batteries and alternator

[cincired...soxnation]

Since upgrading the stereo with Memphis Audio and 2 X 15" Kickers i have had some battery problems.... I have isolated a optima yellow top deep cycle as a starter and have one deep cycle houseboat battery and a second regular deep cycle, up by the stereo, wired in series. The installer also put in a capacitor for the subs. After 1.5 seasons (one winter) the houseboat battery and second deep cycle were discharged and could not fully recover on charger. When running I charge all, but think with the stock 60amp alternator I am not putting back what I am taking out running stereo when tied-up. I was told a 120 or 140 amp alternator can be installed that would help.

2002 Sundeck 240
MX6.2L MPI Bravo III MCM

 

[fc3]

Since upgrading the stereo with Memphis Audio and 2 X 15" Kickers i have had some battery problems.... I have isolated a optima yellow top deep cycle as a starter and have one deep cycle houseboat battery and a second regular deep cycle, up by the stereo, wired in series. The installer also put in a capacitor for the subs. After 1.5 seasons (one winter) the houseboat battery and second deep cycle were discharged and could not fully recover on charger. When running I charge all, but think with the stock 60amp alternator I am not putting back what I am taking out running stereo when tied-up. I was told a 120 or 140 amp alternator can be installed that would help.

2002 Sundeck 240
MX6.2L MPI Bravo III MCM

You wired two dissimilar 12 volt batteries in series?

 

[boatmailster]

Your are mixing different types of batteries on same charging circuit and they require different charging times/amperage. When you charge all 3 together at the same time, some of them may be under/overcharged while other are getting proper charge.

 

[NateRW21]

First mistake... which everyone pointed out is you're running dissimilar batteries. You SHOULD, if running so all your batteries are charging under way, be running all the exact same batteries.

Second... I'd like to help you with your power draw issue, but without telling what amp(s) you're running and their specific out-put... can't really do anything for ya.

 

[cincired...soxnation]

Thanks all,

I know I should have come here first ... after several lengthly conversations with the "manager" at interstate batteries about all the types of batteries, that is what he recommended. I recall him saying the large housebout, being a deep cycle as well, had the resevoir of 3 regular deep cycles. The stereo guy put one deep cycle up right next to the stereo amps claming that the stereo would draw first from that as it was the closest source and when charging the alternator/charging system would recognize what battery needed most. Local boat guy recommended a optima yellow top as starter (higher CCA) and not using it at all for any boat power. I am going to lakehouse this weekend and will get stereo info. Thanks for your help.

 

[eskimo]

Its true that its best to have same size batteries when charging in parralell, but it's not as crusual as some people think. When the smallest battery is full, it will draw less current than the others. What you definetly need is a bigger alternator when you have this large bank of batteries. It is crusual that you get high enough voltage to fully charge them, and that should be 14,4V @ 68 degrees measured on the batteries. More if colder, less if warmer. I have a 95Amp alternator with an adjustable regulator, and that is regulated almost at max to get 14,4V, charging three batteries which together has a capasity of 250Ah. You can also get external regulators that senses on the batteries, taking account for voltage drops in cables and temperature to get the right voltage. So get a meter and see what voltage you've got when charging. If you only get 13,8, you will never charge the batteries fully.
Fred.