Hi everyone,I have a 2004 Winnebago Journey motorhome and I recently upgraded my house batteries to three 12V AGM batteries. The new batteries work great but my current converter charger is not capable of charging them in a reasonable time. My current charger is a Parallax 13.6 VDC, 55 amp model 7455 that was original equipment on my coach. The charger seems to be working correctly but it appears to have two deficiencies:1) It does not have adequate charging voltage (especially in the initial charging stage. 2) It automatically reduces charging current long before the batteries have a full charge.I am considering buying one of the new 55 Amp multi-stage chargers that charge with high voltage initially and turn down as appropriate as the batteries reach full charge. I would like to use my current wiring which is 6 AWG and I believe the max rated current through that cable is 60 amps. Therefore, I think I am limited to no more than a 55 amp charger.Am I on the right track for this do-it yourself project? Will the exisiting 12VDC components in my 2004 vintage coach handle 14.7 VDC during the high voltage charge stage? Should I bite the bullit and change out the wiring to allow a higher amp charger (my batteries can handle up to 190 amps)?Your thoughts and Wisedom will be greatly appreciated.BZP

I have done this before on a prior RV. You may want to consider upgrading the wiring if possible. Depending on the wire path it may be more difficult. I purchased a $50 60,000 psi wire crimping tool at Harbor Freight Tools. Yes you can simply install a 60 amp 3 (or 4) stage converter however depending on your usage you may be disappointed. I have a 90 amp version I installed in my cargo trailer. It sounds like a lot but it isn’t. 100 amps at 12 v is only 1200 watts. At 120 v that’s only 10 amps! I’m assuming that your coach doesn’t have any inverter. If it does or you plan on adding one a small converter won’t work.

What does your battery manual say for charging recommendations? What brand batteries?AGM need careful attention to state of charge and regularly achieving full charge or you can give them an early death by walking down the state of charge. The key to SOC is charge current acceptance at a specified voltage. It’s not as simple as sticking a hydrometer in an open cell battery.If those are Lifeline brand for example, 60 amps or so would be the minimum recommended charge current and the full charge when it tapers to about 1.5 amps at 14.4 volts.

You don't necessarily need to remove you present wire and might be able to piggy back another run. Need to check the lug size on the new converter. They also make adapter lug fittings with larger openings.As they said above about your battery specs. It may be more trouble but now is the time to buy what you really need.

You also mentioned 14.7 volts. AGM sometimes say no more than 14.4 volts.

Converter charger upgrade? | Good Sam Community

msturtz
Explorer
Sep 12, 2018
I have done this before on a prior RV. You may want to consider upgrading the wiring if possible. Depending on the wire path it may be more difficult. I purchased a $50 60,000 psi wire crimping tool at Harbor Freight Tools. Yes you can simply install a 60 amp 3 (or 4) stage converter however depending on your usage you may be disappointed. I have a 90 amp version I installed in my cargo trailer. It sounds like a lot but it isn’t. 100 amps at 12 v is only 1200 watts. At 120 v that’s only 10 amps! I’m assuming that your coach doesn’t have any inverter. If it does or you plan on adding one a small converter won’t work.
time2roll
Nomad
Sep 12, 2018
Original post in 'Tech Issues'
Ductape
Explorer
Sep 12, 2018
What does your battery manual say for charging recommendations? What brand batteries?

AGM need careful attention to state of charge and regularly achieving full charge or you can give them an early death by walking down the state of charge. The key to SOC is charge current acceptance at a specified voltage. It’s not as simple as sticking a hydrometer in an open cell battery.

If those are Lifeline brand for example, 60 amps or so would be the minimum recommended charge current and the full charge when it tapers to about 1.5 amps at 14.4 volts.
azrving
Explorer
Sep 12, 2018
You don't necessarily need to remove you present wire and might be able to piggy back another run. Need to check the lug size on the new converter. They also make adapter lug fittings with larger openings.

As they said above about your battery specs. It may be more trouble but now is the time to buy what you really need.
azrving
Explorer
Sep 12, 2018
You also mentioned 14.7 volts. AGM sometimes say no more than 14.4 volts.
firemedic1992
Explorer
Sep 12, 2018
Talk to BestConverter, I’ve dealt with them when replacing my Parallax converter and they were a great help!
dave17352
Explorer
Sep 12, 2018
firemedic1992 wrote:
Talk to BestConverter, I’ve dealt with them when replacing my Parallax converter and they were a great help!

I agree with this ^^ I believe Randy is the converter guy and he knows his stuff!
azrving
Explorer
Sep 13, 2018
dave17352 wrote:
firemedic1992 wrote:
Talk to BestConverter, I’ve dealt with them when replacing my Parallax converter and they were a great help!

I agree with this ^^ I believe Randy is the converter guy and he knows his stuff!

But DON'T let him sell you a WFCO
msturtz
Explorer
Sep 13, 2018
If you want to go with a good converter here is what I used: https://www.progressivedyn.com/rv/power-converters/pd9200-series-rv-power-converters/
bzp
Explorer
Sep 14, 2018
Thanks everyone for your input. I have Three (3) Cabela's Advanced AGM Series 30 batteries. The specs say they float charge at 13.6-13.8 volts and cycle service charge at 14.6-14.8 volts. I will definitely contact Best Converter and get their input so I can make the best choice for my needs. However, I would still like to know your thoughts about any impacts to my existing 12V RV components (refrigerator, Powerline Energy monitor, fans, other appliances, etc). I have a newer ProWatt SW 600 inverter and don't expect it would be a problem.
Thanks again for your help,
BZP