Is this charger working?

[Cricket Too]

Hey guys, I have a Sears battery charger, it's about 15 years old. It's just a simple 12V 10amp/2amp and 6V 2amp charger, with a 50amp engine start feature, nothing to big or crazy. This charger has always worked well for charging up my Deep Cycle boat batteries and the occasional car battery.<br /><br />Went to charge up my Deep Cycle's and noticed that when I plugged the charger in the needle in the little meter on the charger was bouncing around slightly, rather than being a steady reading as it always has been in the past. I tested the electrolyte in the cells with a hydrometer, then put the batery on charge for about 6 hours on the 12V 10amp setting. Came back to take it off and saw the charger's little meter was all the way down, as it would be if the battery was fully charged, took the charger off and tested the elctrolyte again, and it didn't go up 1 bit. I got the exact same reading on the electrolyte as before 6 hours of charging.<br /><br />So I wondered if maybe this charger was on it's way out. Took my handheld volt meter and hooked it up to the charger leads, then plugged the charger in, and only got about 11.2V on the 12V 10amp setting. I figured that in order to charge a battery it would have to be putting out at least 12.8 or higher, but I guess I could be wrong, so basically my question is, is this too low of a reading and should this charger be putting out a higher voltage than 11.2v when charging? Thanks, Mike.

 

[Paul Moir]

Re: Is this charger working?

It's dead Jim.<br />It might be worth fixing if you're curious & keen, but you could also look at it as a good reason to step up to a nice staged automatic charger. Those normally run 13.8v or more with no battery connected. I think the most likely problem is a partly blown bridge rectifier.

 

[Cricket Too]

Re: Is this charger working?

Thanks for the quick answer Paul. Well that's what I figured, I couldn't see how any charger could be effective while charging at 11.2v or even at 12.2v for that matter, if your engine/alternator was charging at that, you'd be stuck.<br /><br />Well I'm happy and frustrated at the same time. Buying a new charger is no problem, and I actually wanted one anyway, since I want something with a little more charging power than 10amps. Sears has a nice charger for about $80, that's got a 2amp maintainer, a 12amp setting and rapid 30amp setting as well as an 80amp engine start, 30amp should be perfect for charging, and the 2amp maintainer will be nice for storing the battery over the winter, I guess I can just leave it on that charger the whole time, and won't have to worry about buying a separate maintainer.<br /><br />Now to the frustarting part, I've been chasing a cranking/charging voltage problem for about 2 weeks now, actually have a post in the John/Rude forum. Never occured to me that I was starting off with a weak battery, since I had charged it overnight and never thought the charger was bad.<br /><br />Just off hand, would a weak battery, that would run down while cranking and just bareley get the engine started, cause me to have an excess high charging voltage from my engine while running, say about 16v at idle and even higher at WOT?? I noticed this after the battery had sat for a while and I had a slow crank, barely got the engine started and then saw my gauge up in the 16v range at idle and close to 18v at higher RPM. Just not sure if I still need to go chasing this problem, guess I should start with the new charger and fully charged up battery, before I get back into the engine's charging volatge. 1976 Johnson 115, by the way. I've been told it's an unregulated rectifier, so you can see some higher voltages with a weak battery...man it would be so nice and easy if that were the problem, but my luck isn't that good. <br /><br />Anyway, thanks for the help, Mike.

 

[byacey]

Re: Is this charger working?

I'm not familiar with your particular charger, but if it has any sort of regulation, depending on the circuit it may not read anything on the leads without a battery load. My charger will not charge a stone dead battery - there has to be a few volts to start the charging circuit.<br /><br /> If this is just a plain old transformer and rectifier, either you have some shorted or open windings on the transformer, or part of the rectifier is open. does the hum that the charger makes change in volume when the battery is connected versus disconnected? Is the transformer inside getting hot to the touch without a load connected? These arent hard to service if the transformer isn't damaged.

 

[Silvertip]

Re: Is this charger working?

On the other hand, how old is this battery you are trying to charge? A battery with a weak or dead cell will not fully charge and will provide starting and charging problems in the boat.

 

[Cricket Too]

Re: Is this charger working?

Bill....It's pretty much just a simple Sears charger, nothing fancy. I was actually thinking that I may be getting the 11.2 voltage reading since it was not hooked to a battery/load, because when I hook it up to a battery and then stick my meter on the battery while it's being charged, I get a voltage of about 13.4 or 13.6, but even that seems a little low to me, this was also one of the reasons I stuck the meter on the leads by themselves. I also noticed when I was measuring the charger output by itself(no battery), that when I switched down to the 6v 2amp setting, my voltmeter would show 6.2v, but when I flipped it back up to the 12v 10amp setting, it would only show 11.2 - 11.4v. I wasn't sure if this is what I was supposed to see without a load or if this charger was shot, was kind of hoping it was shot, now I'm not sure.<br /><br />Upinsmoke....The battery was brand new last season, towards the end of the season (August), Power Master, 650 MCA, Deep Cycle. I used the boat a couple of times and then the battery sat all winter,from about mid Sept until about 3 weeks ago, charged it 1 or 2 times for a couple of hours throughout the winter, should have done it more or bought a maintainer, but never did. Hooked it up about 3 weeks ago after an overnight charge (8 or 9 hours), and had this slow cranking problem and excessive charging problem, but have been working through that on the JohnRude forum, just popped over here to ask about that charger, figured I might have been starting off in the first place with a weak battery, and not have even know it. Now I'm not so sure. Thanks.

