VSR Vs DC to DC

[Berger4]

Hi haven't posted here in quite a while, however I have recently retired so have a bit more time on my hands. As per the title this is a VSR vs DC to DC question hopefully somebody with more knowledge than me can answer.

I have a small fibreglass side console boat that I don't seem to use as much as I used to. Now I have the time I am hoping to change that. One of the many things/project I have now is I am going to convert it from a side console into a centre. Been through all the pros and cons of doing this and have decided to bite the bullet and do the conversion some time in the next year. Part of this conversion will be a rewire of the boat. In the past when I first got it the boat only had one main battery which basically did the starting running a small sounder , nav light when used and a bilge pump.

That situation has changed over the years and now I have a much larger sounder, radio, bilge pump, phone charging. At some stage I put in a second battery(house) which worked fine for a year, this was charged using a VSR. Anyway first VSR stopped working left me having to get a tow(this was some years ago now). I replaced this VSR everything worked fine for a number of months close to a year until second VSR failed, I had my outboard mechanic look at the problem all he could come up with is that they fail some times. After this I went back to one battery this lasted until the end of last year not that long maybe a year and half or 2 until I had to replace the one main battery. In this time as a back up I had a NOCO jump start which worked fine when I used it to jump start the battery before the battery was replaced. As you can probably guess the main single battery(new) went flat again and I went to use the Lithium jump starter, well what can I say it was fubar.

So I am now at the point of putting a second battery back in the boat. Things is I am not keen on getting a VSR again, not sure if anybody else has had one fail?? I do have a DC to DC(sterling pro) charger that I had in the boat at one stage which I used for a couple of years until I upgraded the sounder and noticed that is for some reason it caused interference on the sounder, so I removed it and put a slightly larger AGM battery in to run the Motorguide.

So now I have an oldish AGM that still holds a charge and is fine, and a DC to DC charger lying around. I am thinking of putting this battery in the boat as the house battery and charging it using the DC to DC charger only problem is how do I use it for back up starting? Or first question is can I use it to start the motor in an emergency??? The battery is a 120ah SGM Giant brand battery.

If I can use this battery or say another AGM battery how do I then use it to start the outboard. Is it as simple a running the positive and negative back to the main busbar near the battery with a simple on/off battery switch? Or would it be more complicated than this?

Or should I scrap all of the above shite and just get a new VSR and second battery? I have tried to research this and all I have managed is to give myself a headache. Hoping somebody has been down this path and can help me out.

Hopefully all of the above ramblings make sense.

P.S. Forgot the outboard is a newish 60hp Suzuki. Not sure how much this matters.

[chris69]

Hi haven't posted here in quite a while, however I have recently retired so have a bit more time on my hands. As per the title this is a VSR vs DC to DC question hopefully somebody with more knowledge than me can answer.

I have a small fibreglass side console boat that I don't seem to use as much as I used to. Now I have the time I am hoping to change that. One of the many things/project I have now is I am going to convert it from a side console into a centre. Been through all the pros and cons of doing this and have decided to bite the bullet and do the conversion some time in the next year. Part of this conversion will be a rewire of the boat. In the past when I first got it the boat only had one main battery which basically did the starting running a small sounder , nav light when used and a bilge pump.

That situation has changed over the years and now I have a much larger sounder, radio, bilge pump, phone charging. At some stage I put in a second battery(house) which worked fine for a year, this was charged using a VSR. Anyway first VSR stopped working left me having to get a tow(this was some years ago now). I replaced this VSR everything worked fine for a number of months close to a year until second VSR failed, I had my outboard mechanic look at the problem all he could come up with is that they fail some times. After this I went back to one battery this lasted until the end of last year not that long maybe a year and half or 2 until I had to replace the one main battery. In this time as a back up I had a NOCO jump start which worked fine when I used it to jump start the battery before the battery was replaced. As you can probably guess the main single battery(new) went flat again and I went to use the Lithium jump starter, well what can I say it was fubar.

