Do you really need a $400 charger?

[Bigjim]

I've been looking at setting up a charging system for shore power. There are lots of systems out there at all different price points. I've got two banks of 2 100 ah batteries.

Do you really need a $400 charger? There are so many chargers that are available for less than that.

[Shrew]

1) The higher the amperage of the charger, then theoretically the faster it will charge batteries.

2) You still want a smart charger with multiple stages.

12 Volt Charger Tutorial | ChargingChargers.com

I think you can get into a decent 3 bank, multi-stage, 30amp charger for less money.

https://www.defender.com/product.jsp...966&id=4173316

[Jammer]

If you're charging a relatively small bank with shore power, it doesn't matter much what you use.


The real benefit of the "three stage" chargers is that they charge the batteries more quickly, which is important if you're charging from a generator.

[Bigjim]

For example, these two charger seem pretty equivalent on paper, but the ProMariner is $100 more:

Guest Charge Pro On-Board Battery Charger - 20 Amp
DC Amperage: 20 Amps, Output Voltage: 12 Volt DC, Banks: 2
Input Voltage: 110-120 Volt AC, Input Frequency: 50/60 HZ
Waterproof, Multi-Stage, Completely Automatic

ProMariner 24 Amp ProTournament 240elite Dual Battery Charger
Charging Stages: 5, Output Voltage: 12 / 24 Volt DC, Banks: 2
Input Voltage: 90-135 Volt AC, Input Frequency: 60 Hz
Application: Lead Acid (Flooded) / AGM Batteries Only

Is it really worth $100 for 4 more amps?

[travellerw]

I know a few people who are using Iota chargers (with the IQ4 option). $160USD will get you a 55A multistage charger.

Of course its not "marine grade". However they seem to be pretty reliable if properly installed in a dry location. Might be an option if you are on a budget.

[thomm225]

You could charge your battery bank with solar and never have to hook up to shore power ever again.

That's what I do with my two 12 volt batteries that I have in parallel. The solar and the batteries also provides all my power when I go out on my short 3-8 day cruises and that is with running an AC fan all night which take quite a bit of power from the inverter

My outboard doesn't have an alternator.

Here's a kit from Renogy with everything you need for just a bit over $160.00. You can find a cheaper kit also if you want with a PWM Controller.

https://www.amazon.com/Renogy-Monocr...05311526&psc=1

[Shrew]

A multi-stage charger has more to do with not cooking your batteries, than the speed of the charge.

[Colin A]

See what your battery maker recommends for a charge profile. Find a decent brand charger that lines up and you should be fine. Some work better then others. The big driver is output amps. If you don't need a lot, (not looking for a quick recharge or have a lot of continuous loads) you can get by on smaller ones.

[Jammer]

Originally Posted by Shrew

A multi-stage charger has more to do with not cooking your batteries, than the speed of the charge.

Chargers vary so it is hard to generalize.


All the cheap chargers I've had essentially operate at "float" the whole time. The drawback of this approach is that it takes 24 hours to get a battery mostly charged.

[Dockhead]

Originally Posted by Jammer

Chargers vary so it is hard to generalize.


All the cheap chargers I've had essentially operate at "float" the whole time. The drawback of this approach is that it takes 24 hours to get a battery mostly charged.

The drawback of this approach is that you will never get the battery fully charged, and thus you will sulfate and kill it.


I would recommend reading up on this topic.






To the OP: You definitely want a multi stage charger which is capable of giving a proper absorption charge, without which you cannot get any kind of decent battery life if you are deep cycling them, and which can be set to the exact voltages needed for your specific type of battery.



Nigel Calder has written a lot of good stuff about this; but our resident guru is MaineSail:


https://marinehowto.com/installing-a...ttery-charger/

[Jammer]

Originally Posted by Dockhead

The drawback of this approach is that you will never get the battery fully charged, and thus you will sulfate and kill it.

That is not my experience.


I had two cheap Group 27 batteries in an RV with a widely panned cheap charger. They lasted eight years until one finally failed.


After seven years they would still hold around 80% of their rated capacity. I actually did load-bank testing on them overnight every couple of years and discharged them until the voltage dropped below 11.5.

[rgleason]

Guest Charge Pro On-Board Battery Charger - 20 Amp
DC Amperage: 20 Amps, Output Voltage: 12 Volt DC, Banks: 2

I had been using a 12 year old Guest Pro Charger 10amp to keep batteries fully charged over the winter. I found it was cutting off way too early. It is basically useless for that purpose, and I have one set of T105's that were in the process of DOA. They are fully charged, next I have to charge again (as they have been sitting) and then immediately do a 20hr test. Meanwhile I purchased new.

[john61ct]

I would love to see links to chargers people think are better value than the top marine brands like Sterling / Promariner, Magnum etc.

Avoid overly "smart" ones with automated pulsing "desulfating" and equalizing routines that can't be disabled.

Avoid cheap "garage style" units designed for, undemanding car Starter battery usage.

Good units for the US RV industry are confusingly called "converters". ​Progressive Dynamics is a good mfg.

You could even use an adjustable straight power supply, but only if you are manually monitoring the charge process, you can't just set it and forget it, like a good automatic charger. Also make sure its current is overrated for your bank, or it has good current overload protection. Mean Well is a good brand, as is Samlex.

For **myself** I require user-custom setpoints / profiles so I can in future change bank chemistries without having to replace my permanent infrastructure.

And then you need to get sufficient amps output, usually 30-80A is a minimum starting point, especially if the bank is AGM, or if an AC genny is used away from shore power.

[rbk]

I figured if I’m spending $1200 on batteries spending $400 to keep them around longer is money well spent.

[barnakiel]

We have a 25A shore charger on a 100Ah bank. It seems to work perfectly OK.


I think you will size the charger (and its related cost) with how much energy you plan to use when at the dock. I generally prefer chargers that, while viable, can provide whatever I draw from the bank.


in a bigger boat I worked on not too long ago the charger was 100A on a 600Ah bank. This one also did its job very well.



Cheers,
b.