Battery upgrade 2022 m240

[justgary]

On 7/22/2022 at 6:08 PM, RCorsa said:

So I used a voltmeter as each battery was at between 11.2-11.4 after sitting on the built in trickle charger overnight.

Lead acid batteries need to be charged with as much current as they will take, not a trickle charger.  Letting them sit uncharged and using a trickle charger are the worst things you can do to them since both encourage sulfation.  Put them on a real charger with some real current (e.g. around 20 Amps for your parallel bank) and let them charge fully.  Maybe you can salvage them with proper charging.

Lithium batteries have a completely different charge profile than lead acid.  They have amazing capacity and current available (due to very low internal resistance), but to use them you would either need to change all of your batteries to lithium and then change your alternator regulator to a lithium profile, or change the house batteries to lithium and use a DC-DC charger specifically made for lithium.  Also, lithium batteries vary widely in their chemistry, and they are not all the same.  I would recommend that you use Lithium Iron Phosphate (LFP) due to its much higher safety.  Finally, if you decide to assemble your own battery from lithium cells, always use a battery management system (BMS) that will keep you from starting a nasty fire.

In short, do not mix lithium with lead acid.

[shawndoggy]

11 hours ago, atLakeSantee said:

Regarding wiring batteries in parallel for same voltage and twice the current/reserve...

Yes; using a manual battery switch or an automatic combiner would prevent the negative affect of wiring batteries in parallel.  Not a problem having them wired together during charging or while discharging (using them).  The issue of parallel wired is when not using them!

Two batteries only act as one big battery if wired in series for twice the voltage.  Two 6 volt batteries work great to provide 12 volts; the two 6 volts would cleanly provide twice the power of the single battery; this is what golf carts do that are 36 volt or 48 volt.  If two batteries of same rated voltage are wired together in parallel (negative-to-negative & positive-to-positive) without a load or without being charged, then they are fighting to maintain exactly one voltage level.  One battery will be a small fraction of a volt less than the other due to physics of temperature, aging, and specific gravity (of the acid).  This small difference in voltage causes the higher voltage battery to trickle current into the lower pulling down the higher and getting soaked up as heat in the lower until they become exactly equal; next day the opposite battery may be stronger and donate its power to the weaker again being converted to heat rather than charging the lower.  After dozens of days of this weaker battery pulling down the stronger, they both become weaker.

The correct way to resolve the issue is either using a battery switch (ideally automatic combiner switch) OR use a pair of 6 volt golf cart batteries wired in series for the needed 12 volts.  A pair of 6 volt AGM golf cart batteries connected for 12 volts would give great service!

How come the paralleled 12v batteries in my F250 don’t crap out after a year then?

[RCorsa]

2 hours ago, Casey211 said:

What do you mean, how did I pick my lithium batteries?

Yes just wondering how you decided on the battery types and brands.   I reviewed these sites and it looks pretty reputable.  Expensive at around $850/each which is fine 

[rennis]

My gut says at least one of the three batteries is weak and needs to be replaced.  Probably more than one.  I would take all of them out, and take them to a shop that can stress test them individually.  They'll be able to tell you how well they are taking and holding a charge, etc.  My local supplier of choice for this stuff hooks them up to a machine that can tell them a lot more than just a simple voltage meter is going to tell you in the boat.

https://pacificpowerbatteries.com/pages/battery-testing

If they test well then you know it's a problem with the boat's charging or other systems malfunctioning. 

Edited July 27, 2022 by rennis

[justgary]

4 hours ago, shawndoggy said:

How come the paralleled 12v batteries in my F250 don’t crap out after a year then?

Because they were both new when installed and have most likely never been deep discharged.

[shawndoggy]

1 minute ago, justgary said:

Because they were both new when installed and have most likely never been deep discharged.

Sure. But @atLakeSantee is saying that paralleled 12v cells will always draw down one another and die in a year or two. He didn’t qualify with adding a new cell to an old one. 
 

One battery will be a small fraction of a volt less than the other due to physics of temperature, aging, and specific gravity (of the acid).  This small difference in voltage causes the higher voltage battery to trickle current into the lower pulling down the higher and getting soaked up as heat in the lower until they become exactly equal; next day the opposite battery may be stronger and donate its power to the weaker again being converted to heat rather than charging the lower.  After dozens of days of this weaker battery pulling down the stronger, they both become weaker.

[justgary]

Even new batteries in parallel will struggle in parallel if they are deep discharged repeatedly (e.g. lots of long days of tunes on the sand bar) without any monitoring or rebalancing.  Like you though, I suspect that the prediction of a year is probably too short.

[Brandonloos21]

8 minutes ago, justgary said:

Even new batteries in parallel will struggle in parallel if they are deep discharged repeatedly (e.g. lots of long days of tunes on the sand bar) without any monitoring or rebalancing.  Like you though, I suspect that the prediction of a year is probably too short.