So I am now at the point of putting a second battery back in the boat. Things is I am not keen on getting a VSR again, not sure if anybody else has had one fail?? I do have a DC to DC(sterling pro) charger that I had in the boat at one stage which I used for a couple of years until I upgraded the sounder and noticed that is for some reason it caused interference on the sounder, so I removed it and put a slightly larger AGM battery in to run the Motorguide.

So now I have an oldish AGM that still holds a charge and is fine, and a DC to DC charger lying around. I am thinking of putting this battery in the boat as the house battery and charging it using the DC to DC charger only problem is how do I use it for back up starting? Or first question is can I use it to start the motor in an emergency??? The battery is a 120ah SGM Giant brand battery.

If I can use this battery or say another AGM battery how do I then use it to start the outboard. Is it as simple a running the positive and negative back to the main busbar near the battery with a simple on/off battery switch? Or would it be more complicated than this?

Or should I scrap all of the above shite and just get a new VSR and second battery? I have tried to research this and all I have managed is to give myself a headache. Hoping somebody has been down this path and can help me out.

Hopefully all of the above ramblings make sense.

P.S. Forgot the outboard is a newish 60hp Suzuki. Not sure how much this matters.

Ive just got a centery 780 marine starter and thats a good for 90amps too and i run 2 sounders off that and ive got DF50 and i just run a cable back to the 3way cut off switch so if i need to i can use the bowmount battery to start it in the all postiion but once running you cant change it,unless your running the new live scope with tv screens sucking 10 or more amps you should be right with a good marine battery i think ,the more you have connected the more things to go wrong.

[Berger4]

Hi Chris

Thanks for the reply. Yep that's why I went back to this single battery. I did have the have a century Marine Pro 680 wasn't that old when I replace it. It looked to me like it was holding a charge but had load tested and it showed that its days were numbered. At the time I changed it to a seamster m70 off the top of my head, it still holds a charge has only gone flat the once when I tried to jump start with the NOCO lithium, don't see any reason to change it just thinking house battery and backup would be good. As an aside I am thinking of adding a second gps to run along with what I currently have a Garmin echomap 95sv, not sure if this is getting up there with power draw?? I should probably should sit down look at it and figure it out. I also tend to sit on the leecy for longish periods without running the motor with the Garmin on, not sure if this would drain the battery??

Like you I like the KISS method but am thinking the second/house battery might be a good idea, originally that's why I went back to the one battery and the NOCO. However you do have the 2 sounders. Hmmm I'm confused now.

[docaster]

I would have 2 marine century pro on a changeover switch to run the outboard. Maintain both to fully charged before leaving, keeping one as a backup up starter battery. Put the dc dc charger on the outboard to run the house battery. Plus have an isolator on said dc dc charger, as i have had them fail and drain the starter battery. With the second starter battery you always have starting power.

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[docaster]

I use century marine pro 780's. I have 2 outboards, one battery each. All interconnecting, if need be.
Electronics and lights run off starboard outboard and battery. Port outboard battery is just for the port outboard.
And recently installed a 160 watt solar panel and 100amp lithium for a 40 litre engel and phone chargers, which works really good.
Plus I use the same battery in both cars, cycle them always putting the new one in the boat. I get over 5 years out of them.

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[docaster]

I also have voltmeters on every battery except the wifes car. I'm over the top since i had the starter battery go flat twice just from having the radio on and doors opening and shutting on job sites. Colorado rg my13. These new cars shit me, waking up everything when the door gets opened.

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[ranmar850]

