Accidental discharge.

[ROBDEN]

Strange occurrence (to my mind anyway)...........

 

Generally, in the mornings my Smartgauge reads about 70% soc then drops to around 66-67% after a couple of hours before recharging the batteries.

Yesterday however, I accidently turned on the electric blanket (I know, I know, a concession to the wife as a liveaboard) and it was on for about 3 hours. Smartgauge had been reading 100% soc but after 3 hours of the blanket being on it was down to 52%. This I noticed at 7pm, so not wishing to break the 8 o'clock rule I ran for the hour and brought the batteries up to 64%. Then 2 hours of TV, an hour or so of reading and off to bed, definitely no electric blanket!

 

Now this is what I find strange. In the morning, Smartgauge was reading 67% and stayed there for the next 4 hours until I decided to run and recharge the batteries. Would this have anything to do with the rapid(?) discharge? The Smartgauge appears to be working as normal.

 

Your thoughts will be much appreciated.

Rob....

[Chris Pink]

yes, normal, after discharging a battery it will recover. Also the Smartgauge is not accurate whilst charging.

[RobinJ]

yes, normal, after discharging a battery it will recover. Also the Smartgauge is not accurate whilst charging.

Also, since the measurements were presumably 'on load' that makes a difference too?

[nicknorman]

Strange occurrence (to my mind anyway)...........

 

Generally, in the mornings my Smartgauge reads about 70% soc then drops to around 66-67% after a couple of hours before recharging the batteries.

Yesterday however, I accidently turned on the electric blanket (I know, I know, a concession to the wife as a liveaboard) and it was on for about 3 hours. Smartgauge had been reading 100% soc but after 3 hours of the blanket being on it was down to 52%. This I noticed at 7pm, so not wishing to break the 8 o'clock rule I ran for the hour and brought the batteries up to 64%. Then 2 hours of TV, an hour or so of reading and off to bed, definitely no electric blanket!

 

Now this is what I find strange. In the morning, Smartgauge was reading 67% and stayed there for the next 4 hours until I decided to run and recharge the batteries. Would this have anything to do with the rapid(?) discharge? The Smartgauge appears to be working as normal.

 

Your thoughts will be much appreciated.

Rob....

 

When the batteries are being charged, SG can't really tell how quickly since it just "sees" the behaviour of the charging system. There is an element of just counting up at a certain rate. Once the charge stops, the SG "sees" the real battery behaviour and after a while, it may adjust its reading. Gibbo has mentioned this in the past. My guess is that you have a fairly powerful charging system and during the bulk phase, the batteries are charging faster than the SG is counting up. I certainly notice that the SG lags behind the AH-counting meter during charging with our 175A alternator, during the early part of the charge.

 

Also, since the measurements were presumably 'on load' that makes a difference too?

Not really, SG is pretty good at coping with measuring "on load", unless you mean during charging.

[RobinJ]

When the batteries are being charged, SG can't really tell how quickly since it just "sees" the behaviour of the charging system. There is an element of just counting up at a certain rate. Once the charge stops, the SG "sees" the real battery behaviour and after a while, it may adjust its reading. Gibbo has mentioned this in the past. My guess is that you have a fairly powerful charging system and during the bulk phase, the batteries are charging faster than the SG is counting up. I certainly notice that the SG lags behind the AH-counting meter during charging with our 175A alternator, during the early part of the charge.

 

Not really, SG is pretty good at coping with measuring "on load", unless you mean during charging.

I thought SG was 'sort of predictive', in that it could calculate charge and discharge rates, but if hit with a sudden charge or discahrge that was unusual, it 'as you say' lead or lagged?

[nicknorman]

I thought SG was 'sort of predictive', in that it could calculate charge and discharge rates, but if hit with a sudden charge or discahrge that was unusual, it 'as you say' lead or lagged?

Only during charging. It's very good at coping with rapid discharge - we have a 2.5kw inverter and use an electric kettle routinely.

[ROBDEN]

Thanks for your thoughts all.