Battery Charge Rate Experts please chime in

[RobRoy]

Battery charge rate experts please chime in on my battery charge rates and settings.

My batteries seen here are now 5 plus years old for sure maybe more.



Seen here are the settings on my Magnum




The issue is that in the last year the batteries seem to be using lots more water than ever before and I also see the battery cases are swelling around the posts and sides indicating overcharging issues.

I'm O.K. with replacing the batteries after 5 years of service but want to make sure that my charge settings are correct so that I don’t incur the same case swelling issue in short order.

Im pretty fuzzy on the " CHARGE RATE " setting

I know there are lots of replacement battery options but will try and use the same wet cell battery because them being decent quality & price and most likely I won’t own this coach 5 more years

Thanks in Advance

Happy Trails

[iluvuk]

Originally Posted by RobRoy

Battery charge rate experts please chime in on my battery charge rates and settings.

My batteries seen here are now 5 plus years old for sure maybe more.

Attachment 231023

Seen here are the settings on my Magnum
Attachment 231024



The issue is that in the last year the batteries seem to be using lots more water than ever before and I also see the battery cases are swelling around the posts and sides indicating overcharging issues.

I'm O.K. with replacing the batteries after 5 years of service but want to make sure that my charge settings are correct so that I don’t incur the same case swelling issue in short order.

Im pretty fuzzy on the " CHARGE RATE " setting

I know there are lots of replacement battery options but will try and use the same wet cell battery because them being decent quality & price and most likely I won’t own this coach 5 more years

Thanks in Advance

Happy Trails

Are those 6v or 12v batteries? How many of them do you have? The one in the pic is 230Ah. You have your magnum set for 1000Ah. Does that mean you have 4 of those?? That would be 920Ah not 1000Ah. Not enough data yet. I am concerned that the 1000Ah may be too high a setting.

[Mark_K5LXP]

Batteries can swell as they age and is not an indication of improper use. Same goes for terminal seals. Enough vibration, temperature extremes and strain from connected cables will compromise them eventually. Water use will go up as the end of life approaches and the more time and cycles you go, the harder it will be to reach full charge and keep water in them. The key data point is 5 plus years, which translates to they don't owe you anything. I don't know the specifics of the magnum charger and I'll let others comment on that but my observation would be you've run these batteries out before they ran out on you. Good job. If you're curious you could put a C/20 load on them and get an exact merit of Ah to see how close you are to end of life but at this stage of the game it may not matter.

Mark B.
Albuquerque, NM

[RobRoy]

Originally Posted by iluvuk

Are those 6v or 12v batteries? How many of them do you have? The one in the pic is 230Ah. You have your magnum set for 1000Ah. Does that mean you have 4 of those?? That would be 920Ah not 1000Ah. Not enough data yet. I am concerned that the 1000Ah may be too high a setting.

Sorry I have 8 - 6vdc batteries

My calculations as with yours come out to 920Ah.

That said the next lower setting on Battery Ah Rating is 800 Ah

[RobRoy]

Originally Posted by Mark_K5LXP

Batteries can swell as they age and is not an indication of improper use. Same goes for terminal seals. Enough vibration, temperature extremes and strain from connected cables will compromise them eventually. Water use will go up as the end of life approaches and the more time and cycles you go, the harder it will be to reach full charge and keep water in them. The key data point is 5 plus years, which translates to they don't owe you anything. I don't know the specifics of the magnum charger and I'll let others comment on that but my observation would be you've run these batteries out before they ran out on you. Good job. If you're curious you could put a C/20 load on them and get an exact merit of Ah to see how close you are to end of life but at this stage of the game it may not matter.

Mark B.
Albuquerque, NM

Hello Mark.

How are the amp-hours calculated when using 8 - 6vdc Batteries?

My thinking was 8 X 230ah divided by 2 ( divided by 2 because of being 6 vdc )


If that is the correct way to do so the AH hours on my Magnum are set wrong and should be 920 Ah ( I just went out to the coach and looked at my Magnum and the next lower setting for Ah is 800Ah and 1000Ah is as high as it goes)

Im also trying to figure out the …. “ Charge Rate “ setting.


With 4 years of the same settings on my Magnum in the coach with no issues and batteries that Im sure are over 5 years old Im quite sure that as you stated the batteries are giving up the Ghost and if so? I have no intention of testing them if one is bad? I will just replace all 8.

I just want to make sure all my charge rate settings are correct before I spend $1k on new batteries to have the same issue.




Thanks for your input

Happy Trails

[iluvuk]

Originally Posted by RobRoy

Sorry I have 8 - 6vdc batteries

My calculations as with yours come out to 920Ah.

