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Sofa King
05-18-2006, 10:11 PM
This is my first trailer boat so it will sit a bit. I have two batteries and would like to throw a trickle charger on em. Should I charge Batt 1 ,than Batt 2 or charge one with the batt switch on both.

TY in advance
Aronowrip

DickB
05-18-2006, 11:45 PM
For a trickle charger it won't matter much, assuming both batteries are in good condition. For a fast charger, which detects a full charge and switches to trickle, it would be better to charger separately. Again, if both battereis are in good condition, it really won't matter much one way or the other.

MOP
05-19-2006, 06:22 AM
DickB is 100% about the trickle charger, but for a heavy charge do one at a time. I learned that the hard way it and a couple of other tricky questions cost me master tech at school, after the test they went over the reason never to heavy charge or run the boat on both. Even brand new no two batteries are perfectly alike, one will be seeking a charge and the other will be being over charged. Over time the healthier of the two will degrade, we were instructed to teach our customers to use the odd (1) battery on odd dates and the even (2) on even date days. By doing so you will not hurt either battery and you will always have a good one in reserve. A good idea is to install an isolator/combiner which will charge boat batteries from a single source either the alternator or your charger. Isolators by Guest are very cheap and do the job, the combiners are more expensive but preferred by some.

Phil

Ranman
05-19-2006, 10:54 AM
Use the batteries seperatly (either "1" or "2", but not "all". The even/odd days trick works well. If you hang at the island/sandbar a lot and like a loud stereo, you will not put back into the battery what you used that day. The alternator is really designed to supply power to the boat's requirements while running. It is not really designed for charging a deep cycle battery.

Chances are the alternator will not have enough running time to bring the batteries back up to full charge before you get back to the ramp. Slowly, over time you will continue to use more than you put back and eventually you will damage the batteries by over discharging them.

If you like to use the batteries a lot while the boat is not running, your best bet would be to charge them between uses (during the week). I recently bought a Battery Tender Power tender and plan to charge each battery between boating weekends.

http://batterytender.com/default.php?cPath=11_4&osCsid=7a035df74fe4a6eb0aa3a93fbf8e89bb


This charger does only one at a time so I may have to switch it to the other side during the week to make sure both are tip top. Because the Donzi is small and lives in my garage, I'm using this as a portable charger though it can be mounted right in the boat as well.

A buddy of mine uses this one by Xantrex

http://www.xantrex.com/web/id/185/p/1/pt/7/product.asp

The 10TB can charge two batteries at once, but is not waterproof.

The key with the deep cycles is to make sure you don't over discharge them and that you use a good charger that will properly recharge and won't cook them

CHACHI
05-19-2006, 11:22 AM
I use Battery Tenders on everything that I own that sees seasonal or sporatic use. The product is excellent and the company is wonderful to work with if problems should arise. The company is a neighbor to Cuda, they are in Deland,FL. Ken

MOP
05-19-2006, 11:23 AM
That 10TB sounds like a very nice unit with all the late good features, I have often thought of mounting a decent charger in the boat. Have to check the TB10 against the S/S Guest.

Phil

Sofa King
05-19-2006, 01:02 PM
Thank Y'all especially u Phill great 411. I have battery tenders on both my bikes, my POS h/d is high comp 10.5/1 so being carb I always need a good battery on it.One of my trickle chargers is called the BatteryMinder which has a button on it u push for desulphication. Sounds cool at least.

Ranman
05-20-2006, 01:11 PM
That 10TB sounds like a very nice unit with all the late good features, I have often thought of mounting a decent charger in the boat. Have to check the TB10 against the S/S Guest.
Phil

Phil,

I was reading some old posts on the subject recently and came across some of your comments on isolators/combiners. I was thinking of installing an isolator so that regardless of the battery switch position, the alternator would be charging both.

Then I got to reading what it actually takes to recharge a deep cycle battery and quickly figured out that if you do a lot of "sandbar running" you'll use more of the battery capacity than the alternator can quickly put back. For what I normally do, I would have to run the boat for a couple of hours to get the batteries fully charged again and that's using an alternator as the charging source (inferior to a good charger).

My solution is to have enough deep-cycle battery capacity to do what I want for the day or two and then use the Battery Tender at home to recharge during the off days (mon-fri) so I'm good to go for the next weekend.

I never used to charge on the off days and sure enough, by the end of the season I have two very weak batteries from major over-discharging due to under charging via the alternator.

The 10TB works well for my bud because he has it wired to both batteries and leaves the charger in the boat. He can connect to standard 110V or shore power as needed. The 10TB is not water proof and thus may not be a perfect fit for say the firewall of a Donzi. My bilge while almost always dry has gotten pretty wet from time to time. Trying to mount it somewhere else becomes more challenging.