 

[Paul Moir]

Re: Is this charger working?

If it's shooting up over 13v when you hook up the charger, then it's working. I foolishly assumed this was a dumb charger with no regulation whatsoever.<br />With that other information, it sounds like that battery is shot. Better dig out the receipt. I think walmart and the like do free battery load testing, but if it's not taking a charge I think they'll just confirm the obvious.

 

[Cricket Too]

Re: Is this charger working?

Paul...I've alrady load tested the battery, and it holds up well under load, only drops to about 11.2v under load and recovers well also, used that little machine they have over at Auto Zone for free. <br /><br />Ok, so my battery and charger are good aparently. Guess I'm going back to the diagnostic check list, the next suspect is my starter solenoid.<br /><br />Thanks for the help.

 

[byacey]

Re: Is this charger working?

What kind of load? If it drops to 11.2V under load, you have a bad cell. A good battery should hold at 12.5V or more for quite awhile before dropping down as low as 11.2.

 

[Cricket Too]

Re: Is this charger working?

Hey Bill....Not sure what you mean by what type of load. It was just a battery load tester that you punch in what type of battery it is marine or auto, and then you punch in the CCA or MCA, and it performs a test. It loads it and shows the voltage as it is under load, then it stops the load and shows the voltage, so you can see how it recovers, then it does it does a second cylce of this and then displays either Good or Bad battery. It showed good for mine. I actually didn't trust it fully, so I took it to Sears and had it load tested there also, and got the same result, a printout from that machine that said Good Battery, I couldn't see the voltages on that one.<br /><br />I never heard that about a battery should hold at 12.5 under load, is that true? If so then I guess this one is shot. But I don't recall seeing any that held at 12.5 under load, actually don't recall many that have a voltage much higher than 12.5 while at rest, not being charged.

 

[Cricket Too]

Re: Is this charger working?

Anybody have any clarification on what a battery should drop to under a load? Thanks.

 

[Cricket Too]

Re: Is this charger working?

Bump.

 

[byacey]

Re: Is this charger working?

It all depends on the battery capacity and what kind of load you are putting on it during testing. A 50A load for about 10 minutes is a good test. If you are drawing 150 to 200A then I could see it dropping down to 11V or so after a short time.

 

[Cricket Too]

Re: Is this charger working?

Hmmm, I'm not sure what amperage load a standard battery load tester puts on it, I would assume it would simulate a normal load of a starter motor, seeing as that is when the majority of batteries are most loaded. What is a normal starter amperage draw? <br /><br />I know I did see 11.2v on the screen when I was watching it. Why would it tell me it was good then? I wonder if it being a Deep Cycle would have thrown it off, there was no separate setting for Deep Cycle.<br /><br />Anyway, I've been testing my sytem with a friends brand new Interstate Deep Cycle and when the engine is running, I'm getting about 15.5V at idle at the battery and about 15.9 when I rev up to higher RPM's, about 3,000, then it drops right back down to 15.3 or 15.5 when it goes back to idle. I've been told this is too high and it shouldn't go above 14.5V no matter what RPM, but I'm starting to feel like I'm overthinking this here, and there is no problem.

 

[rickdb1boat]

Re: Is this charger working?

I believe that an automobile starter will need up to 250-300 or so Amps on start-up, depending on what you are starting. I don't know what the tester at auto parts stores use....

 

[byacey]

Re: Is this charger working?

15.5 will boil and cook the battery before long. Is there any sort of regulator circuit?

 

[Cricket Too]

Re: Is this charger working?

Rick and Bill.....This is my starting battery, so I'm starting my Johnson 115 with it for the most part, some accessories, but mostly for starting.<br /><br />Bill....This particluar year of engine 1976 Johnson 115 does not have a regulated charging system, it charges at 6amps and uses the battery as regulation. I've been testing the entire cranking/charging circuit, and found a slightly higher resistance in my starter motor, even though it's relatively new.<br /><br />Have been going through the system by cranking while testing voltages at different spots. One thing I did realize is that once the battery gets pretty drained down from the cranking while I'm doing these tests, when I actually start the engine again with this drained battery, I no longer have the excess voltage problem.....switch to a charged battery and the problem comes right back, charging ta 15.5V at idle. Assuming the drained battery adds resistance into the circuit and keeps the voltage from going too high.<br /><br />Cannot find any severely excess voltage drop anywhere in the system, and the engine cranks perfectly, just have this excess charging voltage problem. Thinking about putting the newer style regulator/rectifier on my engine, but not sure if the battery would get any charge then. I'll have ot find out over in the JohnRude forum. Thanks.

 

[byacey]

Re: Is this charger working?

You need some kind of series regulator. The reason the voltage is lower with a discharged battery is because the dead battery draws heavy current from the charging circuit. Once the battery approaches being fully charged, the voltage starts to rise as the current tapers off. <br />This is why a regulator is needed.<br /><br />Depending what kind of charging system you have, a shunt regulator circuit like this may work well. You just have to find someone to build it for you. http://img.photobucket.com/albums/v354/byacey/regulator.jpg