Thursday, September 28, 2006

Another Li-Ion recall and a new battery technology announcement

Bad news first: Lenovo and IBM announced a recall of another half million (500,000) Lithium based batteries manufactured by Sony. It seems that after one flamed out at LAX last month, they got the CSPC involved.

Good news last: We may be using the acronym ZMP a lot more in the near future. Zinc Matrix Power has announced their Silver-Zinc rechargeable battery that supposedly has twice the energy-to-weight ratio as current Lithium based offerings without the explosive side effects or transport limitations. They have a low enough internal resistance that a relatively low number (16, producing 20 volts) were used to produce 80 amps to MIG weld two pieces of 1/8" steel (article reference).

In other not so interesting news...

  • I finally got those surplus UPS units converted and we gave most of them away (along with the power conditioners) at the annual Utah County ARES picnic earlier this month. Hopefully they're all set up with some Sealed Lead Acid batteries that have been neglected for too long. If anyone wants help converting a UPS into an SLA battery maintainer, let me know.
  • We were at a wedding reception for my niece a few weeks ago and came out to find a note on our car apologizing for the alterations done to the front bumper. The estimate was $402 so we might not even want to bother the insurance companies.
  • Last week, I took the boys to the Orem Rec Center to play racquetball. The next morning, one of us noticed another alteration that had been done to the right rear pillar above the window. We have no idea how it could have happened unless someone dropped something off a truck parked next to us or something. That one will cost more than the deductible; unfortunately, we'll have to get the insurance involved. They won't be thrilled after the bike rack incident earlier this summer...
  • We ditched the VoIP phone service we had from ACN Digital. Their equipment didn't work right (QOS was horrible, telephone adapter lockups, etc.) and their customer service was pretty much non-existent. My sister and her family were on it as well and like us, they decided to pay the cancellation fee rather than keep it. If you're going to go with VoIP, choose Vonage, they were good for us - we only switched to ACN to try to help a relative who was making a commission on the sale. We decided to go to cell phones instead (I couldn't bear to go back to a land-line provider).
  • On that note, I also switched to a new LG LX-550 Fusic phone (Sprint Review - C|Net Review)from Sprint. I like it, but there are some things from my Motorola V-360 that I'll miss. Best about it is the signal is much stronger at my house because the transmitter is just down the street (there are 3 big "flagpoles" at the Junior High about 2 blocks away) and we can get a signal downstairs. Worst is that the MP3 player is still poorly integrated with the phone operations (I can't make an outgoing call while it's playing, nor does it resume after I finish with an incoming call). All in all, I think it's a slight improvement, but nothing to get too excited about.

Tuesday, September 19, 2006

Talk Like a Pirate Day

International Talk Like a Pirate day is coming on September 19th (just like it does every year). I'm a little early this year, but I didn't want to forget again... I wrote this post last year, but forgot to post it. :)

Arrrr! Welcome to my blauggh. All ye landlubbers have got t' git yer own pirate name:

Fortunately I got a good one:

Red Harry Rackham

Passion is a big part of your life, which makes sense for a pirate. You have the good fortune of having a good name, since Rackham (pronounced RACKem, not rack-ham) is one of the coolest sounding surnames for a pirate. Arr!
Get your own pirate name from

Other pirate resources:

Sunday, September 17, 2006

Plastic batteries!

The folks at Brown University have been working on some cool stuff with conductive plastic. I don't know if their numbers are completely accurate (100 times the power of an alkaline battery?), but it's good news anyway. We really need better power storage for just about everything these days.

Engadget picked up on it and there are more comments there on their blog.

Tuesday, August 15, 2006

Dell & Sony recalling 4 million batteries

Dell (recall notice) and Sony are working together on recalling 4 million laptop batteries (CPSC notice, Breitbart article) that have been prone to burning, venting with flame, exploding, catching on fire, or whatever other terms you want to apply. My other entries here and here told some more of the story.

Hmm, I use quite a few of these Sony 18650 cells which have been removed from surplus (read: non-functioning, dead, bad, defective, etc.) Dell batteries I get from work. I've been careful with them, but I'll be even more so now!

