AC Trickle Charging the House Battery - NOT for Storage

[C42]

"When you mentioned hooking up a charger to your generator I had a question. Was this the rig's built-in generator or an external one? If built-in you didn't need to hook up a charger as your converter should put out more than an external charger. My converter is rated 60 amps. I have some external battery chargers that only go up to 15 amps. If you had a garage type charger then it may put out more."

She mentioned in response to a previous post it was a Champion and fuel usage info. Quick search shows -2500-Watt Ultralight Portable Dual Fuel Inverter Generator (gas/propane) matches that info.

Actually, my generator is a Champion 2000w inverter, gas-only guy. Just a work horse, sips gas at 1 gallon for 11 hours at 25% load and so quiet, most people don't realize it's running. Just love it.


The battery charger/maintainer I used was a generic 15amp device.



Apparently, to convert the house battery to Lithium, I will need a converter that is built for Lithium. (Fortunately, I have one (WFCO 45 amp converter, model WF-9845) for which there is a compatible upgrade that adds Li capability, according to etrailer - but I am confirming that with the manufacturer. A DC-to-DC charger is also needed so I don't blow the alternator out. Again, confirming with the mfr today. I'll report back with what I find out.

 

[billcf7]

Do not believe the stories about the DC leakage and dirty DC. Garbage comments.
A trickle charger does not correctly charge low batteries. Your batteries may be sulfated and that charger can’t do anything for that. I suggest you take them to some place that will charge and test your batteries. Or buy a charger that will de-sulfate a battery.
Draining batteries below 11 volts does damage to the battery, so I am told. They may not be any good now.

Draining lead acid batteries below 12 volts starts doing damage. A lead acid battery at 12 volts is about 50% discharged
https://www.rvtechlibrary.com/images/voltchart.gif

 

[Gregory N Whitis]

Moochdocking on city street

What is the best way to light up your TT while parked on a somewhat busy street at night. I dont want to plug in at a friends house with 110v nor do I want to run a generator. Just need the marker parking lights illuminated. Don’t want to kill my TV battery either. How about hooking up a 5amp trickle charger to TV battery and use my buds wimpy extension cord attached to house current? Suggestions appreciated.

 

[C42]

Hi all -


The battery charger/maintainer was a 15amp Schumacher. I try not to use the engine to charge since it is so fuel-expensive...(also, I didn't think the on-board generator would charge the house battery?)


Regardless - I have a new LiFePO4 battery (12v, 100aH) on the way along with a new converter that is Li capable. A battery monitor is also in the package.


According to Randy at bestconverter.com - a DC-to-DC alternator is not necessary. He says he just doesn't believe they are needed and doesn't even carry them. Also, no wiring upgrade will be necessary. The new battery will fit in the same footprint and weigh half of what the SLA currently does. In the future, I will upgrade with solar as well, but in the meantime will use a portable power generator as back-up.


I will keep you posted on its install and the performance as it goes...


Thanks very much for ALL of the wonderful insights and for sharing your experience and knowledge!!! The people in this forum and simply the BEST!

 

[videoarizona]

Please understand, lithium batteries do not need a special charger for normal usage between 80% and 20%. If you charge no more than 80% and discharge no father down than 20% you will get the most cycles out of a lthium. Look it up. Most lithium manufacturers will say that somewhere. Example: 2000 cycles for 100% DOD. 4000 cycles for 20% DOD. Depth Of Discharge.

What lithium batteries do need is higher voltage to be able to balance the cells. This does NOT need to be done at every charge cycle. Rather, once in a while.
I solved that problem by buying a 20 amp lithium charger. When it's time for me to balance the cells, I fully charge battery then connect up the little charger that finishes the job.

I learned this after changing out my WFCO 55amp regular charger/ converter main board to a WFCO auto detect. I could have saved myself the money if I had done my homework.

Don't get me wrong. The new WFCO unit works great. But it wasn't really needed. The normal charger will charge the lithiums to about 80% which is where I want it to be to get the most life out of it.

So... Having used my 200 amp lithium for a year now on both chargers, I can say I didn't need to change out my converter/charger main board in the WFCO power center. I already had the 20 amp lithium charger for another use.
Live and learn.

By the way, the best thing I did was move my battery inside closer to the power center. I left the battery cables that went to the tongue to be used for a solar charge connection or to be able to connect up my Viair portable air compressor. This necessitated a change of cables to 6gauge since lithiums will handle a much faster charge current. The crap tiny cables that came with trailer would not handle 55amps of charge current which I get now. Lead acids do not take large current loads!

So...I ended up doing some additional wiring, adding 200amp fuse to battery, added buss bars for multiple connection points expansion, added a battery shut off switch, etc..

 

[CayennePepper]

I lost almost 100% battery voltage overnight two nights ago in my house battery so yesterday I hooked up the trickle charger to my generator and then to the house battery and got it back to 100%. I used it minimally last night - but it was down to 11% this morning and throwing an error code to my Norcold - the "E" code indicating it wasn't getting enough DC power to the controller.



While I research the best battery to use for a house battery, can someone tell me if trickle-charging the house battery from an AC source is going to freak out (damage) any of my DC appliances? I have already read about "DC leakage" causing controllers to balk when they detect "dirty DC" - I assume coming from an AC source...but this is pass-through current. AC trickle charger -> House Battery -> DC appliance...


If there is a better way to do this - please let me know...! In the meantime, there is not ONE AGM battery to be found in my entire county...


Thanks in advance -

I have over 60 years experience with lead-acid car batteries. Others who posted discharging a lead-acid battery too far are correct, it can cause sulfation damage. I worry if a weak battery with nothing connected (ie. no load) reads anything less than about 11.5 volts. However, all may not be lost. Some years ago I heard about "smart" chargers. I own several Porsches and dealers sell a Porsche branded charger for the outrageous price of about $250. Many owners swear by this charger for maintaining batteries during winter storage.

Forum research told me they are made by a company called "CTEK" and the exact same model is available from them for about $80-90. I bought one on Amazon, my model is MXS 5.0. I have used this charger to bring back to life several "dead" batteries that would not accept a charge from a conventional charger. The CTEK has a desulfation and recondition mode. It can take a week or ten days to complete the cycle but those batteries fully recovered. A nice thing about a smart charger is they can be left on full time without over charging the battery. I recommend you get a smart charger and use it from time to time (I do this annually) to recondition your battery(s). There are other good brands like NOCO Genius chargers. Do some research and you will find something that works well for you.

Lastly, your battery should not be discharging so rapidly. Have you tested the current draw on each of your 12 v circuits with a multi-tester? I suspect you have a circuit that's drawing an unusal amount. When I store my RV trailer without being connected to shore power, I noticed the battery was down quite a bit after just 4 days although I had nothing turned on. No 12 v devices had been used such as water pump, awning, lights etc. Some testing revealed that the propane detector draws about 0.3 amps. I pull that fuse when I can't be plugged in to 120 v power for an extended period of time. This of course is not something you should do if during that time you plan on using propane for the water heater, stove, fridge etc.