2
\$\begingroup\$

The documentation for my 400 watt inverter says the *inverter will shut down if the input voltage drops below 9.5V+/-0.3V

In the Deep Cycle Battery faq listed here: http://www.windsun.com/Batteries/Battery_FAQ.htm (under "State of Charge")

it shows that my unsealed 85AH Costco deep cycle battery would be completely depleted at 10 volts, which is when my inverter would shut off. If this is correct, it would obviously harm the battery.

Does this mean I need to constantly monitor the voltage of the battery and cut it off manually? Get a better inverter where I can specify a cutoff voltage? Or is there some kind of extra cutoff attachment I can add to my setup? Please let me know if my logic is correct and what the best approach here to saving the life of my battery. Thanks!

*The inverter will operate from input voltage ranging from 10 volts to 15 volts. Optimum performance will occur when the voltage is between 12 volts and 14 volts. If the voltage drops below 10.5V+/-0.3V, an audible low battery warning will sound. The inverter will shut down if the input voltage drops below 9.5V+/-0.3V. This protects the battery from being over-discharged.

\$\endgroup\$

2 Answers 2

1
\$\begingroup\$

Inverted is set too low.

Battery will suffer.

Adjustment probably possible.

As it has got a shutdown system, worst case you can easily make your own monitor and tap into that point, probably. Worst worst cas is it's all done in softwrae with no hardware points in monitoring or shutdown that can be easily accessed. Impossible is nothing, but at some stage it's easier to replace the unit in some cases. Probably not here though.

Tell us more about the hardware integration level.
Do you have a circuit diagram?
Do you have a soldering iron? :-)

\$\endgroup\$
1
  • \$\begingroup\$ The inverter specifically is the Cobra 400 watt power inverter (amazon.com/gp/product/B000MTCRHS). Only costed $23.95 (with cables) so not a huge loss. I don't see any controls on it where I can adjust anything and I don't feel competent enough to take it apart. Do you have a suggestion for a better inverter (can Amazon link it with a referral id). I also see that there are cut-off hardware switches I can add, though they seem a bit pricey: ebay.com/itm/… \$\endgroup\$ Dec 8, 2011 at 21:35
1
\$\begingroup\$

You could use one or more diodes between the battery and the inverter. A typical Silicon diode has a 0.6v forward voltage drop. So when the battery is at 10V, it could be 9.4 (or less) at the inverter and the inverter would cut out as desired.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.