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Boiling Batteries


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#11 harrytom

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Posted 30 December 2017 - 10:29 AM

Battery computer??40 yr old yanmar,no fancy wiring,have battery at home on charge. I presume alternator goes straight to battery,using isolators the old key type.


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#12 island time

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Posted 30 December 2017 - 10:59 AM

OK, so how do you know the batts at 20%?
Anyway, charge at least 12hours, then leave 10 hours, report voltage after rest.
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#13 Knot Me... maybe

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Posted 30 December 2017 - 11:07 AM

I'd like to add that the battery computer needs to be correctly installed -, the shunt being the first connection on the negative lead - NO other wires direct to battery negative. Then it needs to be correctly programmed - battery type and capacity, reset current (circa 1% of capacity), proper purkets factor for that battery etc.
The purkets factor for that battery and the correct charging voltages will be given on the product data sheet, and sometimes on the side of the battery.
Not to do all this means the battery computer will not be accurate, possibly by so much its useless. In my experience 90 odd percent of them are not set up correctly.

All 4 of the other experts who have helped me went to great lengths to say exactly what IT is saying there.

 

ALL MADE IT VERY CLEAR, the battery monitor has to be installed correctly and then calibrated or I may as well rent a hooker for a night, that way I'd get some return on the coin spent as I'll get none from the monitor.

 

Mine has been installed with lots of care and the mates it needs that weave the magic to make it work as good as it can. Also everything was tweaked to 'lithium' mode and one gizmo even wanted to know what Wattage the panels were so it knew what it was dealing with, that's a little bit fancy. I am calibrating it at the moment as per the manufacturers specifications. Should be all good later today or as close as judging by what I was seeing yesterday. It's that easy to do the experts are letting me do it myself, even though 2 do know me well.

 

At work we sell solar Nav lights, ones for buoys etc, and they have lithium batteries. We have a fancy charger that when we plug a battery in for a check it discharges it then recharges it then tells us what state it's in, what usable amps it has and all sorts of fancy stuff..... but it's small and only good for up to 6 cells. It's a cunning bugger though.

 

But lead batteries really??? Delivered to the boat in a Morris Minor were they ;)

Na, there is still a very strong place for lead. Lithium and similar is the future for sure but at the moment it's still not a game for the budget constrained. I spent a couple of years working up to mine so while it still hurt a lot handing over what was a large sum of money I am sure the lifetime cost won't be that dissimilar to top end lead alternatives. The bonus I was willing to pay a lot for was big storage at low space and weight. I now have a everyday usable 160 amps which is lighter and in the same space use to be only 55 amps. The weight and space savings are huge.


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#14 wheels

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Posted 30 December 2017 - 04:14 PM

KM, not all Lithiums are the same and thus not all use the same charging techniques. The kind of Lithiums you have on the boat, being LiPo, would be destroyed if you fully discharged before charging again.
In fact, I don't know what the Cell ph's don't have a charging app or something like that. The worst thing you can do to them is leave them charging while at full capacity. i.e, plug in and leave on all night, like we all tend to do. The other thing they don't like is being fully discharged before charging again. The phone type Lithiums like regular small doses of charge.

Harrytom, the issue with charging from the Alternator only, is that the Alternator (I assume no special charge regulator fitted) is limited to 13.8V. So a Battery is never fully charged. In fact you will only ever get 75 to 80% back into the battery and only then, if the engine is run for hrs and hrs. The Battery (when new) may read like it is charged, but the capacity is severely undernourished and it will lose charge quickly. So you really need a charge regulator fitted to the alternator to ensure the Battery is charged fully, or you will get little more than 5 to 6yrs from it and only half the current capacity of what could be delivered.


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#15 Fish

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Posted 30 December 2017 - 07:00 PM

So these battery computers, what do they cost and what is an example of a good but modestly priced one?

 

I'm after the bit that tells me what capacity is remaining in the battery, how much has been used by consumption and how much has gone in.

 

We already have a smart regulator on the alternator, and a new MPPT controller on the solar.


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#16 island time

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Posted 30 December 2017 - 08:01 PM

Victron bmv700, 2-300 with shunt, bep $550 from burnsco.
I can do the either, but not till I'm back on 19 Jan.
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#17 harrytom

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Posted 31 December 2017 - 01:24 PM

OK, so how do you know the batts at 20%?
Anyway, charge at least 12hours, then leave 10 hours, report voltage after rest.

battery after 24 hr charge shows 13.5v so will see what it reads tonight.this system has been in the yacht for 40yrs,so I presume previous owners just changed out batteries after 4 or so years?

 

Do have a spare alternator onboard which is 80 amp?so could original alt not actually be working at spec?


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#18 wheels

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Posted 31 December 2017 - 03:34 PM

 

Do have a spare alternator onboard which is 80 amp?so could original alt not actually be working at spec?

Why do you think not working at spec?
What size ALT have you got now?


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#19 harrytom

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Posted 31 December 2017 - 04:11 PM

Why do you think not working at spec?
What size ALT have you got now?

same, meter on dash shows charging at 14.5     just put meter on battery showing 12.5 

had 31/2 yrs no issue no change to any wiring. Crank battery always show 13.5v

previous owner fitted amp meter to show battery drain. nothing fancy here. All I need is house battery to power lights/waeco fridge,dvd/tv not necessary keeps no2 amused at night.


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#20 harrytom

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Posted 01 January 2018 - 01:51 PM

just checked dropped from 12.5v last night to 12.3v

 

give it more charge or is it ok??


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