I was wondering if someone could help me out by telling me how much run time I could get on the Garmin DV 151 using a block that holds 8 D batteries? From many of the posts I have read on this forum I know there are some fish finder gurus. MagicPaddler?

Thanks,
DJ

I looked at the owners manual and it lists the Rated Current as 1 amp. I doubt that unit draws an average of 1 amp. I would guess it draws less than .2 amps but that is just a guess. IF you assume it draws .2 amps using the curves on the Duracell Coppertop sight it would run about 19 hours on 8 cells in series before the voltage dropped below what the manual says it requires of 10 volts. IF you put 10 Coppertops in series and IF the detector drew .2 amps it would run about 57 hours before voltage dropped below 10 volts. Without knowing how much the detector draws on average I can’t give a better estimate than this.

That helps a ton Magic. Thank You for your help. Looks like I will pass on this unit.

I too have the Garmin 151dv. Just got it form Cabelas on clearance for $80. I got it rigged up today and put a meter on it to see what it was drawing. Cause I too read the manual and said " no way it draws that much," My results were good. It ran right around 100 milliamps or .100a. That was with the backlight off. With the light on full it bumped up to the .140a range. Changing the transducer from Downvue to the 200 kh and 77kh didnt make much of a difference in draw. To power mine i just ordered 8 18650 Panisonic Li Ion batteries. And two 4 space series battery packs with leads. The batteries are 3400mah , so paralled that would give me 6800mah.
6800ma / 100ma = 68 hours of run time. At the combined weight of 8.2 ounces , plus whatever dry case I decide to put it in. Can't wait to get out and test it out before my May 21st trip. I'll keep you posted.

Trailcheif
I am suppressed it draws that small amount of current but I would trust your meter far more than my guess. That is good news that it only draws about 100 mA. Can you see the display while outside with the back light off? What kind of meter did your use to measure the current? Does your meter have settings to measure peak current and average current?
This year is the first year for using the Panasonic Li-Ion PROTECTED batteries for me. I have been out on the water 4 times and had the detector on for about 12 hours and the batteries are still doing fine. With my detector they should be getting fairly low so I will need to check them before I go out again.

Yeah, I was a bit surprised too. The display should be fine out in the daylight. It was easy enough to read under the fluorescent lights in my garage. The backlight seems to be just for low light conditions . My meter is a fluke. It does have a min, max, and average setting. Although I did not mess with any of those. Im glad you mentioned the" PROTECTED" part. I however did not order those. So I probably will be returning them. I realize how dangerous they can be. But if if they were charged carefully, and not ran down too low. Is there that much risk? The fish finder shuts down around 10v I believe. Im not recommendeding this for anybody. Just bounceing Ideas around.

If you can return them I would recommend returning them or exchanging them. Chargers that are meant to charge them will automatically shut down and not over charge them (That type of charger cannot charge multiple cells in series without a lot of wiring). The problem is with discharge of cells in series. These cells do not balance well. They are all listed as 3400 mAh but one of them is a little less than the others. That one will go below it minimum safe voltage before the bank goes below the operating voltage of the detector. If the first time this happens it does not destroy the battery it will reduce the capacity so the next time it will happen with even more power left in the other cells. I would not know this if I had not already destroyed several cells. If you cannot return them email me and I can suggest some less than optimum possibilities to partially protect them.

Thanks for the advice MP. I have been reading up on them. What i have read is exactly what you are saying. The packs I bought are just the basic spring loaded type with an individual spot for each cell. So i think removeing each one after use, checking them with a meter. Then charging them as idividuals is the key. I even read an argument that the protected cells might be more dangerous. Giving you a false sense of security. That the built in protection can just as easily fail. So the way I'm looking at it, just like anything "dangerous" in life, Guns, Power Tools, Vehicles,,,ect. It's all about safe handeling, and using common sense. Maybe I'll just cgarge them in my fireplace! ??