DC-DC Charger vrs VSR set up

[myusernam]

myusername I am looking at the enerdrive 2000 watt inverter and had thought about the combined set up and yes I also have shore power so a plus also. Any information would be great as I am researching all opinions. Is this the one ? Would I then have a DC-DC charger set up with this ?


VICTRON MULTIPLUS COMPACT INVERTER/CHARGER 12/1600/70A CHARGING - 16A TRANSFER SWITCH

PRODUCT CODE : CMP121620000

$1,464.00

yeah thats the one.
no dc-dc charging. But you would have a two channel charger and an inverter superior to the enerdrive unit. If you leave it on invert and hook power up there is seamless changeover when you loose shore power.
The house bank charger is multistage 70 amp, temperature probe. second channel for start battery 4 amps (but if using vsr not required). You can download the manual from the website. Victron is excellent gear.
still dont know why you are stuck on dc/dc chargers. The output voltage of the alternator is the same as the output of a smart charger. the house bank is big enough that you wont exceed max current. There's a lot of electronics in there and they wont last for too long on a boat.
There's a lot of mis information around about dc-dc chargers imho. Totally not required

[TheRealAndy]

sigh
i still dont iunderstand where we went wrong.
was it where i said agm's are tougher and more forgiving than a normal battery? I stand by that but perhaps i should have said traditional deep cycle battery. there's nothing contraversial about that. And AGM's are common under bonnet now with stop start technology

Mate, I am not silly enough to get in to arguments with blokes who think they know what they are talking about. I have been in the game long enough to know better.

However, just for the record ability to discharge to a greater level does not mean "tougher and more forgiving". Go back and read my posts, you might learn a thing or two.

[Dignity]

BTW, what outboard has a 120A alternator? If the alternator can supply a full 120A then depending on the AGM size you may actually need to go down the DC-DC route. You would need to refer to the AGM manufacturer, but the accepted rule of thumb for charging AGM's is about 20% of the rated capacity, ie for a 100Ah battery the charge current should be limited to 20A.

120 amp alternator mentioned in post #38, but once again I wasn't sure what was being refered to here which has now been cleared up.

[TheRealAndy]

120 amp alternator mentioned in post #38, but once again I wasn't sure what was being refered to here which has now been cleared up.

Yup, got the picture now. 120A alternator and 2 * 120Ah batteries. Good setup, wish I could do the same!

[The Mad Cat]

VSR's seem to have a few failures, would there be a problem with having 2 VSR's connected up between the start and the house bank as a back up if one failed. I have a spare VSR and checking to see if this might work.

TMC

[ranmar850]

Is there really an issue in the short term if a VSR fails? You are never running start current through them, they should be always across the Both ( paralleling ) switch anyway. Failure of a VSR will not affect your ability to start. The only way you would notice if one had died would be that the House battery is not charging. So you operate the Both switch to get it charging again. If that really bothers you, you could have one sitting there, not connected on the non-sensing leg, or with the negative disconnected, ready to go.

I've had a couple on boats over the last 8 years, no failures, both were still working when the boat was sold.

[GBC]

For the money you are talking you could replicate what is in my ute for cheaper than $700 and get the best of both worlds. I have a ctec 250d hooked up to a ctec smartpass 80, giving 100 amp, temperature compensated charging. You can get a 120 smartpass as well which will do 140a all told. Uses the best an old alternator can do until the bank accepts less than 20a then switches to multi stage for a quicker finish, ramping up voltage as the amp draw decreases for 100% charge. The 250d does the solar through the built in mppt charger and will also back charge your upstream starter batteries once the house batteries are charged. The smart pass will supply 12.7v to your 12v non critical users and 14.4 to the batteries at the same time, keeping the load away from the charge profile. Then you plug your shore power/240 charger straight into the smart pass and it administers the whole system. The smart pass also already has the battery protection built an that the victron bloke recommended, and they are waterproof. I've had plenty of VSR's fail and I'll never own another one.

[TheRealAndy]

For the money you are talking you could replicate what is in my ute for cheaper than $700 and get the best of both worlds. I have a ctec 250d hooked up to a ctec smartpass 80, giving 100 amp, temperature compensated charging. You can get a 120 smartpass as well which will do 140a all told. Uses the best an old alternator can do until the bank accepts less than 20a then switches to multi stage for a quicker finish, ramping up voltage as the amp draw decreases for 100% charge. The 250d does the solar through the built in mppt charger and will also back charge your upstream starter batteries once the house batteries are charged. The smart pass will supply 12.7v to your 12v non critical users and 14.4 to the batteries at the same time, keeping the load away from the charge profile. Then you plug your shore power/240 charger straight into the smart pass and it administers the whole system. The smart pass also already has the battery protection built an that the victron bloke recommended, and they are waterproof. I've had plenty of VSR's fail and I'll never own another one.

