new battery

boatman37

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May 14, 2015
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no real reason for this post other than informative...lol

well today i went and bought 2 new battery trays cause i wasn't happy with my old ones and while there i decided to buy a new cranking battery. the one i replaced was in the boat when i bought it and was actually a series 24 car battery with side terminals. i had no reason to believe it was going bad but i bought a new house battery 2 years ago when i bought it so now both have been replaced. i bought a 1000 cranking amp battery and it did seem to start faster than with the old one. my volt meter still reads 12 and i also have a new alternator so my guess is gauge or bad connections. i'm going to take my volt meter down next time to verify the output.

had the boat out for about 1 hour today on plane for just about all of it and all was fine. ran good.
 

Redfred1

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Sep 23, 2013
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629
That engine should turn over like a sewing machine! The last HCA battery I bought was for a Mahindra diesel. My Rude uses a Wally World 850.
 

MH Hawker

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Jul 13, 2011
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5,516
due to my circumstances, i kill battery's, in the past 7 years i have to replace them once a year, i have tried most brands, most of them have been Johnson control battery's no matter what name is on them, i get the warranty period and that's it, that's a year i got a delco voyager year before last and its around 18 mouths right now on a 24 mouths warranty, so i may get 2 seasons out of it
 

boatman37

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well went out saturday for about a 90 minute run and all was fine. volt meter read just under 12 where it did last year with the old alternator. yesterday we went out and went about 1 mile up river on plane (on battery 1) and it stuttered and bogged so i backed off the throttle and shut it off. my first instinct was to switch to battery 2 so did that and it fired right up. ran for awhile close to the marina and all seemed ok so switched back to battery 1 and went about 5 minutes at no wake speed and it stalled again. switched back to battery 2 and made it back in. battery 1 is the new cranking battery and battery 2 is a 2 year old house battery.
i replaced the alternator and charger over winter but is there and special charging instructions on a new battery that might be different than cars? i got the battery from west marine saturday morning and took it from the shelf to the boat. the sticker on it said 5/17 so i hasn't been sitting around long. i installed it saturday morning a few hours before going out saturday evening when it was fine so i assume it had sufficient charge then. i am going down there shortly and checking the alternator output with a volt meter to get a better idea of what it is putting out. the only other thing that i can add is that i bought new belts from here on iboats and ordered what it called for but i can't get the alternator belt as tight as i would like. i am out of adjustment on it and have about 1" of slack. it is a 15455. i see auto zone has a 15450 and 15445 so i am going to stop there this morning and grab one of those to get it tighter. i can't hear any squealing so can't say that it is slipping but who knows for sure. seems to me to be a charging issue rather than a battery issue as it starts right up but dies while under way. and should it die that soon after leaving the dock with a fully charged battery? it died about 10 minutes after leaving. i would think a fully charged battery would hold longer than that even if the alternator was disconnected. nothing was running except the engine and my VHF. and why was it fine saturday then die sunday?

the reason for switching to #2 when it stalled was that this happened last year after anchoring and forgetting to switch back to #1 after pulling the anchor and leaving the fridge run on #2 while anchored then cruising on #2 right after that. i can't say for certainty that it was even electrical but it was very similar to what happened last year
i will follow up later today but any ideas are welcome. i replaced all this over winter to avoid having these types of issues.

the new alternator is from DB Electrical but i am dropping the original off tomorrow to get rebuilt either way so at least i have a spare. i still have my old battery that i replaced saturday and had it on the charger here at home over night and will be taking that with me today for an emergency backup.
 

bruceb58

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Mar 5, 2006
Messages
30,454
Measure the voltage at the battery with the engine running. Should be close to 14V. If it isn't, you have a bad alternator.
 

boatman37

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May 14, 2015
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i checked the voltage at the isolator where the alt. connects to it and got 13.0 volts. at the alternator it was around there but due to the hose configuration i had trouble getting onto that terminal. what i did find though is that my engine battery is connected to switch #1 position. the house battery is switch position #2. i checked both batteries on all switch positions and got the following results:

switch position #1 both batteries are discharging
switch position 'both' both batteries discharging (or at least not gaining charge)
switch position #2 the engine battery charges but the house battery does not.

so the house battery (switch position #2) does not charge on DC no matter where the switch is. the engine battery only charges when the switch is set to #2.

both batteries seem to charge ok with the AC promariner dual bank charger.

so i started thinking and last year when i had trouble it was with the switch on #1, same as yesterday. i went out today and left the switch on #2 and it was fine. so i must have been running on my house battery today? my thoughts are first to try to figure out what the problem is but the band aid would be to switch my battery positions so my engine is actually #2 so i am running on the engine battery and it is recharging as i go? i do have an isolator so not sure how it is 'supposed' to work?

my next move is to start checking wiring off my switch to see if there are any issues with #1 terminal? it looks like i have inline fuses coming off my switch? if my #1 switch position fuse is blown it wouldn't work at all? i also have a wire near my alternator that is not connected. i haven't traced it back to see where the other end goes though and not sure if it has any power going to it. it is all taped off

engine running i was getting readings of 12.4 to 12.7 depending on which battery and what switch position.

i am going to take my original alternator tomorrow to get it rebuilt and hopefully they can bench test it to see what the output is.

EDIT: just looking at my manual and wiring diagram shows an orange wire that is supposed to go from the alternator to the starter. pretty sure this is the wire that is not connected to the alternator but will have to look again next weekend to be sure. what would happen if that wire was disconnected? what does that wire do?
 
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boatman37

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just talked to shop that is rebuilding my original alternator. its done. they said the alternator was fine but the voltage regulator needed replaced. i asked if they replaced the 2 wires coming out the back and they said that is the VR. oh. ok...lol. the insulation was broke off of these 2 wires so not sure if the VR was actually bad or that they replaced it because of the wires? either way it is going back on the boat and i will be taking the DB Electrical alternator up there to have them test it to see how it reads
 

boatman37

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picked up the rebuilt alternator today. the new wires coming off the back are now red and blue. the guy told my wife that they don't match the old colors but that they only needed to be connected to 12v hot wires? i guess these wires are for the VR? is that accurate? can they be hooked up either way? i think the originals were purple and red? this is a Mando alternator if it makes a difference
 

bruceb58

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Mar 5, 2006
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Look at the terminals that the wires come from. One will be the excite and one will be the sense more than likely. You should tie the sense to the alternator output if you don't need to remote sense. Excite needs to be hooked up to your ignition lead so that it is a switched 12V.

Have a picture of the back?
 

boatman37

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i pulled the silver cover off the back but saw no markings indicating what might be what. i am going to take a look at the one on there now and see. i'm thinking they are the same color as what is on this one so should be a direct swap (again). i will let you know what i find
 

boatman37

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i haven't forgot. just been very sick for 2 weeks now. finally starting to feel better. i have taken the boat out a couple times with the new ebay alternator and running on switch #2 it was fine. went about 20-25 miles sunday and it was fine. i will try to get pics this weekend
 
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