circuit wanted for battery %charge monitor

I use the low volt cutout cct set for 11volts. You could set the cutoff to correspond to the battery volts at 50% discharged, it would be approximate due to temperature variations but close enough for your purpose and cheaper than using a pic or whatever to log usage.

Cheers .......... Rheilly P

Battery monitors are best a guess unless you spend a *bucket* of money. Even then they are not that flash as the battery ages. Personally I would recommend you save your money. While you are using the battery and the sun don't shine at night, voltage is an excellent guide when you have a light load on the system. We seldom get our systems below 12.4V at night and usually 12.5V and never below 12.2V.

I have extensive experience in small solar systems and never fitted battery monitors. If you need more capacity buy an extra solar panel or put in an extra battery - NOT in parallel. Split the system. Hopefully you have a decent quality solar regualtor as that makes a *big* difference to how close to 100% the batteries get charged. You can easily have up to 12% from full battery capacity with cheap solar regulators.

If you want to carry this convo on at a higher level leave your e-mail address. Dave.

Thanks for the pointers, I will monitor the voltage and not let it get below 12v or so. (The inverter auto cuts out at 10.5v)

I just need to set the charge voltage with that oately charger circuit, My batteries are 2 of these in series

The pdf data says charge voltage 7.25 - 7.45v float voltage 6.8v - 6.9v

Since there is no float feature on the basic oately charger kit I was just going to adjust the pot to charge up to 14.9v

One reason I wanted two 6v batts in series is because I wanted a 6v tap to directly feed my adsl modem which is always running. plugpack is 5v at 2 amps but modem is drawing about 1 amp max. Running modem directly without an inverter would be most efficient. (5w x 24 hours) . To load balance and kind of drain both 6v batts equally I will connect my ipcamera to the other 6v batt and try to run cam on dc as cam draws about 800ma

Appreciate any other snippets of info. My email is lentildude AT hotmail.com

thanks

George

If you are f....'ing around with an Oatley charger kit on modern batteries, you are *NUTS* putting it nicely. You cannot mess around with rubbish solar regulators on modern batteries and especially sealed batteries. 14.9v would kill your batteries quickly. You need a precision temperature controlled PWM solar regulator for AGM VRLA batteries. On solar you need to spend the money once, do the job once and damn well do it properly otherwise it will cost you an ongoing fortune. Solar done correctly is magic and you use and forget it. Send you an email.

You'd better make sure the grounds of the modem and ip camera don't meet at some point...

Tom

Thanks Dave, will email you in detail but severe budget retraints means compromising and DIY system.

I guess the compromise would be to set charge voltage cutout at 14.2v just above recommended float voltage.

Tom, yes I was thinking an earth loop would be disasterous. The ipcams ethernet cable plugs into the hub on adsl modem so dont think I can run them seperately off their own 6v batts safely. May have to build 12v to 5v inverters but of course wasting power in the conversion.

George

at some point...

There are PWM voltage reducing units on the market. These are generally better than 85% efficiency and about $25.00. Jaycar have one and cannot remember the part number and DSE

has M9889. Much better option than taking power off the 6V battery even though you are attempting to keep it balanced.

I guess the compromise would be to set charge voltage cutout at 14.2v just above recommended float voltage.

Tom, yes I was thinking an earth loop would be disasterous. The ipcams ethernet cable plugs into the hub on adsl modem so dont think I can run them seperately off their own 6v batts safely. May have to build 12v to 5v inverters but of course wasting power in the conversion.

George

Ethernet is dc isolated and usually ok, watch out for some other tricky connections. Tom