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Question re: Dytek chargers
July 29, 2011
9:45 am
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Steve Pooler
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That's a fair question…Another is…Is there a perfect technology for charging batteries ?

We have two technologies you are considering here, One older, One newer…Which is better is hard to say, but there are advantages & disadvantages to each…I'll try to point out some of each as I see it…

First let me say that both rely on having Good serviceable batteries…Weak or shorted cells can mess up what each charger sees, and thus fool it into doing/not doing what it's supposed to do…

Also, that some of this info is for others that may be following…

 

Advantages/Disadvantages of the newer Multi Stage Chargers:

The Good…

  • They are lighter, and usually smaller than a transformer type charger.
  • They often have optional remote panels to view battery/charging status.
  • They will charge deeply discharged batteries back up more quickly…better for inverter type usage.
  • The "Float" mode (trickle) only puts out milliamps at a lower voltage. 
  • The float mode will also match (raise amperage) any load that comes on to maintain that float voltage.

The Not So Good…

  • Everything in the charger is on one circuit board…If the charger acts up there is usually no fix except another board or charger, meaning they are not field serviceable…They work or they don't…Then you replace, or send them in for a new board.
  • Being electronic, they don't handle voltage surges as well.
  • Float voltage is or can be set by temp, it's how the charger responds…A faulty temp sensor or improperly set switch can boil batteries.

 

Advantages/Disadvantages of Sentry Transformer type Chargers:

The Good…

  • Proven track record…Known to last 30-40 years…
  • All parts are available for field service…No removing charger, shipping, waiting, re-installing, etc…
  • Shuts off when batteries are fully charged & comes back on to match load when load is applied to batteries.
  • Can be set for manual mode (flip switch) if a there is a problem with the replaceable control circuit…Will get you by until board is replaced.
  • Transformer & other components are less susceptible/sensitive to surge damage.
  • Has built in battery bank isolator/s…No external battery bank isolator, or charging relay is needed, and the charger is already calibrated for the known voltage drop thru the blocking diodes (inverter chargers usually only have a single output that must be split to charge multiple banks)
  • Ignition cut off circuit so that charger is not trying to act as a Battery Booster causing charger overload…

  The Not So Good…

  • Heavier & Larger
  • Takes longer to charge deeply discharged batteries.
  • By design a transformer charger will lower to float charge but that float is 1-2 amps instead of milliamps, and battery voltage will continue to rise causing boiling/sulfation if not shut off…Sentry shuts off if in the Auto mode.

 

Additional info about both types:

 

The Sentry ignition cut off is not always connected, but the worst thing I have seen happen when used as a booster unknowingly is for it to trip it's internal DC output breaker…Older models were manual reset and the owner at times did not know it had tripped until he returned to boat after going home, and found dead batteries…The new models are auto reset breakers…

I don't see this feature on the newer Multi Stage Chargers…It could be one reason we hear of failures of these chargers…Low or weak (bad) starting batteries causing the charger to try to output more than designed when cranking an engine…Board can''t take it & Pow…You let the smoke out…

As mentioned earlier…If a temp sensor fails or a battery is bad with a Multi Stage charger…It can stay in one of the upper stages too long, or even lock in that stage….Thus burning up other batteries very quickly…

By design nature, a Transformer charger will always reduce to trickle output (as long as there is not a direct short) of a couple amps, even if it's control circuit fails to shut off the charger…Yes it will boil batteries, but at least it's not doing it as quickly as a multi-stage charger could that is stuck in a higher output mode…

 

Transformer type chargers (like your Dytec) that don't shut off…Will boil batteries…In my experience they just do  Frown

The only charger's that I know of that can charge each bank individually (and shut off or float that bank by itself) are the smaller bass boat type chargers that only output 2.5-10 amps per bank…They are actually more than one charger/board inside one box…

They may rate the charger at 30 amps…But that is only 10 amps per bank/output, which is usually not enough to keep up with house type loads…They are mostly meant for recharging upon return to shore…

 

Yes, Sentry chargers are expensive to build…They are hand built here in the US, and have many more components than a metal box & a circuit board…

 

I''m sure I forgot more than something here…But that's it for now, and I guess it's a decision of what is best for you  Wink

 

Steve~

July 28, 2011
7:17 pm
z28jimi
Daytona Beach, FL
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OK, one more question.

If a full-shut-off design is best, why does that design seem to be the exception?

