House/Engine Start Battery Question C-28

[Bob/Bradenton]

I did a post a while back about my 2019 C-28 not starting. Turns out that both AGM House batteries were bad and were somehow drawing down the Engine Start battery. (The Engine Start and Thruster Batteries were still in good shape, just the House batteries were bad).

I replaced all four AGM’s with Interstate G-31 wet-cell batteries. I saw no need for “maintenance free” batteries in a boat like this. I like to check my battery fluid level from time to time. (2 House: Deep Cycle Batteries, Thruster & Engine Start: Starting Batteries). All the new batteries typically show 12.6 volts, resting. I adjusted the Charger for the wet-cell batteries.

The issue that I’d like to address again, is why the bad House batteries could have interacted with the Engine Start battery enough that the engine would not start back then.

Yesterday I anchored out for a while and kept the Garmin system ON. About two hours. The House batteries were reading 12.3 volts and when I tried to start the engine, it seemed like a sluggish turn-over. Not really sure about that since the engine started just fine, but it seemed slower to crank.

So I’m wondering if there is some connection between the House batteries and the Engine Start Battery. There shouldn’t be unless the ACR is stuck. Per Brian’s suggestion during my original post, I checked the ACR green lights and everything seemed fine. The only other “connection” that I can think of would be the solar panel that charges (through its Controller) both the House and Engine Start batteries.

Thoughts/Comments…Bob/Bradenton

 

[BB marine]

If the batteries are wired as per the electrical diagram in the owners manual there should be no connection between the engine and house or the engine and thruster bank. The only connection is the crossover switch and the ACR's. The auto charge relays will make a direct connection when the batteries are charged above 13V and do not discharge below 12.7V 12.7 is considered a fully charged battery.

How could the bad house batteries effect the engine batteries? If you have weak house batteries you may have over charged your engine battery over a period of time. If the house bank is weak it will demand longer charging cycles. If you are charging through the alternator the first battery inline is the engine battery. When the engine battery reaches 13.0 V for 3 minutes or 13.6 for 30+ seconds the ACR close and now connect the house bank to the engine battery. This can cause heat and eventually start to reduce the longevity of the engine battery. The same happens when charging with the shore power charger. As the batteries reach the voltage to close the ACR the charging profile is based on all batteries connected together. If there are weak batteries in a bank the charger is charging to the needs of those batteries but charging against the resistance of the fully charged batteries causing them to get warm.

With the charging systems on board the Rangers and Cutwaters it is always a good idea to maintain all batteries as one bank. The ACR's are just used to isolate them from discharging together but are always used to charge the batteries together.

Battery maintenance is one item that is not done often especially with newer chemistry batteries. I believe a monthly check of the battery condition, connections and monitoring them with some type of battery monitor may help increase the longevity. I to am starting to go back to the old school lead acid flooded batteries. I think that overall they are less prone to damage when discharging below 50% which I tend to do.

 

[Bob/Bradenton]

Hi Brian, As always, thanks for your very good and detailed explanation of how these complicated boats work.

I noted that I did switch out all four AGM's for the Interstate G-31's. Since the G-31's has a different post, I used "Military" style post adapters but also used longer SS bolts so that all the cables would fit again.

(I did keep that 100 amp square fuse on the Positive House battery terminal, which I've already blown once while using the Microwave on the Inverter. Now have a couple spares).

I had to change the charge parameters of the Battery Charger. But Cutwater located it right next to the water heater which eliminated pushing the buttons or reading the screen. No idea why they stuck it there but I extended the wires and moved it next to the Autopilot pump where it's easy to see the screen and enter the new charge changes.

(Also no idea why they placed the solar panel right up against the Radar Dome where it gets shaded when the sun is aft of the boat, plus the rack will not allow the four ceiling hatches to open fully. Added cable to the solar panel and moved the rack forward, fixed).

I've had the boat since this past June/'21. 27 hours on it when I got it. I strongly suspect that the former owner left something like the fridge, ON when he hauled it and killed the House AGM batteries. Another reason why I like wet-cells instead.

Regarding the connection between the House and Engine Start batteries, I suspect the ACR between the two is probably stuck closed so that if the House set is low, it also brings the Engine Start battery down too.

