Charging Lead-Acid Batts with Very Small Charger

[Dockhead]

I switched off the reefers overnight, and hurrah, the El Cheapo emergency charger kicked over into float -- 26.7v. I guess pushing two refrigerators, one a deep freezer (G&T ice muss sein), was leaving too little power left over out of 17 amps, to fully charge the 420 amp/hours of batteries.



So I think I will leave it connected over Christmas.






Yes, two failures of the same device sucks. But this is par for the course for Victron, and apparently Mastervolt too. Sterling might be better, but they don't make any inverter/charger of the right size for my boat, and to boot they are massively huge such that I couldn't find a place for one of them anyway.



The good news is that you can connect multiple Victrons together in a gang, and if one goes down, the other(s) keep going. For my next boat, this is definitely the way I will go. I'm now thinking about where I might put two of the Compact models, on this boat. Not where the I/C is now located, but I'm eying some other spots.


The Oyster 485 I almost bought had its (Mastervolt) gear under the settees. I wouldn't want to pull all those cables, all the way over to such a spot on this boat, but possibly there are some other possible spots. I am somewhat limited because I want this gear ABOVE the waterline, so that it is not immediately drowned in case of a, God forbid, flooding accident.

[smac999]

The battery bank size wil not matter. What matters is your draw. If you are drawing 1-2a unattended. The charger should eventlly go to float. If you are drawing ~13a. The small charger might never go to float as it's always struggling . Weither you have a 100ah bank or 1000ah doesn't matter. Once full.

[smac999]

Originally Posted by Dockhead

The good news is that you can connect multiple Victrons together in a gang, and if one goes down, the other(s) keep going. For my next boat, this is definitely the way I will go. I'm now thinking about where I might put two of the Compact models, on this boat. Not where the I/C is now located, but I'm eying some other spots

Not true for inverter chargers. If one goes down both will. Yiu will need to disconnect and reprogram the working one as a single master unit.

[Dockhead]

Originally Posted by smac999

Not true for inverter chargers. If one goes down both will. Yiu will need to disconnect and reprogram the working one as a single master unit.

With Victron, if the slave is the one which goes down, the master keeps on ticking. You might have to switch off the bad slave. If it's the master which goes down, you just need to flip a single DIP switch on the slave to make it operate as a master.


It's very simple, and a great way to dramatically increase reliability of the system. My boat is very electrical intensive and AC power is nearly mission critical. I even run my emergency crash pump off AC power. One of the really bad things about a charger/inverter going down in such a system is that AC power is not passed through, if the charger/inverter is not working -- so you totally lose AC power even if your generator is working or you're hooked up to shore power. This on top of losing the ability to invert power from batts or alternator, and losing the ability to charge your batts from AC power. So the charger/inverter in a boat set up like this is an extremely important device.

[john61ct]

Have you considered separating the inverter and charger functions?

Is PowerAssist critical for your setup?

Maybe just for backup purposes?

[a64pilot]

My Sterling Pro charge Ultra at 60 amp into 12V isn’t any bigger than a shoe box.
Be 30 amps at 24v of course, and that isn’t very big, but ought to be big enough as a back up.
I assume they make a 24v Charger.
Then God forbid look into a Magnum inverter/Charger. They are not small. Are very heavy, but I’ve not heard of a failure, and they are apparently easily repairable with different cards for each function.
Mine hangs under the chart table, about a foot away from the battery bank. I could have put it under the settee right beside of the bank, but wanted it high and dry, plus I had no idea how much heat it produces.
Turns out it produces very little heat unless your pushing it very hard, which is rare for me in my little boat.

[john61ct]

Magnum also offers the ability with a BM/remote add-on, to

terminate charging based on a direct reading of trailing amps reaching endAmps.

No more adjusting Absorb hold time settings to ensure getting to 100% Full.

I haven't heard of reliability problems, but seem to recall complaints about lack of adjustability.

Perhaps that's just without the remote?

[Zil]

I did not have a sump pump. I drilled a drain hole to get the water out. Now I don't need a sump pump. And it saves on docking fees.

[smac999]

Originally Posted by Dockhead

With Victron, if the slave is the one which goes down, the master keeps on ticking. You might have to switch off the bad slave. If it's the master which goes down, you just need to flip a single DIP switch on the slave to make it operate as a master.


