Bait tank pump & battery life

[seaslug]

I think I know the answer but.... My Thresher tank runs the battery down way too fast, especially if I am also running my fish finder from same battery.

Pump is a Tsunami T-500, 13.6V @ 1.9amps. If I restrict the water to avoid beating up the bait the battery probably wears down even quicker with the load increase.

If I go to a 6V battery the current should go down to half and therefore run the pump slower and longer... right?

This would also solve some of my problem with the fish finder operating erratically most likely.

Downside is carrying 2 batteries with no backup possible.

Any suggestions?

[seaslug]

I just went back to Fry's and got an 8 ampere hour battery (my other is a 7 A/H) in 12 volts. Last time I went out I did fine with both on one battery but ran the tank only about 2 hours.

[jonee523]

Steve,

I just ordered a timer for my bait tank from cabela's. It runs 3min off then 30 secs on. It has a switch that allows for continuious or timed running of the bait tank. I'll let you know how it works when it arrives late next week. I saw it on a thread on plastic navy if you'd like to see it.

jon

[seaslug]

Sounds like the same one that Liquidfishing sells for over $30.

Steve

[seaslug]

I just went out and bought a second 12v battery (this one 8a/h). If you want ot buy the 7a/h let me know.

Steve

[PerryC]

Steve,
In theory, you're correct about current getting reduced to about half with everything else being the same. I originally used a flow restrictor with a 12 volt battery in the beginning, but have since switched to using a 6volt battery because if something happened to one power source, I would still have the other one to use. But, using one 12 volt power source means one battery and set of connections to maintain, instead of two which is easier. With current draw, I dunno if this will help or muddy the water, but it's part of the page we have here on gel-cell batteries.

<-- Start -->
Capacity, expressed in ampere-hours(AH) is the total amount of energy available from fully charged batteries over a 20 hour period.

Discharge Rate is expressed in milliamps(mA) provides the constant current discharge for a 20 hour period. For example, a gel cell battery with a rating of 7.0AH will deliver 350 mA for 20 hours. For a typical example, lets use a fish finder. My Humminbird draws about 250mA. So a battery with a 5.0AH rating would discharge at a rate of 250mA for a period of 20 hours. More than enough for a few days of fishing.

When is a battery considered discharged? It depends on a batteries rated voltage, which for our uses is usually 12volts. Batteries are made up of what are called "Cells". A cell is considered fully charged when it's voltage is a little over 2.0volts. Therefore, a 6volt battery would have 3 cells, and a 12volt battery would have 6 cells. When the voltage of a individual cell drops from a fully-charged state of 2.0volts to 1.75volts, the cell is considered discharged. Therefore, when the voltage of a 6volt battery drops to approx. 5.25 volts (3 cells X 1.75volts=5.25volts), it is considered discharged. For a 12volt battery, a discharged battery would measure about 10.5volts or less.

What is the useful life for a Gel Cell? There's alot of variables, but a few of the manufacturers say somewhere of 200+ charges/discharges. This is largely dependent on how deep the battery was discharged and the charging methods used.

What is the "Battery Memory" I hear about? What this means is that if a battery is repeatedly only partially discharged before recharging, the battery "forgets" that it has the capacity to further discharge all the way down. Lead Acid batteries DO NOT develop any type of memory.

What type of chargers do you use? Chargers made for charging Gel-Cell batteries. Chargers for these operate at a lower voltage and current as stated above. Charging these batteries at too high a voltage/current can cause premature drying of the electrolyte and greatly shorten battery life. Most chargers operate in the 200-800mA range. Some of the better ones automatically switch from Fast/Full Charge to Float Mode where the battery is safe from being over-charged.
<-- End -->

Hope this helps in some way,
Perry

[seaslug]

Thanks Perry, as usual you provide great help. I was a bit confused when you say you use 6volt battery (do you have a separate 12v for the fish finder? I don't believe the fish finder will run much under 8v - at least not my Garmin. My FF lets me set an alarm at 8.5V so that I can shut down the bait tank pump and keep using the FF.

From my old days launching satellites the lead-acid batteries DO develop memory and the gel battery I just purchased says "lead-acid gel" and it has some memory.

You are so right about the charger. I used my "smart" auto battery charger on my old 8ah battery and got away with it about 10 times. The 11th time the battery swelled up to about double size and had most of the cells dead or severely damaged. Still kind of worked for a while but died completely.

I went out and bought a new 12v 8ah.

Steve

[PerryC]

Seaslug,
Yes, I have a dedicated/separate 4ah 12volt battery I use for my Fish Finder. That's a really handy feature on your FF that allows you to set an alarm for low supply voltage, very very nice. Also, Thanks for letting me know about the memory clarification. I'm going to look into it in detail with a few of the manufacturers and make what corrections are necessary for accuracy. Again, THANK YOU!

Perry

[Piranha]

I use a 6volt SLA 12 amphour battery for the bait tank. It works all day(and I mean ALL day!), and provides sufficient flow to keep the bait frisky! The only time I've ever had a slight problem was in the middle of summer when the surface water temp was a lil too warm. I use a separate 12volt battery forthe FF. This works well because the bait tank is behind my seat and the 6v battery goes in the seatback pocket! The 12vv. battery rests in the bow in the milk crate, right in front of to the FF! When I tried a 12 v. battery on the bait tank, it was like putting the dines in the Niagara River! They all died very quickly! If you shop on line, here's a good link for batteries and chargers! I've done business with these folks! I'm not sure how many amphours you need for the FF battery. It doesn't draw energy like the bait tank pump! Good luck! Piranha

6 Volt 12 Ah Sealed Lead Acid Battery: BatteryMart.com

12 Volt 7 Ah Sealed Lead Acid Battery: BatteryMart.com

[seaslug]

Thanks Piranha. I just sent off for the 6v battery. The price is great although with shipping it is almost identical to Fry's with tax. Plus you need a separate 6v charger which again raises the price.

Lower flow rate will be worthwhile to help keep the bait going. The anchovies are much more delicate than the sardines which are much more delicate than the smelt. The smelt do fine in a bucket with just a bubbler.