Like my replacement of the aft auto-sensing bilge pump with a traditional flapper and non-auto pump, I'm thinking of just removing the ACR that is between the House and Engine Start batteries and just replacing it with a high amp traditional battery switch. It would normally be connected or ON, but if I was in an anchorage for a while and not running the engine, I'd just turn it to the OFF position so that the House is separated from the Engine Start. This would eliminate one more questionable gizmo on this boat. Simplicity...

Any comments on that?

Thanks, Bob/Bradenton

 

[Cutwater28GG]

do you have solar?

its a known issue that intermittent sunshine on the solar panel causes voltage levels to increase above ACR switch over limit and then the ACR doesn't open fast enough to stop discharge between the house and engine batteries when the panel gets shaded.

This is magnified by the typical installation under the radar dome with lots of shadow on the panel.

I'm not a big fan of the ACR configuration. its good enough but not a great setup. I think a better approach is DC to DC chargers between the banks and removing any loads off the engine battery. This way all charging goes into house battery which then charges the engine battery. But that's a significant rewire - and probably only worth doing if switching to Lithium batteries

 

[BB marine]

I personally like the Blue Sea ACR's. If they are functioning as per design they work well and should eliminate parallel combinations when the charging system is not available. Think of them as automatic battery switches. The main issue with them is they are regulated by voltage. When batteries are good the ACR do their job without issue. If batteries are marginal that is when issues seem to develop. Like any electrical component they can fail but if the troubleshoot guide is used this will normally find a malfunctioning ACR. If you troubleshoot the ACR and it checks out ok and you still want to have a manual control over them to make sure they are open. You can simply install a small low amperage on/off switch between the small 12 gauge yellow ground wire to the ACR. The ACR must have a connection to ground to function. The ACR can be disabled by a simple ground disconnect at the ACR. This will do the same function as removing the ACR and installing a high amperage battery switch. The difference is the battery switch will not disconnect unless you disconnect. Leaving the ACR in place will automatically do it or the manual small low amperage switch will manually do it. When using the small low amperage switch as a disconnect will possibly give you a better charging cycle when using the 120V onboard charger. The charger will then be charging each battery bank separately if the boat is equipped with a multiple output like the Promariner Pronautic 1220 or 1230 charger. Just an idea to think about.

 

[knotflying]

I would initially check your wiring. Ranger has been known to incorrectly wire things and hence cause issues. As an example, another owner I know actually had his engine and house batteries reversed and could not figure out why his engine battery kept losing charge. Make sure your ignition is off. If it is left in the on position it will also drain the battery. Also check that nothing other than engine wires and the solar panel are connected to the engine battery. As an aside, leaving the chartplotter on while anchored is a big battery drain. If you need an anchor alarm there are quite a few apps for that. A remote possibility is that, although new, there could be a short in the engine battery. I have seen that happen a couple of times. As Brian stated the ACR's are pretty reliable. However you can check them by looking for the small LED green light on each unit. When they close the light will go on.
And bravo going wet cell. We boaters always make mistakes that can destroy our batteries, regardless of type. Granted that AGM can take a beating, but they can be ruined. I understand that on some models it is very difficult to check the electrolyte level. There is an easy fix https://www.amazon.com/Flow-Rite-MP...t=&hvlocphy=9012264&hvtargid=pla-449340766479 You just pump away and can never overfill. I purchase Walmart dual purpose and replace them every three years regardless of condition. At $90.00 each you can't go wrong. If there is an issue, there is always a Walmart nearby to get a replacement.

 

[Bob/Bradenton]

Hi Knot, thanks...

I'm going to check the wiring per your advice. It really seems like the House batteries are somehow connected, permanently to the Engine Start battery. Need to stare at it for a while and also recheck the green lights on the ACR. (Note that this is a low-hours 2019 boat).

I want to post this further question here since it might be a clue to some factory mis-wiring:

I had thought that the only way to "wake-up" the Ignition to start the engine was to use the Key-Fob. Typically it would double beep and stay OFF and then I'd have to wave the Key-Fob over the sensor a couple times to get the Ignition to turn ON.

But, I've noticed that I don't even have to use the Key-Fob. I just turn the Engine master switch ON, then push the Ignition button and it turns ON. Then just push the Engine Start switch and the engine starts. No need for waving the Key-Fob at all.

Is this normal? I had thought that the Key-Fob waving was the only way to turn the Ignition computer ON.

Bob/Bradenton

PS: As a backup to the Key-Fobs, I just bought two extra from the local Volvo dealer for $80/each. Might not have needed them at all...