For those that do 6v banks (say it consist of 8 total 6v’s) wouldn’t the same happen with each of the 4 series pairs ?

[justgary]

3 minutes ago, Brandonloos21 said:

For those that do 6v banks (say it consist of 8 total 6v’s) wouldn’t the same happen with each of the 4 series pairs ?

Series cells don't fight each other for a level of charge.  I think you are asking about a parallel configuration, but you didn't specify a total voltage.  Reading it again, I think you are saying a 2S4P configuration (4 parallel sets of 2 series batteries, for 12v total).  Yes, they will kill each other, and how you wire them is very important so you can maintain balance.

I would recommend that any parallel lead acid configuration use wet cells so that you can monitor each cell by testing specific gravity.  AGM cells can't really be monitored individually.  Any discrepancy should be dealt with promptly by individual charging at the lowest number of cells possible (e.g. three cells for a six volt battery).

[Brandonloos21]

47 minutes ago, justgary said:

Series cells don't fight each other for a level of charge.  I think you are asking about a parallel configuration, but you didn't specify a total voltage.  Reading it again, I think you are saying a 2S4P configuration (4 parallel sets of 2 series batteries, for 12v total).  Yes, they will kill each other, and how you wire them is very important so you can maintain balance.

I would recommend that any parallel lead acid configuration use wet cells so that you can monitor each cell by testing specific gravity.  AGM cells can't really be monitored individually.  Any discrepancy should be dealt with promptly by individual charging at the lowest number of cells possible (e.g. three cells for a six volt battery).

Yes I am talking about 4 parallel sets of 2 series batteries. My apologies I assumed we were all within the world of 12v due to talking about Malibus electrical systems. 
 

So if I understand correctly, the 4 pairs of 6v’s (ideally acting like 4 12v batteries) will compete, though the actual 6vs will not individually compete within the series-pairs. 
 

I see people wiring them like this all the time. Also see sometimes 4 12v deep cells in parallel. What would suggestion for a big system like this be to maintain?

Edited July 27, 2022 by Brandonloos21

[justgary]

9 minutes ago, Brandonloos21 said:

I see people wiring them like this all the time. Also see sometimes 4 deep cells in parallel. What would suggestion for a big system like this be to maintain?

Four in parallel will draw the most current from the outer pair and less from the inner pair (assuming it is wired properly but with typical bus bars).  Charging will do the same thing.  The outer pair will get most of the current, and the inner pair will get less.  This is particularly true if you are drawing very high current, such as a stern thruster or huge stereo.  One way to mitigate the issue is to use very large bus bars between the batteries.  Another way is to just buy bigger batteries.

The correct way to wire parallel sets is to connect the power outputs at opposite corners of the bank.  In other words, force the batteries to share the load as much as possible.  Here is an example (taken from windandsolar.com):

If you look at @RCorsa's photo in the original post, his parallel batteries are wired this way (except the parallel jumper (bus) wires could be much larger).  The reason for huge bus wires is to limit voltage drop under load, allowing all batteries to share the load as equally as possible.

I have eight Group 8D AGM batteries from a solar installation that a friend put together in 4S2P (48V at 450Ah).  He didn't really understand the reasoning, so one bank sucked the other completely dry.  Four of the batteries were at 2.3V, yet the bank still showed 50V total.  The four surviving ones were taxed heavily by constantly having the load of dead batteries connected to them.  These batteries would be great for your boat, but be warned that each one weighs about 150 pounds.  I can't lift one above my knees by myself.

[MLA]

12V batteries have been wired in parallel for decades. With the use of proper sizes cabling or BUS, paired with the speed of electricity, I think we are splitting the short n curlies on a gnat's backside. 

[justgary]

2 minutes ago, MLA said:

12V batteries have been wired in parallel for decades. With the use of proper sizes cabling or BUS, paired with the speed of electricity, I think we are splitting the short n curlies on a gnat's backside. 

It isn't the speed of electricity, it is resistance that is the culprit.  But in general I agree with you.  The issue usually rears its head when drawing large current, and also when using more than two batteries in parallel.  Batteries are a big enough investment that it is reasonable to learn how to care for them.

The issue is much more prevalent in lithium installations because the internal resistance of the cells is so low.  The resistance of the bus wire really starts to make a difference under high currents.

[MLA]

1 hour ago, justgary said:

It isn't the speed of electricity, it is resistance that is the culprit.  But in general I agree with you.  The issue usually rears its head when drawing large current, and also when using more than two batteries in parallel.  Batteries are a big enough investment that it is reasonable to learn how to care for them.

The issue is much more prevalent in lithium installations because the internal resistance of the cells is so low.  The resistance of the bus wire really starts to make a difference under high currents.

