R: [Amel] Re: All Battery Chargers


amelliahona <no_reply@...>
 

Hi Gianni:

I installed 12 new Trojan SCS225 deep cycle batteries about 9 months ago. They are flooded lead acid batteries.
I chose to have these since I had understood that absorbed gas matt (aka gel cell) batteries didn't tolerate
the heat of the Caribbean well. My engine starting battery is a Deka and is a high cranking power battery. Not
sure of it's number but it was a group 31 battery and I considered buying 12 more to serve as my house
batteries because they were compatible with the existing Amel copper bar connecting plates. The supplier
didn't have 12 more available and I further researched the one I had and found that it was not a deep cycle
battery and thus decided on the Trojans.

At any rate, we were in a marina for a few days after having been charging on the generator for a few weeks,
and I had the 30 amp Dolphin charger on to "top up the batteries" One morning I came from the aft cabin
and while walking through quarter-berth companionway, placed my hand on the berth mattress and noticed
that it was very very warm. I opened the battery compartment and found all the batteries actively gassing
and bubbling to overflowing electrolyte. Using an infrared thermometer I measured the temp of the batteries
at 135-145 deg F. The voltage was about 28.3 volts. As I recall they were still having 18 amps pumped into
them even after 36 hrs on the charger. It seemed that the 30 amp Dolphin charger had failed to switch from
"bulk" charge to float charge. Fortunately the batteries didn't have the plates exposed and hopefully they do
not have warped plates from the excessive heat.

I called the Dophin charger people in the US and spoke to them. They suggested re-setting the charger
by disconnecting the voltage to the charger, letting it sit for 30 minutes and then reconnecting to the
batteries. I did this by "turning off the main battery switches" assuming that I was indeed disconnecting
the charger from the batteries. When I didn't see any change in the behavior of the charger I assumed that
the charger was faulty. As we were leaving the boat I didn't take any further action to trouble-shoot the issue.

Now, with the information that the battery switches don't disconnect the batteries from the charger (at least
on SN 318, and will shortly be determined if that is the same on my boat), perhaps my old Dolphin 30 amp
charger can be made to behave. At any rate, I will no longer take the automatic functioning of my charger
for granted, and I am considering installing a temperature alarm on my battery bank so I won't risk
destroying $3,000 US worth of batteries due to a faulty charger. Watch your battery temperatures, and the
amperage going into the battery bank carefully as it sounds like your charger is doing the same thing
mine was.

Just my thoughts,

Gary Silver

Amel SM 2000 #335
s/v Liahona

--- In amelyachtowners@yahoogroups.com, "gtesta23@..." <gtesta23@...> wrote:

Hi Chris,
Thanks for your suggestions
I have 12 new DEKA lead acid deep cycle batteries. About 630 Ah.
My Dolphin 30 A charger works slowly up to 28.1,2 v. Than, I suppose, it should go down to about 27 /26.5 v in stand by. ( no boost).
The my one seems to remain at 28.1 for long time boosting few amperes.
Is the charger to little for my 630 Ah ?
thanks in advance
All the best
Gianni Testa
sv EUTIKIA SM 428

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