Battery Dyno

I have been running the same batterys for almost 3 years now. Sea Volt AGM batterys from West Marine. Im just now starting to notice my batterys seem to be not holding a charge for as long as I thought they did. Last year everyone was talking about the Kenitic batterys. I was having a conversation with Mike. He swapped out his golf carts for Kenitic battery's. I was asking him how his Kenitic battery's were holding up because I was thinking about changing battery's out this winter. He said he didn't think the Kenitics were any better than any other battery. But he did up the load in his boat. Now here is the tricky part.
Because each one of us has a diffrent draw when it comes to current it's hard to judge what batterys last longer. Also its how one charges and re-charges their batterys has alot to do with how long your batterys last.
It's hard to look threw the hype and pick a good, better, best, battery.
Mike and I were talking about some sort of Battery DYNO. A device or machine that could cycle test a battery. Charge & load it for hrs and then re charge it over and over again. Then after a sertan amout of charge and re charge cycle's you could voltage test and load test a battery. That way you could see what battery held a charge over the test of time.

how could you get this battery dyno to work? it sounds like a really good test

The idea would be you hook up a battery to be tested to the Dyno. It would have a volt meter on it and a load tester and a battery charger.

The battery would be charged to full and it would be timed.
The battery is then discharged at let's say 20-40 amp's till its pretty dead lets say 12.0 volts and again its timed. Then its recharged right away.
this is all done automatic. The dyno would record charge and discharge rates/times and record cycles . This way you could get a idea how many times the battery charged and discharged before it started to not hold a charge and voltage.

IMO this is the only way to have a heads up battery test.

You can buy them. It's basically a high draw heating element to give a high load and a guage. Not very sophisticated but they work. You can messure the draw or time to a voltage.
When they rate batteries it's basically amp hours which is what this tester can simulate.
They can look like this.

Yea I have seen them and know about them. Down side is you would need to sit there and time and measure voltage ect and then hook a charger back up to it and do it each time. The idea here would be somthing that simulates you using your stereo while parked and then you re charging your batterys either via a land power or HO alternator and smart regulator

G,

I have a datalogger. We can set it to record the voltage every 15 seconds or less for as long as needed. We could do 14 to 10 volt sweeps. I will need to get a 12v transducer if you want to do this.

Grant - are you not an Optima fan? Seems like they were the battery to use only a couple of years ago...

Brit: I have mixed fellings about the Optima's. Yes I used to run them. When I switched them out like 3 years ago I found the the batterys i switched to worked much better. (note) I added like twice the battery amp hrs. But I also upped the amount of draw I about doubbled it so it was a wash. I noticed that it would hold voltage much longer.

Grant I have a snap on D-Tac Battery Tester. It has all kinds of cool functions like giving you the actual cold cranking amps available on a tested battery. I dont think it will give you everything you are looking for all in it self but it would give you a pretty good start......give me a call and we can put together a test.

Brian I have seen your Snap On Charger/tester that thing is pretty cool. Do you think it could Load/ Draw down a battery and recharge it and test it like what Im talking about>

It does do a load down test but we would have no way of knowing the load amount so we would have to do that with a test tone generator and amplifier I think would be the best way. I have an amp meter and a stopwatch....not the best way but should give us a reasonable reading....

Grant, that would be awesome if you could somehow do this. It would provide very relevant info for many people on this board.

I personally feel that too many people buy Optima's when there are a lot better options out there. Optima has just done a great job of marketing. My company carries Deka Batteries, which we have really been pleased with. They consistently have a higher CCA than rated. Cheap batteries like Exide's that I have tested have always been overrated.

There are a bunch of ways to test a battery. We've got a tool called the Midtronics that tests the resistance of a battery. It gives a good indication of how sulfided a battery has become. The good old VAT-40 is also a great tester. It basically supplies a load, but you can monitor how much load you are supplying and see if the battery is still up to spec. A good battery will do 1/2 CCA for 10 seconds at least 3 times with a 10 second break in between. You can also hydrometer test if the battery isn't sealed. Consistency across cells is key. Another solid test is to monitor the battery voltage while charging. If it goes over 14.5 volts the battery is weak and not accepting a proper charge.

The rule of thumb I usually go by is 2 years for deep cycle batteries that have been worked hard and 4 years for standard batteries. That way you'll never be left without enough juice. I'm sure there are some new batteries out there that will last longer, but I've always gone with this rule and it's worked great.

I have an amplifier we can use for the test too,

burn down = no worries

who wants to donate an old 1 ohm sub?

