Recommend Simple Safe Trickle Charger

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6-Pack

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Jan 16, 2012
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Vessel Name
The 6-Pack
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1974 Custom Aluminum Pilothouse
I would like to keep the genset starting battery charged. Can anyone recommend a simple trickle charger that I can plug into AC when in slip so that my battery stats topped off? I have an outlet within 4 feet.

Suggestions?
 
I use the GUEST Battery Pal. Works good, lasts a long time.
 

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Of course, one of those solar panel trickle chargers at Harbor Freight would also do the job just fine. Pretty cheap too.
 
The most modern chargers SHUT OFF after the charge is finished , do not stay on at some lower float voltage.

This is done to reduce water usage , and the need to water the set.

Of course it resumes charging when required as the voltage falls internally.

However the $50 buck choice will probably give a start batt its normal service life, for a $1.00 gal of distilled water every year.
 
Note that if left attached to the battery without AC on the charger, they will act as a small shunt and slowly drain/kill the battery. I learned this the hard way when boat was in winter storage and only plugged in once a month for topping batteries. The small trickle over 24 hours wasn't enough to overcome many days of drain. Obviously not a problem if always plugged in.
 
Thanks all! Good info:)
 
6-Pack said:
I would like to keep the genset starting battery charged. Can anyone recommend a simple trickle charger that I can plug into AC when in slip so that my battery stats topped off? I have an outlet within 4 feet.

Suggestions?
Click to expand...

I find the Ctek range great. They are all smart charges, and can be left on for long periods, and there is a size for everything. I use the Marine M200 (15Amp) for house coupled with the M300 which is a companion charger to the marine series and designed specifically for keeping the starter batt charged up. It has all the functions, but only puts out about 0.9Amp
CTEK Battery Chargers - The World's Smarter Battery Charger
 
I am wondering how one of these Bosch chargers would go as a permanent install.
Power point is a couple of feet from start batts.

BOSCH 12V & 24V BATTERY CHARGER 7A / 3.5A MAINTAINER TRICKLE AGM GEL MXS7.0 C7

For the last several weeks with constantly changing strong winds trips have been 3 miles to a NE anchorage for a few days then 3 miles to a SE anchorage rinse and repeat and I suspect the start batteries aren't getting enough charge.

At the moment I have a normal 12v charger hooked up to each of the 12v (in series) starts but that is not ideal.
To wire up the trickle charger from the Victron multi plus requires more in wire and labour pulling panelling than the Bosch charger would cost.
 
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Simi 60 said:
For sure, but more than 3x the $ and pretty sure I don't need 25 amps for trickle charging starts.

Bosch used to be a very reputable brand, not sure if anything has happened to change that.
Click to expand...


When I was chatting to me marine electrician he recommended the larger smart charger over the smaller ones available .He said the small ones are ok for a single battery but useless on a bank of battery's.
 
These are not my house batteries, they have a 5000va/100a charger attached.

These are my starts and starts alone.

The ctek 24v "maintenance" charger puts out 4 amp vs the Bosch at 3.5 amp.
Its still 3 x the $
http://www.ctek.com/au/en/chargers/24v
 
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https://www.amazon.com/NOCO-G7200-UltraSafe-Battery-Charger/dp/B004LX3AS6?th=1

Noco Genius brand are smart chargers in a variety of amperages. The 24 volt offerings start at 7.2amp.

I bought the 3/4 amp one and am impressed by its smarts.

I watched it work on an auto battery out of my sports car, that wasn't being driven much this past summer. Battery tested lowest part of "good" on a traditional auto load tester. It needed boosting back in the spring, so I wasn't expecting much...

The charger varied the voltage up and down, each time reaching a little higher. It took a week of this slow cycling to sneak up to 15 volts, then settled back to a rest and charge cycle that stays down in the upper 12-lower 13 ranges.

