Humminbird Side Imaging Forums
General => General Discussion => Topic started by: sonar2000 on March 28, 2012, 11:46:03 AM
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We set up a bench test of two units and a standard car battery to test the length of time it could provide reliable amps.
Battery is a 650 cca battery and fresh charged to 12.6 volts unloaded. (12 hour charge at 6 amps)
Connected two units and set both to use the transducers (placed in a 55 gal drum of water)
At power on the battery voltage indicated 12.6 and each unit screen showed 12.3
6 hours later the battery showed 12.4 volts and the screens showed 11.8 volts.We will leave this on for 12 hours of test and report back..
GPS antenna is connected but nothing else.
Backlights are on and screen is set for sonar display.
Chuck
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I forgot to explain why we are doing this.
We had motorcycle batteries mounted in the sonar case which would (did) work fine..
But we found that we were recharging them sooner that anticipated and also make the case a bit heavy..
And that it required the case to be removed from the temporary boat location to recharge.
By having an external battery we could simply exchange the battery and continue on with our operations...
Chuck
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If you want real world numbers, in average, you take the A/h capacity of your battery, and take 20% off.
Since you shouldn't discharge a deep-cycle battery below 12.0V or 80% full capacity.
So if you start with a Group 27 deep-cycle of around 100A/h capacity, you start your calculation with 80A/h of "usable" current.
Then, you shave again a 20% margin, to which gives you around 64A/h, to account variables internal losses.
Now just measure the current drain of your unit and divide that by that value (64) and you should have a gross ballpark value with some room to spare.
I know that 700 series unit consume around 0.8-0.7A/h
If your units show lower voltage that at the battery post, you have problems in your wiring.
My units always shown the same or 0.1V lower.
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Looking foward to the results :D Thanks for your experiment. BTW
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xSil, thanks for the explanation of current and voltage.
This is good for a calculation of expected time of use, but we wanted to know for sure what actual usage would result in.
We just did not want to run short on a search. Or to know when it is time to swap out to a charged battery.
Good point on the total discharge of a battery. I am thinking that the unit will not go beyond the 80% before it starts to show some inconsistencies.
Since the reading on the unit is different than that actually is in the battery we are setting a point to swap before totally discharging..
Our battery is not connected to the boat so it does not get a charge until we remove it and take it to a charger..
It may be unique for us but we want the search to go for as long as it is needed..and not have to take a timeout for a charge..
We may take a sd card recording and review at the shore on a pc but still want the sonar to be recording the next area in case the review does not show anything new..
Thanks for your information as this may be helpful to others.
Chuck
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Just for your information, Humminbird unit will work flawlessly at 11v, which is way too low for a standard lead-acid setup..
A 1198c SI is stated with a consumption of 1.4A/h.
So for 12 hours search days, you need a 25A/h battery for each days...
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OK, we are running two units on the battery. one for sonar and one for navigation to ensure a consistent search patterns.
1197 and an 1198..
How do we read a battery for amps.
I see a reference to ca and cca.
The ca is 820 and the cca is 650.
What does that mean in battery capacity for usage?
We also use the sealed acid battery so we dont leak any outy or let is get low as the filled batteries can do...
Chuck
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End of 12 hour test:
The supply battery reads 11.8 volts.
The two units read 11.4 volts.
These measurements are taken while all are connected and powered on and running. (under load)
So for our purposes we can expect 12 hours per shift for use and could push it somewhat farther...
that is good news.
Chuck
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Thanks Chuck this is good to know. And gives a good comparative marker with which to give a general assumptive. ;D Now I know the transducer of the 898 c si is touchy on weight distribution on my boat. And another full size battery "Two monsters already for the TM and a full livewell" would tip the scale, but I can deduce that one at half the Ah's as your test. Would give plenty of juice for a days fishing,for the Bow finder :D Nothing A bump down won't cure :P
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If you can, try to not dip the battery below 12.0V
At 11.8V, you start killing them with reduced life expectancy..
You can't derive the capacity from the CA/CCA unit. These are the max amp the battery can supply for a very short period of time...
SLA batteries are the way to go for your setup. You can obtain larges ones in the 70 pound region.
For you, if you run dual units, you will need around 50A/h battery.
