diy solar

diy solar

RV install Input.

G

geraldrd

New Member
Joined
Apr 22, 2023
Messages
3
Location
woodbridge va
I am looking to do my first solar install on my RV currently it has a starter battery and a 100 amp hour SLA house battery I am looking to install a Renogy DC to DC with MPT controller my question for a 30 amp RV power system should I use the 50 amp unit or the 30 amp unit. I don't know the amp output of my alternator but the engine is a 10 cylinder unit it is a Fleetwood Jamboree searcher RV 24 foot no slides year 1997 . I have also seen on you tube a battery bank manager to mix led and lithium battery banks for boats was wondering if this is a good idea as I just want to augment my current battery for the house with lithium.
bellow are the video and his page selling the battery bank manager. Any one has experience with this thanks Gerald

https://www.emilyandclarksadventure.c...
 
Do you have a house battery? If so the solar would charge that independently.
 
What I have as stated is a 100 amp hour sealed lead acid battery SLA currently I believe charger up by both my current alternator and shore or generator power. And also it charger my vehicles starter battery I believe. What I want to do is put a Renogy DC to DC with MPT charge controller to provide both power from the alternator and solar to a lithium battery bank but still want to keep the existing SLA batteries and there charging system but having both provide power. I am not looking to replace my current dc power system just augment and add to. That is why I was asking about the batter bank manager in the previously listed video. I don't want to damage my alternator or the existing DC and AC system I want to keep using the RV Current Inverter system but add amp hours to it by adding a separate 200 to 300 lithium bank Gerald
 
I’d recomend looking at the spec sheet of your current battery you are using. There is a max charge Limit, could be 10 amps to 30 amps. If that is so, the current battery would need to be limited.

Mixing chemistry is not a good idea. Lithiums are charged less, so the SLA battery will never fully be charged. I’d Need to see a diagram. I picture you having a class a with a house battery and a separate engine battery.
 
Keep your start and house battery systems separate. Also I wouldn't mix lithium with SLA. Hook up the mppt to the house lithium then make sure you don't have anything pulling from your start battery when off
 
Here is a drawing using tiny cad for what I know is the DC circuit There are more parts but I need to dig further than I have to fill it out this is what I belive to be true.
 
The DC-DC charger is a one-way circuit. What this means is that if you put it in place of what you have now you won't be able to "jump start" the starter battery from the house battery.

The larger the charger, the larger you may need to go with the cables from the starter to the charger. Depending upon the distance, that can get expensive.

Your attached "drawing" isn't a drawing. Wrong file!
 
Guys, before you say that mixing SLA and Lithium is not a good idea you should probably look at the video linked above. The Bank Manager is designed to be able to mix lead and lithium, that is its purpose in life, and pretty much nothing else. Clark is an electrical engineer and seems to be quite knowledgeable. I'm not even in the same league as most folks on this board but I don't discount something before I know something about it.
 
justinm001 said:
Keep your start and house battery systems separate. Also I wouldn't mix lithium with SLA. Hook up the mppt to the house lithium then make sure you don't have anything pulling from your start battery when off
Click to expand...
Not pulling from your starter battery is a difficult thing to do these days. Even though the OP has a 1997 Ford chassis I'm pretty sure it has various computers that will pull from the starter battery unless you disconnect the battery every time you stop for a few days. What a pain. I use a couple of 1.5 or so watt solar chargers on the dash board plugged into the cigarette errrr power port to keep my motor home starter batteries charged. Even that has its limits as to time. Most motor homes have a momentary contact switch that connects the house and starter batteries when you need to use the house batteries to start. I would not disturb that set up it's there for a reason.
 
Johnny Lightning said:
Not pulling from your starter battery is a difficult thing to do these days. Even though the OP has a 1997 Ford chassis I'm pretty sure it has various computers that will pull from the starter battery unless you disconnect the battery every time you stop for a few days. What a pain. I use a couple of 1.5 or so watt solar chargers on the dash board plugged into the cigarette errrr power port to keep my motor home starter batteries charged. Even that has its limits as to time. Most motor homes have a momentary contact switch that connects the house and starter batteries when you need to use the house batteries to start. I would not disturb that set up it's there for a reason.
Click to expand...
The contact switch should activate only when one battery bank is charging (at a higher voltage) having them connected elsewhere just risks both batteries to be dead. I'd rather my starter battery die so we can use aux start type button and manually connect them (or use junper cables) if ones dead.
 
The momentary contact switch is manually operated by the driver when the chassis (starter) battery is weak or dead. It has nothing to do with charging.
 
Keep your lead starting/chassis battery(s) and isolate them from the house battery - convert that to LFP. Solar and charging to suit your needs/consumption. A trickl-start charger is one way to maintain the starting batteries. I gave them their own solar panel and controller.

I removed the isolator/combiner and put a victron orion dctodc charger in its place for the LFP house battery. Solar panels and an LFP compatible charger for shorepower or generator for the house battery.

LFP needs to be moved inside - they're clean, they need stable temps (not freezing) and do not off-gas when charging. If your starting battery is under the hood leave it there - if it's in a step well or battery compartment, leave them there. Setup your LFP bank in a suitable location in the coach.

