What kind of converter/charge do I have?

[jd4010]

Well my 2 12v deep cycle batteries have failed (3.5 years old) and this weekend I've decided to replace with 2 6v Trojan T-105 batteries. But was curious when trying to educate myself, how do I know if my converter/charger is single stage or multi stage? My readings have led me to believe the multi stage charging is better for the batteries. Rig is a 2019 Silverback 37MBH.

[njfishing]

Given the year and model trailer, I would bet your charger is a multi stage. One way to check is with a volt meter. If your batteries are totally drained down the charger should go into bulk mode and you should see 14.6 or 14.4 volts. After a few hours it will go onto absorption mode and you should see 13.6 and finally 13.2 in trickle charge.

[yukongold]

How about googling the brand and model number and reading the literature?

[jd4010]

Originally Posted by yukongold

How about googling the brand and model number and reading the literature?

WOW! Why didn't I think of that? Sigh....

[camaraderie]

You've definitely got a multistage as that is ALL FR has used since before 2015. Your pair of T105s carries around 220 amp hours. When depleted to 50%...the MAXIMUM Bulk charge they will accept will be around 50-55amps for the first stage of charging which might last for 20 or 30 minutes. So if your existing model charger can put out 55 amps then you are perfectly sized for quickest charging. Buying bigger will not get you there quicker! You should also have at LEAST 25 amps capability for minimum performance. With 55 amps it will take around 6 hours to fully charge to 100% from 50%...with a 3 stage charger. Don't shortchange this as you will slowly kill battery life if you do not take the extra time to get to 100%. Good choice...good luck with them.

[tomkatb]

If your car batteries died early. One culprit is often the lack of a battery monitor. Over discharging can kill a battery in a year. 6 volts might last 10 years if you take care of them.

These are not expensive. Mine is bluetooth and sends alarms!

[jd4010]

Originally Posted by camaraderie

You've definitely got a multistage as that is ALL FR has used since before 2015. Your pair of T105s carries around 220 amp hours. When depleted to 50%...the MAXIMUM Bulk charge they will accept will be around 50-55amps for the first stage of charging which might last for 20 or 30 minutes. So if your existing model charger can put out 55 amps then you are perfectly sized for quickest charging. Buying bigger will not get you there quicker! You should also have at LEAST 25 amps capability for minimum performance. With 55 amps it will take around 6 hours to fully charge to 100% from 50%...with a 3 stage charger. Don't shortchange this as you will slowly kill battery life if you do not take the extra time to get to 100%. Good choice...good luck with them.

THANK YOU! This is exactly the type of information I was looking for!!!!

When not in use, the RV is stored in the barn with commercial/shore power attached. So it should have ample time to get to 100% charge. When it's parked for over a week, usually I let the converter/charger fully charge the batteries and I then use the battery disconnect switch and attach (after 24 hours) a BatteryMinder to keep the batteries full and desulfated.

I've read a lot of articles supporting the move from 2 12v to 2 6V and specifically calling out the Trojan line of deep cycle batteries. At $170 a piece I'm expecting good results and high quality.

Again thanks for the excellent info!

[jd4010]

Originally Posted by tomkatb

If your car batteries died early. One culprit is often the lack of a battery monitor. Over discharging can kill a battery in a year. 6 volts might last 10 years if you take care of them.

These are not expensive. Mine is bluetooth and sends alarms!

Appreciate this suggestion. I was looking online at these this morning and they don't appear to break the bank. Since we don't camp without full hookups, I think the BatteryMinder one will work well as it'll use the same connection as the charger/maintainer I use.

Thanks!

[camaraderie]

Originally Posted by jd4010

THANK YOU! This is exactly the type of information I was looking for!!!!

When not in use, the RV is stored in the barn with commercial/shore power attached. So it should have ample time to get to 100% charge. When it's parked for over a week, usually I let the converter/charger fully charge the batteries and I then use the battery disconnect switch and attach (after 24 hours) a BatteryMinder to keep the batteries full and desulfated.

I've read a lot of articles supporting the move from 2 12v to 2 6V and specifically calling out the Trojan line of deep cycle batteries. At $170 a piece I'm expecting good results and high quality.

Again thanks for the excellent info!

Happy to help. As to your routine...leaving it plugged in full time with a multi stage charger is fine. A battery minder will do nothing useful and will certainly NOT desulfate anything.

[And I don't mean just that brand. The top six were tested extensively by two friends of mine for over a year (one is on the STANDARDS committee of the ABYC that writes all marine electrical rules) Not a one did anything noticeable... less than a single 90 minute EQ from a real charger did to restore SOC.] Battery minders "work" for their owners because they do maintain the charge and parasitic loads don't kill the batteries.
Your built in charger in float mode will provide the same LOW amp and 13.2V supply to your batteries that your minder does so there is no need for any other hookup. Myself...I simply charge fully and walk away after DISCONNECTING THE NEGATIVE battery wire. This allows the battery to gradually discharge and when it finally after several months gets to 12.2V or so...hooking back up and hitting with a 14.4V bulk charge will keep the water and acid well mixed and kill off sulfation. Note...your way works but there's no NEED with your on board modern converter.

[jd4010]

Originally Posted by camaraderie

Happy to help. As to your routine...leaving it plugged in full time with a multi stage charger is fine. A battery minder will do nothing useful and will certainly NOT desulfate anything.

[And I don't mean just that brand. The top six were tested extensively by two friends of mine for over a year (one is on the STANDARDS committee of the ABYC that writes all marine electrical rules) Not a one did anything noticeable... less than a single 90 minute EQ from a real charger did to restore SOC.] Battery minders "work" for their owners because they do maintain the charge and parasitic loads don't kill the batteries.
Your built in charger in float mode will provide the same LOW amp and 13.2V supply to your batteries that your minder does so there is no need for any other hookup. Myself...I simply charge fully and walk away after DISCONNECTING THE NEGATIVE battery wire. This allows the battery to gradually discharge and when it finally after several months gets to 12.2V or so...hooking back up and hitting with a 14.4V bulk charge will keep the water and acid well mixed and kill off sulfation. Note...your way works but there's no NEED with your on board modern converter.

And yet some more great info! Truly appreciate it. Headed out now to get the new batteries. WOOT WOOT.