I also had a problem with VSR's failing on a regular basis. I had the conventional House and Start linked by a VSR, with a paralelling switch, normally left open. But this was not causing my Start battery to go flat, it was the House battery that wouldn't charge, would manifest itself as a low voltage warning on the electronics. Having a paralelling switch across the VSR meant I could just close that and keep operating until I replaced the VSR. The parallelling switch, of course, was meant to be a backup for the Start battery, so you could utilise the House for start duties. But, of course, that idea is a bit flawed, because if you parallel a good battery across a discharged battery, they immediately try to equalise potential, ie, the bad one drags the good one down. often to the point of having two flat batteries.
The VSR failure , I believe, is down to their design. I had that setup for three years on a boat with an F115 Yamaha, no problems. But using the same makes and sizes on the boat with the 150 Merc 4 stroke ( 3 litre, much higher start current) saw them failing annually. If you look into their specs, there is a built-in delay after the sensed voltage( caused by starting) before they open. They might claim to be 140 amps rated, but they are a switching diode arrangements, not physical contacts, and will not take start current very well. So I believe I was starting across both batteries unknowingly, and the VSR was exposed to regular currents which were beyond its ability.
The answer for me, at the time, was to use a higher rated VSR. Redarc make several for 4wd applications, so I bought one , an SBI-12. These are rated for 100amps continuous, and 400 amps peak. I believe another forum member had the idea before me, and had been using it successfully for a number of years. So I fitted one, and had no problems for a couple of years until I upgraded the whole system to a Lithium House running via a DC-DC. Not cheap.

There was a thread on this, try searching VSR in the forum. My project is probably well beyond what you are after, as I camp aboard at times for extended periods. But you can find it here https://www.ausfish.com.au/vforum/sh...attery-project if you are interested.

I still have the Redarc VSR sitting on the bench here, been meaning to sell it. PM me if you are interested, it'll be a lot cheaper than new.

[Berger4]

I would have 2 marine century pro on a changeover switch to run the outboard. Maintain both to fully charged before leaving, keeping one as a backup up starter battery. Put the dc dc charger on the outboard to run the house battery. Plus have an isolator on said dc dc charger, as i have had them fail and drain the starter battery. With the second starter battery you always have starting power.

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Docaster
Let me get this straight is a change over switch one of the 1st battery, 2nd battery and combined batteries type arrangement? The ones that can be switch whilst the engine is running?

Could I not just have a seperate single on/off switch to each battery along with the DC to DC charger on a seperate line to the house battery? I could also then include the separate isolator on the DC to DC if it is needed? Can't say I have ever had the problem with a DC to DC causing that problem, having said that I have only ever had the one DC to DC.

Do I need to have the same batteries or are you just saying it is better to have 2 marine type batteries that are capable of being both start and house batteries?

[Berger4]

I also had a problem with VSR's failing on a regular basis. I had the conventional House and Start linked by a VSR, with a paralelling switch, normally left open. But this was not causing my Start battery to go flat, it was the House battery that wouldn't charge, would manifest itself as a low voltage warning on the electronics. Having a paralelling switch across the VSR meant I could just close that and keep operating until I replaced the VSR. The parallelling switch, of course, was meant to be a backup for the Start battery, so you could utilise the House for start duties. But, of course, that idea is a bit flawed, because if you parallel a good battery across a discharged battery, they immediately try to equalise potential, ie, the bad one drags the good one down. often to the point of having two flat batteries.
The VSR failure , I believe, is down to their design. I had that setup for three years on a boat with an F115 Yamaha, no problems. But using the same makes and sizes on the boat with the 150 Merc 4 stroke ( 3 litre, much higher start current) saw them failing annually. If you look into their specs, there is a built-in delay after the sensed voltage( caused by starting) before they open. They might claim to be 140 amps rated, but they are a switching diode arrangements, not physical contacts, and will not take start current very well. So I believe I was starting across both batteries unknowingly, and the VSR was exposed to regular currents which were beyond its ability.
The answer for me, at the time, was to use a higher rated VSR. Redarc make several for 4wd applications, so I bought one , an SBI-12. These are rated for 100amps continuous, and 400 amps peak. I believe another forum member had the idea before me, and had been using it successfully for a number of years. So I fitted one, and had no problems for a couple of years until I upgraded the whole system to a Lithium House running via a DC-DC. Not cheap.

There was a thread on this, try searching VSR in the forum. My project is probably well beyond what you are after, as I camp aboard at times for extended periods. But you can find it here https://www.ausfish.com.au/vforum/sh...attery-project if you are interested.

I still have the Redarc VSR sitting on the bench here, been meaning to sell it. PM me if you are interested, it'll be a lot cheaper than new.

