Especially for winter storage, for my RV (and boat) I was thinking of getting a simple 20w solar trickle charger to keep the chassis battery topped off.I see simple ones like this for ~$25-$30:https://www.walmart.com/ip/20W-Solar-Panel-12V-Trickle-Charge-Battery-Charger-Maintainer-Marine-RV-Car-T-IT/681175652They seem to come with simple clips to connect directly from the panel to your battery terminals. No charge controller.I've been learning more and more about solar for the house batteries (...I've got a 200w system and a 500w system I'll be installing soon on 2 RVs). Those "house battery" systems all of course have charge controllers which makes a lot of sense. The simple ~20w trickle chargers don't seem to come with (generally) charge controllers....just wires hooked up directly to the solar panel clipped to your battery. My question is: Is it smart/good for the chassis battery to be trickle charged constantly with something simple like this that doesn't have a charge controller? It's hard to find voltages on a lot of these simple trickle chargers (...a lot say "12 Volts", but if they mean exactly 12.0 volts I don't imagine that is useful). Would a constant (....when sunny I guess, so not really constant) 13.0v or 14.0v trickle be okay for the health of the chassis battery?Maybe they don't need a charge controller because the amps they put out is so small??? 20W seems like it would only put out about 1amp or so.Let me know your thoughts.Thanks!Chris

Are you going to use this on the RVs that will soon have solar? If so I recommend a Trik-L-Start combiner instead.

time2roll wrote:Are you going to use this on the RVs that will soon have solar? If so I recommend a Trik-L-Start combiner instead.I wasn't sure what that is, but I googled it. Very cool (provided I have solar on the RV for the house batteries, which I will). Seems like this could be hooked up pretty easily in the engine compartment by tapping off the house-battery terminal on the charging solenoid. Is that what you did?I would still like people's feedback on my original question about whether or not the trickle charger (with no charge controller) is okay for the chassis battery. (...I partly want to know the question because I have the same question for my boat in storage!).Thanks!Chris

I have a truck and trailer. And since the trailer has solar I keep them connected. I have the Trik-L-Start connected over the truck isolation relay. Works perfect.20 watts might be too small for a large set of batteries or too large for a small start battery depending on how much sun you get. May want to monitor the situation a bit depending on conditions. I had 15w maintaining 4 batteries and it was never really enough even in sunny so cal.

time2roll wrote:I have a truck and trailer. And since the trailer has solar I keep them connected. I have the Trik-L-Start connected over the truck isolation relay. Works perfect. I think I have a good picture of how that would work...thanks!Since I'm going solar on my RVs, I'm definitely going with this approach and just be done with it!time2roll wrote:20 watts might be too small for a large set of batteries or too large for a small start battery depending on how much sun you get. May want to monitor the situation a bit depending on conditions. I had 15w maintaining 4 batteries and it was never really enough even in sunny so cal.I still am curious however (...would apply for my boat, or someone else reading this considering a trickle charger for their chassis battery...) for a ~20w trickle charge kit without a charge controller, is it okay to simply connect those clips to your chassis battery and leave it for weeks/months at a time? Is the current so weak (~1 amp) such that you don't need to ever worry about overcharging/etc?

Solar trickle charger for chassis battery......Good or bad?

time2roll
Nomad
Jan 27, 2021
Are you going to use this on the RVs that will soon have solar? If so I recommend a Trik-L-Start combiner instead.
SJ-Chris
Explorer II
Jan 27, 2021
time2roll wrote:
Are you going to use this on the RVs that will soon have solar? If so I recommend a Trik-L-Start combiner instead.

I wasn't sure what that is, but I googled it. Very cool (provided I have solar on the RV for the house batteries, which I will). Seems like this could be hooked up pretty easily in the engine compartment by tapping off the house-battery terminal on the charging solenoid. Is that what you did?

I would still like people's feedback on my original question about whether or not the trickle charger (with no charge controller) is okay for the chassis battery. (...I partly want to know the question because I have the same question for my boat in storage!).

Thanks!
Chris
time2roll
Nomad
Jan 27, 2021
I have a truck and trailer. And since the trailer has solar I keep them connected. I have the Trik-L-Start connected over the truck isolation relay. Works perfect.

20 watts might be too small for a large set of batteries or too large for a small start battery depending on how much sun you get. May want to monitor the situation a bit depending on conditions. I had 15w maintaining 4 batteries and it was never really enough even in sunny so cal.
SJ-Chris
Explorer II
Jan 27, 2021
time2roll wrote:
I have a truck and trailer. And since the trailer has solar I keep them connected. I have the Trik-L-Start connected over the truck isolation relay. Works perfect.

I think I have a good picture of how that would work...thanks!
Since I'm going solar on my RVs, I'm definitely going with this approach and just be done with it!

time2roll wrote:

20 watts might be too small for a large set of batteries or too large for a small start battery depending on how much sun you get. May want to monitor the situation a bit depending on conditions. I had 15w maintaining 4 batteries and it was never really enough even in sunny so cal.

I still am curious however (...would apply for my boat, or someone else reading this considering a trickle charger for their chassis battery...) for a ~20w trickle charge kit without a charge controller, is it okay to simply connect those clips to your chassis battery and leave it for weeks/months at a time? Is the current so weak (~1 amp) such that you don't need to ever worry about overcharging/etc?
pianotuna
Nomad III
Jan 27, 2021
X3 on the Trik-L-Start.
pianotuna
Nomad III
Jan 27, 2021
20 watts is more than I'd be comfortable with--except that it is NOT 24 hours a day.
racer4
Explorer
Jan 27, 2021
This solar battery charger has a MPPT charge controller.

Suner Power BC-20W Solar Battery Charger Pro
SJ-Chris
Explorer II
Jan 27, 2021
Here's an inexpensive option with a charge controller:
https://www.ebay.com/itm/20W-Solar-Panel-12V-Trickle-Charge-Battery-Charger-Kit-Maintainer-Marine-RV-Car/392929424106

I'll be using it on my boat that sits for a good 6 months out of the year...would be nice to be able to keep the batteries charged and with the charge controller I would hope that it handles it correctly...

-Chris
SJ-Chris
Explorer II
Jan 27, 2021
time2roll wrote:
Are you going to use this on the RVs that will soon have solar? If so I recommend a Trik-L-Start combiner instead.

For the RVs with solar, I'm going to order this:
https://www.rvupgradestore.com/Ultra-Trik-L-Start-p/tls-oem.htm

5amp seems like plenty for the chassis battery, right? There is a 10amp version that costs twice as much, but that seems like overkill to me.

If this is hooked up to my RV with solar, it seems like it would be able to steal a few amps per hour if needed for the chassis battery and that should be PLENTY to keep it fully charged. Am I missing anything here?

Thanks!
Chris

PS: RV tinkering is addictive.....
SJ-Chris
Explorer II
Jan 27, 2021
An interesting word of caution about the Trik-L-Start device.....

https://artontherun.art/2015/11/25/trik-l-start-a-word-of-caution/

I hadn't thought about that...

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