It seems that most if not all of the major chargers hype the fact that they are "three-stage" or more, with the last stage being a trickle-charge.

Why aren't more designed for full-shut-off?

Is it more expensive to build a charger like the Sentry?

Just seems odd that if that's the best design from a battery-life perspective, that more aren't designed that way.

Your thoughts? 

June 13, 2011
8:48 am
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Steve Pooler
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It is in stock...

 

Steve~

June 13, 2011
8:44 am
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Steve Pooler
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I am a fan of Sentry...Should be the last charger the boat will ever need...They are almost bulletproof but not cheap...

If you want to call me I can quote price on a Sentry FR-1260/3X...Give me a minute to check stock at the distributor...

 

Steve~

727-365-6123

June 13, 2011
8:25 am
z28jimi
Daytona Beach, FL
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Time is the limiting factor here I guess. I don't have the time to play with the charger much, and to be honest, even if I had the time, I don't have the inclination. I'd much rather have something I can leave turned on when I walk away from the boat for a week at a time, and not worry that my batteries will be dried out husks when I return.

You are obviously a fan of Sentry chargers...would you recommend a particular model for this application?

It appears to be a fairly straightforward matter to remove the old and install the new.

Other then the R & R, will there be adjustments in the new one that someone more electrically inclined would need to make?

June 13, 2011
8:02 am
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Steve Pooler
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z28jimi said:

Steve,

I have a Dytek VHD-1260 that I suspect isn't operating properly. I have two 8-D's on the boat, and they don't seem to be geting charged correctly, but I really don't know how to test the charger.

The batteries are at about 12.6 volts after being charged for 6 or so hours but then sitting all week. No loads, except for bilge pumps, and no indication that the pumps have run....Meaning after a week of no load/no charging they settle at 12.6 volts ?...A fully charged 12 volt battery will stay somewhere above 12.8 volts for quite some time with no load...

An electrician put a meter on the batteries to check the CCA. Said it was within 1% of the value on the sticker, but the meter said "Needs charge"....I'm not clear on this either...Don't know of a test with any meter that could tell him a percentage of CCA but then say that needs charge...I do have a Load Tester that I can dial up as much as 400 amps load to see if a battery will maintain above a certain voltage threshold relative to it's rated AH capacity....

I've never heard the charger turn off, or change pitch in any way, and I'm afraid to leave it on all week, for fear I'll cook the batteries....To my knowledge Dytek chargers are standard Ferro Resonant transformer chargers with no automatic shut off capability...Yes they will run all the time, but just as any other FR charger...They will taper back amperage output to a trickle as the batteries reach full charge...Yes they can boil batteries with no shut off capability, but first we would need to know what voltage they are charging the batteries up to...Above 13.9 will cause the batteries to sulfate & the electrolyte to boil out...If the charger only charges up to 13.8 it's not so bad, but constant voltage that high will still evaporate some... 

As far as I know, the charger is original equipment on my 1990 Ocean CPMY....Yes I believe that's true.

Do you have any experience with this brand?...Only to see them on Ocean Yachts...I've replace a few with Sentry's because of the Dytek boiling batteries

Should I try to work with it, or just go for a new one?...Guess that depends on how much time you have to play...Chargers can take constant attentive monitoring if you want to get the most out of them and keep them from damaging batteries...Some folks install a water heater timer on their power source so that they only run for X hours a day as a fairly cheap fix...The drawback to that is what if the boat springs a leak & the timer won't let the charger to come on to keep up with the pumps...

Steve~

June 12, 2011
6:43 pm
z28jimi
Daytona Beach, FL
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Steve,

I have a Dytek VHD-1260 that I suspect isn't operating properly. I have two 8-D's on the boat, and they don't seem to be geting charged correctly, but I really don't know how to test the charger.

The batteries are at about 12.6 volts after being charged for 6 or so hours but then sitting all week. No loads, except for bilge pumps, and no indication that the pumps have run.

An electrician put a meter on the batteries to check the CCA. Said it was within 1% of the value on the sticker, but the meter said "Needs charge".

I've never heard the charger turn off, or change pitch in any way, and I'm afraid to leave it on all week, for fear I'll cook the batteries.

As far as I know, the charger is original equipment on my 1990 Ocean CPMY.

Do you have any experience with this brand?

Should I try to work with it, or just go for a new one?