Power Issues

[that_guy (Tony)]

I'm currently powering the ZWO ASI1600MC-Cool, EQ6Pro and Kendrick 2 channel dew heaters (2 straps) with my 80aH Deep cycle battery that is constantly topped up in between sessions. However, I've been getting flashing LED on the EQ6 which usually indicates low voltage and the dew controller gets no power when the mount is slewing (and does not power back up once it finishes slewing). They are connected through 12v anderson plugs with cigarette ends (rated at 40amps per plug). I'm using the same power cables that came with the controller and camera. Is this an issue with the battery itself (dying maybe, i did buy it second hand)? Or is this a power cable issue? Any help would be appreciated. While it's still warm enough that dew isn't too much of an issue yet, with the coming colder weather, id like to get this sorted beforehand.

Thanks
Tony

[AndyG (Andy)]

Hi Tony,

Do you have a multimeter handy? If not, something dead cheap like this will help. Check the voltage value of the battery, when:

1. Standing alone (unconnected)
2. Connected to mount only (no movement)
3. Connected to mount (whilst slewing)
4. Connected to mount AND dew heater.
5. Measure the voltage at the end of the power cable, just before it goes into the mount (to check "the cable").

What sort of values do you get in each of the above?

Be sure to check the water level in the battery, if it offers access to that. Depending on the charger you have, the battery can get a bit parched. A cheap charger will boil the battery dry if left running overnight, as opposed to a nice digital "intelligent" charger. If water is low, fill with demineralised water to the proper mark. Without insulting anyone's intelligence, please do wear eye protection on this step...

Lastly, check for muck around the pins in the anderson plugs, or anything that can short out etc.

I've never dealt with (or even seen) a mount bigger than my Nexstar 6/8 AZ, not to mention an EQ6. Having googled whilst writing this, it seems the EQ6 appreciates a between 12 -15v (for which your battery is going to give a tickle more than 12 at best. You *may* find your rig is getting 11.x Volts and "browning out". See what can be done above, before worrying about a new (expensive) battery.

Best of luck

[glend (Glen)]

I never run dew heaters off the same battery as the mount, they just suck to many amps. I have the Kendrick two-channel controller as well. I dedicate one 40AH battery to just the heaters, this avoids voltage drops on the mount power.

[that_guy (Tony)]

I've bought the $10 multimeter from jaycar and measured the voltage of the battery on its own. its more or less 12.5V, havent gotten around to the mount or the dew controller. I have a couple of other batteries I might run my mount off of and see how that goes.

[glend (Glen)]

Originally Posted by that_guy

I've bought the $10 multimeter from jaycar and measured the voltage of the battery on its own. its more or less 12.5V, havent gotten around to the mount or the dew controller. I have a couple of other batteries I might run my mount off of and see how that goes.

A good battery should be holding a higher charge than that. Typically chargers will pump over 13V into the battery and it should hold (unloaded) near that point. If it is rapidly falling off and down to 12.5V i would be considering a new battery. If you get below 12.6V under load you have too much load or the battery is failing. I never run a battery below 12.6V, it will kill them pretty quickly, even deep cycles. Measure your battery voltage under load.

[ZeroID (Brent)]

A good battery should read 13.6 volts, 12.5 is on the way out. Voltage will drop significantly under any load. Time to replace. And I'd keep the dew heaters separated on it's own supply as advised earlier.

[JA]

At 100% State of Charge the open circuit voltage of a 12Volt battery is around 12.7 to 13 Volts depending on Battery chemistry/type (Liquid v Gel v AGM type). Sometimes immediately after charging a battery will read in excess of this, but this "surface charge" as it is known is not considerable and "burnt-off" by internal resistance after a rest or even short duration under load, as is the usually recommended practice before measuring battery open circuit voltage. It is not considered significant enough by to be considered as part of the charge capacity of the battery.

Best
JA

[that_guy (Tony)]

I've noticed that the battery wasnt full charge when i tested the voltage, ill charge it overnight (with a 3 stage 2amp charger) and recheck the voltage

[xelasnave]

Originally Posted by that_guy

I've noticed that the battery wasnt full charge when i tested the voltage, ill charge it overnight (with a 3 stage 2amp charger) and recheck the voltage

Buy a little genny $450 for 750 watts and with it your battery will always be charged...until you turn off the genny... all the stuff you run takes a lot of power so you will need your battery to be first class and powereful enough for the job..cooling or heating draws current big time...I dont know but your could be around 5 amps which means only a couple of hours for a first class 100 amp hour battery...
back up genny is handyfor all the times you dont need it.

alex

[that_guy (Tony)]

I remeasured the voltage reading from the batter after its been fully charged. I left it sitting for a couple of hours just to make sure it isn't the surface charge as JA suggested. It is now reading a steady 13.16V. I'm heading out to Wyaralong dam on saturday and will measure the voltage when the battery is under use.

[that_guy (Tony)]

Just an update on this, went to a dark site this weekend and had no issues with blinking led or dew heater when I used a separate battery for the mount. I guess that dew heater draws a fair amount of power.

Thanks guys