Something like that would be perfect for you at 38 lbs.. not to heavy to lug on the boat..
http://www.batteriesexpert.com/27tmx.html/wp60-12-batt-agm-12v-60a-sealed (http://www.batteriesexpert.com/27tmx.html/wp60-12-batt-agm-12v-60a-sealed)
Just to get you an idea of size/weight.
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Chuck,
One way to greatly extend your run time and not EVER have to worry
about it again, is to hook two fully charged batteries together in parallel.
You'll get more total run time this way than if you ran one battery down,
then exchanged it out for the other fully charged battery.
Just hook a wire to each battery's positive terminal.
Then hook a separate wire to each battery's negative terminal.
Hook your devices to one of the batteries.
It doesn't matter which one.
See the below diagram:
http://media.photobucket.com/image/batteries%20hooked%20in%20parallel%20-%20diagram/HawksCraze/Jon%2520Boat%2520Project/12v_parallel.png (http://media.photobucket.com/image/batteries%20hooked%20in%20parallel%20-%20diagram/HawksCraze/Jon%2520Boat%2520Project/12v_parallel.png)
Get yourself a two bank marine on-board battery charger, and just
plug it in when you are done searching for the day.
I would recommend Guest chargers.
This way, you don't need to unhook the batteries again.
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Thanks ITG. Good points to consider for those having boats.
If we had a boat this would be the way to go.
As it is we are portable and can be on any number of different boats even during a mission.
We wanted to be as totally independent as possible realizing we are portable.
The motorcycle batteries worked well if we were not on a mission all that long.
It does have a bit of time concern if on a day long or several day long search.
We anticipate a two battery supply but only one at a time as we dont want to lug a lot of equipment on someone elses boat but can switch if needed.
Sometimes our searches can go on over night.
Most sites will have a generator or a location near by (a fire station or law enforcement building) where we can take our charger and replenish the low battery.
It would be so simple if we had a boat but because of our travel distances we chose portable. And the guys here at home let us put the portable in their boats.
We sometimes fly to a site so having a boat does not help..
We have never been to a mission where the local guys were not willing to hlep.
We get such good support it spoils us...
Chuck
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If your main goals are portability and long run times, than perhaps you should look at a different battery technology: Lithium batteries. They can store more amperage per pound of weight than a lead acid battery and they can accept very fast charge times. The downside: they are very pricey and you may not be able to take them on the airplane with you (check regulations on this).
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I have a left over deep cycle from grandpa's hoverround scooter thingy sry can't remember the name of it. It's not a full size battery but it has plenty of aH like 54 and will fit inside the cubby hole up front for a anchored mount pretty easy. Then I wouldn't have to run wires more than about two an a half feet. And the 898 at the console is being rewired straight to the cranking battery with a blade fuse inline. One of those on board chargers is now in order. And a possible tweak on the transom mounted transducer :)
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Yea,
One of my dreams is to eventually replace all of my boat batteries with Lithium-ion.
I have 7 batteries on my electric only boat.
It would shed at least 150 pounds if I could do it.
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Seems we have two conversations here.
On battery type. the air line most of the time will not allow you to ship (carry with you) a car battery.
We fly our own plane so dont have that restriction.
Lithium or lead acid makes no difference as we need power anyway we can get it..
SAR is a bit more demanding than fishing.
Sorry fishing guys. I know you need to find the fish also.. ;D
Chuck
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one more thing to remember, even tough the units seem to work fine with low voltage. they sometimes miss important details, and do not preform as well as you may thougt or wanted it to. but its nice to know how long its expected to last. :)
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good point.
for SAR to miss a target is just not going to make for a good day..
As you pointed out we dont need to be working with low voltage.
thanks to all who have given information to this subject..
when we utilize sonar on a SAR mission we need to walk away from the incident with either having found the target or to be able to say with 99% confidence that the target of interest does not exist in the searched area.
Any thing less and we have not done our job..
Chuck
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The 18V lithium-ion batteries commonly available for cordless drills might be a nice solution to powering these sonars if weight is an issue. It would be easy enough to scavenge an extra charger for these to create a quick plug-in battery interface for the sonars. If you carried 3-4 or more of these, it would weigh 1/2 of the lead acid battery weight, for a given capacity. Plus, you then have redundancy in the batteries, and quick-charge capability if 120VAC is available.
The maximum input HB specifies is 20V, at least for the 1197, and the sonar's power supply is a switcher, so the input current goes down significantly if the input voltage is higher. In other words, the power draw is almost independent of the input voltage. Again, at least it is on my 1197, as I have measured it in the past.
