New to Me Boat with Battery Charging Issues

[skyaggie]

So I recently purchased a 1995 Mariah Davanti 215 with a 5.7 Mercruiser.
I took it to the shop and had the mechanics run through and check everything and do a regular service immediately after purchase and everything checked out good....
The only issue I am having is getting the batteries charged. The boat is equipped with dual batteries and a Perko switch, which I dont have any experience with.
The batteries were low so I went to charge them with a regular 6 amp charger and neither battery will take a charge.
I first attempted to charge them with leads attached to one battery and the switch on "both". After That failed I attempted to charge each individually with the switch on "one" and "two" and on "off". What am I doing wrong? These are new batteries as of last year.

Any help is greatly appreciated

[Bubba1235]

So I recently purchased a 1995 Mariah Davanti 215 with a 5.7 Mercruiser.
I took it to the shop and had the mechanics run through and check everything and do a regular service immediately after purchase and everything checked out good....
The only issue I am having is getting the batteries charged. The boat is equipped with dual batteries and a Perko switch, which I dont have any experience with.
The batteries were low so I went to charge them with a regular 6 amp charger and neither battery will take a charge.
I first attempted to charge them with leads attached to one battery and the switch on "both". After That failed I attempted to charge each individually with the switch on "one" and "two" and on "off". What am I doing wrong? These are new batteries as of last year.

Any help is greatly appreciated

Find out if the batteries will take a charge at all by disconecting and charging them (8 hours min.) one at a time.

[kmarine]

Sometimes batteries will not take a charge until they are charged slowly first. This can also be avoided by placing a load on the battery for a few minutes by turning somthing on to cycle battery before charging it. The switch can isolate the two batteries to charge them seprately or together by switching them to all. In your case i would charge them seprately so you can check each battery individually.

[Silvertip]

Are you sure they need charging??? You can do this two ways as you've already done. 1) connect the charger directly to just one of the batteries and set the switch to BOTH. or 2) Charge each battery by connecting the charger to the battery. Switch setting in this case makes no difference. It can be left on OFF. It may be that whoever wired the switch did some "creative" wiring so the switch doesn't work as it was intended. It may also be that the charger has an issue.

[skyaggie]

I know that the batteries need charged. We took the boat out yesterday and sat on the water until sundown with the radio and lights on and by the time we left to come back the motor was cranking slow, volt meter was reading zero, and lights were starting to flicker. Also they haven't been charged all winter which tells me they are probably down on juice.

I used the charger on my other boat and it worked fine so i think i can rule that out.

Maybe they are just so low that it will take a day or so of charging. I'm leaving it on one battery tonight and ill check it in the morning and make an assessment then. Also these are much larger batteries

[tpenfield]

Don't let the Perko switch confuse matters . . . I was not quite sure from reading your post if the batteries are too low to crank the engine.

If my batteries are really low, I turn the Perko switch to "off" and charge directly on the batteries on at a time. If they are just a bit low, then I'll connect the charger to one battery and 'share the wealth' with the other battery by setting the Perko switch to 'both'.

If the batteries won't charge in the boat, then it could mean that something is drawing all the current. You could take the batteries out, as suggested, and charge them individually. That will tell you if the batteries are still among the living.

If you think that you have something draining the batteries while they are in the boat, grab the old multimeter and see what you are getting for amperage draw from the batteries with nothing on and the Perko to 'off'

[Silvertip]

The stereo has a station memory and clock function that is powered all the time depending on how the switch and stereo are wired. While the current draw is low, weak batteries can be discharged quite quickly. You need to charge those batteries and then take them to any auto store for a free load test.

[Bubba1235]

I know that the batteries need charged. We took the boat out yesterday and sat on the water until sundown with the radio and lights on and by the time we left to come back the motor was cranking slow, volt meter was reading zero, and lights were starting to flicker.

A wet cell battery should never be drained that far and can severly damage them. *IF* your voltage meter is right, 12 volts is "discharged" and you should not allow it to drain below that. Caveat: Never trust on board voltage meters, use a multimeter to verify the dash mounted guage until you are certain it's accurate.

[skyaggie]

Thanks guys, all good information. I'll be taking the batteries to the auto parts store to have them tested. If all else fails I will just replace them and go on down the road. A couple hundred bucks is better than being stranded on an empty lake IMO.