Battery question

[J.A. Veil]

I have been using a rechargeable 5-amp-hr battery that fits nicely into a Tupperware box that sits in a convenient space in front of my port-side footrest. In my previous Manta Ray 14, I had an older black and white fishfinder. I could get at least two 3-hr trips on a single charge. On my new Manta Ray, I installed a Lowrance LMS 527 5" color fishfinder/GPS. I bought a new 5-amp-hr battery at the same time. I find that my battery now runs out after two hours of usage. I think I am charging the battery to full capacity with my trickle charger -- at least the charging light changes from yellow to green. If the battery is sound, then the only thing I can think of is that the new electronics draw considerably more power.

If my diagnosis is correct, I need a more powerful battery. The challenge I have is that I cannot fit a larger batter in the space where it now sits. My options then are to place a larger battery in a different spot or carry a space 5-amp-hr battery with me that can be swapped out in mid-trip.

I would appreciate any thoughts and suggestions on dealing with this problem.

[bignose]

John,
You might try Batteries Plus.
We have one here in Columbia, I don't know about Annapolis. They might be able to find a battery with a different size configuration, but the same output, that will fit. Or possibly a battery with a larger capacity rating that still meets your dimensional requirements.

[Rockchaser]

You can also take your battery to Batteries Plus and they will test it for you.

Some times you will have to leave it over night.

[lordofthemanor]

When I was looking to buy a new FF, I was told that the color screens do draw more power than the monochrome ones....
Bruce

[ronaultmtd]

I have three batteries a 7ah, a 9ah and a 9ah- the two 9ah are from Cabela's- $19.99 each- like lawn tractor batteries, they won't last forever- cheap enough to swap them out every couple of years- and I use a motocycle battery charger to re-charge mine- seems to take a little longer to re-charge, but it is a deep cycle charge and seems to last a while- the color chartplotters/fishfinders takes a bit more juice, so be prepared to re-charge more often- and the 5 inch models draw more power than the 3.5 and/or the 4 inch screen models...there is no free lunch in fish finders/GPS units- with the extra bells and whistle features, you use a lot more power-

[tufnik]

Two hrs? With a 5 amp-hr batt? That comes out to about a 2.5 amp draw. I know a 5" color FF draws a lot of current, but 2.5 amps?!?! Something's wrong. I believe a color FF like that draws in the neighborhood of 200-700 ma. A black/white FF draws less that half of that.

You might want to check the amp draw on your FF with a multi-meter. Maybe you have a defective FF.

Also, I'm not sure you're getting a full charge. You may want to test it by loading it with one of your spare FF to verify capacity.

Maybe there's some other type of short that ups the amp draw. In the wiring?

[tufnik]

Check your FF specs for input amp draw. Assuming your FF draws 600 ma, you should get over 8 hrs with a fully charged 5 amp-hr batt. Even if all this works properly, for me, that's not enough batt capacity. I would go with at least 10 amp-hr.

It's lighter and it costs more, but a lithium-polymer battery, which is what I use, may be a good option for you, especially when you use big draw electronics.

[DOGFISH]

I use a 12 AH battery and get about 3 time out with my Humminbird 597. In Annapolis there is Stevens Battery Warehouse on the corner of Forest Dr and Chiquipin Round Rd. They should have a battery. Also, I have bought the Cabelas batteries before. They come with a charger. Stevens may also have chargers for the batteries. A small smart charger should also work for the small 12 volt batteries.

Good luck.

[J.A. Veil]

I use a 12 AH battery and get about 3 time out with my Humminbird 597. In Annapolis there is Stevens Battery Warehouse on the corner of Forest Dr and Chiquipin Round Rd. They should have a battery. Also, I have bought the Cabelas batteries before. They come with a charger. Stevens may also have chargers for the batteries. A small smart charger should also work for the small 12 volt batteries.

Good luck.

Don -

That is where I bought the current 5 amp-hr battery last fall. I have both a small trickle charger for that type of batteries and a larger one for car battery size. Both indicate that the battery is fully charged.

[tufnik]

John,
Just because a charger says the battery is fully charged does not mean the battery is healthy and taking a full charge. A bad battery may not take a full or any charge while the attached charger can say it's fully charged. You are assuming the battery is good just because the charger shows Fully Charged.

What is the current draw on your FF?

[tufnik]

Also, auto chargers are for lead-acid batteries. If it isn't designed for sealed gel cells too, you may not have proper charging.

[J.A. Veil]

John,
Just because a charger says the battery is fully charged does not mean the battery is healthy and taking a full charge. A bad battery may not take a full or any charge while the attached charger can say it's fully charged. You are assuming the battery is good just because the charger shows Fully Charged.

What is the current draw on your FF?

I wish I knew. I went back to the operator's manual for the unit hoping to find the current draw -- it was not provided.

[tufnik]

I checked a couple of FFs. Your model typically draws about 200 ma (when the display turns off automatically) and maybe over 600 ma when in full use (display is on).

If you have a multimeter (MM), you can do a simply test. Hook up FF to batt and turn on. Install MM in series and measure amp draw. You should see up to about 600 ma. If over 1 amp, something's wrong with the FF. Check with Lowrance for normal amp draw.

FFs normally function with input of 10-20 VDC. If the input voltage drops below a preset voltage (say 10 v) under use, the FF will shut down.

In your case, I think the big amp draw drains the 5 amp-hr capacity batt quickly. Since the batt capacity is relatively small (only 5 amp-hr), the load will eventually cause the input voltage to drop below 10 VDC. In other words, the batt can't sustain the voltage under continuous load. Hence, the FF will shut down (assuming preset shut off is 10 v) giving you only 2 hours of use.

Solution? Get a bigger battery (or get another batt and hook up in parallel with your current battery so you have larger capacity). Of course, this assumes the batt, wiring and the FF are OK. Hope that helps.

[DOGFISH]

John,

Bring the battery by West Marine, and I will put it on the battery tester.

[J.A. Veil]

Thanks for all the suggestions and help. I am in the midst of a very heavy travel schedule that has kept me off the water for several weeks. I will end that travel cycle soon and can back to fishing and resolving battery issues.

BTW - greetings from Fort Worth, TX. It was sunny and warm here yesterday. We held our conference reception outdoors yesterday afternoon (much preferred to the 35 deg and windy weather we had in Maryland last weekend).