12v pump to truck battery

Does anybody just hook their 12v pump straight to truck battery?
I don’t use mine much. I thought about just wiring it straight to truck battery and I can just start the truck when I do use it so not to drain battery.

Would that be ok?

You can, but vehicle batteries are designed for cranking power, not long periods of time.

Get a deep cycle (AGM) battery as they are designed for sustained power over a long period.

Another question about the pump.

Can I put a ball valve at the sprayer to calm the pressure down some or will that harm the pump?

Back pressure will cause rapid cycling of the pressure switch. It will wear it out very quickly.

You can use an accumulator tank to act as a pressure buffer if your pump is cycling. But my approach I think would be to either use a smaller pump, or put a PWM controller on the pump to dial it down. Just make sure to get one that’s big enough to handle the current.

Can explain this better to me?

Pump is the pump that came with Pressureteks roof kit. Cant think of the size at the moment. I think 5gpm maybe 6.

It sprays out so fast its hard to keep up with as in you have to move very quickly because its really laying down roof mix!




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Thanks trying to wrap my head around it lol

So if I get the Accumulator I can then install a ball valve and cut back on the flow?

Yeah, I think that’s the general idea. I’ve never used an accumulator personally, so I’m not really sure of their limitations.

I do use a PWM controller on my waterfed pole pump, and I like how it works to slow down the flow. If you can find one with a high enough amp rating to handle your 5.5 pump, then that’s the way I would recommend going. One less component in the path of a highly corrosive liquid. It’ll save some juice from the battery, as well.

Regarding your first question about wiring to the truck battery: that’s what I did for my wfp pump and my electric reels on truck norris. I installed a deep cycle marine battery in place of the regular starting battery, so I can run stuff when the truck is off. I try and put the battery tender/charger on it about once a week overnight to keep it topped off. The alternator isn’t really enough to keep it at 100%.

The longer your power run, the thicker your wire should be. I used 1/0 gauge wire from the battery to a distribution block on the bed. There’s a 300 amp fuse installed close to the battery in case the insulation gets damaged and it shorts to ground.

I used 8 gauge wire to go from ground to my components. The ground wire is much shorter, since you just attach it to a bolt somewhere on the frame.

If/when I install a larger 12v pump for chemical, I will probably start using the battery tender every night that I’ve used the pump.

What size hose you running on you reel and how long?

What pump gpm?

I’m looking at having a ro/die on the box truck and just putting a 50 gallon tank on the flatbed.

Are you running WFP hose the whole way on the reel ?

I’ve currently got about 100’ of 3/8 followed by 100’ of 1/4 (both air hose), and then 40’ or so of 3/16 pole hose. I’ll soon be switching to all 3/8”; I’d like a total of 250’ at least on the reel, and now I’ve finally got the room for it.

I think my pump is a 2.2 from TSC. It seems weaker than other pumps I’ve had, for some reason.

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You can install ball valve anyway. We all have one on our roof gun. that’s not going to effect the cycling for squat. If you’re shooting from gutter line not a big deal and you need the flow. If you’re walking most your roofs, where you’re just laying down a real light coat, an accumulator may help some. 12V roof pumps are like razor blades. Consider them disposable items. One may last you a year and then next one may last you a couple of months.


You just need a larger tip on your Jrod, Jrod. :rofl:

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