That said the next lower setting on Battery Ah Rating is 800 Ah

I prefer to calculate capacity in Watt-hrs because Watt-hours are watt-hours whether it is a 12v system or 6v system, etc.

So, for 230ah battery (assuming they are 20 hr rated for the calculation) x 6 v equals= 1380 watt-hr per battery. X 8 batteries equals 11,040 watt-hours of electricity in that bank (at maximum capacity). 11,040 watt-hours in a 12v system (which I think you have) would be = 11,040 watt-hrs divided by 12v which equals 920 Ah stored in the bank at max. I don't know enough about your charger to know for sure if that will cause a problem to have it set at 1000 Ah capacity. It suspect it might slightly increase the charge rate but seriously doubt it is enough to damage batteries...just my thoughts. Also, realize, you only have about 20-50% of that 920Ah usable because you don't want to discharge your batteries below 50-80% of full charge. The less you discharge the more cycles you will get out of the batteries. Hope this helps a little. I think you just need new batteries...they are old...some if not all are probably dying.

[pduggs]

Thanks for posting this Robroy. I too am concerned about the proper settings on the Magnum. I have read the Magum manuals several times, but they don’t seem to explain some of the settings very well...at least for a novice like me.

I installed new batteries last week, but don’t know how to do the settings on the remote. I just reset to default, until I get it figured out.

I hope some experts chime in.

[Stan&Jacquie]

Hey Pdugs....Stan here. I'm not an expert but I can tell you this. Different battery types (flooded vs Agm vs gel vs lithium) have different charging requirements. Go to your manufactures website to learn the charging recommendation for your batts. I would set your Magnum to the amphr rating that is closest to yours. Setting at 1000 for 920 actual should be ok. See "handy bob.com" for an excellent discussion/recommendations on battery charging but be prepared to do some reading. Hey was an elec engineer and now lives off the grid totally dependent on solar. He is widely and highly respected among us solar folks. Equally important as charging is degree of draw down and water maintenance. Handy Bob will set you straight. Hope this helps. Good luck.

[Stan&Jacquie]

Oooooops! Should have directed the above to RobRoy but Pduggs is welcome also!

[Mark_K5LXP]

Yeah, 920Ah is the final answer. From a troubleshooting perspective you'd test all 8 batteries separately and pass judgement at the unit level but from a practical perspective the set is used as a bank, so test it as a bank. My own method is to come up with a load I can easily repeat over time, and make a record of how the bank does from time to time. Since you have an inverter with a status panel you can easily apply a good charge, turn on/plug in a measured load and watch the bank voltage reach a given point. Doesn't necessarily have to be a C/20 load or run the bank down to 10.5V, just something you repeat consistently from test to test. An example would be to apply a full charge, then connect a simple load like a ceramic heater and note the time it takes to run the bank down to a specific voltage like 11.75V. Whenever you want to do a quick test just repeat the scenario and log the time. You might see some slight variations due to temperature or cycling activity but generally speaking it will be "close". When it starts dropping repeatedly and by a significant percentage you know something is up.

The above interim tests assume a healthy pack to start with, so when starting with an unknown you're pretty much stuck doing a measured capacity test. This would at a minimum mean a C/20 load applied after a complete charge cycle.

920/20=46A

Since you have an inverter and a means of displaying system draw I find the easiest way to dial in a specific load is to use a combination of incandescent bulbs. A handful of 100W, 50W and 25W bulbs in various combinations will get you there. Start the clock and see how close you get to 20 hours before the bank voltage reaches 10.5V. On an old pack it's not likely you'll hit 20 hours so the exercise is to see just where it lands - 75%, 50%, less? Only one way to know for sure. Even if it's only one or two stinkers in the bank you can't mix old and new batteries so if the bank capacity falls short of your requirement you'll have your justification for replacing the set. I personally consider anything north of 80% to be "good"/usable, 50%-80% is in decline and time to start shopping, and below 50% is failed.

Mark B.
Albuquerque, NM

[iluvuk]

Originally Posted by Mark_K5LXP

Yeah, 920Ah is the final answer. From a troubleshooting perspective you'd test all 8 batteries separately and pass judgement at the unit level but from a practical perspective the set is used as a bank, so test it as a bank. My own method is to come up with a load I can easily repeat over time, and make a record of how the bank does from time to time. Since you have an inverter with a status panel you can easily apply a good charge, turn on/plug in a measured load and watch the bank voltage reach a given point. Doesn't necessarily have to be a C/20 load or run the bank down to 10.5V, just something you repeat consistently from test to test. An example would be to apply a full charge, then connect a simple load like a ceramic heater and note the time it takes to run the bank down to a specific voltage like 11.75V. Whenever you want to do a quick test just repeat the scenario and log the time. You might see some slight variations due to temperature or cycling activity but generally speaking it will be "close". When it starts dropping repeatedly and by a significant percentage you know something is up.