Perhaps Greg can chime in as to whether this is true of all the HB SI units?
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The 18V lithium-ion batteries commonly available for cordless drills might be a nice solution to powering these sonars if weight is an issue. It would be easy enough to scavenge an extra charger for these to create a quick plug-in battery interface for the sonars. If you carried 3-4 or more of these, it would weigh 1/2 of the lead acid battery weight, for a given capacity. Plus, you then have redundancy in the batteries, and quick-charge capability if 120VAC is available.
The maximum input HB specifies is 20V, at least for the 1197, and the sonar's power supply is a switcher, so the input current goes down significantly if the input voltage is higher. In other words, the power draw is almost independent of the input voltage. Again, at least it is on my 1197, as I have measured it in the past.
Perhaps Greg can chime in as to whether this is true of all the HB SI units?
I don’t know Mendota but if I had to venture a guess I would say that it was true of all of our units. We try and use common circuitry (and therefore common components) in an effort to keep costs down.
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The problem with power tools batteries, is that they don't have a big capacity....
And for the price and the trouble of switching batteries all day, it would be a pain...
The best here for this application, is running SLA (sealed lead-acid) batteries.
The main question is, how much weight you want to lug around..
50 to 100 A/h batteries will permit 12h+ of ON time..
Which is 40-80 lbs depending of capacity.
Like I posted, a 50A/h battery will last more that 12h each at 38 pound.
Just keep 2 on hand to have 24h+ runtime for an entire 2 day weekend, or 1 day use when the other charge.
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We think that a sealed lead acid will do the job. We probably will use the 60 amp battery as it tested out on the bench with two units for 12 hours..
It is not very heavy and lends itsself to portability and ease of use.
And it easy to recharge..
Thanks to all who have provided their thoughts.
Chuck
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Here is a guide for battery size and A/h rate.
Some common battery size codes used are: (ratings are approximate)
U1 34 to 40 Amp hours 12 volts
Group 24 70-85 Amp hours 12 volts
Group 27 85-105 Amp hours 12 volts
Group 31 95-125 Amp hours 12 volts
4-D 180-215 Amp hours 12 volts
8-D 225-255 Amp hours 12 volts
Golf Cart & T-105 180 to 225 Amp hours 6 volts
L-16, L16HC etc. 340 to 415 Amp hours 6 volts
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Thaks, that is good info.
Most of the car batteries are listed in CA and CCA.
Chuck
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But car batteries are "starting" batteries, so they put the relevant data in CA/CCA which is Cranking Amps.
For real deep-cycle batteries, the capacity is expressed in "minutes" or "A/h" as it's what people using these batteries want to know.
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would be nice if we could see both.
I agree that CA or CCA means nothing to me for extended use..
Oh well. Just more information for us to process and remember..
Chuck
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We had a sonar search last Wed and we had connected two units to a single car battery and were both using sonar and back light.
They started at 12 volts displayed and finished 10 hours later with 11.8.......
We made several recording also..
No sonar interference was detected also..
1197 on the bow and 28 feet to the rear was a 1198.
Chuck
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hat eto bump a old topic.
Dont just connect batters in parral and leave them espically if they are miss matched. each battery has its own reistance and tehy will act as a load on each other sure its not a lot and fine if you are charging them or running them but keeping them like that will end ina dead battery.
think of it like leaving your interior light on sure its a small drain but we all know it will end in tears.
pplease note the stated 1.4A draw im pretty sure doe snot include back light and might not include stuff like gps searching for saterlights or teh cpu recording data onto the card.
CCA is cold cranking amps and not ideal for long term drainage.
a/hr is amps per hours. eg a small 7a/hr battery will last 7hrs at 1 amp drain. how ever this does not mean at 2 amps it will last 3.5hrs or even at .5a it will last 14hrs. Cause the extra amp of power might heat the battery meaning it will use more juice, but still should be ok.
also CCA and deep cycle batterys (a/hr) have different voltages they prefer to be at. eg we charge our car at 14.4v how ever a sla should be closer to 13.8v.
Batterys can be cold cranking and deep cycle my allrounder abttery is both its a calcium and actully likes a voltage closer to 14.7v
from memory my battery in my kayak is 750cc and 120a/hr the battery is teh size up that most trucks would use. darn heavy and ive never really used even half its capacity but hey it doe steh job.