Power Pack FAQ

Q: Do your controllers use a lot of power?
A: No. Apart from a few milliamps (which is very little!) that are required to illuminate the controller LEDs, our controllers use no power. It is the heaters that are plugged into them that consume power. If battery power saving is of importance to you, then you should consider using our low wattage FireFly heaters or use one of our controllers that senses temperature or dewpoint.

Q: Why buy a Kendrick Power Packs when there are many other cheaper models out there?
A: Unlike the cheap, feature laden batteries that can be found everywhere these days, Kendrick only uses the highest quality components in its batteries. Our wires are properly sized for the current they will be expected draw. All our wiring connections are soldered (the battery and LCD terminal connections excepted). We use the excellent Schurter circuit breakers on all our batteries (2080 excepted). Our battery cases are all metal and powder coated (2080 excepted which does not have a case). Our cigarette lighter sockets are of the highest quality available and are American made. We use Deltran battery chargers and include a tough padded cordura carry bag with each battery.Lastly, our batteries are known for the long life span.

Q: What is the lowest safe discharge voltage I can take the battery to before charging it?
A: 11.0 volts, but preferably not below 11.6 volts.

Q: Why is the warranty only 3 months?
A: If a battery is defective, it will show up within the first three months of ownership. Damage incurred after the initial three months is most likely user inflicted.

Q: How long will the battery last?
A: 5 years or 500 charges, whichever comes first.

Q: When the battery dies, can the internal battery be replaced?
A: Yes, and the replacement can be purchased from Kendrick for a fraction of the original price of the entire unit. Simple instructions for doing this may be obtained from Kendrick and are also available on our web site at https://www.kendrickastro.com/astro/battery.html#ReplacementBatteries.

Q: What kind of batteries do you use?
A: Sealed, 12 volt AGM lead acid (absorbed glass matt).

Q: Do the batteries have a "memory"?
A: No.

Q: How often may I charge my battery? Does it need to be at a certain voltage before being charged?
A: You can charge your battery at any time and at any point in its discharge cycle.

Q: Can I leave the battery charger plugged into the battery indefinitely?
A: Yes, the chargers we use are trickle charge batteries and then will step down their input voltage into the battery down to a maintenance voltage once it senses that the battery is fully charged.

Q: My battery says it is fully charged (12.6 to 13.6 volts) but as soon as I put a load onto it the voltage drops dramatically. What is happening?
A: Your battery is, for all intents and purposes, dead and will need to be replaced.

Q: I have only had my battery for a short while and it is not holding a charge or cannot be charged. What is going on?
A: Your battery is dead. Several things can cause this. The most common are:

1. It has been too deeply discharged (below 11.0 volts) thus damaging the battery internally.
2. It has been dropped and damaged internally.

Q: Can I use a bigger charger than the one included with the battery to get a faster charge time?
A: Yes, but with a caveat. NEVER use an automotive charger with our batteries. The voltage output on these types of chargers is too high for a sealed battery and it will cause internal gassing of the electrolyte, which in turn creates internal pressures inside the battery and will either cause the battery to explode of break the seals.

Any charger used with a sealed lead acid battery must be a trickle charger type of battery and should have an output voltage no greater than 14.4 volts.

Kendrick sells a 6-amp charger that will do the job very well if you need faster charge times.

Q: How long will the charge in my battery last before I need to charge it?
A: This will depend on the amount of power being drawn from it at an hourly rate. You will first need to determine the amp draw of the items you are using. Once this has been done the calculation will be as follows:

(Amp hour rating of battery/total amps of devices being used) x.8

POWER SUPPLY AMP HOUR RATINGS Please bear in mind that when using this chart to determine what size of power supply (as opposed to a battery) to choose, you will need to use the full amperage rating of the heaters in question. The heaters will draw their full amperage when turned on and unlike battery operation, the amperage cannot be averaged by the % of your programed controller settings. You will need to refer to your owners manuals for any other items being used to determine their amp hour draw.

Telrad Heater 0.4 Telrad Finder Heater 0.2 .965" 0.2 1.25" 0.2 2" 0.3 3" 0.8 4" 0.9 5" 1.2 6" 1.4 7-8" 1.5 10" 1.9 11" 2.3 12" 2.6 14-16" 4.1

DIAGONAL MIRROR HEATERS S2 0.2 S3 0.3 S4 0.7 PRIMARY MIRROR HEATERS P8 0.8 P10 0.9 P12 2.6 P16 4.5 OTHERS Control Pad Heater 0.6 Laptop Heater 3.0 Eyepiece box heater 0.8