keep killing my lead acid 40ah battery

[gazza2006au]

I went with 2x of the 40ah lead acid batteries i will mark them 1 and 2 and only use them to move the boat

I bought 2x the 45ah lead acid batteries to run in parallel on the boat as a start battery

Its the cheapest i have found, 2 start batteries 90ah 380cca x 2 cost less than $60 total

2x trailer mover batteries cost less than $60 total

I couldnt buy half of a single marine battery for that cost

[NAGG]

Chris, you seem to infer that a deep cycle will solve the problem. My anchor winch draws that much power and i used to use the deep cycle but found it destroys them. It is now on the cranking battery for the last few years and with the motor running works much better.

A deep cycle of the right capacity will solve the issue ..... he is using a hybrid with just 40amps .

a leccy draws around 50amps as well when running on 10s - we all use deep cycle batteries for them

So why were your deep cycle batteries being destroyed ....... ?
What was the wattage of the winch? ...... Unless it was a high draw winch (1000W plus). ? Was the deep cycle a house battery being charged by the boats motor ? did you run the boats motor when using the winch ? ..... how low was the winch pulling the battery down to ? ...... then was the run long enough to put the charge in .

I destroyed a pair of top notch Odessy 100amp deep cycle AGMS on my old Hornet in about 3 years - because I didn't understand that running them flat wasn't a good thing ...... When I went to a 12 volt leccy - I went with a 200amp AGM which I never flattened & hardly got down to 50% ....... That battery spent 8 years in boats & I still have it today (12 years).

Why don't you think that a deep cycle will fix the issue ?

Chris

[NAGG]

LOL...I hope he intends to join the VMR...

I wonder if this could all be avoided by practicing reversing in tight spaces...

Sounds like a hell of a fukk around to take 30 minutes to move the boat back up the driveway

It was his starting battery

Chris

[shakey55]

I went with 2x of the 40ah lead acid batteries i will mark them 1 and 2 and only use them to move the boat

I bought 2x the 45ah lead acid batteries to run in parallel on the boat as a start battery

Its the cheapest i have found, 2 start batteries 90ah 380cca x 2 cost less than $60 total

2x trailer mover batteries cost less than $60 total

I couldnt buy half of a single marine battery for that cost

Gazza, I know money is tight with all of us, but is it worth going cheap on batteries when you are 10 kms out to sea. Please reassess


Shakey - If only I lived near the coast

[gazza2006au]

Hey Shakey just one 380cca 40ah starts my engine i will be running 2 of these batteries in parallel so i'll have 760cca 80ah so long as my connections are tight there ahouldnt be a problem not that i can see

[Dignity]

Hey Shakey just one 380cca 40ah starts my engine i will be running 2 of these batteries in parallel so i'll have 760cca 80ah so long as my connections are tight there ahouldnt be a problem not that i can see

Gazza you will increase your amp hours but I'm pretty sure Ohms law says you won't double the CCA capability

[gazza2006au]

Wouldn't the cranking amps be devided 50/50 from each battery Digs? I bought the 2 batteries as i was worried about pumping 60-70amps back into the single battery at WOT

[Dignity]

Wouldn't the cranking amps be devided 50/50 from each battery Digs? I bought the 2 batteries as i was worried about pumping 60-70amps back into the single battery at WOT

Gazza, generally most sites will tell you it will. You certainly will increase the number of amps you have available but my old boss who was an electrical engineer and specialised in batteries showed me on a bench test with plenty of metering that the cranking wouldn't double due to Ohms law. I have found that running 2 batteries in parallel doesn't help when using the electric winch just spreading current flow not the load. I hate anything to do with batteries as it usually does my head in and I probably got it wrong.

[stevej]

The regulator senses the voltage of the battery and decreases the alternator output as the battery voltage rises
so no your alternator will not output 70 amps into the battery at wot after it is charged

what are the battery specs and brand

also if you have buggered one battery with your mobile mover with the deep discharges and then link then for 12v the second battery won’t perform either

[gazza2006au]

I have bought 2 new batteries just for the boat i didn't want to mess with the battery that has been cycled with the trailer mover than risk wiring that up to a new battery

I have 2 of each of the batteries in the pic, the 40ah will be used for the mover, the 2 45ah will be used on the boat

[NAGG]

I have bought 2 new batteries just for the boat i didn't want to mess with the battery that has been cycled with the trailer mover than risk wiring that up to a new battery

I have 2 of each of the batteries in the pic, the 40ah will be used for the mover, the 2 45ah will be used on the boat

Gazza


Don't you ever ask yourself .... "why so cheap?"

Also I've never heard of anyone running 2 cranking batteries in parallel & yes you will double the amps & CCA

As for over charging via the motor - no you wont ..... unless there is a fault

Chris

[gazza2006au]

The seller is only 20mins down the road if i have a problem im sure they come with 12 months warranty, $120 for 4 batteries is a good deal i'll see how they go first, at $30 a piece i can resell them easily if they dont work, dead old 8 year old worn batteries sell to the scrapper for $10 each so these shouldnt be hard to resell

[stevej]

For someone who is so worried about things failing sinking breaking down I’m not sure why you cut corners

they are not Marine batteries you now have 12 cells instead of six and extra leads in the mix
and on top of that yumcha specials

one tow and you have paid for a decent battery

the main thing is I couldn’t find any specs online to the maximum charge they can accept
so if the battery was dead flat the alternator may overcharge them in the beginning until the voltage comes up
don’t know the year model of your motor but doubt it has a smart alternator in it

[ranmar850]

You will definitely increase your cranking ability with two identical batteries in parallel, vs one of the same type. Exactly double it? Not necessarily, due to construction tolerances leading to internal resistance differences. Anyone who has run an old style 1/2/Both style battery switch has experienced this, the engine will crank over faster due to less voltage drop as you load them up. However, if one of those cheap cells goes down, you probably won't have enough to crank your motor over. Even you can work out which one is bad before you stuff the both of them by repeated trying, you probably won't start with just one of that size. It would be a similar scenario to misuse of the old 1/2/Both switches---if 1 is your start battery and it goes flat, the uneducated have been known to go to Both thinking this will solve the problem. But all you will do is then discharge the good one into the bad one, and likely end with two that are right down.

[gazza2006au]

Hey Ran one battery starts my engine perfectly fine takes about 2 seconds to kick over as the engine is EFI