It's very simple, and a great way to dramatically increase reliability of the system. My boat is very electrical intensive and AC power is nearly mission critical. I even run my emergency crash pump off AC power. One of the really bad things about a charger/inverter going down in such a system is that AC power is not passed through, if the charger/inverter is not working -- so you totally lose AC power even if your generator is working or you're hooked up to shore power. This on top of losing the ability to invert power from batts or alternator, and losing the ability to charge your batts from AC power. So the charger/inverter in a boat set up like this is an extremely important device.

nope if either stops working both stop and error. even if you unplug them, it still looks for the other one and errors. especially if stacked at 240v. and i'm 90% sure when stacked as 120v. with the newer models (after firmware 400) you need a laptop, USB programming cable, and software to re configure it back as a single unit. the 100 firmware you could set with the dip switches.

the only way around would be 2 separate inverters each feeding a different subpanel panel. not networked together and the phases would not need to be synced so it wouldn't know or care. both left as a single master. if one failed you'd lose power to half the boat. this would be best done with 2 shore power plugs (ie dual 30a 120) otherwise the power assist or the charger reducing would not work.

a manual AC bypass switch on the inverter output is a good thing to have.

[smac999]

Originally Posted by john61ct

Have you considered separating the inverter and charger functions?

Is PowerAssist critical for your setup?

Maybe just for backup purposes?

power boosting is only one advantage of an inverter charger. the other one is charger amps reducing if shore amps gets too high. (Ie drawing 25a from shore power, turn on a mircowave. charger reduces from 100a to 20a charging untill mircowave finishes to keep shore under 30a. 1 min later goes back to 100a charging.)

[Dockhead]

Originally Posted by smac999

power boosting is only one advantage of an inverter charger. the other one is charger amps reducing if shore amps gets too high. (Ie drawing 25a from shore power, turn on a mircowave. charger reduces from 100a to 20a charging untill mircowave finishes to keep shore under 30a. 1 min later goes back to 100a charging.)

Yes. Inverter/charger is incredibly useful for running a large electrical intensive boat from dodgy shore power (6 amps common in France and the Baltic), I wouldn't want to do without it.

I would try Magnum - I've heard only good things - but I don't think I can buy them over here. Plus the size would be a problem.

[smac999]

they are a little deeper but shorter. overall not any bigger really. I have put lots in.

the power booster model is useless as they don't have the 2nd output like the victron does. so you either invert the whole boat, or you split off some loads before the inverter input. but then it can't monitor total amps. if you want boosting the victron is best

mostly I use the non boosting magnums. only had 1 or 2 issues in many installs.

so far not to many victrons. but no issues yet.. put a 24/8000 in last month. that was a beast

[Dockhead]

Originally Posted by smac999

they are a little deeper but shorter. overall not any bigger really. I have put lots in.

the power booster model is useless as they don't have the 2nd output like the victron does. so you either invert the whole boat, or you split off some loads before the inverter input. but then it can't monitor total amps. if you want boosting the victron is best

mostly I use the non boosting magnums. only had 1 or 2 issues in many installs.

so far not to many victrons. but no issues yet.. put a 24/8000 in last month. that was a beast

I have the 2d output on my Victron (which cuts off an immersion heater or some other noncritical load when you get to capacity), but I don't use it -- in practice it is not hard to manage the power and avoid overloading it.


Deeper would be fatal for my installation. But the really fatal thing is I can't buy them here and there's no service.


So I think it will be back to old Victron for me, for better or worse. I'm hoping to start building a new boat in the next year or two so I'm not sure whether it will be worth the time to try to reconfigure for a pair of smaller ones. It's tempting just to swap like for like and move on.

[Kenomac]

Here’s my recommendation: Switch over to Mastervolt, why would you stick with a product that keeps letting you down?

[Dockhead]

Originally Posted by Kenomac

Here’s my recommendation: Switch over to Mastervolt, why would you stick with a product that keeps letting you down?

I considered that, but got multiple reports that Mastervolt reliability is about the same or even worse than Victron. One other thing I particularly don't like about Mastervolt is that they use switching transformers which produce a lot of RF noise.


That charger inverter which apparently does have greater reliability than Victron is Magnum -- which is differently engineered from the two complicated very high tech Dutch brands. But I can't buy that here, nor is there any service, so that's out the window.



I seem to be stuck with Victron. Long term -- say, the next boat -- I will install a gang of them, two or even three, so that a failure doesn't take the boat down. And I will sure as heck install them in a more accessible location, than what I have now