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 > Lithium Batteries

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msmith1199

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Posted: 09/17/20 05:30pm Link  |  Quote  |  Print  |  Notify Moderator

Ok, well this subject took off since I started it. Hadn’t been back in a while so I read some of the newer replies but not all. So I’ll get on to my next question. I went ahead and bought two Battle Born 100AH lithium batteries. $2100 for both if anybody cares. There were some cheaper alternatives out there, but the Battle Born factory and factory sales center is a few miles down the road so I opted to pay a couple of extra bucks to have them close by. And they had some mock up batteries at the office so I was able to go down there and use their mock ups to make sure they would fit in my battery compartment. They fit.

So I found out my converter actually supports Lithium batteries with just the flip of a switch. So once I install the batteries just flip the switch and we’re good. But, the lady who I bought them from, said that since my RV has a 230 amp alternator and that need to install a DC to DC charger to bring it it down to 100 amps for charging the battery. She seemed to know what she was talking about but I don’t know her background so I thought I’d ask here. Anybody else that switched to lithium install the DC to DC charger? I know the motorhome is already set up to charge the house batteries from the alternator but I’m assuming the lead acid batteries don’t need this DC to DC charger and can take all the power from the alternator? I’m not an electrician so I’m not sure how this stuff all works.

* This post was edited 09/17/20 06:07pm by msmith1199 *


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msmith1199

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Posted: 09/17/20 05:35pm Link  |  Quote  |  Print  |  Notify Moderator

01tundra wrote:

Bert the Welder wrote:

And just for the sake of wondering.... for temps that cold, could some sort of heat pad, blanket or bag not be used to keep the lith's warm enough to function properly? (I'm picturing a Domino's pizza delivery electric warmer bag) Or, perhaps, would moving your batt's inside your camper living space. Obviously if you go with the SiO2, your good to go. But for those with Lith's already, are there options if they are occasionally stuck in temps that cold?



Or mount them inside the trailer instead of outside, which eliminates the low temp operation issue and increases security. Or buy one of the brands that has internal heaters or use the heating pads offered if you'd prefer to keep them outside. The entire temperature argument is a non-issue in my opinion.


It’s not relevant to my original question as if it’s 40 below outside, you won’t see me there! I do live in Nevada but the lowest temp I’ve even seen here is about 12 to 15 and when it’s that cold the motorhome is comfortably stored away in its indoor storage.

BFL13

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Posted: 09/17/20 05:47pm Link  |  Quote  |  Print  |  Notify Moderator

She wants to keep the charging to 50 amps each so 100a for the two. Meanwhile there have been posts that the alternator will fry from trying to charge the thirsty Li house batts.

Sounds like the way to go is disconnect/disable alternator charging and just leave in the Aux start from the house feature if ever needed.


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msmith1199

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Posted: 09/17/20 06:07pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

She wants to keep the charging to 50 amps each so 100a for the two. Meanwhile there have been posts that the alternator will fry from trying to charge the thirsty Li house batts.

Sounds like the way to go is disconnect/disable alternator charging and just leave in the Aux start from the house feature if ever needed.


So is it likely that in most motorhomes there is no DC to DC charger and the alternator is just wired directly to the house batteries and charges them with whatever output it has?

3 tons

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Posted: 09/17/20 07:28pm Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

She wants to keep the charging to 50 amps each so 100a for the two. Meanwhile there have been posts that the alternator will fry from trying to charge the thirsty Li house batts.

Sounds like the way to go is disconnect/disable alternator charging and just leave in the Aux start from the house feature if ever needed.


