Renogy 100ah Lithium bat $499

[Tightwadted]

OK getting the pieces to setup 4 Renogy 100 Ah batteries, and I read here about a possible problem with the alternator on my truck, having the umbilical cord attached so I have lights, brakes, etc. will the 12V connection through that cord cause me a problem? do i need to disconnect it? just trying to make sense of it all, TIA

[twinboat]

Originally Posted by RPrince

Ok, that makes sense, and is alot easier than what I thought! By doing this, the charging from generator and shore power will be unchanged?

Randy

The change is that your chassis battery will not be charged by the house battery bank charging systems. The B to B charger is one way.

If your generator starts and runs from the chassis battery, it will run down that battery and the generator will shut off.
Any parasitic draw will run it down too.

[RPrince]

Ok, thanks for clarifying the charging process.

If I put a switch in the small wire on the BB instead of disconnecting it completely, would that work for situations where the MH engine isn't running (Gen charging and shore power charging) and keep the chassis battery charged if the switch allowed the BB to work as it does now?

Randy

[twinboat]

Yes, that can work, as long as the house battery lithium charger voltages are in line with the chassis battery requirements.

[RPrince]

Thanks Twinboat. Your feedback has really helped me understand what needs to be done with this upgrade.

Randy

[papagyo]

Hi All,

I too switched to a 180ah lithium battery, I disabled the current BIM and used the ignition signal from it to turn on a small 20amp dc to dc charger I installed. So now my alternator only charges the lithium at a max of 20 amps. The renogy dc to dc charger has a lithium setting.

[mfreyder]

it is said that the internal resistance of lion batteries is very low, so low they are as a short circuit to the alternator. Choosing the DC to dc conv is a good idea. Smart move.

[packnrat]

Originally Posted by RPrince

If someone can confirm that this BMI device will indeed protect the alt from overheating, I would appreciate comments on how to connect it, or what I really need to do if this is not correct. This is the only piece of the conversion that I am not sure about.

Randy

the bmi is only to protect the battery.


you need more "stuff" to protect your alt.


is this the only way you have to charge up your battery bank?


better off with six solar panels set up for 24 volt battery bank but the solar would be down loading a bit more (like 40A) to charge up the system. (its a wire thing here, and save $100's on a charge controller).

4-6 12 volt batteries set up to be at 24 volts. then a converter (top of the line under $50.usd) to drop to 12 volts to power such in your rv. a 2000W, 24 volt inverter will handle all your 110 ac needs. (up to battery supply)

not sure how to do a 24 volt genny, most are only 12 volt. but this system would NOT be hooked to your motors alt and batteries.

but from the question, sounds like your in a class A,B,or C rig. some motors are made to deal with a second alt, maybe a second alt to go with a 24V -min 40A dc,or adjust the second alt to not change its ac to dc. just run the ac straight to the battery system. but only for the coach usage.

[ereck.po]

I must be missing something. I’m not understanding this whole thread; Li is not that exotic, is it? I don’t know what is BIM or LIBIM is or what the alternator needs protection from.
I’ve been running Lithium batteries for 6 years now and did nothing but hook it up. So I’m missing something. My coach is 21 years old and so is the inverter/charger, it doesn’t have a lithium mode. The alternator is controlled by a voltage regulator, as the voltage rises the current is reduced automatically because the regulator thinks the battery is lead acid. I did put a switch on the battery combiner so I can turn it off; someone said that was a must? Every time I start the engine, the boost solenoid combines the batteries automatically anyway.
I did finally, after 4 years, put a Balmar external regulator on the alternator. It’s fully programmable and has sensors for the battery and alternator temperature. But I honestly see no change. I installed the Balmar to protect the battery by not charging it when the temps are too high.
It seems to me that the industry is make problems up to sell more things.

[jabassmaster]

My four golf cart batteries fromSamsclub was an easy drop-in install last year and on sale for total price of $320 plus tax. That's less than one LI battery.

[promaster18]

You cannot connect your lithium battery to your alternator with your vehicle battery as the lithium charges to 14.4 or 14.6 volts . I have a relay and switch to temporarily connect the lithium battery to the vehicle alternator . The lithium battery when connected without vehicle alternator charging will deplete your vehicle battery hence the temporary connection via switch and relay .

[RPrince]

I have a class A Monaco with 4 6v Trojan lead acid batteries. I'm about to replace the old batteries with 4 100ah Li batteries.
From what I understand, the Li batteries will let the alt on the motorhome max out on amps and possibly damage the alt. The current plan is to install a Victron DC to DC charger in line to reduce the amps from the alt to the Li batteries when the engine is running to prevent burning it out.
The coach (Li) batteries will be charged from the 8000kw Onan or shore power thru Magnum 2800 invertor/charger, and/or 1200 watts of solar thru Midnite Classic 150 charge controller, with only about 30 amps from the alternator. It looks like the chassis battery will only get charged when the engine is running, which is different from the way it is currently set up.
My question was how to retain correct charging capabilities of both chassis and coach batteries without damaging the alternator when installing Lithium coach batteries.

Randy

[ereck.po]

Originally Posted by promaster18

You cannot connect your lithium battery to your alternator with your vehicle battery as the lithium charges to 14.4 or 14.6 volts .

I've been doing it for years, with a 1200amp combined LiFePo battery. 14.4v max is the voltage that is put out by chargers and alternators to charge Lead batteries also. Remember that the ability of the battery to take a charge is NOT the controlling factor, it’s the voltage. I'm picking up a difference though, My system has no lead batteries, my starting battery is Li also, it starts a 8.3 L Cat.
The recommended rate of charge for my battery is less than .3CA or 360 amps; the max recommended charge rate is 3CA, 3600 amps. My 160 amp Alternator works just fine thank you, and has for 6 years the max charge I’ve seen is 120a.

[ereck.po]

https://www.youtube.com/watch?v=tAuPfgZgXec

Here is a youtube video of a guy combining Lead and Lithium batteries in spite of the nay sayers. He explains it very well and he makes good sense. He is talking about his boat, but still batteries.