 

[BB marine]

You should need the Fob to start the engine. When the battery switch is turned on the orange blinking light should come on at Start stop switch. When you go to start the engine the fob is used and the green light should tun on. This activates the relays and turns the EVC panel on. You then start the engine. When you shut the engine off you should then wave the fob again confirm that the green light is off and the orange light is blinking. Then turn the battery switch off if you plan to do a battery disconnect using the battery switch.

 

[S. Todd]

I suspect that if you do not need the key fob to start the Volvo it is because when you last shut it down you forgot to wave the fob and turn it off. It is a minor step, but easily forgotten until it becomes habit.

 

[Bob/Bradenton]

Brian and S. Todd:

Thanks for that very good info on "waving the key fob" after you shut the engine/ignition down. Never knew I had to do that and that's why I could push/light up the Ignition button and push the Start button without needing the Key-Fob. Just tried it and yes, by waving the Key-Fob, the Ignition/Engine Start buttons would not operate.

And that's also way when I waved the Key-Fob over the panel, I would get those two beeps (red LED). Thinking that I was energizing the panel, I was actually shutting it OFF as I should have done when I shut the engine down last time.

Amazing the continuing learning that goes on here. Thanks again...Bob/Bradenton

 

[mferguson]

Ok, you got my interest now. I have been dealing with battery drain issues during storage since I got my '18 C28. So, does anyone have an idea of how much drain occurs if the FOB is not used to shut off the ignition?

Mike

 

[Bobby P.]

Should the FOB be waived to turn the ignition off even if you are intending to turn off the starter battery. I generally don't do this and then when I restart, I jut turn the battery back on and hit the starter switch. In this scenario, I don't have to use the FOB again prior to starting. Do you see any concerns with this pattern?
Thanks,
Bob

 

[BB marine]

I would turn the ignition off then battery. The ignition switch activates all engine relays ( powers them up and turns the EVC on. The only relay that gets activated by the battery switch with out the ignition is the fuel pump relay. I can't say you will damage anything but the design is to turn the battery switch on then activate the engine start system. This is the conventional way of operating an engine, Battery, power electronics hit start button. This can also save the chance of wasting battery if when the engine is shut down and the battery switch is left on. All systems are still using battery. This may not be a great deal of power but the ECU, all relays, and any sensors that require power are using battery while the engine start panel has the green light on.

 

[S. Todd]

I concur with Brian's post just previous to this one.
Owners manual to our D4 (printed 1/2020) says: "Wait 15 seconds after turning ignition off before turning off battery power, to let the engine control unit shut down correctly. Not following this procedure can result in fault codes in the displays." Other than that instruction, I can not see anything in the manual that specifically provides you should lockout the EVC with the key fob whenever you turn off the engine.
In addition to powering down the engine vessel control system, I like to lockout my engine EVC with the key fob for a number of reasons: 1) Keeps grandkids or anyone else from accidently turning on the engine when you don't want it on (when swimmers are in the water etc.). 2) Our engine battery switch is not the easiest to access so my preference is to only turn it on before leaving the trailer or dock and then off at the end of the day or when we leave the boat for an extended period of time. 3) Makes it more difficult for someone to steal the boat when we leave it to walk the dogs, go out to eat, etc.

 

[snydzy]

After reading this thread, I must comment:

How could the bad house batteries effect the engine batteries? If you have weak house batteries you may have over charged your engine battery over a period of time. If the house bank is weak it will demand longer charging cycles. If you are charging through the alternator the first battery inline is the engine battery. When the engine battery reaches 13.0 V for 3 minutes or 13.6 for 30+ seconds the ACR…This can cause heat and eventually start to reduce the longevity of the engine battery.

The alternator will not overcharge the start battery, so as long as the inter-battery connections cause no volt-drop there will be no over or under charging. Volvo Penta uses a single wire alternator, so the alternator begins charging the start battery first, 30 seconds prior to activating the ACR. 30 seconds of charging is not charging, even for a minimally depleted start battery. (A battery at 99% SOC is in the worst range of charge efficiency. Despite being minimally depleted it still takes a good bit of time to reach an actual 100% SOC again.)
ACR connects:
Any batteries connected (pos. to pos. and neg. to neg.) will assume the same voltage not the same SOC
Any batteries connected together in parallel will each take the proportion of alternator output that their state of charge requires, so over a period of time the flat ones catch up with the charged ones. You end up with a fully charged batteries as a single bank.
However,
once you start to connect batteries in parallel you will find that one battery with any fault that causes it to have a lower voltage than the rest – say partially short circuited cells – will cause every other battery connected to it, to discharge itself through the faulty battery in an attempt to charge the faulty battery. This causes the whole bank of interconnected batteries to discharge themselves to the same level as the faulty battery. (This is the reason why it is usually recommended that you change a whole bank of batteries at the same time.)

