Replace Battery Charger

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pdserv

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Nov 8, 2006
8
- - Washington, DC
Hello, I'm considering replacing my battery charger and would like some advice. The situation. 1993 Hunter 37.5, two banks, 1 27D starter, 2 27D house. Looks like OEM charger is circa 1993 ProMariner Newpro 20/25 charger. Just checked battery fluid level and found one house battery with several cells dry. I'm blaming this on my poor maintenance practices (several months since last checked levels). Other two batteries looked okay (one truly sealed, one levels are okay). Searched the archives for recommendations about battery type, etc. Found oodles of posts. One post talked about contacting ProMariner for details on a similar charger to what I have. Did this - was told my charger is very old technology and will "boil off" batteries. Suggested replace with newer PM ProTech-4 1230. They will "credit" me my old charger with a net price of $260 - which seems a bit lower than I can get for comparable chargers on the net. BUT, do I really need to replace the charger? The boat is used as a liveaboard with constant AC dock power. Battery charger is left on all the time. Constant DC loads are lighting, fridge, fans. Never seemed to have a problem with batteries before. Battery that died was circa 1996 (as best I can tell from the battery case stamp) so it probably lasted a long time. The boat has been used as a liveaboard since 2003, prior it was probably an infrequent weekend day sailer. The issue is limited boat maintenance funds and not replacing something unless it needs to be replaced (there are plenty of things that do/will need to be repalced). Thanks in advance Peter
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
does it charge the batteries?

Well if it ain't broke don't fix it is my motto. A reefer, lights and fans will not be drawing more than 20 amps continous so you should not have a power management problem. As for the boiling off of the water that is nonsense. Unless the charger is set to the wrong voltage you should not have a cronic problem with boiling the batteries. With that said, wet cells do loose water over time so you still have to do maintenence once a week or so but if the charger is working I'd opt for leaving it in place till it dies.
 

timvg

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May 10, 2004
276
Hunter 40.5 Long Beach, CA
Try 6 volt batteries for house

We have a 1993 40.5 with the original battery charter. We have (4) Trojan 105 6 volt batteries for the house and are pleased with the results. We also keep the battery charger on all of the time, as we keep the refridge and freezer stocked. We got 5 years out of the first set of 6 volt batteries and replaced them about 6 months ago, just because we could. The old batteries were still performing, but 5 years seemed like prudent time for replacement. As far as your case, a 10 year old battery seems to be a bit optimistic.I would assume that most 1996 batteries would not be happy in 2006, almost 2007.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Xantrex & Gels

Peter: The advantage of a new charger is that you can extend your battery life. It is a good time to determine what you want to do and how much you want to spend. Xantrex has a new charger (XC) that will allow you to mix battery chemistries. It would allow you to have a battery like a Optima for a starting battery and 6 volt flooded batteries for your house bank. Gel technology offers the longest life (unless you are going with something like Rolls batteries). AGM will give you a higher capacity in the same size package. Flooded will give you cheaper initial cost, but if you are not doing battery maintenance, they may not be the best choice. Lots of decisions and they are all yours to make!
 
B

Benny

If it ain't broken don't fix it.

Just because a 10 year old battery went bad is no reason to do away with a working charger. New smart chargers will charge your batteries quicker by running a bulk charge rate longer by monitoring temperatures and will gently drop the voltage to a trickle charge when they approach full charge. I don't think as a liveaboard you really need to care how fast your charger is and with constant loads on your system the trickle charge mode won't be missed. The proof is in the pudding, if you are running ten year old batts with little maintenance your charger is doing a very good job in protecting them.
 

higgs

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Aug 24, 2005
3,710
Nassau 34 Olcott, NY
10 years on batteries

sounds good to me. Figuring $250 to replace your 3 batteries + $260 for a new charger - you have undoubtedly done the math. Compare that with new batteries now and forget about them for 10 years (except fluid checks a few times a year) and you come out with a yearly cost of $25 a year for batteries. I could live with that. Will you still have this boat 10 years down the road?
 

pdserv

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Nov 8, 2006
8
- - Washington, DC
More info

Hey, Thanks for the advice. Some more info. First, it seems really strange that I could have gotten 10 years from run-of-the-mill lead-acid batteries. Especially, since I only have owned the boat for 3 of those ten years. So maybe I'm reading the battery labels wrong (wouldn't be the first time for reading things wrong). Second, I called the Professional Mariner tech support again and asked more questions. The tech told me the Newpro was "unregulated" but then qualified it that it is also current limiting. I think what he was saying was current tapers off closer to terminal voltage. Didn't think quick enough to directly ask him. He also qualified his "boil off the battery" comment when I told him the boat was used as a liveaboard. He said the loads from fridge, lights daily would discharge the battery just enough to keep it from overcharging. Third, now that I've actually got to learn something about this stuff I did some tests on the remaining batteries. Off went the charger, ran some loads (macerator - 10A) for a few seconds, then tested voltage. It was going down to mid-12s. Then the fridge kicked in (5A). The little "press this button and get battery state" thing pretty quickly moved from 100% to 25% in, let's say, 60 seconds or so. So I rehooked the charger back up and yes, the battery voltage went up to 13.5 or so. Light said fully charged. As a final test, I then watched the charger ampmeter as I engaged the macerator again. On went the macerator, up went the charger amps to 10A. Coincidently, 10A is the macerator draw and also probably the max current for one bank (of three on a 30A system). So I'm pretty convinced my batteries are pretty much dead and the charger has been "supplying" the amp draw from my small liveaboard loads. Any wisdom on all this? For the Xantrex suggestion, it looks really good. But I've also read that AGM and lead-acid can use the same charge profile. And maybe if you get gels then you have to diddle with your engine alternator. If so, wouldn't you then want to limit your choices to AGM and lead-acid. If so, then having separate AGM and Gel and Lead-Acid choices seems really not necessary. In other words, as long as you can charge an AGM/LA you're set. Many thanks again. Peter
 

higgs

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Aug 24, 2005
3,710
Nassau 34 Olcott, NY
What I would do

Buy new batteries and monitor them closely as youdid your old ones and then make the decision about a new charger.
 
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