petem
Well-Known Member
Sorry, another question. If I have two batteries in my house bank do I need a charger with two outputs thus charging them individually or a single output charging them as a bank? I believe the original setup was the latter.
Flat battery
- Thread starter petem
- Start date
vas
Well-Known Member
house bank implies that the batteries are connected together in parallel (so + to + and - to -) If so, you only need one output to charge them both.
Portofino
Well-Known Member
Agreed one 12 v out put to each bank not separate in this case two to each battery .
Modern chargers normally have a few outputs to do independent banks ,
Eg house , engine str , geny or what ever .
Indeed they are all treated differently and can be at different stages @ diff times .
Further more the engine outlet of the charger does the least work .
This is because while running the pair of alternators should top up the lost charge from the two starts quickly.Theses days how ever modern EDC engines consume a huge amount of juice , feeding the ECU ,s and associating electrotwackerey to keep the thing running , so depending on the alternator(s) output sometimes via a split diode there’s not actually a great deal of spare juice available to get re stuffing the house bank after a extended period say @ anchor .The house bank(s) get there re stuff when @ the dock on charge or geny run @ anchor with the charger on .
We have 2x180:aH for each bank ......house and starter .
Fortunately full monitoring, so I can see how much discharged and when recharging ( alternator or mains / geny charger ) how much is being stuffed back in amp H .
The OEM charger decayed to max out put 3/4 Ah from its 40 , my boat sparky fitted a 3 output 80 Ah .
The 40 fitted the rule of thumb 1/4 of 360 ( 2x180 per bank ) , but he suggested an 80 , so I went with that and it’s all been fine .
For redundancy Infact we have a small 20 Ah Bosch motorcycle charger on the geny 60;Ah bat ( 400cc motor ) and turn the main chargers geny out line off .
This is so if the main charger fails I can still start the geny or get power to it .
We also have a 24 v to 12 v cross over switch to rob power from a either 24 v bank to start the geny .
This set up in therory means after a geny start @ anchor we should be able to source juice from somewhere for a main engine start if for some reason we drain the house and there’s a fault with the engine bats ......very unlikely scenario .
Happened once .
So I started the geny and it’s charger then waited 30 mins and while running started the main engines with the power and x over switches from the geny .
My house where too flat to grab enough and the engine bats too low because they were knackered .....naturally knackered ie 5 y old etc and lost it after a day and night and 18 hrs @ anchor without the main charger from shore .
Modern chargers normally have a few outputs to do independent banks ,
Eg house , engine str , geny or what ever .
Indeed they are all treated differently and can be at different stages @ diff times .
Further more the engine outlet of the charger does the least work .
This is because while running the pair of alternators should top up the lost charge from the two starts quickly.Theses days how ever modern EDC engines consume a huge amount of juice , feeding the ECU ,s and associating electrotwackerey to keep the thing running , so depending on the alternator(s) output sometimes via a split diode there’s not actually a great deal of spare juice available to get re stuffing the house bank after a extended period say @ anchor .The house bank(s) get there re stuff when @ the dock on charge or geny run @ anchor with the charger on .
We have 2x180:aH for each bank ......house and starter .
Fortunately full monitoring, so I can see how much discharged and when recharging ( alternator or mains / geny charger ) how much is being stuffed back in amp H .
The OEM charger decayed to max out put 3/4 Ah from its 40 , my boat sparky fitted a 3 output 80 Ah .
The 40 fitted the rule of thumb 1/4 of 360 ( 2x180 per bank ) , but he suggested an 80 , so I went with that and it’s all been fine .
For redundancy Infact we have a small 20 Ah Bosch motorcycle charger on the geny 60;Ah bat ( 400cc motor ) and turn the main chargers geny out line off .
This is so if the main charger fails I can still start the geny or get power to it .
We also have a 24 v to 12 v cross over switch to rob power from a either 24 v bank to start the geny .
This set up in therory means after a geny start @ anchor we should be able to source juice from somewhere for a main engine start if for some reason we drain the house and there’s a fault with the engine bats ......very unlikely scenario .
Happened once .
So I started the geny and it’s charger then waited 30 mins and while running started the main engines with the power and x over switches from the geny .
My house where too flat to grab enough and the engine bats too low because they were knackered .....naturally knackered ie 5 y old etc and lost it after a day and night and 18 hrs @ anchor without the main charger from shore .
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Portofino
Well-Known Member
Regarding bat life and charger capacity .
I,am no expert but thinking from first principles I suspect you get a better life if the time spent down low is minimal.
So my theory with boats is not the actual number of discharges , cycles if you like or even the depth ......the 50 % theory .This theory goes along the lines of if they suffer a few , a handful of deep discharges then they are knackered .
No it’s more the aggregate time down below a certain point .
So a few down to less than 50 is the same in my book as hours sat at 85 % .
Time down shortens the life .......there’s no good % down be it 50 or 15 % .
So within the realms of physics and chemistry you need with modern none wet bats to re stuff ASAP with either the alternator(s) or charger ..........so bigger charger output as safely possible to minimise time down .
So a day at anchor because our boat is all electric after say 4/6 hrs we start the geny and I put the charger on just to re stuff the house bats .
40 mins an hour or so is all it takes .
So 360 capacity I see initially 40 to 60 ah or going in and this tappers down to 3/5 very quickly in 40 mins .
Engine hold there charge as zero / negligible drain when off .
