Batteries

[westtx]

I need to add @ least 2 AGM batteries to my boat how are they supposed to be run? Are they supposed to be in parallel? Pics or diagram would be greatly appreciated.

[Jason B]

Run them connected neg/neg and pos/pos, that keeps them at 12volts and makes one "big" battery. Connecting them neg to pos will create 24 volts and will likely damage your equipment or cause unwanted negative outcomes. I'm not sure which terms (series or parallel) refer to which scheme, but DO NOT connect the +/- or you will be angry!

[westtx]

Thanks, This is what I was told about the extra batteries, "You do need a better deep cycle battery and prolly a second one, if you plan
on playing those 3 amps for longer than an 30 mins to an hour. Your max
current draw is 280 amps. The deep cycle the boat came with has a capacity
of 50 amps over a few hours discharge. The battery we use for this are Sea
Volt AGMs. (Absorbed glass mat technology) They sell for $230 apiece. I'll
do $210 a piece for you, if you choose to do that. Having the extra
batteries also keeps you from destroying the alternator as fast." Does anyone know where to get these batteries and should I replace my alternator with maybe a little bit better one that will be able handle the amps?

[chpthril]

Are you adding a 2nd deep cycle to the factory EIDB dual battery system, or adding 2 new deep cycles to a single battery setup?

[dogbert]

I'd send a PM to wetsounds1 (Tim White) and ask him what he did on his RZ4. I know he had multiple batteries because he had a ton of amps in his boat.

[chpthril]

Thanks, This is what I was told about the extra batteries, "You do need a better deep cycle battery and prolly a second one, if you plan
on playing those 3 amps for longer than an 30 mins to an hour

.
I'm guessing their idea of a 'better' battery is one with a higher Ahr rating. Do you know what the rating is on the current battery, probably 100 or 120 depending on what group # it is and what's the Ahr rating of the SeaVolts they are pitching. Amp Hr's is really what matters the most.

Your max current draw is 280 amps

.
Is it just me, or does 280A draw sound a bit high! Do not know what amps you are running, or at what impedance they are wired, so it's hard to calculate what your current draw is, but most peeps calculate the Ahr/play time at 1/2 volume or 3/4 at the max as it's more real world then playing wide open all afternoon.

The deep cycle the boat came with has a capacity
of 50 amps over a few hours discharge.

A battery with a 3hr play time @ a 50amp draw is a pretty decent battery, that's jamm'n pretty good IMO

The battery we use for this are Sea
Volt AGMs. (Absorbed glass mat technology) They sell for $230 apiece. I'll
do $210 a piece for you, if you choose to do that. Having the extra
batteries also keeps you from destroying the alternator as fast." Does anyone know where to get these batteries and should I replace my alternator with maybe a little bit better one that will be able handle the amps?

Adding more batteries wont really make the job easier on the Alt, as 2 half run down batteries will still take time and energy to replenish just like on e fully dead. Your best bet is to install an on-board charger/tender to plug up at the end of day or weekend and not rely on the alt to recharge the stereo bank.

[westtx]

Yes, I was going to add 2 deep cycle, making my total of 4 batteries. That amp draw maybe a little high, but that is probably playing the stereo 3/4 to full and having the led's on @ the same time. I will have to look @ my amps, there is a total of 3of them. 1 is the syn 1 cant remember which wetsounds the other 2 are. I am planning to buy an onboard charger and mount it in the boat and charge after our daily outings, but I dont know which one. I will pm Tim or something I know that he had a total of 6-8 batts. I appreciate all the help.

[chpthril]

Yes, I was going to add 2 deep cycle, making my total of 4 batteries. That amp draw maybe a little high, but that is probably playing the stereo 3/4 to full and having the led's on @ the same time. I will have to look @ my amps, there is a total of 3of them. 1 is the syn 1 cant remember which wetsounds the other 2 are. I am planning to buy an onboard charger and mount it in the boat and charge after our daily outings, but I dont know which one. I will pm Tim or something I know that he had a total of 6-8 batts. I appreciate all the help.

Ok, I gotcha, 3 deep-cycles. I'm not a fan of mixing different types of batteries unless they are isolated from each other as they charge at different rates and the alt can leave you with an under or over charged battery(s).

Once you have an accurate current draw of your system at a reasonable volume level, then decide how much play time you want in a day, then you can calculate the Ah's needed. If it looks like you need or want a 3 deep-cycle battery stereo bank, I would get the AMG's and make them a stand-alone stereo battery bank not tied into the boats charging system. If you want to tie it into the alt, you would probably want to upgrade the alt. 3 run down AMG's is a pretty good load on a 90amp battery.

[SPBFAN]

3 run down AMG's is a pretty good load on a 90amp battery.

I think he means alternator.

[Domsz06]

you could also do a search on this site. There are a ton of topics on batteries here.

[chpthril]

I think he means alternator.

Good catch, SPB, thanks, I did mean Alt.

[westtx]

Thanks guys for all the help. I only have a month or two before I get the boat sumerized, so I have to decide soon. Once again thanks for all your knowledge.

Freddy