Ranmar

Not sure why my VSR's failed and can't say I have the same knowledge as you to try and figure it. The first one I had I can't be sure what brand it was, however the second was a BEP marine one that was exactly the same on the exterior as the first one, so it was an easy change over. In hindsight they may have both come from the same Chinese factory just with different labels, I got the BEP marine one as I thought it might be a better quality. All I can say is that mine would have failed because they were POS not the same reason as yours as my motor is only 60hp.

Is the RED arc IP rated in any way? Not sure I need one like that as I can't imagine the a the amp output on mine would be anywhere near that. As for camping about all I do is the occasional over night sleeping on the boat.

Not really that keen on the whole Lithium thing at this stage. Don't really need it, still expensive and I worry about the whole thing going wrong and ending up in a total melt down. I did see the result of a lithium battery melt down in Perth last year down the street from the MIL's place. It was a camper trailer thing that had a lithium setup, not surer what happened spoke with old mate(owner) he was there when it happened hence he managed to push the whole thing into his driveway when he noticed a lot of heat coming from it. Needless to say the camper was just a charred mesh totally unrecognisable, his concrete drive way a cracked, broken mess and his work ute a Triton was all burnt and melted on the front and down one side not sure how it didn't go up also. Didn't know this could happen to lithium batteries before I saw that.

[ranmar850]

Before docaster answers, and feel free to contradict me, he appears to be proposing having 3 batteries on board. Two for start, with one isolated, unused, " just in case" , for failure of one start battery. This is a lot of weight for a small boat such as yours. But, yes, as long as that backup battery is kept charged, you will have another backup. The alternative for a backup start is the little lithium jump packs. These actually do work really well. I had my main drained overnight with the boat on a mooring by leaving a paralleling switch on with one battery dead. I had the little Uniden jump pack--it trimmed the motor down , then started it like a fully charged lead acid. Same thing for my D-max- 3 litre diesel, battery failed overnight, cranked it like new. I saw a bloke use a Kings version to start a 105 cruiser next to me in a carpark just last week.
The only thing to be aware of is that you CANNOT just leave them under the back seat/chucked up forward in the boat for 6 months then expect them to work. They actually work by using a very small lithium battery to charge a capacitor, which then gives the surge of current necessary to crank a motor. Capacitors self-discharge at varying rates--as it does, the little lithium will recharge it. And on it goes. Until it is flat. From experience( I have a Uniden, was $175 at RTM) , charging them once a month is enough. YMMV. Unless your wife is using it to run her tablet instead of putting it on the charger.

So, to summarise, for a small boat, not used for liveaboard, I'd stick to a conventional two battery with a heavy duty VSR (such as the Redarc I described) with a Paralleling ( combiner, if you like) switch across it. Your House load cannot draw current from the Start battery once the voltage drops below 12.6 or so, so is isolated and will keep it's charge, as long as the battery itself is good.

There is one thing I can't get my head around, though--How can the failure of a properly wired VSR cause your Start battery to go flat??? All it can do is stop working, and deny charge to your House. Worst case scenario, your House stuff( EVERYTHING should be House except for the actual motor control wiring loom) will show alarms/stop working , so you fix this by closing the paralleling ( combiner )switch which effectively bridges across the VSR, then carry on . Or are you saying it failed CLOSED instead of Open, which would be normal mode of failure, and the House load then drained your start?
To simplify this, look at the phot below. This is how I originally wired the Reefrunner , with a conventional Start/House/VSR setup. VSR kept failing, changed for a heavy duty VSR, then all good.



As you are viewing it, Left hand switch is Start, direct to motor, +ve connecting to start battery . Middle switch is paralleling/combiner. Right hand switch is House, + ve connecting to House battery VSR is on the right. Negative supply is common to both batteries and motor. Middle switch is normally open/off. You can see it bridges across the VSR. Ignore the CB on the right, that protects the supply to the drum winch up front. This is a really basic two-battery configuration.

[docaster]

Docaster
Let me get this straight is a change over switch one of the 1st battery, 2nd battery and combined batteries type arrangement? The ones that can be switch whilst the engine is running?

