Topic: 898 SI Battery

[Bretthughes1970]

I am looking for a battery for my depth finder. My preference is for something light.  It will be in a small Jon boat so weight is at a premium. The only thing the battery will be powering is the 898 SI.

[edwardpic]

Have you looked into the small batteries on personal watercraft?....Also check the car audio sites or call an installer in your area...I have used smaller batteries in the past when I was in car audio competition...The PWC batteries may be the way to go...small and lite

[Drifter]

Brett,

I carry two UB1280 (12V, 8AH) batteries in a canoe to run a 798c SI. They're light, cheep and can be carried in any position. I never have tried to see how long one would last, but I have used one for fours straight and it was still running strong. I carry two just to have a plan B option.

Darrell

[sonar2000]

We use the small PWC and/or motorcycle batteries and have no problem with early discharge.  We have run up to 8 hours without a charge,   
Make sure you buy the sealed ones.....
Chuck

[Roddy]

Brett'; HB sells batt's on the web acc page. Batt's Plus has them too. Roddy

[Bretthughes1970]

Looked at Battery Plus website and found a Werker 33 AH for $80. I am assuming that this battery would work. The battery weighs only 20 lbs which would be nice compared to the 80 lb current one that's being replaced.

[Roddy]

Brett; Ck out HB web page ACC. HB has two (2) batt's there. about 5 lbs and $30.-40. USD. Roddy

[titansfan2104]

A lot of those kids hot wheels have 12 v batteries. I bet they would work great , just get one with a good high mah

[tambrose76]

Somewhere I read that the 898 pulls 750mAh.  Look at a battery as a pail of energy that has a lot of those A's in it. Smaller battery, usually les A's. I ran into trouble finding out how many amp-hours (Ah) the garden tractors have, and you cannot do simple math with the cold crank info (CCA). I will tell you that I bought a big, plastic tool box and mounted my 737 and Sat to the top, and used swimming pool toy foam pieces to wedge in a garden tractor battery for ~$40--biggest CCA I could find for the price. Been taking to Ontario every year no sweat, covering the terminals or leaving them disc. for the fly-in.  Can run 350mAh 737 for a week, fishing about 12-16hrs per day, locator on quite a bit of that time.  Uses half the power of the 898, so figure a few long days on the water before hooking up a good, 3-level charger.  Keep the 898 head in the tool box, too, plus the charger.

[Roddy]

The 898 is 789 ma. the HB batt's are 7.0 aph. Lots of power, long use.

[titansfan2104]

All the mah rating does is specify the capacity of the battery, meaning the higher the mah is the longer that battery will produce between charges!!! 12 v is 12 v but the mah will dictate how long that baby will last!!!

[Humminbird_Greg]

But even if you knew the mAh rating of the battery, you cannot do straight math to determine how long a battery will power the device.  For example the 898 is rated at 780mA.  I am assuming that this measurement was made at 12.0VDC and please note that this was with the backlight “Off” according to the Humminbird web site (not sure how you can turn the backlight of an 898 off…).  So we can calculate the power draw of the unit because power is voltage X current and we get 9.36W.  Let’s just round this up to 10 watts so it is easier to deal with.  Now the unit will need that 10 watts of power regardless of what the battery voltage is.  Most 12 volt batteries do not have 12.0VDC when they are at full charge.  Most are in the high twelve or thirteen volt range.  But, as the battery discharges; the available voltage will start to drop and as the voltage drops, the current draw of the unit will increase to keep drawing the same 10 watts of power that it needs to operate.  At some point the available voltage will drop low enough such that the 898 unit will automatically shut off.  Without knowing the voltage of the battery at different times while it is connected to a device with the same power needs as the 889 we cannot calculate just how long any battery will last.  You could do some ballpark estimates though as some battery manufacturers have discharge curves posted on their web sites.  Try and match the current draw of your unit to one of the current discharge rates shown but be aware that the cut off voltage for our units is around 10 volts.

Don’t forget too that although a battery may say 7Ah on it, that in fact could supply more amperage than it is rated at when it is new and fully charged.  Know too that how the battery has been used (discharged, charged and cared for) as well as the temperature that it is used in can affect the available power from a battery.

...but I would think that a 33Ah battery would last for more than one day of fishing!