Battery upgrade suggestions

[stevenc]

Looking for some feedback on upgrading our 2017 Geo Pro 19FBS with factory installed 100w solar (existing battery is 75ah) We have been very happy but as expected in New England, conditions are not always prime for solar. 95% of our outings are boondocking.

My goal would be to increase capacity enough to comfortably push us from 3-4 day outings to 5-6 with less concern about extensive drain. We only run the standard 12v devices, no 120v inverters or add ons (TV rarely on, furnace sometimes run briefly in am)

I would like to replace existing with 2 better 12v or (?) Lithium sounds delicious but cost prohibitive & not sure if would play nice with existing solar & controls. After much reading I'm not interested in 2 x 6v. I can easily add a second box on the frame & weight is not an issue.

At what point of upgrading does our existing solar/controls play a role?

What would you go with?

Thanks

[bobpalin]

Just add another 75ah battery, if the existing one is old you should probably replace it so that the batteries are the same. Make sure it is a deep discharge battery rather than a starter battery, I have run for a week on two 75ah batteries but no TV and probably didn't use the heater.

[tomkatb]

Get two new batteries. Simple. 150 amps.

Lithium is great but one 100 amp is close to $1000. Plus your charger might not work. Also they are problematic in cold weather. More than enough.

I hav 4 6’s. 460 amps. We never run low.

If we do the Honda 2200 works swell.

It is important to measure your space available carefully.

6’s have a smaller footprint but, are higher. Measure.

I would get the most amps possible.

[MR.M]

Originally Posted by stevenc

Looking for some feedback on upgrading our 2017 Geo Pro 19FBS with factory installed 100w solar (existing battery is 75ah) We have been very happy but as expected in New England, conditions are not always prime for solar. 95% of our outings are boondocking.

My goal would be to increase capacity enough to comfortably push us from 3-4 day outings to 5-6 with less concern about extensive drain. We only run the standard 12v devices, no 120v inverters or add ons (TV rarely on, furnace sometimes run briefly in am)

I would like to replace existing with 2 better 12v or (?) Lithium sounds delicious but cost prohibitive & not sure if would play nice with existing solar & controls. After much reading I'm not interested in 2 x 6v. I can easily add a second box on the frame & weight is not an issue.

At what point of upgrading does our existing solar/controls play a role?

What would you go with?

Thanks

2 12 v trojan t 1275 batteries would give you 300 amp hr they are group 31 so a little bigger then a group 24 . or a small inverter generator to charge your batteries

[NJKris]

steve, rather than get crazy expensive batteries which will eventually need replacing, I think it is more cost effective to buy an extra solar panel, preferably a suitcase that can be moved away from trailer to capture sunlight better, or an inverter generator. Thousand dollar Hondas are not the only game in town anymore, my Champions were 350 bucks each.

[stevenc]

Originally Posted by tomkatb

I would get the most amps possible.

Yes, this is essentially the goal... preferably at the best price vs payback point

Originally Posted by NJKris

steve, rather than get crazy expensive batteries which will eventually need replacing, I think it is more cost effective to buy an extra solar panel, preferably a suitcase that can be moved away from trailer to capture sunlight better, or an inverter generator. Thousand dollar Hondas are not the only game in town anymore, my Champions were 350 bucks each.

Good thought but I'm not into the generator scene. We already have enough toys to haul, lol. As mentioned, our current setup works most of the time. We are anticipating moving out west within a couple years where the existing solar should be more productive.

I feel like the dual battery setup will give us the extra cushion & prevent excessive battery wear by allowing us to not drain below 50% (which has happened a few times.)

[NJKris]

Yes, definitely go the dual battery route. Just have to figure out how much solar you need. I opted for a generator in the mix as the sun is a fickle mistress. The generator is only 48.5 lbs, 19x13x16 inches.

[TitanMike]

A second battery is definitely the way to go.

Also, add a portable "suitcase" type solar charger. As stated before you can move it around to take the most advantage of sun even if it's minimal.

I have a 160 watt Komaes portable I bought from Amazon last year for around $250. I did some modifications (replaced PWM controller with an MPPT, wired panels in series) and built a larger #10 awg extension so I could "chase" the sun farther from the trailer if parked in the trees. Even is overcast days I get a fairly steady decent charge from the panels and being portable I can change how they are oriented to the sun. Usually twice per day is enough. A cheap tracking system

Since you want to extend for more days and don't want to use a generator then both added battery and more solar are about the only options.

[tomkatb]

The problem with solar is that their output is relatively low. 100 amp panels on the roof on their best day likely supply 25 amps. Half a small battery. So more is better.

But, sometimes it rains a lot. Our first week in our fiver it rained for 5 days straight. Many rv spots are shaded. That helps with cooling.

If you boondock a lot you likely need a generator.


We opted for a generator. And 4 6 volt batteries.

[TitanMike]

Originally Posted by tomkatb

The problem with solar is that their output is relatively low. 100 amp panels on the roof on their best day likely supply 25 amps. Half a small battery. So more is better.

But, sometimes it rains a lot. Our first week in our fiver it rained for 5 days straight. Many rv spots are shaded. That helps with cooling.

