After much research I decided to go with 4 6V Trojan T105's for my stereo bank (separate from alternator or boat batteries). I thought this would be more then enough juice to play my system loudly while floating/partying for at least 5-6 hours. <BR> <BR>I finished installing all my system to find out the volts drop to about 10.3 when my bass hits hard and my sub amp cuts out. <BR> <BR>Can someone please give me some suggestions on what I should do now? My alternator is a 90amp running to 2 blue tops for staring and back up battery’s. <BR> <BR>My system consists of: <BR>JL 1000/1 to 2 12W7's <BR>JL 300/4 to 4 Polk Momo 6x9's (tower) <BR>JL 450/4 to 6 6.5's (boat) <BR> <BR>Thanks for any and all help.

Matt ( xaggie) has almost the exact setup and can proabbly help more. I have just two t-105's. Are you sure the t-105's are good? Have you had them tested? What voltage do they have when fully charged? Are you sure you have them wired correctly? I'm assuming you have those batteries free standing from everything and not taking a charge from the alt. Where are you measuring 10.3 votls at? If your really reading that low, your batteries are dead...very dead.

Jonny: You say "the volts drop to about 10.3 when my bass hits hard" Question what is your voltage when you start out fully charged. #2 after the heavy bass hits your voltage dip's down then what does it pop back up to? <BR>I havent used the T-105's so Im only going to tell you what Mike Ski told me. He said that under a hard load the T105's build up internal resisitance and can give you a low voltage situation. He recomened running a large cap in line with the T105's. I hate recomending somthing that I havent tryed and I dont know works for sure. But what he says makes sence and If I was in your shores thats what I would be doing. Richard(coop) is running t105's with 2 15 inch subs and a big old power sucking 3000watt rockford amp He is running a 20 farid Stinger cap and he dosesnt have the dips your talking about

All the T105's are brand new and fully charged. They are free standing seperate from everything else. When fully charged I'm getting 12.6 at the battery’s and 12.6 at the distribution block next to the amps. I am measuring as low as 10.2 at the distribution block when the bass drops really low. <BR> <BR>How many volts should they be reading when fully charged? I am using a Sentinel 7amp maintainer which I think you recommended. <BR> <BR>Thanks for your help.

I've read that about the golf cart battereis and their technology. A cap would help. But IMO your system is not that big....I'm running 2000RMS to subs with a pair of t-105's and don't have that issue.

check your batts like Adam said. Used T105's before and they seemed like they wouldn't hold a charge for very long. not sure what you have for a charging system, but it may be worth upgrading to ensure you always have fully charged batts when you head out. <BR> <BR>If your batts are good, then i think a cap is in order, like g suggested

Thanks Grant, the highest I have gotten when fully charged is 12.6 (should it be higher)? <BR>After the dip they go back up to about 11.8 right away till the next low bass note. <BR> <BR>Would a large farad cap help even though I don't really have that many watts? I thouhgt a rule of thumb was about 1 farad/1000 watts. <BR> <BR>Thank Grant.

fully charged is 13. could it be the wiring from the batts to the dist block?

These batterys are brand new. I just paid about $400 for them. The charger is a Sentinel 7amp mauntainer I just leave plugged in overnight. It's been plugged in for about 2 weeks.

Check the trojan website for the exact voltage number. I would have your batteries load tested. It's very quick and would 100% rule out a bad battery. They make small hand held testers. <BR> <BR>Haev you tried using a different battery.It should be easy to switch your power/ground over to another battery. Does the same thing happen?

What do you mean by another battery? Dissconect 2 from the bank and use 2 only? All 4 batterys are wired together. Or maybe one of my extra blue tops?

one of your extra blue tops.

Thanks Adam, I will try that this afternoon.

What kind of battery charger do you guys reccomend and how many amps do I need to fully charge these batterys?

Hey Adam, I just hooked the system up to a fully charged bluetop and I got the same exact result???

I havent had any of the issues your talking about.. The cap idea makes sense, but seems like allot of people are fine running with out them..

Sounds like your wiring is undersized to me... <BR> <BR>A cap might be a cheap easy fix for undersized wiring.

Bad Distro block?

I have 0 awg running from both banks grounded to the engine running up to the distribution blocks + &amp; -. What kind of volts should I be geting from the batterys when fully charged? Is 12.6 normal?

by hooking up an optima and getting the same result , you've pretty much ruled out the battery's are bad. <BR> <BR>Did you buy the amp new/used? <BR> <BR>0 awg is more than suffecient wire.

If you are measuring a voltage drop a cap isn't going to help. In order for the voltmeter to be able to get a reading the drop has to be there for several seconds. Any reasonable sized cap wouldn't be able to provide that kind of current for more than 1/100th of a second. <BR> <BR>12.6 volts is the voltage for a fully charged battery. That part is good. <BR> <BR>Those T-105' should be able to provide you with all the current you need. You said you have four, so I assume that you have two sets of two hooked in series, so you actually have two sets of batteries providing you with current. That setup should have no problem delivering several hundred amps. <BR> <BR>I suspect that your problem is in the wiring between the batteries and the point at which you are taking the voltage measurements. Try measuring directly at the battery and see what you get. <BR> <BR>Describe everything between the battery and the amps, for both the Positive and Negative side. Fuse/circuit breaker? How long are the wires? Distrubution block? What size wires from the distribution block to the amps? <BR> <BR>Rod

Thanks Rod. I have O awg running from + to - on bank 1 (16"). + to - on bank 2 (16"). Then I have + to + - to - from bank 1 to bank 2 (8' each). From there the + go's to a 220 anl fuse and straight to a Stinger fused distribution block (22')(the one with a digital voltage display) The ground go;s to the engine block (5') then straight to my ground distribution block (16'). <BR> <BR>From the distribution blocks I ran 4 awg- these runs are shorter then 2' <BR> <BR>I measured the voltage drop with a meter at the distribution blocks not just the digital reading on the distribution block. <BR> <BR>I will measure at the batterys and see if there is a difference. <BR> <BR>Thanks for your help.

Are you by chance using snap or plug fuses? Sometimes fuses cause more problems than they solve. If the 0 gauge can handle the short circuit current the batteries can deliver it does not need to be fused.

This is the distribution block I am using, it uses ANL type fuses. I wonder if this is whats causing the problem. So you are saying I don't have to run fuses on my amps? <BR> <BR><img src="http://www.wakeworld.com/MB/Discus/messages/65921/496220.jpg" alt="Upload">