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Hephastion Samba Member
Joined: June 14, 2021 Posts: 3 Location: Portland, OR
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Posted: Mon Jun 14, 2021 4:38 pm Post subject: Victron Smart DC to DC Charger, 12V 18Amp |
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New here, but what an amazing site!
I've a '97 Eurovan Camper that we've been thoroughly enjoying. I've added a Victron MPPT Solar charge controller, a 100W solar panel, a Victon 500Amp Smart Shunt, an Ampere-time 100AH Group 31 LiFePo4 couch battery, and a Victron AC to DC charger/converter for charging when idle. I've been relying on the stock alternator and the stock battery isolator for charging when in motion (relying on the AC/DC converter and the MPPT solar charge controller to top the battery off to 14.4V frequently), but I think I may have killed my alternator (when running the engine, driving, etc, I now just seem to be draining the coach battery instead of charging it).
My question: Do you think I can just install a Victron smart DC to DC charger on the firewall where the existing battery isolator lives, connecting it to the same chassis and coach circuits and the ignition sensor wire?
Additionally, do you think I killed my alternator with my setup?
Thanks in advance! Please let me know if you need more information.
James |
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subdewd Samba Member
Joined: January 16, 2018 Posts: 238
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Posted: Tue Jun 15, 2021 3:57 am Post subject: Re: Victron Smart DC to DC Charger, 12V 18Amp |
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Why would that kill the alternator? |
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Steve in Colorado Samba Member
Joined: April 26, 2020 Posts: 22 Location: Boulder, Colorado
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Posted: Tue Jun 15, 2021 9:12 am Post subject: Re: Victron Smart DC to DC Charger, 12V 18Amp |
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Hephastion wrote: |
New here, but what an amazing site!
I've a '97 Eurovan Camper that we've been thoroughly enjoying. I've added a Victron MPPT Solar charge controller, a 100W solar panel, a Victon 500Amp Smart Shunt, an Ampere-time 100AH Group 31 LiFePo4 couch battery, and a Victron AC to DC charger/converter for charging when idle. I've been relying on the stock alternator and the stock battery isolator for charging when in motion (relying on the AC/DC converter and the MPPT solar charge controller to top the battery off to 14.4V frequently), but I think I may have killed my alternator (when running the engine, driving, etc, I now just seem to be draining the coach battery instead of charging it).
My question: Do you think I can just install a Victron smart DC to DC charger on the firewall where the existing battery isolator lives, connecting it to the same chassis and coach circuits and the ignition sensor wire?
Additionally, do you think I killed my alternator with my setup?
Thanks in advance! Please let me know if you need more information.
James |
Could it be that your isolator is dead? I use a simple USB outlet with a voltage indicator in my cigarette lighter, which is connected to the starter battery, to check the alternator. But maybe EVCs are set up differently than my Weekender. |
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Steve in Colorado Samba Member
Joined: April 26, 2020 Posts: 22 Location: Boulder, Colorado
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Posted: Tue Jun 15, 2021 9:14 am Post subject: Re: Victron Smart DC to DC Charger, 12V 18Amp |
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Steve in Colorado wrote: |
Hephastion wrote: |
New here, but what an amazing site!
I've a '97 Eurovan Camper that we've been thoroughly enjoying. I've added a Victron MPPT Solar charge controller, a 100W solar panel, a Victon 500Amp Smart Shunt, an Ampere-time 100AH Group 31 LiFePo4 couch battery, and a Victron AC to DC charger/converter for charging when idle. I've been relying on the stock alternator and the stock battery isolator for charging when in motion (relying on the AC/DC converter and the MPPT solar charge controller to top the battery off to 14.4V frequently), but I think I may have killed my alternator (when running the engine, driving, etc, I now just seem to be draining the coach battery instead of charging it).
My question: Do you think I can just install a Victron smart DC to DC charger on the firewall where the existing battery isolator lives, connecting it to the same chassis and coach circuits and the ignition sensor wire?
Additionally, do you think I killed my alternator with my setup?
Thanks in advance! Please let me know if you need more information.
