftermarket pulse devices that you can share or point me to?|
|04-02-2008 10:39 AM|
|camaraderie||Assuming you are buying wet cells...just a tip...buy the freshest ones you can find which usually means buying from a place that sells a lot of batteries. Try not to buy ones that have been sitting on the shelf for more than 6 months. Usually by or on the negative post there is a 2 digit code. "87" would be August of 07. Sometimes letters are used B6 would be February of 06.|
|04-02-2008 10:37 AM|
New flooded lead-acid batteries begin to deteriorate from the moment they are shipped from the manufacturer. Just sitting on the dealer's shelves for a long time can reduce their capacity.
The self-discharge rate of these batteries can be on the order of 10-15% per month @ 70 degrees F. Some have reported even higher rates, depending on the antimony content.
When batteries are left in less than a fully-charged state, they begin to sulfate. Lead sulfate crystals (PbSO4) form on the plates, and can grow and embed themselves into the surface of the plates, thereby permanently reducing capacity. This is the principal reason for early battery deterioration and failure.
New battery capacity -- in the store -- can vary considerably, even as much as 30-35%.
Contamination, corrosion of the positive plates, stratification of the electrolyte, and other factors contribute to the deterioration of the battery's capacity.
Given these considerations, what should you do with new batteries?
|04-02-2008 10:35 AM|
|TrueBlue||Most modern chargers have over-temperature shutdown and overload protection features. But I suppose if the charger is original to the '78 c-30 . . . then it may be time for an upgrade (g).|
|04-02-2008 10:28 AM|
|Rockter||The charge monitors are often used for winter-sleeping motorcycles. They kill the battery, completely, if they overdo it, even if slightly. Beware.|
|04-02-2008 10:11 AM|
Not sure what you mean by "topped off". If your boat has an automatic charger and is connected to shore power while at dock, the new banks should reach full charge with no extra effort required by the captain.
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