Battery question on amp hours

[Line Dancin]

I already have a two bank system that everthing on the boat is connected to. But: After going to a seminar and talking with Lance Valentine. It was suggested to have a battery not in the charging system to get away from noise issues. I have had a noise issue and am considering doing this to eliminate my noise problem. I have determined it to be when the engine is running , when i shut off the engine my noise problem vanishes. So i am looking at two different batteries a 105 amp hour and a 115 amp hour. What does the amp hour rating mean. How long would a battery last running a fish finder gps combo unit HDS-5 and a marine radio.

[Nailer]

Aaron what is the amp draw for the units you want to run?

A 105 Ah battery can sustain a 10-Amp draw for 10.5 hours before reaching 100% dead.

A 115 Ah battery can sustain a 10-Amp draw for 11.5 hours before reaching 100% dead.

The more Ah the longer it will last.

This site may explain it better.

[Line Dancin]

i cant find anything is the manuals that tells me that. I am elertrically ignorant so i am not sure what to even look for to be honest

[1mainiac]

A little clarification on amp hour ratings and cycles first off most batteries are considered dead at around 10.5 volts taking a fully charged battery down to this point is considered a cycle. Deep cycle batteries are rated by amp hours and cycles as Ken stated a 105 amp hour battery will provide a 10 amp draw for 10.5 hours and be ready to recharge however many 12v loads will continue to work below 10.5 volts so you can actually continue to use the battery however it will damage the battery eventually. I brought my 18ft Starcraft in from several miles out on a Minn Kota trolling motor and it made it back but ruined 2 batteries doing it. To have a good idea of what you need you need the power requirement for everything you plan on running on it and try to give a 20% or more buffer because as the voltage begins to drop the amperage will go up. I guess I would like to know what the noise is and just filter it out solving what is likely more than one problem.

[Line Dancin]

I talked to johnsons in ludington and they think it is the alternator. the plugs are new and wires new last season. It has a new distributor in it from three years ago and the cap and rotor replaced last season in the tune up also. When they did the new distributor i went to an electronic and got away from points. I really dont have the money right now to do an alternator as i am still not working very much. I had the alternator rebuilt about 4 years ago. I did put an inline filter in for the marine radio. it cut down the noise but i am still getting some noise when transmitting. The fish finder i have to use the built in noise reduction which decreases the sensitivity on the unit. I want to be able to use it without having the nosie reduction turned on. i have on the one battery the boat connections to the post and the marine radio and the fishfinder to the other post. the down riggers and other stuff is hooked to the second battery.

[1mainiac]

How about letting it go for a bit and we can get together when the weather warms a bit and see if I can verify the problem. If it is the alternator it will likely be causing other issues but lots of electrical interference problems are easy to fix esp once you zero in on what they are. Rewiring you boat to not fix a bad alternator is not going to solve the problem.

[Line Dancin]

OK sounds good Jim. I have no clue on electrical stuff.

[Eliminator]

I have a noise issue with my CB radio. I had the same noise with it on my old boat and moved it to my new boat and it still makes noise. Whenever a fish finder is on it make a pulsing noise like the MIC trigger. If I turn the Sonar off it goes away. It’s like the antenna is picking up the sonar. Any thoughts?

[Line Dancin]

Is it a CB or a Marine Radio (vhf)? My dad used to get that noise in his small boat. He put in a filter and it helped. But that was back in the day of paper graphs. I hate electrical problems like that. this is similar to what he used. I also put one in last summer trying to take care of my problem:

http://www.sportsimportsltd.com/10ampauelnof.html

I have another one i am going to install on the fish finder.

[jimcr]

I have a noise issue with my CB radio. I had the same noise with it on my old boat and moved it to my new boat and it still makes noise. Whenever a fish finder is on it make a pulsing noise like the MIC trigger. If I turn the Sonar off it goes away. It’s like the antenna is picking up the sonar. Any thoughts?

where is your antenna located ? How is it grounded , the same with the radio and your locator. I would also check your SWR on the antenna. That it self will tell you if your ground is good on you antenna. Is your boat aluminum or glass.

It sounds like a ground issue or its just too close to the antenna or radio.

Have you tried a different antenna?

[Eliminator]

It is a Lowrance Marine radio.

The antenna is on the oppisite side of boat. I know the radio is not grounded only hooked to a positive and negative ternminal stripe with not filter. My boat is fibergass. Do I need to ground the antenna and radio together plus the battery? The antenna is 15 years old, and the radio is 2. Is there a compatabilty issue?

[jimcr]

No the antenna is grounded through the cable to the radio, Is the antenna for Marine radio? or is it a CB antenna. Check your cable for cuts and damage. The cable is shielded but if its damaged it could gather interference. Does the transducer cable run in the same place as the radio coax.