Dual Battery Question

[castlemaine]

Hi All

I've got dual batteries with isolator switch (0 or 1 or 2 or 1&2).

My questions are

1. Can I safely switch from 1 or 1&2 to 2, vise versa, while the motor is running.

2. Can I leave the main leads attached and charge batteries with external charger? Will it charge both batteries at the same time?

Cheers8-)

[kokomo]

1)yes
2)yes

[Angla]

I will second that

1.Yes but do not slide through the off position
2.Yes. Only if the switch is in position 1+2

Chris

[dnej]

Just check your switch first.
Some stupid ones disconnect, as they move from pace to place.I have never seen one my self, but they are out there apparently
David.
PS never turn the switch to off,with the motor running

[finga]

(1) yes but as Angla and David has mentioned check that the switch does not go through an off phase when it goes from either to both. ie it's only off when the switch says off and only run on both if the batteries are the roughly same type/size
Some switches do momentarily go off when switching.
(2) personally I would not charge both batteries through the switch.
That would be dependent on your charger though
If your charging through the switch that usually means the motor and accessories are still connected (depends on how the boat has been wired) and you never know what voltage the charger might spike to which may damage electronics or if any damage is happening with the current present ie regulator/rectifier, motor electronics
Just too much electronics to worry about IMO.
Not to mention if one battery is a bit wonky or different sizes/types some funny things can happen.
Plus it's a good chance when your disconnecting and reconnecting to check the battery terminals and cable cable connections
Sorry...just my thoughts :(
Cheers Scott :)

[Mindi]

Just check your switch first.
Some stupid ones disconnect, as they move from pace to place.I have never seen one my self, but they are out there apparently
David.
PS never turn the switch to off,with the motor running


For some motors....ie 4 strokes wont run without an operating battery but some DI 2 strokes will...and can be hand started without a battery. An important 2 stroke advantage not promoted much at all.

[cormorant]

I think Finga advice is on the money

Switch in off position charge each battery independently direct to the battery. If you have electronics attached direct to the battery ( not best idea) remove the positive lead before attaching charger.

The terms used on switches is "make before break"in regards to battery circuit. If your switch is a Make before break switch and is a quality one it is OK to change from batt 1 to batt 2 or both.

It is a great risk to ever have it on both as a deal battery can quickly take the charge from a good battery and leave you stranded. Going through both if you have a battery with shorted paltes can cook and kill you 2nd good battery by dead short.

Always best to have motor off when changing battery switch's position where possible.

Check your motor manual as some now have an accessory ( on larger motors) which is a dual battery charging system which will enable both batterys to get a propper charge from the motor and enable 2 different sizes and styles of battery to be used.

[bobbyb]

hi castlemaine.

i have isolater......... 1&2 and both. but also a on/off isolater on the main

battery cable going to the starter motor. that way you can charge both

batteries on 2 and turn off the other to insure no power at all can get

to you electronics or engine. works for me.......... cheers.

[glennaus]

just wondering if anyone is using a smart solenoid that isolates the the start battery once the voltage drops to around 12.7 v and won,t charge the aux battery till the start battery is at full charge was thinking of changing my system to this if there is a marine application available at a reaonsable price,

cheers glenn

[STUIE63]

they were advertising one on ET the other day I think it was a BLA product
Stuie

[finga]

just wondering if anyone is using a smart solenoid that isolates the the start battery once the voltage drops to around 12.7 v and won,t charge the aux battery till the start battery is at full charge was thinking of changing my system to this if there is a marine application available at a reaonsable price,

cheers glenn
Here's a couple that should suit you
http://www.bla.com.au/index.php?fn=SubSectionView&dId=1&id=1431&eId=10&sId=3900723476c74f21b91c2feab0a7a579

[John Buoy]

just wondering if anyone is using a smart solenoid that isolates the the start battery once the voltage drops to around 12.7 v and won,t charge the aux battery till the start battery is at full charge was thinking of changing my system to this if there is a marine application available at a reaonsable price,

cheers glenn
The Bep VSR switch that Finga has posted the link to in the above post
is brilliant just set and forget.
But this only useful for onboard charging thru your engine and not a battery charging system external source
When charging batteries thru smart chargers or trickle chargers it is best to have
all electricity flow isolated.
I have a brand new 125 amp Bep VSR switch for sale $100 if interested.
pm me if interested.

Regards Frank

[MarkDiver]

I use one of these VSR's in my Landcruiser with dual batteries, works a treat. I haven't bothered on the boat but I alternate between batteries on each trip rather than always riding on 1+2 so that they each get a good work out and charge if that makes any sense to you electrical gurus out there. My batteries are 2005 models and working fine today.

[glennaus]

thanks for the reply,s thats exactly what i,m after, just looking at the schematics would i have to change the circuit to have a separate isolator for each battery or could i just add it in to the existing circuit and leave the isolator on 1-2

cheers glenn

[juju]

[. My batteries are 2005 models and working fine today.[/quote]
Thats a kiss of death

[John Buoy]

thanks for the reply,s thats exactly what i,m after, just looking at the schematics would i have to change the circuit to have a separate isolator for each battery or could i just add it in to the existing circuit and leave the isolator on 1-2

cheers glenn
Quite simple glen fit the switch next to your battery switch.
then alter your battery switch arrangement so that the positiveson the back of the switch go to each positive connector on the battery and the house and engine positive go to the common connector on your switch.
Then the vsr is connected as this
2 connectors on the back of the VSR one goes to Battery 1 the other to Battery 2
connectors on your battery switch;)

Regards Frank

[castlemaine]

Hi All
Thanks for all the great replies. :)

I did an experiment today and found a slight 'power-off' when switching over from 1 to 1&2 to 2, with my sounder going off but my GPS was fine. Did it a few times and some of the time, no effect on any equipment.

