question

doublebubble avatar image
doublebubble asked

BMV700 connected to lithium house bank and reading alternator charge amps.

I'm about to fit in a 480ah lithium house bank of batteries to replace our AGM bank, the current system works fine, 2 engines and 2 start batteries with a combiner switch but the question is can I put the engine start battery grounds on the load side of the shunt along with the lithium negative? The lithium's and the two AGM start batteries will be charged via the alternators through 2 x DCDC chargers so will that still show me the alternator amps.

BMV Battery Monitor
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2 Answers
pwfarnell avatar image
pwfarnell answered ·

A diagram would explain this better including what you want the shunt to measure.

IF you want the shunt to measure the lithium then the lithium negative is connected to the battery side of the shunt, everything else including the boats grounding point, the starter battery negative, the dc-dc negative all go to the system/load side of the shunt.

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doublebubble avatar image
doublebubble answered ·

Thanks I appreciate the reply, yes I really only want the shunt to be monitoring the lithium bank, the two engines will have there own separate start battery solely living alone as this will be all they will be doing, starting the engines, the only connection between the two banks will be the two dcdc chargers to be able to charge the lithium via the two alternators, so your saying that the starter batteries neg including the two dcdc charger negitives should be connected to the load side of the shunt to complete an earth circuit.

2 comments
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pwfarnell avatar image pwfarnell commented ·
Yes, all negatives go to the system/ load side of the shunt except the lithium battery.
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klim8skeptic avatar image klim8skeptic ♦ commented ·

@doublebubble have a look at this, example.

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