X2, 50a per battery is a conservative rate that’ll never but your pricey batteries at any risk, and the actual receptivity rate will typically be even lower (depending on SOC) ..Due to Li’s high receptivity rate, if you have a decent amount of solar (as a fellow Nevadan - lol) you’ll likely not get much value outta the vehicle’s alternator anyway... I would however be interested to know what brand or model of switchable charger your rig has - would be nice to understand the Li charger’s stated algorithm...Of the one’s I’ve considered, most tend to be of the ‘one size fits all’ variety...JMO



Congrats,

3 tons

msmith1199

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Posted: 09/17/20 09:15pm Link  |  Quote  |  Print  |  Notify Moderator

Not being an electrician I don’t completely understand your question. Are you asking about the existing Converter in the motorhome? If so it’s a PD4560 by Progressive Dynamics. It’s basically the entire 110 volt and 12 volt electrical panel all in one with the converter built into the panel. The one I have has the switch to turn it to Lithium mode. Per their website having that switch is an option. So luckily for me Nexus ordered the panels with that option. So I’m good for charging the batteries with the generator or when I’ve got 110 power. But I have a residential fridge so I want the batteries to charge from the alternator too because on long drives there will always be a draw on them otherwise. I understand it may not fully charge the batteries, but as long as it keeps them going.

3 tons

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Posted: 09/18/20 09:25am Link  |  Quote  |  Print  |  Notify Moderator

msmith1199 wrote:

Not being an electrician I don’t completely understand your question. Are you asking about the existing Converter in the motorhome? If so it’s a PD4560 by Progressive Dynamics. It’s basically the entire 110 volt and 12 volt electrical panel all in one with the converter built into the panel. The one I have has the switch to turn it to Lithium mode. Per their website having that switch is an option. So luckily for me Nexus ordered the panels with that option. So I’m good for charging the batteries with the generator or when I’ve got 110 power. But I have a residential fridge so I want the batteries to charge from the alternator too because on long drives there will always be a draw on them otherwise. I understand it may not fully charge the batteries, but as long as it keeps them going.


So I went to the PD site but did not see any algo specifics on the 4560

https://www.progressivedyn.com/lithium-battery-power-centers/

When PD ‘suggest’ they’ve worked with several LiFePo4 manufacturers, this simply means that they’ve decided on a constant ON 14.4v charge methodology (with no programmability, the easy way out $$), but understand that Li’s don’t like to be stored for an extended period in this way - in fact, in some of their other chargers 14.4v is stated to be an equalization mode (i.e. every 21hrs/15 min for lead acid batts).

So I’ll just assume the 4560 has the same algo as their Li 9100-L series which simply remains at a constant 14.4v throughout the entire charge and never shuts down - ordinarily not an ideal plan IF left continuously on, but since you have a compressor refer (duty cycle enters the pic) I would think that this concern becomes a lesser issue...JMO

My main grievance with these ‘so called’ LiFePo4 chargers is their lack of programmability, thus I just stayed with my 9245 (with charge wizard in 14.4v boost) and (when on shore power) just added a simple battery post disconnect to prevent extended charging....

3 tons

Itinerant1

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Posted: 09/18/20 10:51am Link  |  Quote  |  Print  |  Notify Moderator

I remember reading a thread on another forum that the person added a on/ off switch on the dash so that the charging to the batteries could be turned off during the drive so not to hold the batteries at a high voltage once it was charged. I don't remember all the exact details.


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pnichols

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Posted: 09/18/20 10:54am Link  |  Quote  |  Print  |  Notify Moderator

3 tons,

I'm wondering about your last sentence above.

Doesn't your 9245 automatically drop back to a 13.XX volt float voltage at some point when it's charging batteries?

I believe that LiFePo4 batteries have a recommended float voltage such that they can be left hooked up full time to a converter/charger that eventually settles at their float voltage, just like any other type of battery.

For instance Battle Born LiFePo4 batteries can be floated at 13.6 volts or lower indefinitely according to their specifications, so you shouldn't have to disconnect them from your 9245 when it drops down to it's float voltage.

As for when driving with the engine alternator hooked up to the batteries, after just a few minutes when things are warmed up, our RV's alternator settles in around to the mid-13's in voltage, anyway.


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3 tons

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Posted: 09/18/20 11:00am Link  |  Quote  |  Print  |  Notify Moderator

Itinerant1 wrote:

I remember reading a thread on another forum that the person added a on/ off switch on the dash so that the charging to the batteries could be turned off during the drive so not to hold the batteries at a high voltage once it was charged. I don't remember all the exact details.


And a possibly more temporary option might be to simply pull the trailer power supply fuse (normally supplies the 7 pin plug) inside the under-hood fuse box - there’s usually a printed fuse diagram just inside the lid...

3 tons

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