Lithium battery plug and play?

[jcussen]

Believe the battery manufacturers say little, with the possible exception of battleborn who usually recommend a LI-BIM or a DC-DC charger, except for a small system, is because they are not responsible for an alternator problem. Have followed a lot of AM Solar lithium installations and they appear to install DC-DC chargers in all their systems. They have been in business quite a while and have a lot of experience, so would rather rely on their collective knowledge rather than a one time example.
To RVingNow. 30 amps for 6 hours driving is 180 amp hours back into your batteries. I have dry camped with 600 a/h for several days and not used that much. Of course, having solar as well will help greatly. Don't forget lithium, unlike lead acid will take 100% of the charge whether from your converter/inverter, alternator, or solar until almost full.

[CountryFit]

Originally Posted by jcussen

Believe the battery manufacturers say little, with the possible exception of battleborn who usually recommend a LI-BIM or a DC-DC charger, except for a small system, is because they are not responsible for an alternator problem. Have followed a lot of AM Solar lithium installations and they appear to install DC-DC chargers in all their systems. They have been in business quite a while and have a lot of experience, so would rather rely on their collective knowledge rather than a one time example.
To RVingNow. 30 amps for 6 hours driving is 180 amp hours back into your batteries. I have dry camped with 600 a/h for several days and not used that much. Of course, having solar as well will help greatly. Don't forget lithium, unlike lead acid will take 100% of the charge whether from your converter/inverter, alternator, or solar until almost full.

Agreed, don't take an unnecessary risk.

My system is a little different though - one jumbo lithium pack for both house and chassis. My alternator cables are for bi-direction of current flow - at the engine start, it draws a big load; when engine runs, it charges battery. All of known devices out there such as Sterling Power, Balmer, dc-dc charger won't work (or at least I haven't found one working for me; let me know if you know). I designed a circuit board to automate the solenoid operation which worked for a few months then burned out. Now I'm stuck with a manual switch... lol.

[SV K]

Hi Countryfit,

What problems did you have with the Balmer? I ask as my first Lifepo4's bus is still charging fine after 6 years. Haven't decided yet in going that route again on my current coach or DC-DC or...

As a side note just ran into a gent we helped install Po4's and he runs without any control, BUT, that is with an oil cooled alternator. Says it charges at 250amps, hits target voltage and backs off. Not advocating this, just throwing it out there for those with big batteries and oil'd alternators.

[CountryFit]

Originally Posted by SV K

Hi Countryfit,

What problems did you have with the Balmer? I ask as my first Lifepo4's bus is still charging fine after 6 years. Haven't decided yet in going that route again on my current coach or DC-DC or...

As a side note just ran into a gent we helped install Po4's and he runs without any control, BUT, that is with an oil cooled alternator. Says it charges at 250amps, hits target voltage and backs off. Not advocating this, just throwing it out there for those with big batteries and oil'd alternators.

SV K, I remember we have a similar setup - 1200ah with Thundersky cells; and a big size of solar panels... Seeing them working together tirelessly, it's fun, isn't it?

But I have a unique scenario I had to deal with... Recall the basics on Class A or C - there is a house battery pack and a chassis battery pack. When we talk about lithium, we are mostly talking about the stories on the house battery side. In my case there isn't a chassis battery, the lithium pack handles the demands from both house and the chassis. That's where it gets complicated.

I have four sets of cables to the battery - the set used to be connected to the chassis battery, let's call it S1; a set for house, say it S2; a set for inverter S3, and the last set for solar S4. I'll leave S3 and S4 alone as we are interested in S1 and S2 only.

S1 needs to be connected when engine is starting or when engine isn't running because the coach steps are on it. S2 is required for interior 12v power. Once engine is started, the alternator will provide the power to both locations (so I could cut them off). On S1, I can't add a device(s) to regulate the charging as the back flow for starter to work is in place. That was the reason I said "Sterling Power, Balmer, dc-dc charger won't work".

My initial design was cutting off both S1 and S2 after engine's up. I don't really need the charge from the alternator because my 2750w solar offers enough power on the road unless it rains all day long and days in a row. I installed a rocker switch in cockpit to turn both S1 and S2 on remotely just in case. It worked. But the solenoids I had gotten were cheap chinese made, one of them was burnt out in a few months :-). Before I can find a good quality solenoid (12v 200a continuous duty normally-closed) I had to manually turn it off after engine is started.

Safe travels!

[wanderso]

Originally Posted by jcussen

To be safe, would go with a good dc-dc charger, not only will it protect your alternator, it will also provide the proper charge voltage to bring your lithium batteries to 100%. I use this one,
https://www.solar-electric.com/victr...87&utm_source=
Lithium batteries require a constant voltage of 14+ volts to charge properly, so when you upgrade your inverter, and buy a solar controller, look for ths ability.

I see that you chose the non isolating model. In most motorhomes of my vintage (2004) designed for flooded cell lead acid, the setup runs cabling from the coach battery and charging system and includes a battery isolator. They also include a switch on the dash that engages the house battery to act as an emergency starter battery / combiner if the coach battery is dead. There is no special DC to DC charger in the setup, instead it simply taps into the engine alternator. It also may have a house battery disconnect switch for when stored/not in use. Mine does, with a relay-activated disconnect switch.

I’m looking at updating to lithium. If your coach is similar to above and had an isolator when it left the factory, did you leave your existing wiring as-is between coach and house, adding this DC to DC charger near the battery bank? Or did you do something else?

I have to upgrade the 12v converter charger to be lithium compatible as well. Due to the power center being integrated, I have to use this setup for lithium or attempt to add something separate. Yep I know that WFCO is not well regarded.

https://wfcoelectronics.com/product/wf-8950l2-mba/

[jcussen]

Originally Posted by wanderso

I see that you chose the non isolating model. In most motorhomes of my vintage (2004) designed for flooded cell lead acid, the setup runs cabling from the coach battery and charging system and includes a battery isolator. They also include a switch on the dash that engages the house battery to act as an emergency starter battery / combiner if the coach battery is dead. There is no special DC to DC charger in the setup, instead it simply taps into the engine alternator. It also may have a house battery disconnect switch for when stored/not in use. Mine does, with a relay-activated disconnect switch.

I’m looking at updating to lithium. If your coach is similar to above and had an isolator when it left the factory, did you leave your existing wiring as-is between coach and house, adding this DC to DC charger near the battery bank? Or did you do something else?

I have to upgrade the 12v converter charger to be lithium compatible as well. Due to the power center being integrated, I have to use this setup for lithium or attempt to add something separate. Yep I know that WFCO is not well regarded.

https://wfcoelectronics.com/product/wf-8950l2-mba/

I actually mounted the dc-dc charger in the same place as the isolator when I removed it. Alternator and start battery combined on one terminal and existing cable from house battery to charger on the other. And of course a common ground for both banks, the frame. I have a boost solenoid that will combine both banks in necessary but don't normally use it.