More about Li-Ion batteries from Battery University.

Thursday, July 20, 2006

100 MPG in a converted Toyota Prius?

This article talks about supplementing the battery pack of current Hybrid Electric Vehicles by adding your own batteries. The scary part with all the recent talk about exploding Lithium based cells is that at least one company's solution is a 150-pound, 16-inch-by-33-inch box of lithium-ion batteries that fits in place of the spare tire.

That said; I want one! It wouldn't be very practical right now and certainly wouldn't save me any money, but I'd sure have a lot more stuff to play with as I drove and maintained it. Maybe I should just see if any of the DARPA Challenge vehicles are up for sale instead...

How about this electric vehicle from Tesla? They claim 250 miles per charge and 0-60 in 4 seconds for somewhere around $100,000. People are talking after Engadget posted an article this morning .

Wednesday, July 19, 2006

More info on burning Dell at Novell

According to this article on CRN, the battery in the burning Dell notebook was not manufactured by Dell. I suppose that lets Dell off the hook for this particular incident, but I wonder if that will make anyone that owns one feel better...

In the article Edward F. Moltzen writes:

I asked Novell spokesman Kevan Barney if this was, in fact, the case. Sort of, he said, but there was more to the story.

Yes, the Dell notebook caught fire and, yes, Novell's Building D was evacuated. But a security investigator who looked into it said the person who was using the notebook inserted a non-Dell battery into the unit just before it went up. "It was not a Dell battery," Barney said.

The investigation is continuing, Barney said.

Tuesday, July 11, 2006

Dell Laptop battery trouble at Novell; aka "Venting With Flame"

After reading all the recent news about exploding and burning Li-Ion laptop batteries and this story today about Dell's new effort to try to buoy it's reputation, I decided to give this story a home online. Just to inform, not to bash anyone (my first Dell was a 286-12 back in 1988). It was sent to me on July 6th, 2006 by a fellow Amateur Radio operator in the local area.

"Building D of Novell in Provo was evacuated at about 1:30 PM today because of fire alarms set off by a Dell D600 battery "venting with flame" under normal use/charging conditions. It took the laptop out with it, of course.

Yesterday, he sent some pictures and I thought I'd share. Here's a sample:

Monday, July 10, 2006

Timely news story

I know this is old news now, but it was *relatively* new until 36 hours after I posted it! :)

In other news...

- I took our new car into the shop today to get the roof fixed after I tried to drive into our garage with my bike still on top. The bike (Cannondale F500) and the Yakima rack both survived (I rode 70 miles the next day). I hope to get some pictures back from the body shop when I pick up the car.

- Our dog caught (and killed) the neighbor's cat this morning. Unfortunately, it was the one that the kids in our cul-de-sac were most attached to.

- Just as I was going to leave for work, the sprinklers came on and I saw that we had a broken head right next to the house. Glad that cat slowed me down this morning or we would have had a nicely flooded basement!

- I found out that I'm not going to get the $50 rebate I was promised for buying a new cell phone a while back. It has taken a while because I kept forgetting to call the store and ask why I hadn't received it yet. When I purchased it, I was away from home and on my way to the airport to go on a trip. The store owner who sold it to me said that he'd send me the rebate along with the contract paperwork in the mail when he got the computer problems figured out. Unfortunately, it turns out that the deal he made me was only supposed to be valid at a "corporate" store. On the positive side, I have a new phone and didn't have to do the 2 year contract extension. Good thing, 'cause I don't really like the phone (Motorola V360) that much!

Monday, June 26, 2006


I'm going be jumping on the Fon bandwagon. My equipment should arrive soon and I plan on putting up an antenna (got one like this) on the roof so I can access it while I'm out and about.

Friday, June 23, 2006

UPS waveform article

Saw this article about waveforms from UPS units today and since all 16 of the APC-650 units I have are exactly what is shown in this article, I thought I'd link over to it. I have experienced problems with running UPS units from my small portable generator before, so now I want to go check it out a little and see if I can determine why. Just need to find someone with a scope and some time...

