Using a generator to charge batteries

[Ivan Desjardins]

Hello to all of you:

I bought the 17A last year and had a solar panel installed on the roof of the unit. Up to now, the solar panel has always been able to recharge my batteries (two 6v deep cycle batteries that came with the trailer) and there was no need to use my generator. This week was the first week of camping where I experienced sufficient cloudy and rainy conditions to justify using my small Honda 1000i generator. When the batteries were down to 50%, I plugged my electrical cable into my generator and ran it for 2 hours. I am aware that the EMS unit must be put into the bypass mode for the current to flow into the trailer. I know I was getting power because the fridge switched to AC mode and the microwave lights came on. The electrical outlet in the trailer also became useable.

The problem that I had was even after running the generator for a full two hours, the battery charge % only initially went up by 10 % and then started going back down, even with the generator still running. I tried the next day, but this time I made sure that the fridge was switched to the gas mode and all lights, fans and other items that could possibly be drawing power were turned off while I was running the generator. To my surprise, the same thing happened again… a small increase in the % of battery charge followed by a decrease. When my solar panel is in full sun, 2 hours would be more than enough to recharge my batteries. Am I doing something wrong or is there something in the trailer that is not working properly?

Thanks in advance,

Ivan

[Vermilye]

Originally Posted by Ivan Desjardins

Hello to all of you:

I bought the 17A last year and had a solar panel installed on the roof of the unit. Up to now, the solar panel has always been able to recharge my batteries (two 6v deep cycle batteries that came with the trailer) and there was no need to use my generator. This week was the first week of camping where I experienced sufficient cloudy and rainy conditions to justify using my small Honda 1000i generator. When the batteries were down to 50%, I plugged my electrical cable into my generator and ran it for 2 hours. I am aware that the EMS unit must be put into the bypass mode for the current to flow into the trailer. I know I was getting power because the fridge switched to AC mode and the microwave lights came on. The electrical outlet in the trailer also became useable.

The problem that I had was even after running the generator for a full two hours, the battery charge % only initially went up by 10 % and then started going back down, even with the generator still running. I tried the next day, but this time I made sure that the fridge was switched to the gas mode and all lights, fans and other items that could possibly be drawing power were turned off while I was running the generator. To my surprise, the same thing happened again… a small increase in the % of battery charge followed by a decrease. When my solar panel is in full sun, 2 hours would be more than enough to recharge my batteries. Am I doing something wrong or is there something in the trailer that is not working properly?

Thanks in advance,

Ivan

I posted an answer in your question in the admin forum; I copied it here where it makes more sense.

If you have the typical WFCO 55 amp converter, one would expect it to fill the batteries quickly. Unfortunately, the WFCO brand of converter is notorious for not going into the bulk stage where it provides its full current output. In the absorption stage it may only produce 8 - 10 amps.

You also have a limited output of around 8 amps @ 120V with a 1K generator. You might find that getting the WFCO to go into the bulk stage will overload the generator. The specifications for the WFCO 8955 show 940 watts output, and with a poor power factor & other losses, it it will likely draw more than 1000 watts if it actually goes into bulk and produces 55 amps output.

Some have had success getting the WFCO converter to go into the bulk stage by putting a heavy load on the 12V system for a minute or so.

Another point - even with a well designed converter, lead acid batteries will only charge to around 80% in the bulk stage. After that the converter will switch to the absorption stage, limiting current to well below the converter's maximum output. If it stayed at the full output for the last 20%, it would "boil" the electrolyte and overheat the batteries. That points out one of the advantages of lithium batteries - they stay in the bulk stage until close to 98% of a full charge.

[Ivan Desjardins]

Thanks for the information Jon, that was very helpful.

