dpb

How many volts ( using my portable volt meter) should my 105 a/h trojan deep cycle battery go up to , iv got regulator controlling input
So I presume that ll cut out supply when battery is full

neil-h

Should be 14-15V I'd have thought, i.e. the normal alternator charging voltage.

dpb

Ah , sounds ok then

This is on my boat btw ( don't have an engine)

c_maguire

Usually a resting fully charged 12v battery will show around 12.85v disconnected from any load.
Immediately after charging you may see close to 13v but let it sit for 5mins and then check.

dpb

Its full time connected to solar panel through PWM controller .....it was /has got up to 12.75ish since I connnēctd up about a week ago

Was 13.17 this morning

c_maguire

Was that disconnected from the charger? That's the only way you will know .

dpb

Good point , ill take off supply from panel next time I'm down there

ALi-B

iTrader: (1)

IIRC float charge (as in safety maintaining a charged battery without boiling it) is 13.4volts for a lead/acid battery (not AGM/Gel) at 25degrees. That's with the charger connected to a fully charged battery.

There is a calculation for temperature compensation. Its something like 0.1v per 5 degrees C. The basic rule is to increase the voltage as the battery temperature drops.

Add 0.1V for every 5 degrees below 25degrees C. (so add 0.4v if the battery is 5 degrees C = 13.8V ).

Its reverse if its warm: Subtract 0.1v for every 5 degrees above 25 degrees C.


With the battery disconnected and allowed to rest. It should be as C Maguire's post...roughly 12.8V for a lead-acid battery. Depending on temperature.

dpb

Cheers.

Jamie

14 ish.

dpb

More than happy with the solar , its only 20w panel - wasn't expecting much this time year out of it

I only use led lights , small water pump and will be putting tripath amp .