RV lithium, no solar yet, how to manage charge settings

[riverbug]

Cannot find this specific question answered...
I do not yet have solar for my new RV. I ordered a 206AH SOK battery, which will be charged via the onboard converter charger (swapping the OEM with a lithium compatible converter charger). Without the typical solar controllers, panels, etc., in place, how could I set charge cutoff at 85% until I get a full solar setup installed?

It may be a year or two before I am ready for panels, etc. But SOK tells me that I should set the charge cutoff at 13.5v and discharge cutoff at 12.8v. Is there a component that enables me to set those parameters when only using a shore power converter/charger?

Thanks!

 

[DerpsyDoodler]

Cannot find this specific question answered...
I do not yet have solar for my new RV. I ordered a 206AH SOK battery, which will be charged via the onboard converter charger (swapping the OEM with a lithium compatible converter charger). Without the typical solar controllers, panels, etc., in place, how could I set charge cutoff at 85% until I get a full solar setup installed?

It may be a year or two before I am ready for panels, etc. But SOK tells me that I should set the charge cutoff at 13.5v and discharge cutoff at 12.8v. Is there a component that enables me to set those parameters when only using a shore power converter/charger?

Thanks!

Get a converter/charger that lets you set the voltage output and set it accordingly.

 

[Zwy]

Cannot find this specific question answered...
I do not yet have solar for my new RV. I ordered a 206AH SOK battery, which will be charged via the onboard converter charger (swapping the OEM with a lithium compatible converter charger). Without the typical solar controllers, panels, etc., in place, how could I set charge cutoff at 85% until I get a full solar setup installed?

It may be a year or two before I am ready for panels, etc. But SOK tells me that I should set the charge cutoff at 13.5v and discharge cutoff at 12.8v. Is there a component that enables me to set those parameters when only using a shore power converter/charger?

Thanks!

You need to research your converter and determine if you can change settings before hooking up the battery.

You might be able to use something like a Victron Smart Sense shunt to help control cutoff and prevent charging in cold temps.

 

[chrisski]

I do not know of a RV converter that does what you’re asking and I looked quite a bit.

THere’s a coupe of models that can set the absorption voltage with some sort of variable resistor, but I have not found one to set a float voltage with some variable resistor or a discharge voltage. Aims has a 12 volt 24 volt converter charger with adjustable absorption voltage, and Powermax has several sizes with adjustable absorption voltage.

I’d like to see what you settle with until you can get a SCC powered by solar panels.

You’d think something like you’re asking for is available.

 

[John Frum]

Get an inverter/charger with automatic transfer switch.
The better ones have granular configuration of charge and discharge profiles.

 

[riverbug]

Maybe this was wishful thinking. From reading the manual for the Victron Smart Shunt, it doesn't appear you can control the charge/discharge, just monitor it. I would need something that tells the charge to stop charging at a specific voltage. I have not found a converter/charger so far that has programmable settings. Might just have to let it charge to 100% until I get a full setup with a SCC. I'm still learning...

Thanks for the replies!

 

[John Frum]

Maybe this was wishful thinking. From reading the manual for the Victron Smart Shunt, it doesn't appear you can control the charge/discharge, just monitor it. I would need something that tells the charge to stop charging at a specific voltage. I have not found a converter/charger so far that has programmable settings. Might just have to let it charge to 100% until I get a full setup with a SCC. I'm still learning...

Thanks for the replies!

This is one of the things that an inverter/charger serves up a treat.
I really don't understand the resistance to a product that is absolutely tailored for the use case.

 

[chrisski]

This is one of the things that an inverter/charger serves up a treat.
I really don't understand the resistance to a product that is absolutely tailored for the use case.

You’re saying a Growwatt or something similar would do this perfectly?

 

[John Frum]

You’re saying a Growwatt or something similar would do this perfectly?

A Growatt is an all in one which is an inverter/charger + solar charge controller but yes, pretty much.
Growatt's are not made for the mobile application so I would choose an inverter/charger that is.
Samlex Evo are my goto.
Victron are also good.

Perfection is not a word I typically use.
inverter/chargers with granular configuration will have bulk/absorb voltage configurable to .1 volts.
And likely have one or both of configurable absorption timer or tail current.
Float voltage should configurable and optional.
They will have more or less elaborate re-bulk configuration.
Finally the huge feature that is so often overlooked is they have a configurable low voltage disconnect.

After botched top balance this is probably the second biggest battery and/or bms destroying scenario.
Discrete inverters are a legacy technology that has had just about no R and D in years and were designed with lead acid batteries in mind.
Inverter/chargers are under active development.

 

[John Frum]

@riverbug you also need either a bms that does current accounting or a shunt based battery monitor.

 

[Zwy]

Maybe this was wishful thinking. From reading the manual for the Victron Smart Shunt, it doesn't appear you can control the charge/discharge, just monitor it. I would need something that tells the charge to stop charging at a specific voltage. I have not found a converter/charger so far that has programmable settings. Might just have to let it charge to 100% until I get a full setup with a SCC. I'm still learning...

