Charging deep cycle batts out of the rv (Mastercraft battery charger)

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clemon

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Joined
May 15, 2012
Posts
279
Location
Kitchener, Ontario Canada
Hi folks,

I've got two 12v deep cycle rv batteries I pulled out of the MH for the winter, currently sitting in my basement. I'm wondering if my battery charger (a MAstercraft model from Canadian Tire) is charging them properly..... The charger has settings for regular and deep cycle batts, and 2A and 10A charging. The manual that came with the unit was sketchy on details at best (some English translation from Chinese, I think).

Anyway, I've tried both the 2A and 10A deep cycle settings, but the batteries do not seem to charge properly. The unit works just fine on either Amp setting with regular (starting) batteries - red light on when charging, green light when finished/maintaining). The unit does not seem to want to switch to the maintenance cycle (green light on) with the deep cycle batts.

My dilemma here is whether to replace the charger, the batteries or both!

Any advice?
 
How old are the batteries. Most only seem to last around 5 years or so. If they are getting old, have them load tested to see what state they are in.
 
Hi Muskoka. I'm not sure exactly how old the batts are - I bought the rig used last year and these are the batteries that came with. Probably time to replace the darned things..... :-\

On that note, any opinions on the deep cycle batts sold at Costco (Kirkland branded)? My local store has 'em for $79CAD each, which is the best price I've seen so far. Haven't found any 6v golf cart batts there yet, but it's a little early in the year for them, I think.....
 
I've noted similar results with more than one of the cheaper lines of chargers (no "float" mode) when charging my deep cycle boat batteries.  I suspect many deep cycle batteries draw too much current even when fully charged to trigger the full charge indicator light.  I usually just leave mine on the 2 amp charge level and the batteries seem to last long enough.  I just keep an eye on the water level.  As for my MH house batteries, I let the converter handle it and so far so good.
 
Most batteries will either have a date (year) stamped on top of the lead post or a sticker on the battery somewhere. I am no battery expert, but most any deep cycle battery is good. Make sure that they are not marine type ones if you do any amount of boondocking. If you are more the campground type, probably not worth the extra money to buy premium batteries. If you do boondock, buy the best ones you can afford with the biggest amp hrs. The more you spend usually the better amp hrs you will get.
 
The charger lights basically reflect the battery voltage, so if the green light doesn't come on, the battery is not coming up to the expected voltage.  That may well mean the battery(s) are weak. If they are flooded cell batteries, make sure the water in the cells is over the top of the plates inside.
 
Gary RV Roamer said:
The charger lights basically reflect the battery voltage, so if the green light doesn't come on, the battery is not coming up to the expected voltage.  That may well mean the battery(s) are weak. If they are flooded cell batteries, make sure the water in the cells is over the top of the plates inside.

Hi Gary. The batts are wet cell. I did top them up before storing them for the winter.

Guess that's another check in favour of buying new batteries!
 
muskoka guy said:
Most batteries will either have a date (year) stamped on top of the lead post or a sticker on the battery somewhere.

If the battery seller punches/stamps the date!  Or do it yourself as a reminder.  I have found many sellers don't take the time to do so.  Maybe a ploy for you to lose track of date of purchase and/or your receipt before its time or defect!  No proof of purchase could equate to selling you a new battery at full price.

Gary RV Roamer said:
If they are flooded cell batteries, make sure the water in the cells is over the top of the plates inside.

While I believe there has been debate on this subject, I prefer to top my flooded TT batteries with fresh acid.  Been doing so for years with no problems and have gotten more than my money's worth out of the batteries.  The practice does take special care!  No doubt.  If anyone reading wants to give it a try, PLEASE BE CAREFUL!  If you don't know how to handle the acid, don't do it.  You could cause great bodily harm and damage if not respected.

My point is I have bought used batteries that are only a year or two old, had them load tested, cleaned them up and topped them off/maintained with Sulfuric Acid.  I have always gotten extended life out of the batteries I would not have bet on.

Not sure why.  But convinced me and I still do it.

 

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