LifePo Shorepower Charger

[Ronin]

Hi All,

I recently installed a Renogy 100ah LiPo battery and dc-dc charger. I plan on disconnecting the battery at 50-70% charge while on an extended vacation. I'm looking for an inexpensive home charger to charge the battery when I return. Any recommendations on a charger? Or why I shouldn't do this? I don't have shorepower hookup from my camper and use a 120watt portable solar panel.

 

[Utah]

I have a similar approach when not using my camper for extended periods.
Victron makes an IP65 charger (12V 15amp version) that works well for this purpose. Inexpensive? NO.
I would not mess around with a charger that is not configurable to the battery manufacturer’s recommended charging parameters.

 

[rubberlegs]

We also disconnect a day or two before returning home, so we end up with 50-70% charge.

We have our old lead-acid battery shore charger still installed, and it will charge the battery, but extremely slowly. At first there were a lot of amps going in, but as it got to higher state of charge, it slowed down until there was barely an amp going into the battery. It took more than 30 hours. I'm comfortable using it though, since the voltage is lower than the battery manufacturer recommends.

Or we charge with solar the day or two before a trip. We have a 100W portable, similar to yours. Unfortunately, we get a lot of cloudy weather at home...

Or... it only takes two hours at 25 amps to charge it another 50% while driving. That consumes more gas though. I did a quick estimate:

(50Ah) * (13V) = 650 Wh energy to charge up battery 50%

gasoline has 33,700 Wh per gallon
let's say conversion via alternator is 25% efficient, so you need 650Wh / 25% = 2600 Wh gasoline

2600/33,700 = 0.1 gallons of gas.

I wonder if I messed up something, as this seems low. But the point is that it's not a LOT of gasoline to charge up your battery.

So... maybe do nothing? Just drive it?

 

[Jon R]

Your calculations are correct. Using your 25% efficiency assumption I get 0.08 gallons. A gallon of gas has a lot of energy.

 

[Ronin]

Thanks for the input. This is all new to me and I just want to be able to start off a trip with a fully charged battery. Guess I'll drive down the coast, see where the SOC ends up and top off with my solar if necessary.

 

[CPT Davenport]

I use a Norco Genius 10 for shore tie charging. It does a great job and is reasonably priced. In the last power outage I used my FWC 206ah battery to keep my house refrigerator going and most other household lights and appliances. I would use the battery at night then run the generator for a couple hours during the day with the Norco to top off what the 310 watts of solar (175w fixed + 135w portable) couldn't keep up with on the rainy days.

You should look into a fixed roof solar panel as well as your portable. The 175w on my camper keeps up a great majority of the time under sunny to partly cloudy days on trips.

Also I have not had any issues running my lithium down to 30% or even less.

 

[Ronin]

I have a similar approach when not using my camper for extended periods.
Victron makes an IP65 charger (12V 15amp version) that works well for this purpose. Inexpensive? NO.
I would not mess around with a charger that is not configurable to the battery manufacturer’s recommended charging parameters.

The IP65 looks like a great charger and is comparable in price to the Renogy. I don't know if I'm needlessly concerned but will the Victron will activate the battery in case of a low temp shut off? I'd like to think that my MPPT charge controller would automatically re-active the battery but I haven't been able to confirm this with Renogy.I often camp in the winter where outside temps can hit the low 20s.

 

[Ronin]

I use a Norco Genius 10 for shore tie charging. It does a great job and is reasonably priced. In the last power outage I used my FWC 206ah battery to keep my house refrigerator going and most other household lights and appliances. I would use the battery at night then run the generator for a couple hours during the day with the Norco to top off what the 310 watts of solar (175w fixed + 135w portable) couldn't keep up with on the rainy days.

You should look into a fixed roof solar panel as well as your portable. The 175w on my camper keeps up a great majority of the time under sunny to partly cloudy days on trips.

Also I have not had any issues running my lithium down to 30% or even less.

A fixed solar panel is in the future, especially here in the PNW. I used to live in a pine forest and my rig was constantly covered with pine sap, pollen and dust not to mention falling branches, so I didn't want the chore of having to clean a solar panel. During recent fall trips to the No Cascades and Olympic Peninsula there was virtually no sunlight and using the furnace really challenged my old AGM battery which is why I upgraded to Li.

 

[Vic Harder]

The IP65 looks like a great charger and is comparable in price to the Renogy. I don't know if I'm needlessly concerned but will the Victron will activate the battery in case of a low temp shut off? I'd like to think that my MPPT charge controller would automatically re-active the battery but I haven't been able to confirm this with Renogy.I often camp in the winter where outside temps can hit the low 20s.

Are you asking if the Victron will respect the low temp shutoff, the answer is - it depends. You can use the relay function in the BMV to control stuff by temperature.