Solar charging and battery monitoring question

[cmcdar]

I have been using solar panels for charging my camper batteries for a few years now.

I learn something new EVERY DAY!

Something I have recently learned was that the charger/converter that came in my camper may only keep my 2 6-volt batteries charged to only 70% and also may boil them dry in the process. YIKES!

Yesterday, I replaced my factory charger/converter with a "Smart" charger/converter.

Also, I am adding a portable solar panel, where is the best place for locating the charge controller? Closer to battery or closer to panel?

Although I have dry camped, once for a whole season (may - oct), I have always been insecure about knowing when the batteries where getting dangerously low.

Is there an affordable monitor available that I can install to give me the feedback I need?

Any other insights would also be appreciated.

Thanks

[time2roll]

Fair enough... more batteries does not always fit the puzzle.

How much solar were you thinking?

Consider panels etc at SolarBLVD.com

160w 12v panel $125 (get 2)

MS Sunsaver 20a controller $87

You can put a hinge between the panels to make them fold then some handles for transport. They have smaller panels too.

[BFL13]

So you have an LK 100 amper? You linked an old style PM on Amazon--not the same thing. Confusing.

Here is the LK--internal fan, the two holes in the side, except this photo is the 55 amper with the two fuses. The 100 amper has four fuses.

https://www.amazon.com/Powermax-PM3-100LK-Power-Supply-Light/dp/B01MS4F5QT

Anyway, a heck of a price for a 100 amper with adjustable voltage-- Holy Cow! Plus you can switch it to the auto 3 stage and just leave it, if you want.

Some PowerMax customers like car showroom folks, have asked them to just leave it as a 3 stage on delivery and tape over the holes! 🙂

Too confusing it seems. 🙂 Of course we RVers are way smarter than that, and can really appreciate just what this is!

[cmcdar]

BFL13 wrote:
The PowerMax 100 amper is too much for a pair of 6s. A 75 amper is the most for that.

The 100 will cause the voltage to spike right away, and trigger dropping to 13.6. You will still get good amps, but not at 14.6v which the batteries want for Bulk.

The other thing is that 100 amper will not run on a Honda 2000 at 14.8 ( it just might at 13.6)-- it needs a 3000.

I have a PowerMax 100, but I opened it up and changed the voltage to 14.8 so it is no longer a three stage, just a two stage (Bulk and Absorption), all at 14.8. When I have done my 50-90 I shut off the generator. At home I still use the 13.8 Parallax 7355 as my shore power converter, so I don't need the 100amper to drop to Float.

If you get two more 6s, that 100 amper will be getting used. In fact for 4 sixes you could use their 120 amper 🙂

I am a big PowerMax fan, but you have to know how to use them to advantage. Their new model, just came out, is perfect IMO--you can pick (and go back and forth on that) auto-three stage or set your own voltage like I did without having to open it up--it has an access hole to the voltage pot inside. They have the "LK" designator in the model name.

I have the "new' model with the pots right in the front so it is easy to make adjustments.

[cmcdar]

Thanks time2roll .

I will not be adding more batteries to this rig. No room and too much weight.

We are very frugal on energy consumption so the two 6Vs are working for us now. When I had the bank of 4, I was boon docking in one place for 6 months out of the year so did not have to worry about lugging them around.

I'll continue to "wing it" till I can't live with out a monitor...

[BFL13]

The PowerMax 100 amper is too much for a pair of 6s. A 75 amper is the most for that.

The 100 will cause the voltage to spike right away, and trigger dropping to 13.6. You will still get good amps, but not at 14.6v which the batteries want for Bulk.

The other thing is that 100 amper will not run on a Honda 2000 at 14.8 ( it just might at 13.6)-- it needs a 3000.

I have a PowerMax 100, but I opened it up and changed the voltage to 14.8 so it is no longer a three stage, just a two stage (Bulk and Absorption), all at 14.8. When I have done my 50-90 I shut off the generator. At home I still use the 13.8 Parallax 7355 as my shore power converter, so I don't need the 100amper to drop to Float.

If you get two more 6s, that 100 amper will be getting used. In fact for 4 sixes you could use their 120 amper 🙂

I am a big PowerMax fan, but you have to know how to use them to advantage. Their new model, just came out, is perfect IMO--you can pick (and go back and forth on that) auto-three stage or set your own voltage like I did without having to open it up--it has an access hole to the voltage pot inside. They have the "LK" designator in the model name.

[time2roll]

PM4 is known to drop voltage to a trickle at about 3/4 charged. PD or IOTA hold the voltage up for an extended period and may have been a better choice. However the solar will be perfect to fill in the gap.

Controller close to the battery is always best. Good controller with adjustable set points is also very helpful to get back to full charge.

There are battery monitors to count amp/hours and let you know when to charge and when you are full. I get by fine with just a voltmeter and I recommend adding two more batteries before you get a monitor. Although people that have the monitors really seem to love them.

[Unyalli]

Midnite Solar "The Kid" for your solar charge controller.
Most advanced solar controller for the price out there.