Jesse (the author of the article I mentioned) has also written about a UPS modification he did.

I have a couple of power conditioners from someone who didn't want to bother trying to surplus them. Never had a use for them before, but perhaps now I do! These are the type that claim to create clean power from dirty. They are quite heavy. I want to see if putting them between the generator and the UPS units clears up the problems I have seen in the past. I'll update this article with a model number and a link when I can.

FWIW, I have one of these 110 <-> 220 Step Up / Step Down Transformer / Voltage Conversion units too but I have absolutly no use for it that I can fathom right now. I'm pretty sure it's a model UDC-1500. If anybody locally needs one, you know who to ask!

Friday, June 16, 2006

Moto-M3U playlist fixer utility

I thought I'd share a new utility I wrote for my phone. I got tired of editing the playlists manually so they would work and just wrote a program to do it. It's available from my home page. It works with MediaMonkey and my Mototola V360 phone. It may work with other phones and applications, I don't know.

Tuesday, June 06, 2006

More UPS units

Since the power outage I blogged about a while back the power has gone out a couple more times and I have inherited (for a small fee an IT auction last month :) several UPS units that are no longer welcome at the company. I need to get them home, remove the batteries, test them, and modify the good ones like I described earlier. Any good ones will be available to the amateur radio community here in Utah County.

These are all 650VA units like this only black. I would be willing to bet that most of them are perfectly operational and that the batteries are just worn out.

If anyone local knows of small personal UPS units like these (I'm not interested in large data center units) that are no longer welcome in their present homes, add a comment here to let me know and I'll do my best to give them a new lease on life.

Tuesday, March 28, 2006

UPSs save the day

Well, okay, not my whole day, but put together they saved my group at work an awful lot of time today. The power went out this afternoon while I had several long processes running and at least 15 edit windows open (with various stages of unsaved work). While some people here have all of their stuff (typically two 21" CRT monitors and a CPU) plugged into one 800VA UPS, I had the foresight to horde enough older units that I could plug each component into its own UPS (I have a 650VA unit for each monitor and a 1000VA hidden behind the filing cabinet for the CPU :).

The power was out for about 30 minutes. Both of my monitor UPS units died (one after 10, and the other after about 20 minutes), but my CPU stayed up (along with my work). Most people were at least able to save their work (they lasted 10 minutes or so). Sure makes me wonder why some people think that UPS units are not worth what we pay for them...

Tuesday, March 21, 2006

Link added on VIP Bloggers

OK, so I'm not a VIP, (or a CEO, CTO, HMO, or anything else) nor do I think that I really have much on this page that people who come here from the VIPBloggers web site (first square on the second line) will want to read. Most of my ramblings are about battery chargers and other technical stuff that I have played with.

When I originally got the block of pixels on the site, I didn't even plan on linking back to this blog. I had it pointing at Paul Allen's blog and I was going to wait 'till I thought I had something worthwhile to link to. Like maybe the genealogy I've been working on, or the archive of information on converting old UPS units for Amateur Radio use (yeah, you don't want to miss it). Then Paul went and got his own space and his own link (the nerve!). So, anyway, here you are. Have at it...

Thursday, March 16, 2006

Charger "upgrade" disappointment

The Schumacher Speed Chargers are pretty similar in looks, but I have discovered that they do not all operate the same way. I'm disappointed in the upgrade I did when my previous one developed a bad fan. I expected too much I suppose. In going from the 12/25 to the 10/30, I was hoping to have a faster charger when I needed it (after all, 30 amps is more than 25!). I was hoping to be able to charge at a lower rate (10 amps is less than 12) when I needed to because it would be better on my smallish batteries. I was wrong on both counts.