It did the same thing with a brand new YUASA battery that I bought for my Yamaha generator that ships dry, add the acid and charge up. It varied voltages, up to 15 and then settled back.

I like that I can see it leaving the battery alone once it is charged, unlike the simpler ones of the past, they just inflict a steady voltage all the time.

RB
 
Not sure if these would be appropriate for the application you're wanting but I've used the 'Battery Tender' line of products for years for all of my cars and motorcycles. In fact, I'm using one of their products at this very moment on my vintage Land Cruiser which is parked in my garage in Colombia (I'm currently in Huatulco, MX):

Chargers


.
 
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Looking at the manual for the victron multiplus 5000 that we have and the aux charger designed for connecting to the start batteries puts out 4 amps.

It says run a wire from the victron to +start and a wire from -start to -terminal on house bank.

Seeing as its a 4 amp charge but is a longish run I would think a 10amp extension lead cable would be up for the job.
I have a newish one sitting in front of me now that is missing an end So this will be a good use for it.
 
Simi 60 said:
Looking at the manual for the victron multiplus 5000 that we have and the aux charger designed for connecting to the start batteries puts out 4 amps.

It says run a wire from the victron to +start and a wire from -start to -terminal on house bank.

Seeing as its a 4 amp charge but is a longish run I would think a 10amp extension lead cable would be up for the job.
I have a newish one sitting in front of me now that is missing an end So this will be a good use for it.
Click to expand...

What is the length of the run?
You need to factor in the voltage drop for distance.
 
mbevins said:
What is the length of the run?
You need to factor in the voltage drop for distance.
Click to expand...
7m max

That's why I thought 4 amp @ 24v running through what was a 20 metre 10 amp @ 240v cable should be fine.
 
RickB said:
12v Battery Charger, Battery Desulfator, Battery Maintainer, Charger
Click to expand...

I second the Battery Minders - Have several and have used them for yrs.
(others may work equally as well but I know these work well)

I believe they at least partially restored an older battery via the desulphation mode -
I did a little experiment when i first started using them...
Fully charged (via normal charger) rest & measure V
Used batty Minder w/ desulphation - rest & measure V
Improved after desulphation w/ BM but don't recall the exact #'s

I keep several stored batt'ys topped up w/ them

One caveat - BM tech rep indicated it is not a good idea to leave them connected if the 120V power is disconnected as the unit puts a small? drain on the batery w/ no 120V power applied - short term no problem longer term will run a batty down eventually
 
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Simi 60 said:
7m max

That's why I thought 4 amp @ 24v running through what was a 20 metre 10 amp @ 240v cable should be fine.
Click to expand...

What's the gauge of the wire. We can calculate the V drop with that. My concern is that your cable might only be 16ga. If so it is definitely to small.
 
I don't have a charger on my genet battery. Others have posted they don't either.

One might argue that if you aren't running the genset enough to keep the battery charge, you aren't doing the genset any favors.
 
psneeld said:
I don't have a charger on my genet battery. Others have posted they don't either.

One might argue that if you aren't running the genset enough to keep the battery charge, you aren't doing the genset any favors.
Click to expand...

I took our genset battery off of a charger, too. It was originally on the main 3-bank charger, but that meant we had two large banks and the (relatively) tiny genset battery... so a mis-match in bank size...

And then we recently installed an inverter/charger on one of the large banks...

So I just decided to devote all the amps from the original charger to one bank, all the amps from the inverter/charger to one large bank, and the genset battery can fend for itself.

We DO have an alternator on the genset, so that battery gets charged while the unit is running. And we're out and running often enough. Also, we had already made that a Grp 34 AGM battery, so self-discharge isn't much of a problem. And then I'm also intending to get a set of short jumper cables, just in case.

-Chris
 
Ooops...sorry, should have mentioned the genset alternator requirement

Thank you Chris!
 