With the Wizbang Jr NO ONE gives you what the kid does. Actual ending amps.
Midnite Solar Wizbang Jr

To use the Wizbang Jr you will need a shunt.

Last but not least no matter what controller you decide on battery temp monitoring is critical.
Midnite Solar Battery Temp Sensor

- Jeff

[cmcdar]

RoyB wrote:
I built me a nice three digital meter panel using Shure Electronics meters from ebay-china. Was not expensive and looked real nice. Mounted in PVC speciality three position switch box from Lowes. Glued the meters in the large switch holes. Monitors two channels of DC VOLTS 0-19VDC (Bank 1 and Bank 2) and also monitors the whole battery system for INPUT/OUTPUT DC amps (0-75AMPS DC). Lets me know how much is being drained and also how much is being provided by the converter/charger when in charge mode.

Roy's Images

Works great but after looking at some of the manf meter panels I sort of wish I went with the Bogart Engineering TriMetric 2025-RV battery monitoring system. Probably double the cost I spent with the Sure Electronics Meters. It has preset alarms and is in a nice looking meter console. Also provides alot of history of when things were done charging wise etc..


Google Image

I keep it simple when camping off grid and always keep my eye on the Battery Monitoring Panel which is just inside my OFF-ROAD POPUP access door. When i see the battery banks approaching 12.0VDC I know it is getting close to its 50% Charge state. I beefed up my battery bank and cabling to have this happen to me around 8AM each morning when i am allowed to use my 2KW generator to power up my PD9260C Converter/charger unit and recharge my batteries back up to their 90% charge state. this usually takes around three hours of generator run time for me starting with 14.4VDC smart mode charging.

This has been my off-road camping routine since 2009 and I just started to seeing my GP24 12V Interstate batteries start falling off in performance last season... Working on a new battery bank now...

Curious which smart mode converter/charger unit you purchased. I did same thing back in 2009 and picked up the WFCO WF-8945 charger unit which I immediately found out it would never go into smart charge modes. This was a well known thing back then which I was not aware of... So I just replaced the charger in the WF 8900 series Power Distribution panel with a Progressive Dynamics PD-9260C charger unit... It works just fine for me...

Roy Ken

Really nice set up, Roy!

I have looked at the TriMetric but chocked at the price... (I do that). I no longer boon dock let I did a few years ago. Now I spend 4 months snow birding, mostly plugged in. Right now I only spend a few weeks a year un-plugged.

In the future I hope to boon dock in BLM in the southwest. THEN the $$ would be well worth it.

Any cheaper alternatives?

[cmcdar]

Bobbo wrote:
What converter/charger did you have?

What converter/charger did you go to?

I removed the original Atwood 55 Amp Converter/Charger.

I replaced it with a PowerMax PM4 100A 110V AC to 12V DC 100 Amp Power Converter with built in 4 Stage Smart Battery Char...

[Bobbo]

What converter/charger did you have?

What converter/charger did you go to?

[RoyB]

I built me a nice three digital meter panel using Shure Electronics meters from ebay-china. Was not expensive and looked real nice. Mounted in PVC speciality three position switch box from Lowes. Glued the meters in the large switch holes. Monitors two channels of DC VOLTS 0-19VDC (Bank 1 and Bank 2) and also monitors the whole battery system for INPUT/OUTPUT DC amps (0-75AMPS DC). Lets me know how much is being drained and also how much is being provided by the converter/charger when in charge mode.

Roy's Images

Works great but after looking at some of the manf meter panels I sort of wish I went with the Bogart Engineering TriMetric 2025-RV battery monitoring system. Probably double the cost I spent with the Sure Electronics Meters. It has preset alarms and is in a nice looking meter console. Also provides alot of history of when things were done charging wise etc..


Google Image

I keep it simple when camping off grid and always keep my eye on the Battery Monitoring Panel which is just inside my OFF-ROAD POPUP access door. When i see the battery banks approaching 12.0VDC I know it is getting close to its 50% Charge state. I beefed up my battery bank and cabling to have this happen to me around 8AM each morning when i am allowed to use my 2KW generator to power up my PD9260C Converter/charger unit and recharge my batteries back up to their 90% charge state. this usually takes around three hours of generator run time for me starting with 14.4VDC smart mode charging.

This has been my off-road camping routine since 2009 and I just started to seeing my GP24 12V Interstate batteries start falling off in performance last season... Working on a new battery bank now...

Curious which smart mode converter/charger unit you purchased. I did same thing back in 2009 and picked up the WFCO WF-8945 charger unit which I immediately found out it would never go into smart charge modes. This was a well known thing back then which I was not aware of... So I just replaced the charger in the WF 8900 series Power Distribution panel with a Progressive Dynamics PD-9260C charger unit... It works just fine for me...

Roy Ken

[red31]

cmcdar wrote:

Also, I am adding a portable solar panel, where is the best place for locating the charge controller? Closer to battery or closer to panel?

where you can use it to monitor the battery! Close to the battery.