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t a

Battery completely dead while using on shore charger

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t a

Hey guys, this is a two part question:

First, I have two DEKA group 24 batteries, one deep cycle and one for starting wired on a perko switch. I also have a prosport 12 charger that I always have them plugged into when parked at the house. My system includes the kicker 6500.2 tower speakers running off a cadence amp pushing 250w rms per pair of speakers with ws420 EQ. Interior is stock alpine and a 10" sub running off of stock amp (not sure of make and model). I don't really like to go to party cove or anything, but sometimes we do park and float off the back of the boat for an hour or so to hang out. Even then, I only play the towers only at about half volume and interior completely off. I understand the group 24 is a really small battery but i figured it could handle playing my modest set up at half volume for about an hour. Nope, with/in 20 min i'm getting low voltage numbers. Does that sound normal or is something else maybe draining the battery? Also, last time out, after sitting on the charger for 2 weeks i took the boat out and there was zero power from the 2nd battery. Put a voltmeter on it and said 8.9 volts. Obviously that battery is beyond hope but is that just a completely incopetant battery for what i was trying to do or do yall think there could be another issue draining my batteries. The prosport seems to be working fine as far as i can tell, everytime i plug it in it goes into charging mode and everytime I uncover the boat to take it back out it is in float mode, although I'm not sure why it was in float mode with that battery at 8.9 volts...

Secondly, looking for a group 29 or 31 battery to replace this one for stereo bank. Any recommendations in the $100-$150 range? Again, not looking for massive reserve capacity to play hours on end at full volume but do like to anchor for an hour or two every once and ahile.

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MLA

The first thing i would do is confirm that the battery is indeed reached the end of its life. Have it tested with an inductance tester as opposed to the old style "toaster" testers with the heater grid. next, confirm the charger is working correctly. You need to test is output while charging and also confirm that the batteries are reaching a full charger. Is it a 2-bank charger? Wired directly to each battery, correct?

Yes, a group-24 should you just fine, but more Ah is always a plus. This can mean shallower cycles.

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FastFreddy

That battery should keep you going for an hour easily. 20 minutes seems very low. My guess is that the battery is done based on your description. It is possible that the charger is undercharging the battery and that could be whats killing it. MLA had it right check the charger, it should put out 13.5V+ when charging a good battery.

A few questions:

1. Are you charging both your batteries when driving around? Do you have both linked on the perko while engine is running?

2. Do you have both batteries on the float charger?

3. What is the voltage of the primary battery?

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t a

Yes, when running around switch is always on "both." When parking I switch to "two." And at home switch is on "off" with 2bank charger hooked up individually directly to each battery.

Here's a description of how everything is hooked up:

+ and - cables coming from engine hooked to perko

Battery1 (starting)

+ and - to perko

+ and - from prosport charger

2 random black cables hooked to positive ( I think these are accessory power/bilge ect. but not sure at all.)

Battery 2 (deep cycle)

+ and - to perko

+ and - from prosport charger

+ and - to amp1

+ and - to amp 2

Not sure of voltage on battery 1 but it seams to always be fully charged and always fires the boat right up with no hesitation. Battery 2 would usually do the same as I've tested it before cause its seemed kinda weak since day 1 but it just seems to drain really fast but always seemed to be charged up next time out. Any obvious problems with the wiring that may be sucking the lif out of battery 2? These batteries are 1 1/2 years old.

Edit: that is off memory, negatives on each battery might not be going to perko. Now that i think about it perko just takes the positive cables...

Edited by t a

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t a

With charger hooked up battery 1 is showing 13.4v

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MLA

With charger hooked up battery 1 is showing 13.4v

But Batt-2 is the suspect one, right?

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t a

Yes battery 2 is the problem

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David

You cannot use the voltage number while the charger is hooked up or for several hours after the charger is disconnected since you have to allow for the charger voltage to dissipate before you can get an accurate reading.

Correct, there are no negatives related to a Perko switch.

Only the memory (optional) and the bilge pump/float switch (if applicable) should be battery-direct. The positives from the alternator/starter feed, helm buss supply, and ALL audio equipment should be connected to the output/common post of the Perko switch. No exceptions when using a simple dual battery switch. All ground/negatives are common.

Make certain that all grounds are connected and in really good condition, especially the one leading to the engine block.

A battery in bad shape may show a healthy surface charge temporarily, heats up, but never really accepts or holds a lasting deep charge.

Make sure you have at least 12.5 volts after a full charge and the charger voltage dissipates, then unhook the batteries and let them sit isolated for several days . Self discharge might be several percent a month but you should not see a drop in two or three days. If you lose a volt in just a couple of days, this is an indication your battery(s) need replacement.

You can use an inexpensive multimeter ($10+) to check the amperage draw of each individual circuit for a parasitic drain.

As mentioned above, measure, measure & measure rather than speculate.

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t a

Hey David, I used to have all positives in my system hooked up to the common on the switch like you mentioned and the system seemed to always have power. Even with the switch "off" I could turn the key, run pumps, stereo, lights, etc, and that seemed really odd to me...hence why I rewired it the way I did, I thought that was somehow draining my batteries at all times...

