Replacing failed Guest Charge Pro 2722-B on-board battery charger

[fishlips]

Need to replace the original 2 bank 30 amp charger on my 2005 282 Sailfish - twin 250 Yamaha outboards (3 batteries - 2 starting and 1 house loads - with dual battery selector switches) and looking at the Guest 2731A 10/10/10 amp 3 bank charger. Assuming I'd configure with one bank on each battery instead of the current set up of Bank 1 (Starboard engine starting paralleled with house load battery) and Bank 2 with Port engine starting battery. Can you configure with a individual charger bank to each battery and still maintain a 2 battery switch configuration for engine / battery alignment? Someone at a local dealer suggested to go with a Guest 5/5/5 3-bank model and use a 15-amp extension cord for AC input instead of powering through the 30-amp shore power connection. I was thinking a 10/10/10 amp for 3 - group 27 batteries would be better for charging and I really wanted to keep the 30 amp shore power / thru on-board AC panel battery charger switch instead of a separate 15 amp extension cord for charger. Anyone with experience making this original 2-bank charger swap to a 3-bank charger?

 

[Legend]

Not sure I would 0d that unless you change the current setup of having two batteries in parallel. The original design had two batteries in parallel on one charger bank. Rationale to change?

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arger bank

 

[fishlips]

I guess I was thinking the 2 batteries in parallel on one charger bank was somewhat of a one-off setup in the first place...and the 3 bank charger with a battery lined up to each bank is more in line with the charger manufacturer's design intent.

 

[DennisG01]

Typically, yes, you would have a lead to go to each individual battery. It's not "bad" to run a single lead to a "bank", though. However, I would suggest, if you wanted to go this route, to contact the battery charger manufacturer and ask for their recommendation. Yes, stick with your gut - don't use a plug-in cord - that's just more hassle.

You might consider upgrading the charger to a ProMariner P-Series charger, though. It's a smarter charger and can also (in the case of a 30a, 3-bank model) divert ALL 30 amps to a particular bank if needed. This makes much more sense since the starting batteries will need very little attention.

 

[wspitler]

I did exactly what you are planning, except I had two banks of two batteries, 4 batteries total. Highly recommend you go through the 30 amp shore power remember that’s 30 amp at 115 V not 30 A at 12 V. A 30 amp charger only requires about 5 A at 115 V for the starting power of the battery charger. I replaced mine with a four bank 30A Promariner and have a separate bank for each battery, two banks of batteries in parallel. The engineers at promariner recommend not charging two paralleled batteries with a single lead. It works but they said it’s better to have a separate lead for each. I and they, would recommend the 30 amp three lead charger connected through the original 30 amp shore power.

 

[fishlips]

I haven't thoroughly reviewed wiring diagrams yet, but can you stick with the dual battery switches (pos 1,2, both, off) when converting to a 3-bank charger with individual battery/bank alignment?

 

[DennisG01]

I haven't thoroughly reviewed wiring diagrams yet, but can you stick with the dual battery switches (pos 1,2, both, off) when converting to a 3-bank charger with individual battery/bank alignment?

The charger doesn't care about your battery switch - it has absolutely no effect, regardless of position, on charging. If that doesn't answer your question, can you better explain what you're asking?

 

[wspitler]

Charger connects directly to the batteries. Switches don’t matter.

 

[fishlips]

That's what I thought regarding battery switches, just looking to get confirmation, Thanks.

 

[fishlips]

I'm getting some conflicting info from charger tech support staff. Is it advisable to hook up a 3-bank charger (10amp / bank) with a single charger bank output to each battery when 2 of the batteries are connected in parallel? My OEM install had starboard engine starting battery and house battery jumpered in parallel and fed from a one charger bank output. The port engine starting battery was fed from the other bank output on the original Guest 2-bank (15amp / bank) charger. One guy says that's ok. Another guy says to install one battery charger output to each battery and eliminate the jumper on the 2 batteries currently in parallel. I thought an advantage of keeping the 2 batteries in parallel was that when engines are running the house battery would also be getting an alternator charge.

 

[seasick]

The batteries are either in parallel or they are not. That is to say that the batteries would be hardwired to each other for parallel service. Electrically that looks like one battery with twice the capacity ( a little simplified but good enough for my argument), Since they are wired in common, a single charger feed will charge both batteries. ( the charging will be slower since the batteries will 'share' the charge current.
The person who said to connect two charger banks to the two 'parallel' batteries and remove the jumper either was misunderstood or hasn't a clue in my opinion. Maybe I missed his point. bear in mind that in a parallel battery configuration , if the voltages of the two batteries are different, one battery will charge the other or to look at it another way, one battery will discharge the other until the voltages match That is why it is important when using a parallel setup that both batteries have similar characteristics; same brand, model and age

 

[fishlips]

The tech was saying to separate the batteries that are parallel and line up individual battery charger banks to individual batteries. I didn't like that option since I the house battery would no longer get charged with the engines running, only with shore power from the charger. That's why I asked about keeping the 2 batteries in parallel (maintain engine alternator charging). But didn't get a consistent answer about if ok or not to have a separate charger battery bank connected to each of the batteries that are connected in parallel.

