Just suppose,...

[billi]

I think Justme `s battery monitor ( if allowed to call it so  ) is the more clever idea   than Billi or Billy has 

But  beside the monitor a temp sense to adjust charge setpoints automatically makes a fool out of my Batterymonitor , when showing 100 % charged and high volt alert  , because he thinks we have 25 ° .

I tried to figure out  the Victron temp sense and connected it to the Battery , but sad enough i have not seen any changes in charging  , while the solarchargecontroller and the temp sensor tells me " MR Billi ,  its cold so we try to reach 30 Volts before going into Absorption charge "

Better check my water level tomorrow morning

Billi

[Amy]

So a batt monitor senses the temp and decides from that how well charged the battery is?

If its hot it must have been charging hard for a while, so time to slow down as we must be nearing completion?

[billi]

A Battery Monitor is just a Battery  Monitor , more or less to calm us control freaks down ,

the chargecontroller is the work horse and in control of the right charge , and there is the temperature  sensor attached

[EccentricAnomaly]

Are you saying that you can get a surface charge on the plates that will give the appearance (voltage) of full charge but not really without a good boil, as it were?  I think I'm learning here.

Not so much a good boil as a long, lower current absorption phase charge.  Good (or, at least, plausible) discussion of surface charge here:

http://www.smartgauge.co.uk/surf_chg.html

So a batt monitor senses the temp and decides from that how well charged the battery is?

If its hot it must have been charging hard for a while, so time to slow down as we must be nearing completion?

I think it's more that the voltage which appears on the terminals for a given state of charge depends slightly on the temperature so when the battery monitor is trying to estimate the state of charge by looking at the voltage it needs to take the temperature into account.

[Justme]

Temperature compensated charging increases or decreases the charge voltage dep on the bats temp. Whilst the bats temp will rise with fast charging the compensation is more about the environments effect on the bat. When its very cold you need higher volts to gain the same effect.

You dont need to "boil" the bat, you just hold the volts at a high level to allow the charge to penertrate the plate fully. That said a "boil" (you want the V to be just under the gassing voltage so you dont evap the electrolyte or do it with a higher V & just top them up more, so no doing that to sealed /gel bats) is used for doing an EQ charge to ensure that all the cells are at the same value. The cells that are bubbling / gassing are full ish & the ones that are not still need charging. When they are all gassing about the same & the SG stops rising then they are full.

Billy when your meter says no charge at all it MUST be lying. Even a fully fully charged bat will take some amps on a trickle. I doubt its is even possible to get to the stage when it accepts none at all. I think the meter just refuses to show any amps when the amp hour counter has reached 0 / full. On days I do a long charge I get down to 15amps which is 1% of total capacity. So I would expect yours to still be doing 2 amps ish when full (plus any loads).

[Billy]

Justme,

I did a check today as the tide was right, as are you.  The regulator shuts the alternator charge to nil for a 15 min rest period (adjustable) then goes to 2-5 amps.  This happens when the batteries are low ish and have been on a high charge for a time, doesn't happen on medium or nearly full batteries.  Hence the zero amps that I clocked.  Monitor is new so still in play mode.

Billy

 

[Justme]

Monitor is new so still in play mode.

Billy

 

Ah thats a good place to be.

Have fun.