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New questions about lithium batteries


saflyer
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I’m getting closer to installing my LiFePO batteries. I just read something I hadn’t thought of before. Actually, in a way the subject did come up. Previously, the issue arose that lithium house batteries may not be very useful to help the chassis batteries if they are too low to start the engine.

Now an added issue. I only recently found out my generator uses the house batteries to start. It was pointed out in an article I read that lithium batteries don’t have the current capacity needed to start a diesel generator. I do know that I usually have to crank the generator starter for some time when it is cold. Is this going to be a problem?

Question two. I was planning to add a DCDC charger to effectively use the engine alternator to charge the lithium house batteries. Now I learn about a product called a battery combiner that will need to be upgraded. I have no idea what one of those is. I read the description but remain confused. Is it the same as my Trombetta relay? I know the two voltages of the different battery banks are compared to tell the system when to charge the house batteries when the alternator is charging? Can someone educate me on this?

Ed         
’05 HR Ambassador 

From amsolar.com

2.  Alternator Charging:  When upgrading to lithium batteries you will need to upgrade your battery combiner for alternator charging. Without this modification, the higher resting voltage of a lithium battery will trick the existing battery combiner relay into thinking the alternator is running and the lithium battery bank will be paralleled to the starter battery, even when the ignition is turned off. The result is lithium batteries draining into the starter battery until they crash to a dangerously low voltage or the lithium batteries’ internal BMS engages, preventing further discharge.

If you have a lithium battery system that can handle a charging current of 150A or more (three or more Battle Born lithium batteries), and you do not have a smart alternator (here’s the Smart Alternator Test) you use the Victron Cyrix-Li-Ct battery combiner, variant “Lithium / 230A”.

The Victron Cyrix-Li-Ct can quickly charge a lithium battery up to about 80% state of charge.

If you have a smaller battery bank (one or two Battle Born batteries) and/or a smart alternator, you will need to use the Sterling Battery to Battery Charger. The Sterling is programmable for any battery chemistry and can bring a battery up to 100% state of charge.

Neither device is needed if you plan on using AGM batteries.

Estimated Installation Labor
High Current Alternator Charging
3 hours / $435

Victron Cyrix Battery Combiner
 
Victron Cyrix Battery Combiner
from 40.00

Victron Cyrix battery combiners connect your house battery bank to your starter battery and alternator to allow alternator charging. Additionally, when a charge is applied to a house battery bank the Cyrix will close and allow current to flow to the starter battery. Select an appropriate Cyrix based on your house battery type and alternator current rating.

Alternator 160A or less - 120A Cyrix
Alternator more than 160A - 230A Cyrix

Battery Type / Rating: 
         Select Battery Type / Rating         AGM / 120AAGM / 230ALithium / 120ALithium / 230A       
Quantity:
ADD TO CART
Sterling Battery to Battery Charger 12V/60A
 
Sterling Battery to Battery Charger 12V/60A
425.00

This device is ideal for lithium alternator charger system upgrades in motorhomes where a smart alternator is used, or when the lithium battery bank cannot handle high current.

 

 

 

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  • 2 months later...

Read through your post. 
 

are you upgrading your Inverter/charger as well?

Looking at this upgrade myself. 
 

I have not delved in the specifics much as it’s a later project, but I’m looking at the Victron Multiplus 2 and it will charge the chassis  batteries. Has a plug in for it. 
 

https://www.victronenergy.com/upload/documents/MultiPlus-II_12V_3kVA_2x120V/MultiPlus-II_3kVA_120V-en.pdf

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I’ve got the chassis-side combiner disconnected from my lithium house batteries.
It would be nice to have some power from the chassis while underway, but in general I’m not looking for the alternator to charge the house batteries. As as long as I don’t depart at night with low batteries, the house should be able to run for 2+ days. And the generator is there as an alternative charging source. 
At some point I’ll probably reconfigure the combiner relay or add a dc/dc charger, but so far I haven’t been real motivated to try and connect the alternator to house batteries.

Cheers

Walter

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Using the boost switch when starting the generator should solve the need for more starting amps. I’m building six 100AH for a total of 600AH of Lithium’s.

Instead of adding a dc-dc charge limiter, I’m thinking if adding a heat sensor to the alternator that will disconnect power  to it when it gets to hot???

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20 hours ago, JDCrow said:

Read through your post. 
 

are you upgrading your Inverter/charger as well?

Looking at this upgrade myself. 
 

I have not delved in the specifics much as it’s a later project, but I’m looking at the Victron Multiplus 2 and it will charge the chassis  batteries. Has a plug in for it. 
 

https://www.victronenergy.com/upload/documents/MultiPlus-II_12V_3kVA_2x120V/MultiPlus-II_3kVA_120V-en.pdf

Yes. Exchanging a Magnum MS 2012 for my ME 2012. Pure sine wave with lithium setting. Decided to keep it as simple as possible so stayed with same brand. Should be a connection for connection replacement. 

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  • 4 weeks later...

I just did the lithium upgrade. Combining the two banks will depend on the the type of starter battery’s you have. If they are agm the charge profiles is close to lithium that a battery combiner will work I use the magnum SBC it limits the draw from any charge source to 30 amps. This allows me to charge both directions depending on what I am doing at the time.

if you have standard lead starting battery’s you will need 2 dc/dc charger one for one direction and one for the other. Or you can use a standard battery charger when not driving off the inverter to charge the chassis.

My understanding is not to start while the boost switch is engaged with lithium house batteries but what you can do is boost to charge the starter battery’s for like 20 min then disconnect the boost and start.

The boost will charge the starter battery’s usually very fast from the lithium.

my genny starts from my chassis battery’s so no issues there I prefer that so if my house batteries get to low I can still start the genny. I don’t know how you would convert your genny starting battery’s.

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20 minutes ago, Biljol said:

I just did the lithium upgrade. Combining the two banks will depend on the the type of starter battery’s you have. If they are agm the charge profiles is close to lithium that a battery combiner will work I use the magnum SBC it limits the draw from any charge source to 30 amps. This allows me to charge both directions depending on what I am doing at the time.

if you have standard lead starting battery’s you will need 2 dc/dc charger one for one direction and one for the other. Or you can use a standard battery charger when not driving off the inverter to charge the chassis.

My understanding is not to start while the boost switch is engaged with lithium house batteries but what you can do is boost to charge the starter battery’s for like 20 min then disconnect the boost and start.

The boost will charge the starter battery’s usually very fast from the lithium.

my genny starts from my chassis battery’s so no issues there I prefer that so if my house batteries get to low I can still start the genny. I don’t know how you would convert your genny starting battery’s.

I just bought a new Victron Multiplus 2 and it will charge the chassis batteries, it has a direct wire feature. 
 

I haven’t had time to wrap my head around the solenoid or the Bird for that matter. Not sure if they just need to go. 
 

Also, a dc/dc charger to have the alternator charge the lithium while going down the road? Someone mentioned that earlier, and victron had a way to do it, but again, in a holding pattern at the moment  

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