Re: [Amel Yacht Owners] Re: SM Batteries


islandpearl2_sm2k332
 

Hi Alan

Thank you very much for your ever generous and excellent advice as usual.

I will do exactly as you have done once again. It has been great to be a year or so behind you on this site, and to copy much of what you have done ahead of us.

Trying to think through how 300w of direct wired solar could cook a 450amp robust Trojan battery bank?? A German cruiser friend (pretty technical guy/ enginer) advised me to do that as the output ftom 300w solar was well below 10% of battery bank...

BUT this has been the first marina since where we have plugged in to shore power for more than one day. So whilst cruising all was fine. I assumed the Victron Inv/charger would sense those extra amps trickling in and stop charging ... which it does ... BUT ... I guess if tge Charger had already got tge banks to 100% and then on a bright sunny day tge 300w solar just kept pushing it up and up.

When I returned to the boat late afternoon after 4 days away the Link was showing 29v and +69.5 amps over 100%!!

Do you think that is how this could have ocurred?

PS I should add that it was well over 25kts those days too and one of our Rutland1200's wind gens was on however that is usually pretty good at shutting down when charge is up.


On Fri, 29 Jun. 2018, 05:22 divanz620@... [amelyachtowners], <amelyachtowners@...> wrote:
 

Hi Colin,


There's probably little doubt that attaching the extra 300W of solar directly to your battery bank did them more harm than good. The constant 28.8V from the alternator doesn't help either if you do long periods of motoring.

Our 12 x 6V AGM batteries came with charging ranges Absorption 7.25 - 7.45V, Float 6.8 - 6.9V.
I opted for the middle of the range so for 4 in series as a 24V system, we have Absorption 29.4V and float 27.4V.
All our charging systems (Engine Alt, Solar, D400 wind, Victron 100A and Promariner 30A) are set to those voltages and all bar the D400 wind generator have a battery temperature input, so those voltages vary depending on the temperature of the batteries.

Cheers
Alan
Elyse SM437

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