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thebarold avatar image

Charging Profiles

I have been reading up on batteries and charging after the early demise of my house bank on my sailboat. This has been a great resource! The manufacturer supplied my boat with Exide AGM batteries which according to their datasheet for absorption specifies "Charge with 14.8V - 15.0V limit for 12 to 24 hrs or when current drops below 1% of the C20 rating..."

As my supplied charger (cristec) only charges at 14.4V absorption for a maximum 4 hours (on AGM profile), do the Victron chargers allow for custom charge profiles that closer match the battery manufacturer's recommendations? Under charging is a suspected cause for the demise of the 2-yr old AGM bank.

charging batterychargersAGM Battery
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Justin Cook - Bay Marine Supply USA avatar image
Justin Cook - Bay Marine Supply USA answered ·

For shore power charging, I'd definitely recommend a Multiplus charger/inverter. Auto-switching from shore power to inverting, will charge 12v battery bank while plugged into shore power, too many options to list here. Fully configurable charging profiles, however, so you can set it up for your current AGMs and then change the programming when you get your LiFePO4s in. Have a look: https://www.victronenergy.com/inverters-chargers/multiplus-12v-24v-48v-800va-3kva


We are the largest stocking Victron and Sterling distributor in the western US (largest Sterling distributor in the continental US, for that matter) and the Multiplus 12/3000/120 is definitely the most popular of the Multiplus line among our customers, but the entire line is full-featured and really a joy to work with as far as dependability, configurability, and ease of use -ie, set-it-and-forget-it usage. On the other hand, if you're not looking for inverter capability, the Centaur chargers are great for just charging up your banks when connected to shore power, using a preset 3-stage charging profile: https://www.victronenergy.com/chargers/centaur-charger-12v-24v

For similar functionality with a configurable charge profile, the Phoenix line of chargers is fantastic: https://www.victronenergy.com/chargers/phoenix-charger-12v-24v

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Southace avatar image
Southace answered ·

AGM exide MSDC31 battery's recommend charging at 14.4 volt and no more than 14.7 volts.

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JohnC avatar image
JohnC answered ·

Hi Barold. 'Undercharging' could also be defined as 'not-enough' charging. Ie. Storing your batts 'half charged' or even less. There's a big difference, and a big Pb batt killer is storing them at lower than optimum V.

Frankly (just me though), 14.8 - 15.0 V I'd consider 'overcharging', even maltreatment. Temp compensation might take mine up nearer there in cold weather, but I'd never go that far with the base settings.

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I would have thought 14.4V was generally accepted. Exide provides this sheet (mine were Marine Dual Purpose, second row) which specifies the absorption voltage. I will have to look carefully at the specifications and recommendation on batteries if I do not buy a charger that is programmable.

Yeh, I've seen that chart before. I recall it because it was 'memorable' for it's aggressiveness.

I too use 14.4V (+/- tc). You can't hurt your batts at a softer charge level, but the discharge V and time spent down there can be telling for batt life.

Your existing kit is probably adequate, but most Victron chargers can be customized as you want. Perhaps with the exception of Absorb time, 12-24 hours is at the ridiculous end of practicality.


Murray van Graan avatar image
Murray van Graan answered ·

A SmartSolar Victron MPPT is fully configurable via Bluetooth, from the charge voltage settings to the absorption time can be set to your requirements. You can also configure temperature compensation which is critical for lead based batteries.

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I will be adding a smart solar charger with two 100w panels. But for the shorepower charging - are all of the Victron chargers this flexible? I am considering chargers and charger inverters but would need a 120V charger for 12V batteries.