My new charger operates in a single 10/30 mode, not two separate modes (10 or 30). I've actually measured the rates with my Whatt Meter and they are a little higher than the rated rates. The charger will start at a 12 amp rate as it checks the battery to see how it is responding. Then ramps up to 34 amps if it thinks it's doing OK. It will stay at the 34 amp rate for 1.5 minutes or so, then taper back down to 12 amps for 2.5 minutes. It probably averages out somewhere around 25 amps because the tapers between the different rates take about 40 seconds to complete. So, overall, I probably get about the same charge out of this unit than I did out of the old one (it measured 31 amps constant into a discharaged battery).

The 6000A is probably smarter and probably will handle most larger batteries better than the 2500A, but since I have a mixture of large and small batteries that I want to use with it, I don't have as much flexibility. I can't put anything smaller than about 65AH on it and set it for 10/30 because it will hit it with too much current. I wish, for example, that I could limit it to 10 amps (or less) when I use the 18AH batteries from the UPS units I just received (more on these later). For a 32AH battery, a rate of 8 amps or so would be ideal for me. While the 2 amp rate is probably better for the battery, it simply takes too long to charge.

Oh well, it will still work well for chaining up several together and doing them all at once if I need them quickly*. And it will certainly work great for when I'm running it off of my generator if my solar arrays aren't getting the sun they need (if I ever get some solar arrays :). I think I'll go hook it to the 1984 Blazer I've had sitting in the street for the last 6 months (because it needs work). I'm sure it could use a little electron boost by now.

*Be sure to wire up all of YOUR batteries with at least TWO Anderson connectors each so you can do this kind of thing whenever you need to.

Sunday, February 05, 2006

Another article and a dead fan.

This is good (if biased and stale) information:

Ample Power Primer

"Biased" in that the company's products are mentioned throughout the articles. Based on what I've read from them, I would probably be happy owning some of their products if I had the need.

"Stale" is relative though. This technology hasn't been changing as much as in the computer world I move in daily. If nothing else, at least read The Power Equation article.

On another note...

The battery charger that I had before developed a problem in the fan. At the charge rates it used (25 Amps) not having a fan would have been very bad (it was not a large heavy transformer based charger). I returned it and switched to its cousin: Schumacher WM-6000A. The two are not that much different in charge rates, but the new one seems to be somewhat smarter in how it applies the charge to the battery. It was $72 at Wal-Mart. I'll write some more about its charge methodology later when I've had time to analyze it more. For now, it seems to do fine - and as a bonus, the fan is functional (and much quieter).

Friday, February 03, 2006

Sometimes "good" batteries do bad things

Well, after several years now of working with SLA batteries, I still haven't learned nearly all my lessons!

I hooked one up to the power supply this morning that I received from the IT group at work (I have them trained to bring me all of the old UPS batteries that they don't want anymore). This afternoon, my family called me and said that there was a really bad smell coming from my office. It turned out that it was coming from that battery. It was having a difficult time venting through its built-in valves and seemed to be getting ready to expand rapidly (burst!). I wasn't about to touch it (let alone pick it up), but I did reach over to carefully unplug it. I let it cool down for a while until I figured it wouldn't follow through with its explosive intentions and I picked it up for photographing. As I type this almost 3 hours later, it's still quite warm.

Anyway, here are some of the lessons I learned:
  1. Never believe sticky notes placed on batteries unless you write them.
  2. Never hook questionable batteries up to an unintelligent source of power.
  3. Be extremely careful charging batteries indoors near things that can be damaged by heat, acid vapors, smoke, explosion, etc.
1. When I received this battery, it was in the pile that was being handed out to replace batteries in ailing UPS units around the company. The UPS at my desk had been complaining and I had requested a new battery for it. This is the one I was given. I put it in, but it did not work. This should have been my first clue that something was wrong! The "Good" sticky label on top obviously fooled someone else before it got me. Since there are no battery testers around (or at least no people in the IT department who use them), once things get mixed up, no one really know what is what. Shh, don't say anything, but I'm pretty sure that I've received several that have never been in service before. At any rate, I figured it was just dead from sitting around so I took it home to charge it up and see how "good" it really was.