I to am starting to go back to the old school lead acid flooded batteries. I think that overall they are less prone to damage when discharging below 50% which I tend to do.

This is exactly the opposite. The worst thing for lead acid chemistry batteries is discharge them below 50%. AGM will go as low as 20%…I’m not going to waste time explaining the advantages of AGM over traditional lead acid batteries, but you get what you pay for. So selecting batteries under the umbrella “you might ruin them” doesn’t seem sound.

Additionally, S. Todd is correct: using the fob to lock the engine EVC is not necessary Not using the fob is more akin to leaving the keys in the ignition. When it’s off there is no battery drain.

 

[BB marine]

Any batteries connected (pos. to pos. and neg. to neg.) will assume the same voltage not the same SOC
Any batteries connected together in parallel will each take the proportion of alternator output that their state of charge requires, so over a period of time the flat ones catch up with the charged ones. You end up with a fully charged batteries as a single bank.

This is true if the banks are all wired in a balanced parallel configuration. I know my C26 was not and I know The Ranger Tugs I have been on board and Cutwaters are not. Possibly a single battery bank is. Engine ,house and thruster banks wired in a balanced parallel configuration would guess can be done but isn't done in most cases. There can be an amperage differential between the first battery and the last battery in an unbalance system. Theoretically, each battery would be receiving the same amount of current when charging, however, small yet measurable amounts of resistance between each battery connection makes this not the case. There can be has much as a 50% difference between the first battery and the last battery when charging parallel circuits that are unbalanced. Now add a bad battery in a bank to the equation.

Engine alternator is sensing the battery voltage in the complete system. The Charge goes to the battery that the alternator is connected to. In my boat and most Rangers and Cutwaters this is the engine start battery. If an amp meter was put on each battery. The battery first in line will have the highest amp draw from the charging source. The battery at the end of the line will have the least. This was why I suggested in a previous post that the engine battery may have reduced capacity because of other batteries. It may have been in an over charge condition.It was a suggestion based on the way the batteries are installed. Just a suggestion.

This is exactly the opposite. The worst thing for lead acid chemistry batteries is discharge them below 50%. AGM will go as low as 20%…I’m not going to waste time explaining the advantages of AGM over traditional lead acid batteries, but you get what you pay for. So selecting batteries under the umbrella “you might ruin them” doesn’t seem sound.



You are correct the worst thing to do to a lead acid battery is discharge it below 50%. Flooded are Lead Acid batteries so are AGM batteries same chemistry different design but still lead acid batteries. A flooded can be discharged to 20% the same as AGM battery can. The difference is the AGM will have a faster recovery or charging time. The amount of damage to the batteries can be equivillant. I agree selecting a battery that I will ruin it is not a way to pick a battery but in some cases it makes economical sense.

In my experience and this is what I am basing my decision on. Or my Opinion. We all have them. I know that in my past cruising experience that there are many times I bring the house and thruster banks ( switched together when at anchor) to below 50%. I did this with my flooded maintenance free and received 3 years of service. I did this with my North Star AGM. I had the Northstar AGM load tested at year three because I noticed I was not getting the same "time usage out of a full charge" The dealer that I purchased the batteries from load tested them. The batteries tested to be acceptable but in his load testing indicated 80% of capacity when fully charged. So now I have 1200.00 worth of batteries that I'm going to live with being 80% and probably reducing capacity over the next couple of years until I give in and replace them. I don't bring the batteries down to 50% or lower because I want to ruin them I do that because that is the requirements of our boating. I could add extra capacity and add a great deal more weight or change the comfort level that we enjoy when on the hook and use less battery AH . We don't want to do that. I except that for our use I get the best bank for our buck using Flooded Lead acid batteries maintaining them correctly but using them for the power use we need. Old school thinking but I have been using Flooded batteries most of my boating years except once. I found that the old school works for me.

Snydzy I read your comments and you may be correct with all. I'm just posting why I made the comments I did. Right or Wrong we post what our experiences have been to help others understand or troubleshoot issues or at least think about possibilities of the "causes".