North Australian FISH FINDER TM forums

I bought one locally, 120AH, 1 year warranty, died after about 18 months... Only ever ran it in the back of the car charging via a CTEK DC-DC inverter so it was always charged correctly.

I bought a couple of AGM's from adelaide last year, they were 120AH with a free voltmeter/cig socket gadget for $339 delivered, 2 year warranty. The ones I ordered from Adelaide weight considerably more than the local ones.

Till's 80lb thrust electric is a 24v job.

At 24volts the current requirement is only half that of a 12v job. So he doesn't have to go overboard with battery capacity.

Here's how it works.

Say Till's 80 lb thrust electric was producing 55lb of thrust and doing what he wants. It'd be drawing a certain number of amps of current to do that.
If however he had a 12v 55lb electric instead, he'd be drawing twice as much current to do exactly the same job.

The rule with electric motors is the higher the thrust the higher the voltage motor needed which means the lower the current draw and therefore the lower the AH capacity of the required battery.

Have you noticed that the higher thrust motors have higher voltage requirements right up to 48 volts? A 48v electric would draw only 1 quarter of the current than a 12v motor @ 55lb thrust.

2 x 90 - 110 a/hrs @ 20amp rate is more than adequate for him provided he uses real deep cycle batteries and not the tupperware marine or cranking batteries misleadingly advertised and sold as deep cycle. He can use deep cycle AGM type construction batteries if he wishes.

Advice to the commenter who's thinking of using 130ah as a cranking battery. If its a true deep cycle - don't do it (pouring money down the drain). If its a cranking or marine battery it'll be ok.

Hope this helps.

Always use AGM in the alloys, even considering a AGM for the 100 series