[Lanark Camper]

Jon’s advice is excellent.
I have not been impressed with the converter supplied with our 17B. You may be better off with a quality battery charger plugged into your generator. There are some very good programable charger’s available now.
The plan should be to charge the batteries to 80% or so in the morning, then the solar should finish them up over the rest of the day.
So far our panel has been able to keep up with our electrical needs.
Good luck, Bob

[Iowa Dave]

The little bit bigger 2200 will charge the battery pretty effectively. I used ours for air conditioning last summer and when I was not needed ( in the mid morning till about 2 PM my son in law used it to charge his group 27 12 volt battery he has on his Boler. He said it brought him up to an acceptable level in about 3 hours. They “sip” gasoline so the battery charge is not that expensive and allowed them to charge laptop batteries etc. as well as charge the battery.
I don’t have any real numbers but he was very happy to be able to run a 12 volt fan on a hot night. He also has a suitcase solar. I remember having a 1300 watt Honda back in the eighties.
Great for running a pitching machine, not so good powering a contractor grade circular saw cutting down full dimension 3X10s. Had to get something more robust from the park operators.
Iowa Dave

[Ivan Desjardins]

Thanks Bob:

If you don't mind answering the following two questions:

1- Would I have to disconnect my batteries from the trailer electrical cables before hooking up the charger to my batteries or can I simply leave them connected and just hook the charger clips onto the positive and negative terminals . I have two 6v batteries connected in series.

2- When buying a battery charger that I will plug into the Honda 1000 Generator, how many amps should the battery charger have (1,2, 5 amps??)

thanks,

Ivan

[Ivan Desjardins]

Thanks Dave

[Rossue]

[QUOTE=Vermilye;422319]I posted an answer in your question in the admin forum; I copied it here where it makes more sense.

What they Hey is the "admin forum"?

My experience with my 17B/dual 6V was when it was down to 50% it took loooong time to recharge on AC. Would advise charging sooner.

[CharlesinGA]

My Bigfoot has the excellent Parallax power center (Its all metal, I love that) but when I bought it the first thing I did was look to see what converter was in it, and someone in the past had replaced the original Parallax converter (good move) with a WFCO WF9845 (bad move) mounted in a special tray WFCO makes to fit into the Parallax panel (the WFCO 9845 is actually a deck mount unit that happens to fit in the space where the original converter was located. I checked the voltages and tried different scenarios and it refused to go to bulk charge. Out with the WFCO China junk and in with the Progressive Dynamics 4645.

Charles

[John in Santa Cruz]

Originally Posted by Ivan Desjardins

Thanks Bob:

If you don't mind answering the following two questions:

1- Would I have to disconnect my batteries from the trailer electrical cables before hooking up the charger to my batteries or can I simply leave them connected and just hook the charger clips onto the positive and negative terminals . I have two 6v batteries connected in series.

2- When buying a battery charger that I will plug into the Honda 1000 Generator, how many amps should the battery charger have (1,2, 5 amps??)

thanks,

Ivan

you can leave them connected to the trailer when charging.

for dual golf cart batts, you can charge as high as 50A, but a decent 25A smart charger such as a NOCO GeniusPro 25 would do nicely. Due to how lead acid batteries have to be charged, to get a 100% charge pretty much takes at least 12 hours.

frankly, I'd consider replacing the power converter in your existing WFCO unit with a PD4645.. these are bolt in, with just 5 wires to connect (ac black, white, green, DC black, red). They are much more effective chargers than the WFCO, and in lead-acid mode have a 'boost mode' for fast charging while on a generator for a few hours. The new ones have a jumper for lithium batteries which can be charged a lot faster than lead-acid, my PD4655 outputs a steady 50 amps until the lithium batts are 95% fully charged, then 14.4V til they are topped off and self-equalized.

[Lanark Camper]

Originally Posted by Ivan Desjardins

Thanks Bob:

If you don't mind answering the following two questions:

1- Would I have to disconnect my batteries from the trailer electrical cables before hooking up the charger to my batteries or can I simply leave them connected and just hook the charger clips onto the positive and negative terminals . I have two 6v batteries connected in series.

2- When buying a battery charger that I will plug into the Honda 1000 Generator, how many amps should the battery charger have (1,2, 5 amps??)

thanks,

Ivan

Ivan, you can leave the trailer connected to your batteries while using an auxiliary charger.

I suggest you deal with a company like Battery World, https://buyabattery.com/ for advice on charger sizes, programmability etc. they could also test your batteries capacity. I don’t know this particular company but I deal with similar battery specialists and found them to be very helpful.

Bob