burnttech avatar image
burnttech asked

Solar charging, SOC required for boat?

For setting up solar charging for boat only after use when its done for the day. Would it be required to have bmv for SOC or does that mainly help with charging and discharging at the same time? The solar setup is on the boat shed not on the boat.

BMV Battery Monitorsolar
2 |3000

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

2 Answers
Paul B avatar image
Paul B answered ·

if you wanted the SOC to work then the BMV would have to be on the boats electrical systems you can then see the battery status at all times.

2 |3000

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

JohnC avatar image
JohnC answered ·

Hi BT. Welcome.

SOC is one of those things you might either love, hate, distrust, don't care, or be misdirected by.

It's a calculated figure, and in your case likely totally irrelevant to controlling your charge needs. To have it you'd need a BMV well-tuned onboard.

With Li or exotic batts there may be value, but if just Pb's it's really just an 'extra' for the geekish. :)

2 |3000

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

kai avatar image kai ♦ commented ·

Popped in to say that I went through all of those feelings for SOC!

Unless you've got a particular use case in mind, I'm not sure whether you absolutely need to measure the SOC. The charger will work irrespective of whether you have a BMV or not - if the charger is dialled in correctly, it doesn't need a BMV to tell it that the battery is full.

0 Likes 0 ·
burnttech avatar image burnttech kai ♦ commented ·

Thank you that was helpful I figured solar chargers would correctly charge batteries maybe based on age assuming they aren't too damaged. Does the BMV combined with BlueSolar charger allow for discharge and charging at the same time more efficiently for something like a camper? If you are using 20 amps (through BMV shunt) will the solar charger base its charging rate on voltage or SOC?

0 Likes 0 ·
JohnC avatar image JohnC ♦ burnttech commented ·

The BlueSolar will use V, and load compensation is just 'soaked into' the V, if that makes sense? :)

And really, would you want it to do anything else? The BMV is a (very accurate) monitor, and in a simple situation like this, provides no miracle-working functionality.

Mind you, I'm a big fan of good monitoring, but that's for you to decide.

0 Likes 0 ·
burnttech avatar image burnttech JohnC ♦ commented ·

When you say BlueSolar I wasn't able to see how it would use load compensation. Bluesolar itself doesn't have a shunt; does it need to be configured to use BMV's shunt?

0 Likes 0 ·
kai avatar image kai ♦ burnttech commented ·

John was referred to battery temperature compensation I think. With the temperature sensor from the bluesolar connected, it will adjust the voltage going to the battery to account for the temperature being measured (ideally at the battery).

Have a look at the blue solar manual - section 4.1, which talks about the 3 step charging process. The charger does its magic without needing the BMV.

0 Likes 0 ·
JohnC avatar image JohnC ♦ kai ♦ commented ·

I wasn't actually. Just V. When a load is applied to a batt/system, the V will (usually) drop. And whatever charger there is trying to hold that V will wind up its output to compensate. That happens virtually instantly, and the V will stay pretty stable, but the W will follow the batt's acceptance of charge and the load together.

There may well be a need for SOC to be involved in some special requirements in a complex/higher-end system. Most of us will never see such needs. Not to say some wouldn't like to see it displayed, but it needn't be involved (& normally isn't) in the charging process. V rulez..

0 Likes 0 ·
kai avatar image kai ♦ JohnC ♦ commented ·

oh right. well, ignore the 1st para of my above response then :P

0 Likes 0 ·

Related Resources

Victron BMV battery monitors product page

Additional resources still need to be added for this topic