Edit: battery 2 is not charging at all, battery 1 still seems healthy. Battery 1 has not been hooked up for 3 days and showed 12.5+v. When charger hooked up it was 13.4-13.5v. I'm assuming that one is still ok since it's never been run down and had a charger on it since day 1 when not in use. Battery 2 has been run down quite a bit due to my delimma and also has had charger since day 1

Edited by t a

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MLA

Hey David, I used to have all positives in my system hooked up to the common on the switch like you mentioned and the system seemed to always have power. Even with the switch "off" I could turn the key, run pumps, stereo, lights, etc, and that seemed really odd to me...hence why I rewired it the way I did, I thought that was somehow draining my batteries at all times...

Edit: battery 2 is not charging at all, battery 1 still seems healthy. Battery 1 has not been hooked up for 3 days and showed 12.5+v. When charger hooked up it was 13.4-13.5v. I'm assuming that one is still ok since it's never been run down and had a charger on it since day 1 when not in use. Battery 2 has been run down quite a bit due to my delimma and also has had charger since day 1

How are you determining that batt 2 is not charging? This is important. You need to A) test the battery and B) make sure that that charge circuit of the charger is working. A bad battery could lead to a false diagnosis of B.

A quick way to knock off the surface charge of a battery, is to apply a load. For the cranking the battery, you can crank the engine over a couple of times. For the house bank, play the stereo and other accessories for a few minutes.

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David

Hey David, I used to have all positives in my system hooked up to the common on the switch like you mentioned and the system seemed to always have power. Even with the switch "off" I could turn the key, run pumps, stereo, lights, etc, and that seemed really odd to me...hence why I rewired it the way I did, I thought that was somehow draining my batteries at all times...

Edit: battery 2 is not charging at all, battery 1 still seems healthy

If the Perko switch was in the 'Off' position, and you still had functionality on those operations mentioned, then it absolutely could not have been wired as you thought it was. I wonder if there is a lingering issue with that even after the re-wire.

Battery #2 is probably toast. Also, consider that if the battery is allowed to discharge too low then the charger may go into protect and not charge at all. However, I doubt the charger would have individual bank protection circuits...but possible.

Double check all grounds on battery #2 even if they appear good. Try switching the Perko to 'Both' thereby combining both batteries for a period with the charger on battery #1 only. See if you can get the charge to elevate on battery #2 this way, and enough so that the charger can be re-attached to #2 and charge the rest of the way.

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t a

Does anyone know what the two black cables are? They are about 12 or 14 ga. Is one bilge and the other helm buss supply that David mentioned?

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FastFreddy

Hey David, I used to have all positives in my system hooked up to the common on the switch like you mentioned and the system seemed to always have power. Even with the switch "off" I could turn the key, run pumps, stereo, lights, etc, and that seemed really odd to me...hence why I rewired it the way I did, I thought that was somehow draining my batteries at all times...

Edit: battery 2 is not charging at all, battery 1 still seems healthy. Battery 1 has not been hooked up for 3 days and showed 12.5+v. When charger hooked up it was 13.4-13.5v. I'm assuming that one is still ok since it's never been run down and had a charger on it since day 1 when not in use. Battery 2 has been run down quite a bit due to my delimma and also has had charger since day 1

Battery 1 seems healthy and your charger seems healthy from what you describe. I think you do have your wiring figured out now and that the Perko is correct. Sounds to me like battery 2 is the culprit. What is the voltage of battery 2 after it sits for a while? What is the voltage of battery 2 on the charger? If it doesn't match the numbers from battery one then the battery is likely toast.

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FastFreddy

Does anyone know what the two black cables are? They are about 12 or 14 ga. Is one bilge and the other helm buss supply that David mentioned?

Bilge and ??? You can disconnect them and see if that is the parasytic drain. I would only connect the bilge wire to my battery all the time, the other should go to the Perko common.

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David

Does anyone know what the two black cables are? They are about 12 or 14 ga. Is one bilge and the other helm buss supply that David mentioned?

I'd be apprehensive about moving anything without knowing exactly what it is in advance.

If the bilge pump has a manual switch this should be easy enough to check when connected and disconnected. If not, this is where an investment in an inexpensive multimeter helps. You only have to learn a couple of basic functions to test just about everything.

12 to 14 gauge sounds too light for the helm buss supply. 8 gauge is generally minimum on any boat with 6 gauge typical. Also, the helm buss supply would be fused or have a breaker at the supply end.

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t a

Ok reworking everything, found the helm buss supply it is 2 ga. Now everything positive will be going to the switch. I will figure out those two black wires as soon as I get power to the boat again and can start testing things. Question is everything is currently grounded on the starting battery. The ground for amp 2 ( tower) isn't long enough to reach the starting battery. Can I ground that one only off the house battery or do I need to run a new longer ground cable to starting battery where everything else is grounded?

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FastFreddy

I think you may have found your problem. Both batteries need to have a common ground.

Here's my setup:

Negative from battery 1 goes to negative from battery 2 via a 2 gauge cable. Then my amps are connected to battery 2 and the engine ground/buss is connected to battery 1. The important part is to have battery 1 and battery 2 grounds connected together with large gauge cable. All the grounds need to be joined together ALL the time. The perko battery switch does the rest on the positive side of things.

Here's a crude drawing.

post-20325-0-14800100-1380389547_thumb.p

Edited by FastFreddy

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t a

Ahh that's easier...will connect the grounds on batteries

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t a

Thanks for everyone's help, I hope grounding everything together and running all positives off the switch will fix my issues. Will let y'all know once I get to test it out. It's pouring rain here now though...thank god we need it here in Texas...

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