Humminbird Side Imaging Forums
Side Imaging Forums => 997c SI, 998c SI & 999ci HD SI => Topic started by: SkeeterMatt on July 29, 2011, 06:19:18 PM
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is this calculated as an hourly incremint or is it a steady current needed to run the unit? i'm not much of an electrician but have been studying. say i have a full charge at 14 volts, is there a calculation i could use to figure out hours before my boat won't start?
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Voltage is important, but when talking about longevity for any electrical draw, amperage is more important. Most 12 volt electrical devices will run as long as the voltage stays above 10.5 volts.
The draw rating is how much the unit draws anytime it's on.
The battery amp hour rating is very important.
Let's say you have a battery that is rated at 100 amp hours.
This battery can run a device that draws 100 amps for one hour or run
a device that draws 1 amp for 100 hours, or run a device that draws 50 amps for two hours.
To compute how long an electrical device can run off a battery, take the amp hour rating of your battery and divide that by the number of amps the electrical device draws, and that will tell you how many hours you can run the device off that battery.
There are also many variables involved:
What kind of shape is the battery in?
What kind of shape is the electrical device in. If it is not operating efficiently, it will probably produce more heat and draw more amps.
Are your cables/wires/connections adequate for the job?
You said something about starting your motor.
If you have a large gas engine, it probably has an alternator in it which will charge the battery while it runs.
It also requires juice to crank the motor. If your motor is not tuned properly, you will waste juice trying to get it started which will run down your battery.
If you have doubts about your battery and electrical devices,, then keep a backup battery on board that isn't hooked to anything. In an emergency, you can hook that to your gas motor to get you home.
Good Luck.
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thank you.....sound advice.
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It is a good idea to have the HB products on their own battery....there are (can be) interference problems when hooked to shared batteries.
Of course this mean monitoring the condition of the isolated battery..and having a way to charge or maintain the battery charge level..
Chuck
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I have both my 898 and 1198, radio and vhf running off one battery in my CC...Those are the only things attached and have a 40Watt solor panel mounted on top of my T-top with a charge controller wired directly to that battery...So far I have never worried about the battery voltage or affecting my starting batteries.....
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that sounds like a great set up ed....I guess my problem is fishing at night, the solar panels sound like a great idea during the cooler months.
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Before I had the solar panel I had the battery set up like described.....I could go all day from 6am to 5 or 6pm with my electronics-vhf-and livewell pump constantly on.....I had a simple guest portable charger and would just charge up the battery after I got home....added the solar panel because im old n lazy....lol
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ITGEEK you have to watch using that simple calculation (100 AHr battery powering a 1 amp draw device for 100 hours). That would work if the electrical device that the battery is connected to will work down to 0 volts. However most will shut down or stop working properly at a much higher level as in the 10.5 volts that you stated. So what you need to know is what the discharge curve of the 100 AHr battery is when connected to a 1 amp device or more precisely: how many hours can 1 amp of current be drawn from that battery before it discharges to a 10.5 volt level. Without that vital bit of information you are just making a guess as to how long it will all work. Unfortunately battery manufacturers do not usually supply this data, so you are stuck guessing or just buying the largest battery you can fit or afford and using it.
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It is hard for the unit to know amps remaining so that is why they show volts. They can measure that.
But look at it this way. 100 amps at 1 amp per hour is 100 hours. Or 100 amps at 3 amps is 33 hours. Most of us wont be fishing that long of a stretch.
Ok so it is a 65 amp battery. That is 65 hours or at 3 amp 20 hours...
I would use amp rating and not worry about volts when figuring time...
Unless you are using multiple items on the same battery. Then maybe a good meter to show amps might be in order...I really dont want to think about going max
so maybe set the volt reading to 11 amps..
Chuck