2. I didn't test it on my smart charger to see if it would take a charge, was shorted or anything. I hooked it to my Amateur Radio 12 V 15 Amp power supply along with the other dozen or so batteries I usually have floating there. The power supply doesn't have a built-in meter, but I keep one that I made connected inline with the batteries so I can see what is happening. The needle jumped as it always does when hooking up a battery that has not been on charge for a while. As the voltage quickly rose to the level where the supply floats, the ammeter went down to a normal level. Nothing seemed amiss. I left for work.

I believe that something caused the cell to start drawing more power than it could handle and it began to heat up badly. My power supply is happy to deliver as much power as it takes (up to its 15 Amp limit) to keep a connected load at 13.8 volts. The casing bulged under the pressure which the valves didn't seem to release. Perhaps it was just that it was warm enough due to the internal problems that it deformed fairly easily even though the valves were doing their job and venting the gas that was building up inside.

I really don't know yet what caused the failure. I'll look around eventually and try to find answers, but if anyone knows right off and could point me in the right direction, I'd love to hear from you!

I'm no longer sure that a simple power supply is a good way to keep SLA batteries charged. Although I haven't had any fail while they were connected (this one was bad before I connected it), it seems to me that the possibility exists for this to happen. I'll have to do some more research and see what others think.

3. Thankfully, nothing tragic occurred. No fluid made it out of the battery in liquid form, but plenty of gas escaped and made the house smell pretty bad. It was also rather difficult to breathe comfortably in my office for about 15 minutes after I started the fans going. Had I not cut off the power and stopped whatever reaction was occuring, I'm not sure there would have been much left of my house.

Friday, January 27, 2006

More batteries

I got a whole boat load (well, trunk load really) of batteries from a friend to test. He inherited them from someone who moved out of state and didn't want to take the whole load with him. There are some that are unused (still in their original boxes). I calculated that on the way home, I had 800 Amp Hours of 12 v power in the vehicle. That would have been at full rated capacity of course. These are all AGM batteries (like this one) that were either used or destined for use in wheelchairs.

Anyway, the first couple I tested were not so good; they are rather old and had been in use for quite some time (one was dated 1998). These 70 AH rated batteries topped out at 30 and 50 Ah after three cycles of charge/discharge.

Next, I tested (well, I'm still working on them) two of the "unused" batteries. They look fairly new, but I can tell that they've been hooked up to something before - even if only for a short time - because of the marks on the terminals. These two are doing much better! I charged one of them up partially (using my new Schumacher WM-2500A charger). The first time around it tested at about 50 AH. On the next cycle after charging it fully, it was up to 67 AH under a 0.1C load (this is actually its rated capacity - 75 AH * 0.9 = 67.5). On these big batteries, 0.1C is about the highest load I can use on my tester.

The second "unused" battery is undergoing its second test. I charged this one up completely for its first test and it measured 63 AH. The trace on the current test is running somewhat higher than the first one so far, but I'm only about 10 AH into it.

I'll probably cycle these two batteries one more time after this to see if they continue to improve significantly.

Interesting notes:

  1. I learned from the spec sheet I listed above that they recommend a maximum 15 AH charge rate. I had read elsewhere that you can use a rate up to 40% of the rated capacity of the battery. This was why I selected the 25 AH charger to begin with for these 70-80 AH batteries. It's not that big of a deal to use the 12 AH rate; it still takes overnight anyhow. I like having the capability of getting a battery (or multiple batteries) charged up quickly if need be...
  2. Even though a charger is rated at 25 Amps, you can't charge a dead 75 AH battery in 3 hours. It takes overnight or so (each battery is a little different) for it to absorb that last 10% of energy before it's "fully charged."
  3. My fancy new charger does a few cool things to keep the charge rate up. Initially, it hits the battery with as much current as it can while keeping the voltage under a certain level (it seems to use about 15.5 volts or so). This seems high, but it only does it for a short time to gauge the battery. Then, it just dumps as much charge into the battery as it can (it peaked at 30 Amps according to my Whatt Meter in the 25 Amp mode) until the voltage nears the maximum for whatever battery type it's charging. It tapers off until the voltage tops out at whatever its cut-off voltage is and it goes into "float mode" (where it seems to hold at about 13.8 volts - which is perfect for AGM batteries). This taper period is why the charge takes longer than just Capacity / Charge Rate. On batteries that are badly sulfated (at least I think that's why it was doing it in one of these batteries), the voltage quickly goes high and the charger went into float mode. It was putting 2.5 Amps constant into the battery for several hours before it tapered again and then started cycling up and down to a maximum of several hundred milliamps while holding at 13.8 volts.
  4. The "float mode" of this charger is really a cycle where it raises the voltage to 13.8 volts and then shuts down until the voltage drops a few tenths of a volts and it ramps back up again. It does it quickly so it's hard to get a good reading on my digital meter.
  5. Because of this pseudo float mode, getting the battery completely and fully charged would take quite a while on this charger. I would say that charging it up most of the way with the fast charger and then putting it on a power supply (like a UPS or a Ham Radio supply) that holds a constant voltage is a faster way to get a full charge.