Yeah, the speed comment was based on how i envisioned your description of current drawing from the outer batteries and then having to be replenished by the inner batteries. In my mind, I pictured water over the bulkheads as the Titanic slowly sank. Or current slowing flowing into the next battery after it was removed by the load.   

[Dirtysidedown]

Looking back at the picture you posted on the 1st page. I only see a charging lead hooked up to the “Starting” battery.    I definitely could be missing it, or it could be connected somewhere else, but I don’t see one anywhere on the “house” bank.  If your charger is anything like my NOCO I’m pretty sure the wire with the inline fuse in the ribbed loom is coming from the charger. Not sure why they have 2 going down to 1 ring terminal.  Anyway may be worth a look to make sure the charger is actually hooked up correctly.

Another question are you plugging in your charger with the main battery switch On or Off?  I ask because if the battery charger is in fact only hooked up to the Start bank and you have the battery switch OFF, the ACR that is part of battery option 3 that you have, is isolating your battery from the other 2 and you are only charging the “start” battery, which is not going to be any where near as depleted as the “house” batteries. Where as if you charged the battery with the switch in the ON position, once the Start battery sense a charge the ACR will do its job and then connect the the house batteries to the start batteries just like it does when the alternator is giving it a charge.

This is the opposite of how most people I think that have ACRs and dual banks set up.  I charge with my battery switch in the OFF position. This isolates the banks and let’s them charge independently and keeps the ACR from cycling.

I think one way you could test this theory is to plug in your charger then use you volt meter to check the batteries with the switch off/on. They should all be in the 13-14 range if they are getting a charge I would think. Switch the switch and see if the same is true.

Not that your set up is wrong it just could be what is preventing the batteries from charging if that is in fact the situation, that you only have one charge lead hooked up and the battery switch off.

Edited July 28, 2022 by Dirtysidedown

[MLA]

It actually looks like both charger leads are on the group-24 cranking bank. 

[RCorsa]

Yes I think you might be right. I’m not sure the charger is even hooked up.  
 

That lead that you are going the starting battery is labeled for the bilge.  
 

I probably need to take down the screws on port storage and see where the leads from the charger go.  Once it cools down this evening I’m going to do a little digging. 

[shawndoggy]

42 minutes ago, RCorsa said:

Yes I think you might be right. I’m not sure the charger is even hooked up.  
 

That lead that you are going the starting battery is labeled for the bilge.  
 

I probably need to take down the screws on port storage and see where the leads from the charger go.  Once it cools down this evening I’m going to do a little digging. 

It could well be that they wired the charger leads to the switch.  Not really "ideal" but it could work.

That would be a real bummer if the charger weren't even hooked up!

[RCorsa]

Also I always have the boat in the “Off” position When charging.  I assume if you left it in the “on” position you would get some constant draw off the batteries and the charger would just be fighting the draw down 

 

Any issues keeping the batteries hooked up if I brought out a mobile battery charger out to the dock. I have a really good one I’ve used for my cars that sit a lot and I have a 110 power out there and it would certainly be easier that unhooking them and hauling them up to the garage. .  

Edited July 28, 2022 by RCorsa

[RCorsa]

So after a week of non use and leaving on the internal charger I check with a new battery tester. And batteries showed below. Initially the battery test only said 23% health but I repeated the test 3 times on Each battery and they came out ok. 
 

I then hooked up the house batteries to a marine grade 15a charger.  One was at 93% and the other at 87%.  I topped both up to 100%.  
 
I’ll plan on leaving in the internal charger overnight and surfing first thing in the am. 

[RCorsa]

[ahopkins22LSV]

@RCorsa, sorry if I missed it, but did you confirm how the battery charger is hooked up to the batteries?

[Surf4FamFun]

8 hours ago, RCorsa said:

That is either a huge battery box or the battery went thru the dryer on high heat once by mistake.  Is it possible the battery is undersized?  You probably addressed this in an earlier post but quick look did not find it.  

[RCorsa]

That photo is a photo of the cranking battery which is a 24.  The housings hold 3 27s so that one looks small but the other two are normal. I’m pretty sure the charger is at least partially working as last week the batteries were at 11.2 and this week they are all nearly charged at 12.4-12.6.  They all required a little top off to get them to 100% 12.7. 

[Surf4FamFun]

19 minutes ago, RCorsa said:

That photo is a photo of the cranking battery which is a 24.  The housings hold 3 27s so that one looks small but the other two are normal. I’m pretty sure the charger is at least partially working as last week the batteries were at 11.2 and this week they are all nearly charged at 12.4-12.6.  They all required a little top off to get them to 100% 12.7. 

There is an easy Napoleon joke here but it would not be constructive.  Going to take a pass on it but really hard not to go there!