Quick questions on solar integration in an RV

[FASTLIKEJUDY]

Hello, We purchased a toy hauler for our motorcycles and would like to upgrade the electrics to include 300 watts of solar.  We have a 3500 watt generator/ inveretor that we use for about 1/2 hour in the morning and 1 hour night.  My questions center on upgrading the system so we can run our 12 volt propane refrigerator, radio, charge the laptop via 12v power, 12 volt tv and ocassional water pump.

Our toy hauler has room for two Group 27 AGM batteries and we are thinking about running them in parallel.  Now the questions:

1. Does one charge the two batteries as one?  

2. During generator operation do you charge the batteries even though the generator will only run for 1/2 hour?

3. Is there an integrated charge controller for both 120AC and solar DC?

4. Do you discard the toy hauler charger?

5. Do battery monitors read amp-hours and voltage?

The answers to these questions will help be continue my research.

Thank you

 

[John61CT]

Best to do all / most of your genny usage in the morning, then only relatively a little solar is needed over the rest of the day to get the bank back to 100%.

Our toy hauler has room for two Group 27 AGM batteries and we are thinking about running them in parallel.

Yes, keep to 12V. Room for G31? Multiples of 6V? Why AGM? Not the best choice unless spending big buck$ for quality, and don't last as long as flooded.

> 1. Does one charge the two batteries as one?  

Yes, one bank.


> 2. During generator operation do you charge the batteries even though the generator will only run for 1/2 hour?

Yes but best in the AM to keep going until 80-85% full, depending on the weather.


> 3. Is there an integrated charge controller for both 120AC and solar DC?

No, one is a charger (sometimes "converter" with RVs) then solar controller)


> 4. Do you discard the toy hauler charger?

Only if no longer suitable.


> 5. Do battery monitors read amp-hours and voltage?

Good ones show SoC as a %, some also Amps live as well as tracking total AH in an out over time.

 

[highdesertranger]

ok here you go,
1. yes, you now have a battery bank. you treat it as one big battery.
2. yes, if you are running the genny get the most out of it.
3. I don't believe so. I would want separate units anyway for redundancy. if one fails you still have the other.
4. depends, the newer converters are smart chargers, the older ones are dumb. you need to find out what you have. BTW the dumb ones can be upgraded to smart ones.
5. the better ones read AH in and out and volts.
highdesertranger

 

[tx2sturgis]

Is this a toy hauler trailer, or, a toyhauler motorhome?

Cuz there might be some different answers depending on what it is.

For sure, John's answers will get you there...

I would add that some built-in chargers, called 'converters' when built-in to the RV, tend to dry out a battery after a long time on trickle charge. You can keep it for shore power use and when running the generator, but if you install and use a good solar system, it might never, or rarely, be needed.

 

[FASTLIKEJUDY]

Thank you.
Our toy hauler is a trailer.

I was considering an AGM battery as it is reported these are durable. I would be interested in suggestions. I do not wish to modify the battery box and have room for two Group 27 batteries.

KRR

 

[tx2sturgis]

I would not use an expensive AGM battery bank with a factory RV converter charger UNLESS it has a setting for AGM.

Can you dig up the manual for the converter and either look for that info, or post the brand and model here so we can research it for you?

Sometimes the converter is easy to find and look at the label, but on some RVs that thing is hidden behind a panel or buried under a cabinet or drawers.

 

[HumbleBeginnings]

I would not use an expensive AGM battery bank with a factory RV converter charger UNLESS it has a setting for AGM.

Could you elaborate on this please? I recently got the PowerMax 55 amp converter to charge my SLA/AGM bank on the understanding that it was a smart charger, but it doesn't seem to have any selectable modes.

 

[highdesertranger]

what do your AGM batteries call for? it seems they are non adjustable you have to match the converter to the battery bank. they have different converters with different outputs. highdesertranger

 

[tx2sturgis]

Could you elaborate on this please? I recently got the PowerMax 55 amp converter to charge my SLA/AGM bank on the understanding that it was a smart charger, but it doesn't seem to have any selectable modes.

When I used the term 'factory' I meant OEM converters from the RV manufacturer. Those units are not normally 'smart'...You bought an aftermarket smart charger so that's a different animal altogether.

I did find this basic description for the PowerMax 55:

"55 amp 3 Stage Charger

KEY FEATURES:
Automatic three-stage battery charging maintains your battery's life with three nominal voltage output models: 
* 13.2 Vdc range "float" mode
* 13.6 Vdc range "absorption" mode
* 14.4 Vdc range "bulk" mode
* Electronic current limiting automatically shuts down power during overload or short-circuit conditions.
* Quiet operation in a wide range outputs. Convenient deck mount installation."



That seems fairly conservative and suitable for your use but I would double check the charging specs for the AGM batteries you have.

 

[HumbleBeginnings]

Thanks to both of you. I haven't been able to find charging specs for my batteries yet, but I'll keep looking. (I have two of these)