The problem with that solution comes with reduced battery life. As I suggested previously, its all a trade off between speed of charging, cost and battery longevity.

Using a DC-DC is the best way to increase the life of the battery, but its done so at the cost of a lower rate of charge. The model Brett is looking at is capable of 50A and has a temp sensor, and for 240aH (depending on battery manufacturer) it is probably less than the maximum current most AGM's will tolerate. However for that you get a proper charge algorithm and a guarantee your battery wont start venting due to overcharging. BTW, 50A charge current is nothing to sneeze at either, its fair wack of current.

OTOH, using VSR (which is more or less what the smart pass is) you are going to get a whole lot more charge current, probably exceeding what most AGM manufacturers would recommend and at the risk that you will overcharge your battery which is detrimental to AGM's. Using the datasheet I posted earlier, the max recommended current was 36A, double that for 2 batteries and you have 72A. The Alternator is good for 120A. This unlikely to kill the batteries, but its still above whats recommended and will certainly reduce the usable life of the battery, especially if it starts overheating. To be honest, unless the battery is less than about 70% state of charge, it wont draw the maximum current** when charging anyway, but the risk is still there once you go below 70%.

Again I say it, both options are valid options, it just comes down to compromises and what you want from it. If you happy to change batteries every few years, then VSR is fine. If you want to get the longest life (I have seen better than 10 years) then a proper charge is essential.

Another thing I want to reiterate is the fact that the typical rec boatie wont run their engines long enough to fully charge a battery. It can take 5 or more hours to charge a battery from flat to about 70% using the max recommended charge current (at which point the battery will not draw the full current any longer**), and another 7 or more hours to go from 70 to 100%. This is where solar and charging from 240V at home makes a difference.

**provided the charge voltage is below the manufacturers recommended charge voltage.

[GBC]

Both my ctec chargers have temperature probes. My batteries (optima) have unlimited initial recharge amps and very low internal resistance. As you state, full charge isn’t that often so getting best bang for your buck while the engine runs is often the name of the game. I had the 250d on its own for a few years which was fine if not a bit slow. Now with the smartpass it exceeds expectation.

[TheRealAndy]

Both my ctec chargers have temperature probes. My batteries (optima) have unlimited initial recharge amps and very low internal resistance. As you state, full charge isn’t that often so getting best bang for your buck while the engine runs is often the name of the game. I had the 250d on its own for a few years which was fine if not a bit slow. Now with the smartpass it exceeds expectation.

I tried to look at the CTEK website, but it made me want to stab someone in the face with a broken rusty bread knife! Sometimes you just need to put a leash on the marketing departments. I think the CTEK stuff is fairly decent. I have a ctek charger, and I am pretty sure if you trawl the depths of Ausfish you will see a report on it from me with some fairly technical detail. I am also fairly sure that you would find info on me bagging CTEK for the (annoying) million stage charge process that all charger manufacturers have since stolen, but that deserves a thread on its own. I immediately get suspicious when I see a technical product from a company that spends so much time and money on marketing. And to boot, the graphics intensive website makes it so f*cking slow I want two of those rusty bread knives!!!!!.

Anyway, whinging aside I could not find the 250ds on their website. I have no doubt that the manual is there somewhere, I just gave up trying. I did pick up a brochure from a retailer recently that showed a similar set up to what you have done, but alas I could not find that either! I have since found the manual for the SmartPass 120. Buried deep is one really important feature

Battery temperature protectionSMARTPASS 120 protects the battery by switching off charging if the service battery temperaturerises too high.

Bingo, CTEK has won the race on VSR's. I was almost going to write into one of my previous posts that using a thermostat on a battery post to disconnect the charge source if battery temp got to high would be a good work around. I decided against it, because I had not really thought through all scenarios. Once again though, the CTEK marketing department leaves off critical information that would drop them off the list if I was to use them in a industrial/commercial environment.

CTEK stuff looks really good, but they are clearly chasing the consumer market not commercial/industrial. That's fine with me, because no consumer person wants or needs to know that info. It just makes it hard for someone like me to make an objective decision on the product. The fact that their engineers have thought about things like temp cutout make me feel subjectively pretty confident that the product is good. I have no doubt that if I contacted them for more detail that CTek would supply that info.