I have a couple of older subs in the garage (not sure if any of them are 1ohm)? I think I have an original JL-12W3 (I believe it is 2ohm but it has dual VC I think). I also have an old Rockford sub. I'll dig them up tonight. You are welcome to have either/both if it helps to determine the best battery currently on the market for high current boat stereo's (I'll likely be re-doing batteries over the winter, so it would be great to get a consensus).

Grant just let me know, I have all of the woofers and amplifiers that we need....just need to figure out the amperage amount and how long the tests needs to be.

Im thinking to really test a battery it need's to cycle'd (fully charged and fully discharged) like at least 50 times's. 100 would be a better test IMO.

I was thinking of somthing that drew down the battery at like 30-40 amp's till the battery was dead. This dosen't have to be a Amp and speaker draw
IMO a draw is a draw. The battery dosen't know if its a light or a amp it's powering. That way you don't have a amp and woofer overheating after 30 min's and the test is over.

The load tester like in the post Art showed will work fine. Its a simple short. Now if we could just find or work somthing out like what Brian has (Snap On battery charger) and Arts load tester combined with Mike's Data logger and a way they all work together that would be awesome.

Any other Idea's Am I right about the draw/load? You dont need a Amp and woffer to create the draw.

IMO an amp / woofer combo is more real world testing. ( very dynamic load)

The link below is how I test my Mako scooter batteries. Change it over to 12 volts, simple numbers game. The load you choose to run will vary on the battery capacity.

http://www.bentleytech.com/cave/resistor/index.html
http://www.jetboots.com/scootbat/
http://www.direxplorers.com/specialist-dir-kit/5238-burn-tester-scooter-primary-light-2.html

For batteries Hawker Odyssey's

BTW those cheesy load testers can not be used on an AGM battery. Plus they would never handle the amperage draw for more than a minute before it smoked. The D-Tac draws 150 amps for a short duration load test. We used a Snap-on VAT 45 to test the draw. The D-Tac does not use a carbon pile either, which is a good thing. AGM's are tested differently than other batteries, much like they need to be charged differently.

You never fully discharge a battery or it will cause damage. Depending on the battery you set up a cut off voltage and that is the end of the test. The discharge time vs load is what you are after. Maybe recharge time too, since the boat may not be moving far enough to produce a full charge. Which battery charges the fastest is also important. D-Tac can do that. What you need then is an amperage alarm along with voltage. Hmmm...only some scopes can data log and set an alarm off. DVOM can get the job done.

Peter: I agree you. You should never fully discharge a AGM battery. When I say draw or load the battery till its dead that's somewhere around 12v. I guess each battery has a diffrent bottom than the next.

So the link's you have provided are part's to build your own Battey Dyno like what we are talking about?
Do you have one for your Underwater scooters?

I think the test is going to take a while because while draining and recharging the battery is the basic goal. The important thing we are looking for Imo is how they react in real world conditions. While this is still not real world because there are differnt voltage draws depending on the music dynamics this would be the best way to get a test that can be done over and over again with the same accuracy every time.

How quickly you charge and discharge the batteries will have a large effect on performance. You'll be creating lots of heat and will quickly degrade performance with each cycle. I could see this being a good test to see what battery is a more durable unit, but in terms of testing a batteries condition there wont be anything left of it after this test is run.

As Peter said, Gel and AGM batteries require different test methods and chargers.

The goal is to see what battery last's longer.
No use doing a test if its not how we use our systems/battery's. If you think a constant load is not real workd and other agree then lets do somthing else. Mike had suguested hooking up a Amp and a woffer to a I pod and putting it on a 30hz bass tone. IMO thats just like putting a constant draw. I guess if you made a playlist of like 20 song's and put it on repeat you could simulate the diffrent voltage spikes diffrent types of music would draw/create. I guess this is as real world as it get's. Mike said he has a storage shed where we could hook up the woffer/sub combo and it could play for how ever long and we could run the test. Im guessing it would work like this. The test start's at like 12.7 or 12.8 volts they system starts playing untill the battery voltage drops below 12 volts. The Music stop's playing. The run time is recorded and it starts re charging. The charge time is recorded till the battery holds 12.8 volts and then the test starts over again.

Quite an elorabrate piece of quipment to built to find out what you would think would be easy to find information.

I think that would work grant we would just need to find a low voltage alarm like they have on the malibu that we can set to sound an alarm to get the amount of time of play and set it to recharge.....I think that is a very good idea. Its easily recreatable by anyone as long as you have the same playlist, amplifier and Woofer.