question

sweyn avatar image
sweyn asked

Automatic Bilge Pump

I have a Lynx Smart BMS and distributer with LifePo4 and I’m wondering where the best place to connect the bilge pump is.

Before the Smart BMS to guarantee it always works?

Worried that it can then run the battery dead.

lynx distributorbilge
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

3 Answers
kevgermany avatar image
kevgermany answered ·

Dead battery or dead battery and sunken boat?

Is there any full time charger?

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

sweyn avatar image sweyn commented ·
Valid point.
0 Likes 0 ·
Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

@Sweyn

You could connect the bilge pump to the AUX terminals. This would require a relay as the AUX terminals max. amperage is 1.1A.

But in case the Lynx Smart BMS opens the contactor (OFF mode) for whatever reason (low cell voltage, user turned the LSB manually off), the AUX output is turned off as well.

I am a boat owner myself and have connected my bilge pumps directly to the battery positive terminal just in case. My bilge pumps protect my ship (not my batteries), which value exceeds that of lithium smart batteries by far.
Sizing of my battery system takes bilge pumps into account and ensure they are are running for at least 48 hours continuously. Enough time to take action.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image
seb71 answered ·

Before the Smart BMS to guarantee it always works?

This will not guarantee that the pump will always work.

When the battery is empty, it's empty no matter where you connect the pump.

10 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

sweyn avatar image sweyn commented ·

Factually correct and obvious, but not helpful.

0 Likes 0 ·
seb71 avatar image seb71 sweyn commented ·

It was not obvious, because you stated the contrary (which is wrong).

0 Likes 0 ·
sweyn avatar image sweyn seb71 commented ·

Everyone, including you, understood what I meant.

Nothing will ever always work, because you could always drop a nuclear device on it.

Pedantry is unhelpful.

0 Likes 0 ·
seb71 avatar image seb71 sweyn commented ·

So you think that the Lynx BMS will randomly and needlessly disconnect the battery?

0 Likes 0 ·
sweyn avatar image sweyn seb71 commented ·
No, I think the Lynx BMS will disconnect the battery if the voltage gets below a certain point.


The balance of risk is whether killing expensive batteries in the case of a faulty bilge pump is more of a concern than potentially turning off a bilge pump that is keeping the boat afloat to save the batteries.

0 Likes 0 ·
Show more comments

Related Resources