I think gel / AGM bats are more suited to rapid stuffing ......which is what we have ....no wet acids on my boat ,
I know on here many go down the cheap wet acid route and almost consider bats a annual or biannual expense ......buy if you get the AGM or gel bats and figure out how to NOT let them stay down long ( sync the charger output to them ) it’s amazing how long they can last
I,am no expert but thinking from first principles I suspect you get a better life if the time spent down low is minimal.
So my theory with boats is not the actual number of discharges , cycles if you like or even the depth ......the 50 % theory .This theory goes along the lines of if they suffer a few , a handful of deep discharges then they are knackered .
No it’s more the aggregate time down below a certain point .
So a few down to less than 50 is the same in my book as hours sat at 85 % .
Time down shortens the life .......there’s no good % down be it 50 or 15 % .
So within the realms of physics and chemistry you need with modern none wet bats to re stuff ASAP with either the alternator(s) or charger ..........so bigger charger output as safely possible to minimise time down .
So a day at anchor because our boat is all electric after say 4/6 hrs we start the geny and I put the charger on just to re stuff the house bats .
40 mins an hour or so is all it takes .
So 360 capacity I see initially 40 to 60 ah or going in and this tappers down to 3/5 very quickly in 40 mins .
Engine hold there charge as zero / negligible drain when off .
I think gel / AGM bats are more suited to rapid stuffing ......which is what we have ....no wet acids on my boat ,
I know on here many go down the cheap wet acid route and almost consider bats a annual or biannual expense ......buy if you get the AGM or gel bats and figure out how to NOT let them stay down long ( sync the charger output to them ) it’s amazing how long they can last
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omega2
Well-Known Member
Heavy rain, auto bilge pump, flat battery!
Portofino
Well-Known Member
That’s my point your charger capacity ( at the dock plugged into shore power ) should be able to easily keep up the pump drain .......thus the bats don’t notice a % drop of any significance to shortening there life .
MapisM
Well-Known Member
If I should find any of my bilges wet after heavy rain, that would already annoy me.
But having enough water ingress to start an auto bilge pump would drive me nuts! :ambivalence:
In such case, it ain't battery draining the real problem to troubleshoot, imho.
petem
Well-Known Member
Cringing as I write this.....
Guys have checked my house batteries and there's no water in them*. They've added 9lt of water between the two and they seem to be holding charge. I'll know for sure when I have my swanky new battery charger that's on it's way to Spain.
* Note to self, don't leave them for years without checking them.
Guys have checked my house batteries and there's no water in them*. They've added 9lt of water between the two and they seem to be holding charge. I'll know for sure when I have my swanky new battery charger that's on it's way to Spain.
* Note to self, don't leave them for years without checking them.
BruceK
Well-Known Member
5 demerit points for brazen honesty.
and as loosing so much water would only happen over time will effect capacity and voltage. Time to re-investigate your other issue
and as loosing so much water would only happen over time will effect capacity and voltage. Time to re-investigate your other issue
petem
Well-Known Member
!
MapisM
Well-Known Member
Yup, that didn't help for sure, but how many years are you talking about?
I can't remember to have ever used more than one 5L bottle each season, for all of my 8 domestic+2 starting batteries, in the last 20+ years.
I'm not sure about whether, once you start neglecting them, the water consumption can accelerate exponentially. If so, that can be the reason for your huge 9L in 2 batteries.
But other than that, I would also consider if they are possibly placed in a spot that gets way too hot when the engines are running.
BruceK
Well-Known Member
Well holding thumbs. Elec-trickery on these modern engines. Anything that cant be spun with a spanner should be viewed with utmost suspicion in my book.
vas
Well-Known Member
+1
OTOH, my 4X T105RE Trojans like a drink way too often!
with a victron mppt and 600W solar they probably need 4-5lt per season... And they also drink a bit off season with the boat tied on the dock or on the hard with no systems running.
Installed self filling thingies a couple of months ago, so now plan is to go in the e/r midday when fully charged once a month and lift the 4lt canister that's connected to the self fill pipe for a minute or so and fill them all up, better than struggling for 10mins with reduced visibility and access
V.
MapisM
Well-Known Member
Yeah, that and a hammer are sufficient for 90% of what you need to do onboard, according to an old friend of mine whose business was the production of OEM custom mechanical parts.
He owned a small powerboat with an ancient BMW petrol engine+outdrive, and how he kept that thing running efficiently for decades is a mistery to me.
BruceK
Well-Known Member
You keep the wisest of friends M. :encouragement:
MapisM
Well-Known Member
Interesting.
With my standard (non-RE) T105, I topped them at the beginning of the season.
IIRC, I used less than a couple of liters for 8 of them, and at the end of the season, they were still very close to the mark.
I re-topped them with maybe half a liter overall, just because while the caps were already open it only took me a few minutes more to squeeze a bit of water in them.
Unless you also have them placed in a very hot spot, I guess that's down to your batteries being the RE version.
The following video gives a nice overview of the difference between them.
MapisM
Well-Known Member
Well, I try, though sadly that chap can't do boating anymore, by now.
He's the one who pulled me out with a monoski for the first time with that BMW powered boat, btw.
Happy times!
jrudge
Well-Known Member
If taking that much I would assume you need to refil with Acid and not water?
MapisM
Well-Known Member
My understanding of FLA batteries is that you should NEVER refill them with acid, because it's purely water that evaporates.
What I would rather think after such huge consumption is that they are ready for the garbage bin... :ambivalence:
Croftie
Well-Known Member
+1, As I understand it the acid salts are still left after the evaporation
