morningstar 30 amp charge controller load question

wast

I have a morning star prostar 30 charge controller.. question is can I hook up the load directly to my batteries.. I have 3 banks of surrette 550 batteries connected  using bus bars for the positive and negative (12 volt system) .. If  I hook up the load from from my charge controller to the + & - bus bars  will that tell me what my system is using when in use.. on my charge controller that reading is 00 now as it is not connected to anything.. this is a remote cabin and inverter is turned of when we are away so there is no draw at all until we return..

oil pan 4

I have the Morningstar prostar as my backup charge controller on my solar hybrid generator.

I don't have anything permanently connected to the output terminals.

Basically the output terminals are for any small simple electronic device that you could connect straight to the batteries, such as a light and if you were to accidently leave it on or inadvertently turn it on it would kill the batteries flat dead if left unchecked.

The Morningstar prostar kills power to the output terminals when battery volts drop below 10.5v. If you left some kind of halogen light on connected directly to the battery it would completely shut off when battery voltage reaches 0. And that would be bad.

Most inverters cut off some where between 10 and 11 volts, so you can hook the inverter directly to the battery.

Are these bus bars you are talking about are they connected to the batteries?

BB.

Remember that most LVDs (low voltage disconnects) are set to around 10.5 volts (charge controller LVDs, AC inverter low battery cutoffs). And they are designed to protect the attached loads/devices. For example, an AC inverter will draw more an more current as the battery voltage falls and can overheat the inverter and/or "brown out" the loads.

A lead acid battery at 10.5 volts resting voltage is pretty much "dead" (0% state of charge). And taking lead acid batteries that low will pretty much end their life (aka "murder" the battery).

For the most part, you do not want to cycle very often below ~50% state of charge (for longer battery life). The resting terminal voltage is ~12.0 volts and the voltage under moderate load is something like 11.5 volts. Again, battery terminal voltage for lead acid varies a lot (temperature, loads, charging current, state of charge, age)... So the operating voltage is just a rough guess as to the actual state of charge of the battery.

However, if you use a hydrometer to measure the state of charge (flooded cell batteries), and everything else is constant (i.e., normal loads, room temperature, etc.), you can use the voltage as a quick check as to "how low" you want to take your battery bank in daily operation before you "cut the loads", start a genset, etc...

-Bill

littleharbor2

Is the Morningstar Prostar 30 the only charging source you are using to charge the 3 banks of Surette 550's? If so it seems awfully inadequate  for that much battery.

wast

littleharbor2 said:

Is the Morningstar Prostar 30 the only charging source you are using to charge the 3 banks of Surette 550's? If so it seems awfully inadequate  for that much battery.

No I also use a iota 55 amp charger with my generator.. I have 3 130 watt solar panels that seem to keep everything up during the summer months.. we don't see a whole lot of sun in dec thru feb..

oil pan 4

If you don't get much sun get a Morningstar MPPT. It has an adjustable load shut off. The higher voltage cut out is 11 or 11.5 volts. With an MPPT you could get as much as 50% more total power out of your solar panels and into your battery.

The MPPT will put out about 30% more power in full sun and I noticed the MPPT starts charging the battery earlier continues to charge it later into the evening and gets some charging done during heavy overcast.

I guess you can say that MPPT chargers are the holy grail of off grid solar, well because they really are.