The above interim tests assume a healthy pack to start with, so when starting with an unknown you're pretty much stuck doing a measured capacity test. This would at a minimum mean a C/20 load applied after a complete charge cycle.

920/20=46A

Since you have an inverter and a means of displaying system draw I find the easiest way to dial in a specific load is to use a combination of incandescent bulbs. A handful of 100W, 50W and 25W bulbs in various combinations will get you there. Start the clock and see how close you get to 20 hours before the bank voltage reaches 10.5V. On an old pack it's not likely you'll hit 20 hours so the exercise is to see just where it lands - 75%, 50%, less? Only one way to know for sure. Even if it's only one or two stinkers in the bank you can't mix old and new batteries so if the bank capacity falls short of your requirement you'll have your justification for replacing the set. I personally consider anything north of 80% to be "good"/usable, 50%-80% is in decline and time to start shopping, and below 50% is failed.

Mark B.
Albuquerque, NM

Great advice! I agree!

[RobRoy]

Originally Posted by Stan&Jacquie

Hey Pdugs....Stan here. I'm not an expert but I can tell you this. Different battery types (flooded vs Agm vs gel vs lithium) have different charging requirements. Go to your manufactures website to learn the charging recommendation for your batts. I would set your Magnum to the amphr rating that is closest to yours. Setting at 1000 for 920 actual should be ok. See "handy bob.com" for an excellent discussion/recommendations on battery charging but be prepared to do some reading. Hey was an elec engineer and now lives off the grid totally dependent on solar. He is widely and highly respected among us solar folks. Equally important as charging is degree of draw down and water maintenance. Handy Bob will set you straight. Hope this helps. Good luck.

Thank You

Happy Trails

[RobRoy]

Originally Posted by Mark_K5LXP

Yeah, 920Ah is the final answer. From a troubleshooting perspective you'd test all 8 batteries separately and pass judgement at the unit level but from a practical perspective the set is used as a bank, so test it as a bank. My own method is to come up with a load I can easily repeat over time, and make a record of how the bank does from time to time. Since you have an inverter with a status panel you can easily apply a good charge, turn on/plug in a measured load and watch the bank voltage reach a given point. Doesn't necessarily have to be a C/20 load or run the bank down to 10.5V, just something you repeat consistently from test to test. An example would be to apply a full charge, then connect a simple load like a ceramic heater and note the time it takes to run the bank down to a specific voltage like 11.75V. Whenever you want to do a quick test just repeat the scenario and log the time. You might see some slight variations due to temperature or cycling activity but generally speaking it will be "close". When it starts dropping repeatedly and by a significant percentage you know something is up.

The above interim tests assume a healthy pack to start with, so when starting with an unknown you're pretty much stuck doing a measured capacity test. This would at a minimum mean a C/20 load applied after a complete charge cycle.

920/20=46A

Since you have an inverter and a means of displaying system draw I find the easiest way to dial in a specific load is to use a combination of incandescent bulbs. A handful of 100W, 50W and 25W bulbs in various combinations will get you there. Start the clock and see how close you get to 20 hours before the bank voltage reaches 10.5V. On an old pack it's not likely you'll hit 20 hours so the exercise is to see just where it lands - 75%, 50%, less? Only one way to know for sure. Even if it's only one or two stinkers in the bank you can't mix old and new batteries so if the bank capacity falls short of your requirement you'll have your justification for replacing the set. I personally consider anything north of 80% to be "good"/usable, 50%-80% is in decline and time to start shopping, and below 50% is failed.

Mark B.
Albuquerque, NM

Thanks & Happy Trails

[RobRoy]

Originally Posted by Stan&Jacquie

Hey Pdugs....Stan here. I'm not an expert but I can tell you this. Different battery types (flooded vs Agm vs gel vs lithium) have different charging requirements. Go to your manufactures website to learn the charging recommendation for your batts. I would set your Magnum to the amphr rating that is closest to yours. Setting at 1000 for 920 actual should be ok. See "handy bob.com" for an excellent discussion/recommendations on battery charging but be prepared to do some reading. Hey was an elec engineer and now lives off the grid totally dependent on solar. He is widely and highly respected among us solar folks. Equally important as charging is degree of draw down and water maintenance. Handy Bob will set you straight. Hope this helps. Good luck.

Thanks & Happy Trails