Friends don't let friends buy renogy. :giggle:

My LFP setup with 230A battery, inverter, and charger, under the sofa - 2005 Winnebago:



The external step-well tray now has the chassis/starting batteries:

 
I replaced my RV rooftop 100 watt Rich Solar panels with 200 watt versions. I have discovered my battery isolator (Li-BIM 225) doesn't connect the house and chassis batteries without the engine running - which is really a bummer with the RV in "storage" sitting in the backyard for the 6 month Ohio winter. Since the chassis battery isn't receiving any charge, I would like to use one of my unused 100 watt panels with a 10 amp PWM solar controller as a "trickle charge" setup.

First, with no voltage monitor (stopping the charge when full) will this boil the battery or otherwise damage it? I considered purchasing a cheap solar trickle charger, but heck... I already have the panel(s) and controller. I COULD just connect it /disconnect it every few days, but that's a hassle. Thoughts or suggestions??
 
I have a 170 watt panel and PWM solar charge controller attached to the "chassis" battery on my RV trailer. It's been in use for 5 years and hasn't killed a lead acid battery yet. For my "house" LiFePO4 battery bank I use a separate system that is much more sophisticated. The two systems are separate - there is no tie-in between the two. I keep it that way so that I can always start the on-board generator from the chassis battery.
 
I upgraded to LiFePO4 for the motorhome house batteries, but the chassis battery is still Ford stock FLA. The 600 watts roof solar goes through a 40 amp MPPT controller (I removed the stock 10 amp PWM) to the house LiFePO4 batteries. In an emergency start situation I can connect house batteries to chassis battery via a momentary switch... other than that they're totally separate systems.

I figured I'd rig one of the 100 watt panels, PWM controller and leftover 10AWG cable as a temporary trickle charger - awkward but otherwise they're not being used. I just need to figure an easy way to secure the panel so it won't blow away.

Thanks!
 
I don't see how it'll be an issue. As long as the pwm limits the voltage below the battery limit you're fine. This is how alternators work as they just send the same high voltage the entire time.
 
I would not combine lithium and lead bank the way the YouTube video does.

Yes it sounds like it will work - but you will need to be constantly watching it - making sure everything is going smoothly.

The YouTube video was he had a large house battery and didn’t want to replace it yet and replacing it with a large lithium bank would be VERY expensive- this video is a few years old and lithium prices have come way down since then.
 
geraldrd said:
I am looking to do my first solar install on my RV currently it has a starter battery and a 100 amp hour SLA house battery I am looking to install a Renogy DC to DC with MPT controller my question for a 30 amp RV power system should I use the 50 amp unit or the 30 amp unit. I don't know the amp output of my alternator but the engine is a 10 cylinder unit it is a Fleetwood Jamboree searcher RV 24 foot no slides year 1997 . I have also seen on you tube a battery bank manager to mix led and lithium battery banks for boats was wondering if this is a good idea as I just want to augment my current battery for the house with lithium.
bellow are the video and his page selling the battery bank manager. Any one has experience with this thanks Gerald

https://www.emilyandclarksadventure.c...
Click to expand...
I have been running a hybrid FLA/LFP system in my trailer for five years now. So it can be done. Clark's " Bank Manager" in the simplest terms allows the charge source(s) to continue to charge at higher voltages by disconnecting the LFP bank at a set voltage and when the charge voltages match it reconnects the two banks. I suggest that you download the install/operation PDF to help with your decision.
 
A question for those familiar with how a Precision Circuits Li-BIM 225 battery isolation manager works:

My intent is to keep a trickle charge going to the motorhome chassis battery during 5+ months winter storage. Consider that the "house" batteries (200Ah LiFePO4) do not connect with the coach chassis battery (FLA) via the Li-BIM 225 solenoid without the engine running. It seems a simple way to "trick" the Li-BIM to connect would be to run a jumper wire from the "ignition" terminal on the Li-BIM to the chassis battery during storage. With the Li-BIM seeing 12 volts, wouldn't this theoretically trigger it's programmed connection strategy?
 
chateau_nomad said:
A question for those familiar with how a Precision Circuits Li-BIM 225 battery isolation manager works:

My intent is to keep a trickle charge going to the motorhome chassis battery during 5+ months winter storage. Consider that the "house" batteries (200Ah LiFePO4) do not connect with the coach chassis battery (FLA) via the Li-BIM 225 solenoid without the engine running. It seems a simple way to "trick" the Li-BIM to connect would be to run a jumper wire from the "ignition" terminal on the Li-BIM to the chassis battery during storage. With the Li-BIM seeing 12 volts, wouldn't this theoretically trigger it's programmed connection st
Click to expand...
I think it connects whenever the difference of the voltages of the two batteries is a certain amount, doesn't matter which one is higher or lower. At least that's how it appears to work for me, the relay will connect periodically when parked and the SOC of my lithium house batteries is nearly full and the solar is charging.

You can also use a 12v source, independent of the ignition, to open and close the relay overriding the on/off timer and voltage sensing functions.
 
You must log in or register to reply here.

Similar threads

L
Inductance or Capacitive Cell Balancer
Replies
2
Views
131
KnobCountry
KnobCountry
C
Rookie looking to convert to lithium 12 volt
Replies
11
Views
683
0truck0
0truck0
J
Upgrading AGM to Lithium in RV and retaining slide and awning safety features.
Replies
6
Views
327
scrubjaysnest
S
RV Steve
Travel Trailer Solar Wiring with Multiple Fuses?
Replies
1
Views
244
Scott SD
S
N
Should I Upgrade My RV to 48 Volt System?
Replies
3
Views
132
chrisski
chrisski

diy solar

diy solar
Back
Top