Could I not just have a seperate single on/off switch to each battery along with the DC to DC charger on a seperate line to the house battery? I could also then include the separate isolator on the DC to DC if it is needed? Can't say I have ever had the problem with a DC to DC causing that problem, having said that I have only ever had the one DC to DC.

Do I need to have the same batteries or are you just saying it is better to have 2 marine type batteries that are capable of being both start and house batteries?

Yes, the 4 position switch 1, 2, 1+2, and off. I think it's better to have the same batterys, otherwise they can drain and charge different. I've never used a vsr, only a dc dc charger in the ute. I think an adjustable voltage cutout on them would be good, but more expensive i think, as 12.6 is too low. 13volts is better.

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[docaster]

Ranmar

Not sure why my VSR's failed and can't say I have the same knowledge as you to try and figure it. The first one I had I can't be sure what brand it was, however the second was a BEP marine one that was exactly the same on the exterior as the first one, so it was an easy change over. In hindsight they may have both come from the same Chinese factory just with different labels, I got the BEP marine one as I thought it might be a better quality. All I can say is that mine would have failed because they were POS not the same reason as yours as my motor is only 60hp.

Is the RED arc IP rated in any way? Not sure I need one like that as I can't imagine the a the amp output on mine would be anywhere near that. As for camping about all I do is the occasional over night sleeping on the boat.

Not really that keen on the whole Lithium thing at this stage. Don't really need it, still expensive and I worry about the whole thing going wrong and ending up in a total melt down. I did see the result of a lithium battery melt down in Perth last year down the street from the MIL's place. It was a camper trailer thing that had a lithium setup, not surer what happened spoke with old mate(owner) he was there when it happened hence he managed to push the whole thing into his driveway when he noticed a lot of heat coming from it. Needless to say the camper was just a charred mesh totally unrecognisable, his concrete drive way a cracked, broken mess and his work ute a Triton was all burnt and melted on the front and down one side not sure how it didn't go up also. Didn't know this could happen to lithium batteries before I saw that.

Do you know what type of lithium? My understanding is lithium phosphates are safe as and won't catch fire.

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[docaster]

Before docaster answers, and feel free to contradict me, he appears to be proposing having 3 batteries on board. Two for start, with one isolated, unused, " just in case" , for failure of one start battery. This is a lot of weight for a small boat such as yours. But, yes, as long as that backup battery is kept charged, you will have another backup. The alternative for a backup start is the little lithium jump packs. These actually do work really well. I had my main drained overnight with the boat on a mooring by leaving a paralleling switch on with one battery dead. I had the little Uniden jump pack--it trimmed the motor down , then started it like a fully charged lead acid. Same thing for my D-max- 3 litre diesel, battery failed overnight, cranked it like new. I saw a bloke use a Kings version to start a 105 cruiser next to me in a carpark just last week.
The only thing to be aware of is that you CANNOT just leave them under the back seat/chucked up forward in the boat for 6 months then expect them to work. They actually work by using a very small lithium battery to charge a capacitor, which then gives the surge of current necessary to crank a motor. Capacitors self-discharge at varying rates--as it does, the little lithium will recharge it. And on it goes. Until it is flat. From experience( I have a Uniden, was $175 at RTM) , charging them once a month is enough. YMMV. Unless your wife is using it to run her tablet instead of putting it on the charger.

So, to summarise, for a small boat, not used for liveaboard, I'd stick to a conventional two battery with a heavy duty VSR (such as the Redarc I described) with a Paralleling ( combiner, if you like) switch across it. Your House load cannot draw current from the Start battery once the voltage drops below 12.6 or so, so is isolated and will keep it's charge, as long as the battery itself is good.

There is one thing I can't get my head around, though--How can the failure of a properly wired VSR cause your Start battery to go flat??? All it can do is stop working, and deny charge to your House. Worst case scenario, your House stuff( EVERYTHING should be House except for the actual motor control wiring loom) will show alarms/stop working , so you fix this by closing the paralleling ( combiner )switch which effectively bridges across the VSR, then carry on . Or are you saying it failed CLOSED instead of Open, which would be normal mode of failure, and the House load then drained your start?
To simplify this, look at the phot below. This is how I originally wired the Reefrunner , with a conventional Start/House/VSR setup. VSR kept failing, changed for a heavy duty VSR, then all good.



