Re: [Amel Yacht Owners] Battery Charger Thoughts?

Stephen Davis

Hi Bill,

On our older SM, we have a single 100 amp Mastervolt charger which works well, and yes, we upgraded the wiring size. The charger does draw about 10 amps when it is putting 100 amps into the batteries in bulk mode, but usually steps down to a lower rate quickly, as I never discharge my batteries too far.

Because we are circumnavigating on our boat, redundancy is very important, and we carry a spare 80 amp mastervolt charger. I can change the chargers out in under 30 minutes, and never have to live with a greatly reduced charging capacity. It's a great solution for us, but a little more expensive than having a 2nd 30 amp charger. 

We also installed a Watt and Sea hydro generator on the transom while in St Maarten last spring. We made a 3 day passage to Bonaire after installing the unit, never ran the generator, and arrived with full batteries. For anyone considering long passages, I think this is a great option. If anyone is interested in the installation, I can provide some pictures in a couple of weeks when we return to the boat. These are expensive gadgets, but we were fortunate to obtain a lightly used one from a friend in Martinique along with the custom made stainless mounting bracket for the SM. Sorry for the thread creep, but it seemed to fit in with charging the batteries. 

Steve Davis
Aloha SM72

On Aug 30, 2017, at 06:49, greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:



Thanks for the input.  That is pretty much the way we use ours. 

I believe Amel's rational for installing a small charger to use a the dock was a 100 Amp charger can draw almost 10 Amps @ 220VAC when in bulk charge mode, out of the 16Amps total available from the shore power connection, leaving very little left over to run house loads.  

All of the modern chargers I have seen have an easy way to limit their AC current usage when supply is restricted, so the need for the smaller charger seems to have gone away as chargers have gotten more sophisticated.

I am definitely thinking we will be keeping at least two chargers installed.  Not being able to charge batteries because of a single point failure would be a problem.

Bill Kinney
SM160, Harmonie
Boston, Mass

---In amelyachtowners@..., wrote :

Hi Bill K,
    I have a smaller bank of 6 AGMs with a Mastervolt 40 and a Dolphin 30.  I run them both for the high amp portion of a charge then finish with the Dolphin.  It works fine, both are "clever" so I can run either to hold a float on the battery.

One reason (aside from cabling size) to stick with two is the redundancy two chargers bring.  One failure does not leave you cold.

If you have a larger battery bank then perhaps slightly larger units are in order.

Regards,  John

John Clark
SV Annie SM 37
Pamlico Sound

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