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sweyn avatar image
sweyn asked

Multiplus 12/800/35 to trickle charge Lead Acid starter battery.

Is it ok to use the 1A trickle charge output of the Multiplus to charge a lead acid starter battery when the main batteries house batteries are Lifepo4?

Multiplus-IIchargerstarter battery
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klim8skeptic avatar image klim8skeptic ♦ commented ·
Are you using mains power (multiplus) to charge your batteries, or a solar array/mppt??
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sweyn avatar image sweyn klim8skeptic ♦ commented ·

The House Lithium batteries will be charged from either mains through the Multiplus, MPPT or DC-DC from the alternator/Starter battery.

The starter battery will be charged by the alternator, but I’d like to have the ability to trickle charge it from the Multiplus if possible.

Not sure if the 1A trickle charge will be a problem if the Multiplus is configured for lithiums through.

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klim8skeptic avatar image klim8skeptic ♦ sweyn commented ·

It is probably best to read this thread.

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2 Answers
pwfarnell avatar image
pwfarnell answered ·

The trickle charger is taken off the main DC feed to the Multiplus. The Multiplus contains a current limiting circuit and a diode so it will always lift your starter battery to within 0.4 to 0.6V lower than your house battery because of the voltage drop. When full the battery will limit the current lower than 1A. If your house is at 13.25V, the trickle charge will keep the starter at circa 12.65 to 12.85V so OK for the starter battery long term, but there will be a small current draw from the house.

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sags65 avatar image
sags65 answered ·

@pwfarnell just further to the question , I have 2x multiplus 3000 with 2 AGM starter batteries that I would like to trickle charge from the multiplus 4A, I have lithium house bank, is the situation the same?


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pwfarnell avatar image pwfarnell commented ·

Yes. One thing to remember is that depending on the lithium system, the trickle charger may not be disconnected on low battery voltage.

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sags65 avatar image sags65 pwfarnell commented ·
Thank you for your reply, the installer is suggesting that victron don’t show the trickle charge in their diagrams , they are suggesting that a charger, Blue smart charger 12v 5A can be added to the already expensive complicated install.

there seems to be a draw from the starter batteries ,I am thinking the Orion non isolated dc dc charger is causing this.

I have port and stbd battery switches that I guess I could isolate the starter batteries so essentially they are off.

I just want the batteries charged so they are available when needed!

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