Since Flooded Lead Acid and AGM batteries can easily loose 10% or more charge per month, storing them over winter without a maintenance charger can result in loss of longevity.
Hi Mike thanks for this article. I have two Lion energy 100ah lithium battery’s but my 5th wheel doesn't have the option for charging lithium batteries and the voltage never gets to 14 bolts. Can I hook up my Victron IP22 30a charger to the batteries while they are still hooked to the trailer to change them and maintain them? And can I leave it on to maintain them? Thanks Tex
Lithium batteries don’t require a charger with maintenance of tender mode. You just disconnect them with your battery switch and they generally loose less than 1% charge per month.
And yes, you should be able to hook up your Victron charger while the batteries are still connected to top-off the charge, but you should confirm this with Victron.
Also, many of the WFCO and Progressive converters have a drop-in replacement module for their load centers to add Lithium compatibility.
I have a 660 AHr battery bank in my motorhome with a Magnum MS2812 Inverter/ charger, which allows a maximum charge rate of 100 Amps. From what you say in this post, charging should generally not exceed 10% of capacity, which in this case eould be 66 amps. Should i decrease the maximum charge rate to 70%?
Actually, most modern Lithium RV batteries can be charged at up to 1C rate, which would be 100 Amps of charging current for each 100Ah of battery capacity. So up to 660 amps, which will never happen.
For FLA batteries it’s generally a max 0.2C rate, or 20 amps of charging per 100Ah of capacity. In your case with 660Ah of batteries, if they’re Flooded Lead Acid or AGM that would still be 132 amps max, so you would be okay at 100 amps. But check with your battery manufacturer to be sure.
If I live in a relatively temperate climate(Texas), can I just leave my batteries in my motor home connected to the internal charger using shore power?
I would only charge them separately if you discharged them completely. Most of the time charging them in series is just fine. A quick test is to measure the voltage across each battery separately (you don’t have to disconnect any wiring) and if the voltages match within 10 millivolts or so, then their SoC levels are equal. If they’re off by 1/10th volt or more, then it time to charge them separately.
Since Flooded Lead Acid and AGM batteries can easily loose 10% or more charge per month, storing them over winter without a maintenance charger can result in loss of longevity.
Hi Mike thanks for this article. I have two Lion energy 100ah lithium battery’s but my 5th wheel doesn't have the option for charging lithium batteries and the voltage never gets to 14 bolts. Can I hook up my Victron IP22 30a charger to the batteries while they are still hooked to the trailer to change them and maintain them? And can I leave it on to maintain them? Thanks Tex
Lithium batteries don’t require a charger with maintenance of tender mode. You just disconnect them with your battery switch and they generally loose less than 1% charge per month.
And yes, you should be able to hook up your Victron charger while the batteries are still connected to top-off the charge, but you should confirm this with Victron.
Also, many of the WFCO and Progressive converters have a drop-in replacement module for their load centers to add Lithium compatibility.
I am uncertain as to how much water should be in my batteries. What al level constitutes full?. How far from the top of the cell?? Thanks!!
Guess I need to do an article on that with pictures…
I have a 660 AHr battery bank in my motorhome with a Magnum MS2812 Inverter/ charger, which allows a maximum charge rate of 100 Amps. From what you say in this post, charging should generally not exceed 10% of capacity, which in this case eould be 66 amps. Should i decrease the maximum charge rate to 70%?
Actually, most modern Lithium RV batteries can be charged at up to 1C rate, which would be 100 Amps of charging current for each 100Ah of battery capacity. So up to 660 amps, which will never happen.
For FLA batteries it’s generally a max 0.2C rate, or 20 amps of charging per 100Ah of capacity. In your case with 660Ah of batteries, if they’re Flooded Lead Acid or AGM that would still be 132 amps max, so you would be okay at 100 amps. But check with your battery manufacturer to be sure.
Thank you. The batteries are Duracell FLA "golf cart" batteries and so far have handled the100 amps without problems.
A follow up question. If my batteries are charged 90-100%, is using a “float” charger a good idea?
If I live in a relatively temperate climate(Texas), can I just leave my batteries in my motor home connected to the internal charger using shore power?
In other words, does the charging system on the motor home have a tender mode?
I would only charge them separately if you discharged them completely. Most of the time charging them in series is just fine. A quick test is to measure the voltage across each battery separately (you don’t have to disconnect any wiring) and if the voltages match within 10 millivolts or so, then their SoC levels are equal. If they’re off by 1/10th volt or more, then it time to charge them separately.