James |
Could it be that your isolator is dead? I use a simple USB outlet with a voltage indicator in my cigarette lighter, which is connected to the starter battery, to check the alternator. But maybe EVCs are set up differently than my Weekender. |
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Oh, and I use the same gizmo in the rear 12v outlets to check the charge to the coach battery while the engine is running. |
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Hephastion Samba Member
Joined: June 14, 2021 Posts: 3 Location: Portland, OR
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Posted: Tue Jun 15, 2021 9:18 am Post subject: Re: Victron Smart DC to DC Charger, 12V 18Amp |
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subdewd wrote: |
Why would that kill the alternator? |
Good question. I'd read a few places that LiFePro4 batteries can be hard on alternators. I need to test more, I suppose, to see if it's really dead. When I turn on the key I can see current dumping out of the LiFePro4 battery into the start battery through the shunt. Before, when I'd start the vehicle, if the LiFePro4 battery was in need of charging it would starting sucking current from the alternator, but now it just discharges continuously as I drive. I consumed about 40AH on a 4 hour drive from the Painted Hills back to Portland. |
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bigfoot_ev Samba Member
Joined: March 13, 2018 Posts: 153 Location: Anacortes, WA
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Posted: Tue Jun 15, 2021 9:54 am Post subject: Re: Victron Smart DC to DC Charger, 12V 18Amp |
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I haven't dug into the specs of your Ampere Time battery, but lifepo4 batteries, in general, can consume large amounts of current during charging. If the BMS inside the battery case doesn't limit input current you could very well have over stressed the alternator. Again, not knowing your specifics, it is not unreasonable to see a lifepo4 battery consume a constant 100 amps. You should be able to remove your coach battery, ie disconnect it and test out the van's starting battery circuitry. If everything is not fine with the coach battery disconnected, you will know there is a problem.
I built a solar generator and this was one of my biggest challenges. I had to find ways to limit input charge current. I burnt out 2 benchtop power supplies trying to solve this. The second one had current limiting, but I was impatient and limited current to over 80% of rated capacity and killed the power supply. For the van input on the solar generator, I limit input current to 15 amps and the source has a 20 amp fuse all to prevent damage to wiring and the alternator. The DC/DC charger should have a lifepo4 setting and a current rating so as not to stress your wiring and alternator. My current coach battery is AGM and I have used a DC/DC/Solar charger from CTEK for a number of years. I highly recommend DC/DC chargers. |
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Hephastion Samba Member
Joined: June 14, 2021 Posts: 3 Location: Portland, OR
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Posted: Tue Jun 15, 2021 10:13 am Post subject: Re: Victron Smart DC to DC Charger, 12V 18Amp |
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bigfoot_ev wrote: |
I haven't dug into the specs of your Ampere Time battery, but lifepo4 batteries, in general, can consume large amounts of current during charging. If the BMS inside the battery case doesn't limit input current you could very well have over stressed the alternator. Again, not knowing your specifics, it is not unreasonable to see a lifepo4 battery consume a constant 100 amps. You should be able to remove your coach battery, ie disconnect it and test out the van's starting battery circuitry. If everything is not fine with the coach battery disconnected, you will know there is a problem.
I built a solar generator and this was one of my biggest challenges. I had to find ways to limit input charge current. I burnt out 2 benchtop power supplies trying to solve this. The second one had current limiting, but I was impatient and limited current to over 80% of rated capacity and killed the power supply. For the van input on the solar generator, I limit input current to 15 amps and the source has a 20 amp fuse all to prevent damage to wiring and the alternator. The DC/DC charger should have a lifepo4 setting and a current rating so as not to stress your wiring and alternator. My current coach battery is AGM and I have used a DC/DC/Solar charger from CTEK for a number of years. I highly recommend DC/DC chargers. |
This is basically what I found snooping around the net. Thanks, I'll try disconnecting he house circuit from the alternator/start battery and check voltages running/off.
On the plus side, the battery is fantastic. No issues anymore with voltage sag and I get to use 85+% of the rated 100AH w/o issue. The battery will easily last a couple of days w/o solar (all it powers is lights, water pump when used, charging of family phones and tablets, and an ICECO fridge) and I think during sunny weather I could probably go 4-5 days using the solar panel. |
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