Monday, January 23, 2006

UCARES Training Item

Training Item given on the Utah County ARES net on 23 Jan 2006
(It was originally scheduled for 17 Jan, but was delayed a week)

[2006-02-03 Note: Eric Harrison KE7BQE send me an e-mail saying that he recorded the net and has posted it here: Thanks Eric!]
I’ve played a lot recently playing with batteries and I thought I’d talk tonight about some of the many types of batteries we may encounter in the Amateur Radio world, and I’ll briefly mention a few of their characteristics.
First, the standard non-rechargeable types everyone has used are of course the Alkaline batteries that we get from the grocery store. These come in all sizes from N to D. One of the most important attributes of Alkaline batteries in Amateur Radio or Emergency Communications situation is that they are available almost anywhere. I’ll come back to this point later.
Non-rechargeable lithium batteries are widely available in 9v, 123 and AA sizes. Some of the advantages of non-rechargeable lithium batteries in commonly used sizes are that they are lighter than akalines and they last longer in devices like GPS units, flashlights, digital cameras, and so forth. Hikers, cavers, and others are often willing to pay a little extra for these high-performance batteries.
Rechargeable batteries in commonly available sizes come in two main chemistries, Nickel Cadmium (also referred to as Ni-Cad) and the newer Nickel Metal Hydride (or NiMH). A key advantage of rechargeable batteries over alkaline is that they cost less for the power that they provide over their lifetimes.
Rechargeable battery packs for Hand-Held radios come in three main types, NiCd, NiMH, and the newer Lithium based chemistries.
Other types of batteries I’d like to include as useful to Hams tonight are Lead Acid batteries. Car and Boat type Lead Acid batteries are most often the Flooded Electrolyte type (they have liquid that sloshes around inside them which can spill if they are tipped over). Sealed Lead Acid batteries – the kind that Hams like to carry around – don’t spill if tipped over and are often used in things like wheelchairs, electric scooters, those cordless 20 trillion candle-power spotlights, and so forth.
Rechargeable NiCd batteries have been in use for over 60 years. Sealed Lead Acid batteries have been around for 30-40 years. NiMH and Lithium-Ion batteries became widespread in the 1990’s. The new polymer based lithium batteries are barely 5 years old. And more types are coming I’m sure.
So now that I’ve mentioned a few different types of batteries, I’d like to talk a little about the advantages, disadvantages and care of each type.
First, back to the point I made earlier about batteries you can buy at a grocery store. If your equipment can run from these types of batteries, you will have a very good chance of being able to borrow some spares from someone else if yours happen to go dead sometime. Whether it’s a public service event or an actual emergency you will probably be able to get AA size batteries. While I have not always been completely successful, I have made an effort to make sure that all of my portable emergency communications gear can run from AA sized batteries. This way I don’t have to carry separate sets of spares for each device and my radio can share batteries with my flashlight if the need arises.
A little now about rechargeable battery packs like the ones on most handheld radios. I’m going to be fairly simplistic here as there is quite a lot of science behind these packs and yours may differ or contain a new technology or whatever; so IN GENERAL here are some tips to help your battery packs last longer and give you the most operating time per charge.
If you have a Nickel based pack (NiCd or NiMH), run it down at least every 5-10 times you charge it. If your radio automatically shuts itself off when the voltage drops too low, you are better off than some of us who have Kenwood radios that don’t do that. Some radios really will run a battery pack down completely – all the way to 0 volts if you let it go that far. This is particularly bad because a battery pack is typically made up of multiple cells. Running the pack completely dead will most likely damage one or more of the weaker cells inside. In short – run it down, but not dead every 5 to 10 times you charge it.
If you have a lithium based pack, charge it at any and every convenient time. Lithium based batteries do better if they are discharged partially and recharged multiple times than if they are completely discharged on each cycle. Lithium batteries will die within a few years whether they are used or not. Their chemistry is such that they are on a downward slope from the day they are made. Lithium packs cannot be charged with chargers that are not specially designed for charging them.