The little Guest brand charger mentioned by SteveH above has worked well for me for years and years and may be all you need. Don't be fooled into getting a $9. copy at Harbor Freight, they are not the same. One person I know boiled his batteries away, and another burned his garage down with one.
 
6-Pack said:
I would like to keep the genset starting battery charged. Can anyone recommend a simple trickle charger that I can plug into AC when in slip so that my battery stats topped off? I have an outlet within 4 feet.

Suggestions?
Click to expand...

What is keeping your main bank charged at the dock or is the main bank 24V, 32V, 36V etc.?

If you have an outlet/AC nearby I would suggest a good quality dry-mount charger with external temp sensor such as the Sterling ProCharge Ultra 10A. They are really not that much more expensive than some over priced "maintainers"..

If your other on-board batteries are 12V then a simple Echo Charger or ACR would work fine.


A "safe" float or maintenance charger is one that would have the exact float voltage setting your battery requires or that features a user programmable setting. Most are one-size fits all over-priced snake oil & some can actually be bad for your batteries..

A good float or maintenance charger would also revert to a gassing voltage (absorption) periodically, for flooded batteries, to prevent electrolyte stratification. Pulse charging can also work okay, if properly implemented, though it rarely limits electrolyte stratification. Avoid pulse-type maintainers if you have any parasitic loads that can trigger continual or frequently repeating absorption cycles.

Float or maintenance chargers are often misidentified as "trickle chargers" but trickle chargers, historically speaking, are constant current devices not constant voltage. Lifeline battery for example specifically prohibits the use of "trickle chargers"... Be sure what you are buying is not a "constant current" trickle charger.

"Trickle Charging:
Method of charging in which the battery is either continuously or intermittently connected to a constant current charging source to maintain the battery in a fully charged condition. Not recommended for use with Lifeline® AGM batteries."


A good safe unit would also have on-battery temp compensation not "near battery ambient " temp compensation, especially in an engine room. It would also have a zero or very near zero parasitic current for when power is lost and also have extremely low ripple. It would also pass UL 1236 & the UL 1236 "Marine Supplement".


The prices of some of these glorified snake-oil maintainers are absolutely offensive. Over $100.00 for .75A to 1.5A charger...?? Really?

If someone finds a quality float/maintenance charger please let me know. I have never seen one but I have seen a lot of BS marketing to make them appear great......;)
 
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Brooksie said:
Don't be fooled into getting a $9. copy at Harbor Freight, they are not the same. One person I know boiled his batteries away, and another burned his garage down with one.
Click to expand...

I know a number of folks who have murdered batteries with the HFT maintainers.

One HFT maintainer I tested had a 0.048A draw when unplugged but still connected to the battery. When you consider that most boat yards do not allow on-the-hard charging, while in storage, it becomes easy to see how his expensive start battery was ruined when the boat yard unplugged his vessel per the contract rules.

0.048A X 24 = -1.152Ah each day

-1.152 X 7 = -8.06Ah's per week....

In the winter battery capacity becomes effectively smaller. He had left his $400.00 Odyssey TPPL AGM starting battery on-board so when he went to the boat he would have lights...

Long and short, he did not visit the boat from mid November until mid March or about 17 weeks for long enough to even come close to restoring the capacity the charger ate through while it was unplugged...........

17 X 8.06 = -137 Ah's.....

$400.00 gone........

The absolute safest practice for winter storage (in climates below 60F) is to charge to 100% SOC, equalize if suitable for your batteries, then 100% disconnect them from the vessel and each other.
 
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For full time operation you need a charger that will operate in "float" mode.

That can either be a smart charger that will switch to float mode, or a charger that operates in float mode only.

"Float" mode is where the charger maintains a specific voltage known as a "float" voltage.

The best charger on the market for this has been the Charles Industries CI series available in as small as a 5 amp capacity. These are super reliable. I have used literally hundreds of these on generator installations and they work forever.

The only challenge is finding one. Charles Industries unfortunately recently left the marine/industrial market.
 
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