deep cycle battery output.

[jurgenscraft]

deep cycle battery output.

I have two 90 amp 12 volt deep cycle batteries that I want to connect in parallel ( posative to posative , negative to negative ) and use this to run a 12 volt trolling motor system.this type of setup should give me 12 volts at what amperage?in theory double the amps,this is not true because as the batteries discharge as they are used, so the power available will decrease and no battery system is 100% effecient, I would like to use a minnkota 30 lb thrust trolling motor.How long should I be able to troll using the above mentioned trolling motor, I use a seperate battery for starting and other accesories,<br />Kind Regards William Wright

 

[notarealone]

Re: deep cycle battery output.

Re: deep cycle battery output.

Do a search on the internet for the formula for Ampere's theory, and also Mr. Watts theory on power. Both forumla's will tell you what you need to figure this out. You will need Mr. Ohm's theory to figure resistance in a circuit. Any high school science book has these theorems.<br />Here is a good website for those Laws of electricty.<br /><br /> http://www.elec-toolbox.com/Formulas/Useful/formulas.htm <br /><br /> http://www.engineeringtoolbox.com/electrical-formulas-33_455.html

 

[Richard Petersen]

Re: deep cycle battery output.

Re: deep cycle battery output.

A 30 amp motor pulls about 30 amps per hour @ full speed. The batteries should put out close to the rated amp hours at say 15 amps. 180 amps of battery divided by 15 = more than 10 hours steady running with no stops. All day with ease if FULLY charged and in good condition.

 

[Dunaruna]

Re: deep cycle battery output.

Re: deep cycle battery output.

Ditto @ cyclops.

 

[Pogo123]

Re: deep cycle battery output.

Re: deep cycle battery output.

I agree with Cyclops2.<br /><br />I have a 1994 Minn Kota 27# thrust - close to yours and with a full charge I can run ALL day on an Optima Blue Top deep cycle and still show about 30% charge when I get home and put it on the charger. <br /><br />I've only done that twice, but on a normal full day's fishing and running the troller about half the time there's over 50% charge left after 14 hours on the water.<br /><br />Then, too ... my favorite boat for fishing the Intracoastal is a 12.5 ft aluminum skiff that I can scull at 3 kts one handed - easy to move. If your rig is heavier with more drag, you'll have to consider that with these numbers.<br /><br />Theoretically, you are correct. A Parallel connection would give 12 volts at twice the single battery amperage capacity, but ...<br /><br />With the setup you are attempting, you could run that motor longer than you'll last ..

 

[jtexas]

Re: deep cycle battery output.

Re: deep cycle battery output.

I use a 34lb motorguide on a 15ft fiberglass bass boat, with 2 parallel deepcycles...on my last camping trip I fished three days without recharging.

 

[18rabbit]

Re: deep cycle battery output.

Re: deep cycle battery output.

Jurgens – you are correct, a battery is not 100% efficient. As it discharges its voltage drops. Also, the faster you discharge a batt the less amps you can get out of it. Presuming you will not be discharging a typical deep cycle batt below 50%, your 90-a/hr battery will yield 45-a/hrs at most. The 90-a/hr rating is based on a 20-hr (or 5% of the batts capacity) constant discharge. That is optimum/industry std for getting the most pwr out of a batt. To get the full 45-a/hrs out of your 90-a/hr batt, you should not exceed a load of 5% of the batt’s capacity (4.5-amps) over 10-hrs. Two 90-a/hr batts in parallel will get you a 9-amp load over 10-hrs. You can discharge a batt faster (over 5%) but the voltage drop will increase exponentially, i.e. you won’t get 45-a/hrs out of the batt before you reach the 50% discharge limit. A 45-amp load on your 90-a/hr batt will reach the 50% discharge limit in as little as 8-mins but typically about 15 to 20-minutes, not 1-hr as if the batt was efficient. How many a/hrs you get out of a batt is relative to the rate a discharge, every batt has a spec showing this that you should be able to get from the manf.

 

[Richard Petersen]

Re: deep cycle battery output.

Re: deep cycle battery output.

Rabbit, read what is really happening to people who use trolling motors in water.