Cycling either Nickel or Lithium based battery packs in hot environments significantly shortens their lifetimes. Cycling them at 85 degrees, will reduce their life by about 20%, and their life may be reduced by as much as 40% at 100 degrees. That doesn’t mean that you will get less talk-time if you charge a battery while it’s at 100 degrees, it just means that you won’t be able to cycle them as many times. Sitting a radio on the seat of a car in the summertime and charging the battery pack while it’s at 120 degrees is hard on the pack. Some smarter battery chargers won’t even start to charge when they detect too high a temperature.

Sealed Lead Acid or SLA batteries, like Lithium based batteries, do great when they are charged as often as possible. Unlike the other types, SLA batteries do great when they are left on float chargers that are designed specifically for them. Unfortunately, car or boat float chargers, or motorcycle battery chargers are not designed for use with Sealed Lead Acid batteries. Let me repeat this in stronger terms. Hooking an SLA battery to a float charger not designed for an SLA battery could destroy the battery in a relatively short time. Most of the power supplies that we use with our Ham gear can (and often do) provide the perfect voltage for floating SLA batteries. However, caution is in order here in case you’re thinking of hooking up your battery to your power supply. Most power supplies are not designed as battery chargers and they may not work well if you try to hook up a battery (especially a discharged one). In this situation they may simply shut down if they have over-current protection built into them. If they don’t have this protection, they may blow a fuse or they may liberate some of their carefully stored smoke. Also, if you turn the power supply off (or lose shore power) the battery may be completely drained. I have found that a really great way to keep my SLA batteries charged and ready to go is to hook them up to a computer UPS. Most UPS units have chargers in them that are designed for use with SLA batteries (since they have batteries in them). I’ve got some pictures and other notes about doing this on my web log ( I’ll post a link to the site on the page as well.
The last thing I’m going to talk about is Self-discharge. Batteries that are left disconnected discharge slowly. For non-rechargeable lithium batteries the self-discharge rate is very low. They will easily last 10 years with only a small loss of charge. That’s why these batteries are so good for long term storage or very low drain devices like clocks and smoke alarms. Alkaline batteries can be good after several years of sitting around too – just check the dates they print on them nowadays. However, at the high temperatures encountered in hot cars even Alkaline batteries can lose half of their charge within a year. Nickel based rechargeable batteries have a much higher discharge rate of 1-2 percent per day. NiMH batteries can lose 10% in the first 24 hours and then another couple percent per day at room temperature. After a few weeks in a high temperature environment Nickel based batteries may be completely drained due to self-discharge. Lithium based rechargeable batteries fare much better than other rechargeables and only self-discharge at about 2-3% per month at room temperature. SLA batteries will self-discharge at about 5% per month. Self-discharge does not harm any rechargeable battery types except SLA. If you let an SLA battery sit around disconnected for long periods, it may destroy itself. Charge those jump starters in your trunk at least once every six months! If you have SLA batteries sitting around that you’d like to test, charge them up and get in touch with me – I have a tester that can measure exactly how much power a battery can provide.


Many, many other web sites.