What Battery Charger

[mahoganybd]

Is there any type of battery charger that I can use to keep my battery charged whenever I take it out? My boat is stored in an outdoor storage lot that does not have any electrical outlets. I have 2 12volts batteries on board of my fishing boat, a 50hp engine and a trolling motor 28# thrust.

 

[GA_Boater]

mahoganybd

Moved this post out of an old thread to one of your own. Please avoid posting in threads with no activity over 3 months unless it is a thread started by you.

What 50HP motor do you have. Some have a charging system only capable to maintain a charge on a starting battery. Some are rated for higher charging current.

On all likely hood, the motor won't be able to keep a battery used for a trolling motor charged. With no power in your storage lot, taking the battery home for charging is probably best. Inconvenient, but not many choices.

 

[km1125]

You could rig up a solar charger on the trailer or boat so that it will charge whenever there is sunlight. You'd have to (or should) size it so that it could fully recharge your trolling batteries between trips. Depending on where you live will determine how much per day it can charge (FL more than MN). For example if you got a 50 watt charger it could do about 12 to 24 amp-hours per day, so it could recharge an 80 amp-hour battery from Monday to Friday if you only went on weekend trips.

 

[mahoganybd]

Thanks for the information. Do not want to take battery in and out of boat. Live in the Chicago area and the motor is a 50hp Mercury, 1994. The solar charger would be something that I could work with, depending on cost. Any suggestions? We have a short fishing season, when you consider the weather (rain, snow... ) I try to get out about 2-3 times a month, some days back to back.

 

[ondarvr]

You would need a panel rated higher than that to reliably charge the batteries between trips, and you couldn't do it on back to back trips. The probelms with storage areas and solar charging systems is that they tend to disappear. Removing the batteries between trips is the only reliable way to charge them.

 

[fishrdan]

Without electrical power at the boat, you don't have many "good" options. Solar will be slow, expensive and could grow legs as ondarvr mentioned.

Here's another not so good idea... I have seen a couple people use Honda inverter generators to run an onboard battery charger. Charging times could be cut to 4-10 hours, depending on; size of batteries, discharge state, size of charger. That Honda generator is guaranteed to grow legs, if left in a storage lot...

How long is your run on the main engine back to the dock, or how long do you run the main engine in a day of fishing? MinnKota makes a DC Alternator Charger that takes power from your outboard to help recharge the TM batteries, this won't completely recharge the batteries, but will put power back into them. The DC Alt Chargers are 10 amps/circuit (Max - if available from the outboard), so they don't put out much.

When I used to go on multi-day fishing trips to different lakes, I rigged up a circuit on my truck to charge the trolling batteries. Worked well to keep the TM batteries from going completely dead and it could charge them back up on a trip back home. Depends on how long/far you tow the boat.

 

[gm280]

You could buy a portable power generator and run it while you are on the water. If you use it solely to charge the batteries, it would work and some of them are very quite as well. Other then that, I don't see any quality option. JMHO

 

[km1125]

To get good suggestions, we really need to know what the typical cycle of use is. How long is it stored, how long is the trailering trip from storage to launch, how long do you run the motor when you're on the lake, and how long do you use the trolling motor. This gives and idea of what is available and what is needed.

You have a lot of options. You could rig a connection to the tow vehicle and use a DC-DC converter to charge the battery. This is realistically limited to about 20 amps, so unless you have a long trailering trip, it might not be so useful

The example I used with the 50watt solar charger, I discounted capacity due to daylight, so it would be fairly accurate. I would think this would work fine if there is at least a week between trips, or/and if a fully-charged trolling battery would suffice for two back-to-back trips. You would want to secure the solar charger well though, so it would not disappear between trips. Most criminals are pretty lazy, so some well-constructed brackets would probably do the trick. A 50 watt panel runs from $75 to $150 and you could add two to increase capacity. Not sure what the boat and boat cover look like, but it might also be possible to permanently attach them to the boat so they would always be charging the battery as long as the cover could be put around it without blocking it.

 

[bruceb58]

Just so you know, all solar panels are rated at their working voltage which is around 17.3V. This means a 50W solar panel will have a current output of 2.9A. You will need to size what solar panel you need accordingly.

 

[Rick Stephens]

Just so you know, all solar panels are rated at their working voltage which is around 17.3V. This means a 50W solar panel will have a current output of 2.9A. You will need to size what solar panel you need accordingly.

That is exactly correct. In years past I installed dozens of solar panels on horse trailers and RVs to maintenance charge their batteries. They can be permanently installed, or set on top and clipped onto the batteries. In pretty much most cases you can accomplish this for under $100. Some decent ones are half that. I couldn't find the flexible one that I used to use for portable, clip on and toss it on the roof applications, but there are many many solutions out there and if you aim for around 3-4 amps you can walk away from it for weeks at a time. I probably wouldn't leave fully charged batteries on 17 volts for very long, it will overcharge/boil out the cells. But if you get a solar panel with a lead acid battery charging controller, which adds to the cost some, it will charge as needed and stop.

Rick

 

[km1125]

If you go the solar route ** definitely** get a charge controller.