[GBC]

Yep, they have a very 'swedish' way of disseminating info.

It is a bit more than a glorified vsr, it works quite well and is much simpler to install than it appears.


SMARTPASS
Smart Pass can operate as a stand-alone unit, but works best in combination with D250S
Dual . The Smart Pass creates a priority path for charging the Service battery to recharge
it more quickly and efficiently. Attached energy sources like solar, wind or shore power will
charge both the Service and the Starter batteries through the Smart Pass . Service batteries
that are overheated due to age, high ambient temperature or other battery problems will be
protected from high alternator current.
SMARTPASS 120
• SMARTPASS 120 is a solution for supplying current to charge and manage consumers in a dual
battery system consisting of a starter battery and a service battery.
• SMARTPASS 120 separates the batteries in a dual battery system and thereby replaces, for example,
a separation relay, VSR (Voltage Sensitive Relay), diode isolator or a mechanical battery selector.
• SMARTPASS 120 connects the starter and service batteries together in order to charge them both
from the alternator.
• SMARTPASS 120 protects the service battery from deep discharge which would damage the
battery.
• SMARTPASS 120 supplies consumers from the alternator instead of from the service battery while
the service battery is charging, which permits faster charging.
• SMARTPASS 120 can be used on its own or in combination with D250SA. In combination, the
D250SA and SMARTPASS 120 can charge at up to 140A.
FUNCTIONS:
• Charging a service battery
SMARTPASS 120 charges the service battery from the starter battery or another current source
that is connected when the alternator is running or when the starter battery voltage is high enough.
• Battery guard
SMARTPASS 120 disconnects consumers when the service battery voltage is low in order to
avoid deep discharge, which would damage the battery. The consumers are reconnected after the
service battery voltage has increased. Connect critical consumers directly to the service battery so
they will not be disconnected if the voltage falls to lower than 11.5V.
• Start assistance
SMARTPASS 120 automatically connects the service battery to the starter battery for 10 sec to
assist, if the starter battery on its own is unable to start the engine. After the start assistance function
has been activated, SMARTPASS 120 will display a fault indication until starting has been
achieved without using the start assistance function.
• Separation of the starter battery and the service battery
SMARTPASS 120 separates the starter battery from the service battery when the engine is not running.
• Assigning current source priority
SMARTPASS 120 can sense when the alternator is running and in that case supplies consumers
with current from the starter battery to work with the D250SA and maximise charging efficiency.
Otherwise the consumers are supplied with current from the service battery.
• Dynamic overcurrent protection
SMARTPASS 120 has overcurrent protection to shield the product. Overcurrent protection permits
maximum current to be sent from the alternator temporarily so that charging will be accelerated.
• Battery temperature protection
SMARTPASS 120 protects the battery by switching off charging if the service battery temperature
rises too high.
• Starter battery trickle charging
The service battery trickle charges the starter battery without assistance from the solar panel or
alternator to compensate for the self-discharge of the starter battery. The service battery charges in
3-second pulses when its voltage is higher that of the starter battery and the voltage of the starter
battery is low.


Combined 250/smartpass manual below.

There are plenty more ways of doing 12v, I just settled on this one and am happy enough with the results.

https://www.google.com.au/url?sa=t&r...bk8C95Qy7_1eT1

[EdBerg]

The dealer has informed me that the engine has a standard alternator which I am happy with as I can go either way with charging. I told him the reason I was asking and they said that they prefer the DC-DC when doing installations as it's the only way to fully charge a deep cycle battery bank. Said it's also better due to multi stage charging and if you install a quality unit it will charge all the different types of batteries.
I am now undecided which way to go. It seems to be like which is the best fuel to use, 91 or 98. Thank God I don't have too worry about that.
I still need to go down the path of deciding on what batteries to use which is also another mine field. I started researching that today and my head hurts.

The batteries that I bought for my last boat have been the Giant brand AGM types from Aussie Batteries up the sunshine coast. I bought a dual purpose AGM start/deep cycle 135A which was my main start battery, (not sure if they still do that type) and also a deep cycle 150A AGM which I used as a house battery, however either battery could be used as a engine start battery as they had 1200-1350CCA rating. They didn't give me any dramas over 4 years when I traded the boat. Aussie batteries also have sales frequently (join their email mailing list for current specials) and you can pick up these batteries for a decent price compared to other brands. If I were to buy another battery I wouldn't have any hesitation buying from them again. Just a brand to consider!