If you boondock a lot you likely need a generator.


We opted for a generator. And 4 6 volt batteries.

Fixed panels on the roof will always be limited, especially small panels. If one has to stay with small (low wattage setups) then portables at least have the advantage of "tracking" the sun for max outputs.

I was at Quartzsite in January and saw all kinds of solar setups. Very common were panels on top of RV's that could be elevated on one side. Owners parked their rigs so they were pointing East/West and elevated panels so they were at a more optimum angle facing more directly at the sun's path.

[stevenc]

All good suggestions & I agree that active solar is more efficient. I would like to reiterate that our current setup has handled most of our outings. On the few occasions where we ran short additional solar panels would have been no benefit due to canopy or weather.

I was hoping for a bit more discussion about choosing x y or z batteries based on users' experience. ie. the Trojans look great, but in real life practice are they all that vs standard marine/rv deep cycle options with respect to increased cost? Do they lose a significant % off the top after a few cycles?

[stevenc]

Originally Posted by TitanMike

... I did some modifications (replaced PWM controller with an MPPT, wired panels in series) ...

Mike, what is the benefit in upgrading the controller?

[stevenc]

Originally Posted by stevenc

Mike, what is the benefit in upgrading the controller?

Never mind, I now see the different control strategies.

[stevenc]

Originally Posted by stevenc

Mike, what is the benefit in upgrading the controller?

Never mind, I now see the different control strategies.

[rk06382]

Originally Posted by stevenc

Looking for some feedback on upgrading our 2017 Geo Pro 19FBS with factory installed 100w solar (existing battery is 75ah) We have been very happy but as expected in New England, conditions are not always prime for solar. 95% of our outings are boondocking.

My goal would be to increase capacity enough to comfortably push us from 3-4 day outings to 5-6 with less concern about extensive drain. We only run the standard 12v devices, no 120v inverters or add ons (TV rarely on, furnace sometimes run briefly in am)

I would like to replace existing with 2 better 12v or (?) Lithium sounds delicious but cost prohibitive & not sure if would play nice with existing solar & controls. After much reading I'm not interested in 2 x 6v. I can easily add a second box on the frame & weight is not an issue.

At what point of upgrading does our existing solar/controls play a role?

What would you go with?

Thanks

I have read the other posts. I think you should start with a battery monitor like the Victron BMV-712.

I did not start with a battery monitor and I regret it, because without it, I could not tell how many amp hours my Battle Born batteries had available. If you are going to boondock, you need to know your battery SOC (State of Charge).

I liked the Victron bluetooth app on my phone so much I upgraded to a Victron SmartSolar MPPT 100/50 solar charge controller.

[stevenc]

Originally Posted by rk06382

I have read the other posts. I think you should start with a battery monitor like the Victron BMV-712.

I did not start with a battery monitor and I regret it, because without it, I could not tell how many amp hours my Battle Born batteries had available. If you are going to boondock, you need to know your battery SOC (State of Charge).

I liked the Victron bluetooth app on my phone so much I upgraded to a Victron SmartSolar MPPT 100/50 solar charge controller.

We have the factory installed solar charge controller which displays SOC along with other data.

[FFred]

"the Trojans look great, but in real life practice are they all that vs standard marine/rv deep cycle options with respect to increased cost?"

The RV marine batts are a compromise for small boats.
Folks can fish using a tiny electric motor , for hours, and have enough juice to get the gas outboard started to get home.

Trojans or any golf cart style deep cycle batt are designed and built differently and with a SOC (state of charge) meter are the best at deep cycle use while camping.

Two 6 volt batts in series will have more amperage available than two 12v in parallel.

First, Install a SOC meter , the house battery gas gauge , and recharge at 50% discharge , to have longest batt life.

Then you can observe how much juice you use and install larger , better batts for your loads.

[rk06382]

Originally Posted by stevenc

We have the factory installed solar charge controller which displays SOC along with other data.

I did not know of any solar charge controller that displays SOC. It will show voltage of the battery but not amp hours available. You need a shunt to measure all current into and out of your batteries. It is normally on the negative battery cable.

The shunt for my Victron BMV-712 is in the center with the black cables.

[stevenc]

Originally Posted by rk06382

I did not know of any solar charge controller that displays SOC. It will show voltage of the battery but not amp hours available. You need a shunt to measure all current into and out of your batteries. It is normally on the negative battery cable.
Attachment 197123
The shunt for my Victron BMV-712 is in the center with the black cables.

https://gpelectric.com/wp-content/up..._GP-PWM-30.pdf

[rk06382]

Originally Posted by stevenc

https://gpelectric.com/wp-content/up..._GP-PWM-30.pdf

Your GP-PWM-30-SB uses the battery voltage to measure the SOC.


A BMV-712 screenshot from my smartphone last summer.


A SmartSolar MPPT 100/50 screenshot from my smartphone last summer. The solar charge controller can only measure amperage that goes through it from the solar panels.

Notice the 10% higher amperage going into the batteries than from the solar panels. You would not see that with a PWM charge controller.
https://www.victronenergy.com/upload...verview-EN.pdf