Thanks for the replies!

You might be better off with just an AC charger and not use the converter. Then add a shunt to monitor charge. But you would still need a low voltage cutoff.

 

[Zwy]

A Growatt is an all in one which is an inverter/charger + solar charge controller but yes, pretty much.
Growatt's are not made for the mobile application so I would choose an inverter/charger that is.

I and many others use them mobile. All would depend on what/where he has to mount it.

Samlex Evo are my goto.
Victron are also good.

Perfection is not a word I typically use.
inverter/chargers with granular configuration will have bulk/absorb voltage configurable to .1 volts.
And likely have one or both of configurable absorption timer or tail current.
Float voltage should configurable and optional.
They will have more or less elaborate re-bulk configuration.
Finally the huge feature that is so often overlooked is they have a configurable low voltage disconnect.

After botched top balance this is probably the second biggest battery and/or bms destroying scenario.
Discrete inverters are a legacy technology that has had just about no R and D in years and were designed with lead acid batteries in mind.
Inverter/chargers are under active development.

 

[DerpsyDoodler]

A Growatt is an all in one which is an inverter/charger + solar charge controller but yes, pretty much.
Growatt's are not made for the mobile application so I would choose an inverter/charger that is.
Samlex Evo are my goto.
Victron are also good.

Perfection is not a word I typically use.
inverter/chargers with granular configuration will have bulk/absorb voltage configurable to .1 volts.
And likely have one or both of configurable absorption timer or tail current.
Float voltage should configurable and optional.
They will have more or less elaborate re-bulk configuration.
Finally the huge feature that is so often overlooked is they have a configurable low voltage disconnect.

After botched top balance this is probably the second biggest battery and/or bms destroying scenario.
Discrete inverters are a legacy technology that has had just about no R and D in years and were designed with lead acid batteries in mind.
Inverter/chargers are under active development.

The evo I bought is amazing. And samlex america has excellent customer support.

 

[riverbug]

This is totally confusing. Is the idea that I would add an inverter charger to my existing system, or replace the existing converter charger altogether? If replace it is the suggestion, how would I then convert 120v to 12v for lights, fridge, furnace, etc.? At the moment, I do not need to convert 12v to 120v - that may come down the road when I have solar. But that still wouldn't negate the need to convert 120v to 12v. I would still need a converter of some sort. I was just trying to figure out how to limit the charge threshold when I do not have a complete solar package and rely on a converter charger configuration.

 

[John Frum]

This is totally confusing. Is the idea that I would add an inverter charger to my existing system, or replace the existing converter charger altogether? If replace it is the suggestion, how would I then convert 120v to 12v for lights, fridge, furnace, etc.? At the moment, I do not need to convert 12v to 120v - that may come down the road when I have solar. But that still wouldn't negate the need to convert 120v to 12v. I would still need a converter of some sort. I was just trying to figure out how to limit the charge threshold when I do not have a complete solar package and rely on a converter charger configuration.

The inverter/charger functionally replaces the converter plus much more.
When connected to shore power or generator the battery is charged by the inverter/charger.
The 12 volt dc stuff runs off the battery and/or charge current from the inverter/charger
Also the AC distribution panel for the RV is power by shore power via the built-in transfer switch.

The instant shore power is not available the transfer switches and the ac loads are supplied by the inverter.
Its so seemless your desktop computer won't even notice.

 

[riverbug]

Ah ha! I think that makes sense. So if I get the inverter charger now, it doesn't matter that I would add solar panels and related components later - it wouldn't be wasted money and it gets me one step in the right direction?

I'll have to research more about inverter chargers. The reason I wanted to wait to install solar is because the RV is new and I wanted some time under my belt to really see how we will use it (will we really boondock as much as we think, etc.), so that any investment will be appropriate for the needs.

Appreciate everybody's insights!

 

[John Frum]

Ah ha! I think that makes sense. So if I get the inverter charger now, it doesn't matter that I would add solar panels and related components later - it wouldn't be wasted money and it gets me one step in the right direction?

You will also require a shunt based battery monitor or bms with current accounting.

 

[John Frum]

The vast majority of RVers will want shore power or at least an alternate charge source to solar and Alternating current capability.

 

[John Frum]

I updated this post https://diysolarforum.com/threads/r...w-to-manage-charge-settings.26492/post-313825

 

[time2roll]

It may be a year or two before I am ready for panels, etc. But SOK tells me that I should set the charge cutoff at 13.5v and discharge cutoff at 12.8v. Is there a component that enables me to set those parameters when only using a shore power converter/charger?

Thanks!

Consider an $8 charge controller with your existing converter. Upgrade to inverter/charger or solar at your leisure.

https://www.ebay.com/itm/122112737703?