 

[wspitler]

I discussed this with the "design engineers" at Promariner when I replaced mine. As I said before. they recommended a charge lead for each battery. The smart chargers are apparently able to differentiate between a single battery and two in parallel. I was told by them that you will get smarter charging with each battery being provided a lead. I have a four lead Promariner charger with four batteries of two banks and I have been impressed with how it keeps the batteries maintained and they seem to be lasting longer as well. Your tech seems real confused. Why you would ever have a battery that was not being charged while underway is beyond me. If you have 2005 Yamaha four stroke, you have the option of four charging leads from your engines, but your engine output for charging is quite different from today's smart AC supplied chargers.

 

[DennisG01]

Who is the "charger tech support staff"?

The reason that your original setup only had a single charging lead going to the 2-bank setup is simple... Grady put a less expensive, lower amperage, 2-bank charger in there. 2-bank being the main reason, of course.

As mentioned a few times, best practice is to have a charging lead direct to each battery.

Note... you really don't have a dedicated house battery with your current setup. You have a 2-bank setup with the "double battery" bank serving as BOTH the engine and house battery.

Yes, you could separate them into 3 specific banks and use a large, DC battery for you house (or two in parallel). Add a Blue Seas ACR between the house bank and the engine battery - the ACR will constantly determine which bank needs charging.

 

[dogdoc]

don't your 250's have aux charge leads? if functional (mine are not) they should handle charging house bank when running and not need an acr. you will need a third battery switch if you go with 3 banks. i would go with 3 banks, 3 1-2-both switches, and a 3 bank charger using original 30 amp shore plug. i am a fan of the promariner 3 bank smart/distributive charger and have one on my boat. that set up gives you all the possible configurations and can prevent discharging start batteries with house loads .my biggest problem upgrading was getting the old charger out. they installed it before finishing the livewell.

 

[seasick]

I discussed this with the "design engineers" at Promariner when I replaced mine. As I said before. they recommended a charge lead for each battery. The smart chargers are apparently able to differentiate between a single battery and two in parallel. I was told by them that you will get smarter charging with each battery being provided a lead. I have a four lead Promariner charger with four batteries of two banks and I have been impressed with how it keeps the batteries maintained and they seem to be lasting longer as well. Your tech seems real confused. Why you would ever have a battery that was not being charged while underway is beyond me. If you have 2005 Yamaha four stroke, you have the option of four charging leads from your engines, but your engine output for charging is quite different from today's smart AC supplied chargers.

I have a hard time understanding that setup, parallel batteries with a separate charger feed to each one. I am an electrical engineer although it has been quite a while since I have been in that business so I am probably not up to snuff with the newest technology. That said, the Promariner web site is pretty useless when it comes to technical documentation.
If two batteries are wired in parallel, it is possible that the voltage at each positive ( and negative) terminal could be different assuming the cables have some resistance, small but some and there is some current flow. The current flow could be caused by loads, different standing voltages, or actual charger current.
Does your charger have indidual ground connections for each bank or does it have a common ground?

 

[DennisG01]

don't your 250's have aux charge leads? if functional (mine are not) they should handle charging house bank when running and not need an acr.

Good point. If he doesn't already have the aux cable from one of the engines (for some reason, I thought that started to become an option, rather than standard issue?)... I think I would rather install the ACR than go through the hassle of running the aux cable through the rigging hose. I enjoy working on many things on boats... but I absolutely detest trying to get the wires back in that rubber grommet the right way. Most times I just cut away some of the rubber. I find it's also REALLY hard to fish a new wire through the rigging hose without first straightening the hose out, which means disconnecting everything on the engine - which is not a "hard" job, but just adds to the time and hassle.

 

[wspitler]

I have a hard time understanding that setup, parallel batteries with a separate charger feed to each one. I am an electrical engineer although it has been quite a while since I have been in that business so I am probably not up to snuff with the newest technology. That said, the Promariner web site is pretty useless when it comes to technical documentation.
If two batteries are wired in parallel, it is possible that the voltage at each positive ( and negative) terminal could be different assuming the cables have some resistance, small but some and there is some current flow. The current flow could be caused by loads, different standing voltages, or actual charger current.
Does your charger have indidual ground connections for each bank or does it have a common ground?

I also have difficulty fully understanding the concept as well. Each charge lead has a separate ground to the negative terminal on the battery itself. A total of eight leads. My thought is if you treat the battery as a load on the charger it will have resistance, some degree of capacitance and some degree of inductance. These new chargers are simply not fixed DC output. I believe they do a pulse DC which could be thought of as pseudo AC but not sinusoidal. Given that, there is a big difference between two parallel resistors and parallel capacitors or coils. I have taken a number of electrical engineering courses up to circuit design, but that was years ago when we drew on paper and used a slide rule to calculate circuit parameters. Things have come a long way.

 

[seasick]

Wow,
I remember taking physics classes and using a slide rule for the calculations. Just old geezers.

 

[seasick]

. but I absolutely detest trying to get the wires back in that rubber grommet the right way.

You made me smile. I just went through this a few months ago and although I was sure I noted what hole or indentations the various cables and hoses were in, I just couldn't get things to fit. Determined, I started over maybe ten times and after an HOUR all the parts lined up. next time, I guess I will have to number all hoses and cables and make a good sketch of what was where