As you are viewing it, Left hand switch is Start, direct to motor, +ve connecting to start battery . Middle switch is paralleling/combiner. Right hand switch is House, + ve connecting to House battery VSR is on the right. Negative supply is common to both batteries and motor. Middle switch is normally open/off. You can see it bridges across the VSR. Ignore the CB on the right, that protects the supply to the drum winch up front. This is a really basic two-battery configuration.

Yes Ranmar. Correct on the 3 battery proposal.

Agree with your set up when using a vsr.

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[ranmar850]

Do you know what type of lithium? My understanding is lithium phosphates are safe as and won't catch fire.

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LiFePo4 , the type mostly fitted to mobile conversions, cannot catch fire in itself. HOWEVER, and this is a big however, installations can catch fire, always have, just happens there is a lithium battery sitting in the middle of it, supplying power. Lots of bad installations out there. Too many diy'ers having a quick look at Youtube and going for it. An awful lot of energy contained there, seeing as everyone seems to want 400ah and a 3000w inverter to run their induction cooker on the back of their ute. Personally, I'll tend to point the finger at cheap DC-DC chargers--internal fault on the load side can see a big battery setup without proper protection happily supplying 400 amps down a 10mm2 cable, hello electrical fire. if you don't thnk that can happen, take a battery with a 200amp-capable BMS built in ( high current BMS's are needed by the Big Inverter crowd) , paralleled with another same, there's a steady 400amps. You can weld steel with a lot less. You might have a 35mm2 cable battery to inverter supply side, but hey, the DC-DC can only max at 30-40 amps, so, smaller cable needed. Mostly, with zero protection between the battery and the DC-DC

[Berger4]

Hi

I originally had a single switch that came with the VSR and is just a single switch where you put it on battery 1 or number 2 or combined. I had it wired as the attached diagram. Not sure what was going on the first time the VSR stopped working as I noticed that the voltage was low on the house battery as I just monitor it through the sounder. So I went to start the motor to go for a run for a while and it would only turn over slowly and didn't start, I think I may have had a second go and no luck. I then to combined both batteries and nothing just a click i.e. some power but not enough. Anyway got a tow back put the main battery on charge and it took a charge, when I do this the VSR has an LED light that usually comes on to say it is charging the second battery this didn't come on. I assumed it was no good, checkd the power at the house battery can't remember exactly what is was but nothing seemed to be going in. Replaced the VSR with a BEP marine brand it worked for quite a few months, this time the start battery didn't go flat just the house, did the same thing no LED light coming on no power going to the house. I had my outboard mechanic have a look at the set up, he did say there was a bit of corrosion on the back of the switch but this shouldn't have made a difference. I am not sure what happened as electrics is not my strong suit, I can manage to do simple wiring and understand the theory in how the VSR work, but it still a little bit Voodoo to me. Bit like the DC to DC for the motor guide causing interference on the new Garmin but not on the old Lowrance.

Yes 3 batteries plus the one up front for the Motor guide is way over kill. I did have the Lithium jump starter but as I said it was no good last time I tried to use, assumed as you said I may not have been as regular in recharging it, but I tried to maybe every 2 to 3 months recharge maybe not regular enough.

The battery was a Lithium ion, can't tell you make or model. I was like you and thought they were safe until I saw the damage that it had caused, I was even thinking of putting one in my boat and toying with the idea of having one installed for the house considering the cost of electricity these days. After that I looked into it and yes it is pretty rare but if they go into thermal runaway, then best thing to do is runaway. Certainly put me off having one in a boat late alone a timber Queenslander.

Just thinking about what I said re battery in camper. Pretty sure it was Lithium phosphate just not sure of brand or size. Yep as you said they are meant to be pretty safe?? Not sure what happened left a couple of days after.

Hope all that waffle makes sense???

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