So I guess the next question is will that harm my electronic equipment (gauges, GPS, Sounder, etc).

Cheers8-)

[finga]

Hi All
Thanks for all the great replies. :)

I did an experiment today and found a slight 'power-off' when switching over from 1 to 1&2 to 2, with my sounder going off but my GPS was fine. Did it a few times and some of the time, no effect on any equipment.

So I guess the next question is will that harm my electronic equipment (gauges, GPS, Sounder, etc).

Cheers8-)
The motor is the main trouble in this instance.
What sort of motor is it??

[cormorant]

On the house battery we have a pair of anderson clips. Same on battery charger. Just means a quick spark free connection with decent surface area. Battery switch remains off

As for 2005 batteries- well i'd play it safe and swap one out into the 4wd for city driving as it has done the best for you. Let it die in the 4wd where you won't die if you get stranded if both batteries fail. Put the better one in the 4wd if going bush.

We rotate batteries out of boat about every 3 years and they may last in machinery or car for up to 2 years after that but have never had one survive 5 plus years. Don't run em till they die as we have stuffed a couple of alternators and starter motors doing so and just get them load tested if they are not doing cold starts perfectly

I never like swapping both batteries out at once but that is more a superstician and a little to do with getting 2 out of 4 dead ones that collapsed after 2 weeks in a batch

Might get closer now that the marine alternaters are getting better but not worth the risk in my case.

[banksmister]

I have a bep vsr in my car [5 years old ] works a treat but do your homework first.


you must check your alternator size before u fit one of these as you can get cave down
[chattering of the vsr] caused by voltage droping below 12.8 when relay engages
then disengages very rapidly
Wont be a problem in most new outboards but some older ones only have 20 amp alternator


here is a graph by bep for there vsr





Alternator vs battery capacity
Alternator Size Second battery size
10 Amp 60 AH GRP 22
16 Amp 85 AH GRP 24
25-35 Amp 85-100 AH GRP 27
50-60 Amp 100-130 AH GRP 31
80-90 Amp 130-220 AH GRP 80

[timbo1]

I use one of these VSR's in my Landcruiser with dual batteries, works a treat. I haven't bothered on the boat but I alternate between batteries on each trip rather than always riding on 1+2 so that they each get a good work out and charge if that makes any sense to you electrical gurus out there. My batteries are 2005 models and working fine today.

Someone correct me if I'm wrong but lead acid batteries should be kept fully charged if at all possible. If stored partially charged or even worse completely discharged your battery life with suffer.

[MarkDiver]

[. My batteries are 2005 models and working fine today.
Thats a kiss of death[/quote]

JuJu, with a name like that you're obviously superstitious :-/ Don't suppose you eat bananas on your boat or take the missus with you either?

I on the other hand am not superstitious and carry out routine maintenance including periodical battery water level check and 240V trickle charge. That's why I have two batteries as well should one expire.

[MarkDiver]

On the house battery we have a pair of anderson clips. Same on battery charger. Just means a quick spark free connection with decent surface area. Battery switch remains off

As for 2005 batteries- well i'd play it safe and swap one out into the 4wd for city driving as it has done the best for you. Let it die in the 4wd where you won't die if you get stranded if both batteries fail. Put the better one in the 4wd if going bush.

We rotate batteries out of boat about every 3 years and they may last in machinery or car for up to 2 years after that but have never had one survive 5 plus years. Don't run em till they die as we have stuffed a couple of alternators and starter motors doing so and just get them load tested if they are not doing cold starts perfectly

I never like swapping both batteries out at once but that is more a superstician and a little to do with getting 2 out of 4 dead ones that collapsed after 2 weeks in a batch

Might get closer now that the marine alternaters are getting better but not worth the risk in my case.

;) Thanks, fair comment!

[Kevin Ferguson]

Timbo 1
you are correct , with your second point being a definite no - no. Batteries can be brought back up from this condition , but continually doing so will have a dramatic effect on battery life. Both situations can lead to sulphation of the plates with a resultant drop in performance. Sulphation will be broken down in the charging cycle , however heavy sulphation from continual storage in a discharged state would be beyond the scope of the chargers that the majority on this site would use. Keep them clean , dry & charged ( 12-60 S.G. / 12-6 V ) and you should get well beyond the warranty period.
Cheers Kevin

[castlemaine]

The motor is the main trouble in this instance.
What sort of motor is it??

The motor not the electronic equipment? Appreciate your input.

Yammie, 50hp, 2 stroke.

Cheers8-)

[finga]

The motor not the electronic equipment? Appreciate your input.

Yammie, 50hp, 2 stroke.

Cheers8-)
In this case I'd be worried about the electronics in the motor.
Back-fed currents and voltages can do really funny things to electronics
As mentioned the house electronics would be most likely turned off by a master switch which would isolate them from the charger anyways.
Cheers Scott :)

[glennaus]

I have a bep vsr in my car [5 years old ] works a treat but do your homework first.




you must check your alternator size before u fit one of these as you can get cave down
[chattering of the vsr] caused by voltage droping below 12.8 when relay engages
then disengages very rapidly
Wont be a problem in most new outboards but some older ones only have 20 amp alternator


here is a graph by bep for there vsr





Alternator vs battery capacity
Alternator Size Second battery size
10 Amp 60 AH GRP 22
16 Amp 85 AH GRP 24
25-35 Amp 85-100 AH GRP 27
50-60 Amp 100-130 AH GRP 31
80-90 Amp 130-220 AH GRP 80


thanks for the info mate i,ve been trying to find out how many amp hours my battery,s are can,t find the info anywhere both battery,s are seamaster m70 660 cca and the alternator on the engine is 40 amp suzuki df140

cheers glenn