Esc or Battery problems? What do you think?

[Dale Koblitz]

I just got my SV for christmas but it's winter and frozen in Wisconsin "Go Packers". So I'm getting it ready for spring by sealing it all up, added the port fin, put an airtronics MX-3 in it, added a Bru-Line whip antenna to transon with a custom aluminum mount, boared out all the cooling fittings, etc., etc. When I put it in the tub to check the seal job I armed the esc and gave it some throttle. Everything seems to be fine until I go over like 3/4 throttle. After that it beeps and shuts off? The only batterys I have that I can use in it are crummy venom 3000 that I rebuilt SXS with deans: bars, noodle, and connectors but they did get very hot in my BL truck a couple times and one actually hissed and let off some steam. They do still hold over 8 volts but I'm not sure if it's the batterys or the esc is bad? If I hold the back of the boat out of the water so the prop pierces the water it seems to be ok but if the boat is sitting down low it seems like the load makes it shut down. The problem is I can't get it out to test it on open water and the warrenty will be up by the time I can. I only have 3s 5000 lipo's and smaller batterys for mini's right now. I'm going to run 2s's and maybe the ocasional 5s2p but I don't have the 2s's yet. I called aquacraft and the woman didn't help at all. She just said if the esc is not working send it in. But I'm not sure if it's the batterys or esc? Can I test it with a 3s? If so would I just bridge the extra connector or how would I do that? Is there anything else I could try to determine what the problem is? Another guy on either here or rcu said he had a bad esc and it did the same thing but I know my batterys aren't very good and think they could be the problem. Is this possible or is my esc a defect? I hate to send it back but if I wait till spring and it is bad I'm sol!

[Dale Koblitz]

Also does the stock esc have a bec or is it just in the stock reciever? Because the MX-3 reciever doesn't have a bec so I'll either have to add a pack or wire in a UBEC if the esc doesn't have one. I run a ubec in my mini-v but if the esc has one there wouldn't be any reason to add the extra weight/wiring and something else to waterproof.

[Rex R]

yes the stock esc has a 'bec' function. if you have an old head light handy connect your batt.s to it and moniter the voltage. I'd be willing to wager that the voltage drops fairly rapidly.

[Dale Koblitz]

Whats up T-Rex-R, JK.
So you think I'm dealing with a juice problem or a faulty esc? Sounds by your response you are leaning towards a battery problem. I guess I should have waited to get it in the spring. The only problem is my wife gives me $hit about spending $$.$$ on "toyz" so by asking for all gift certificate's for X-Mas she can't say anything about it. It beats trying to hide the bank slips!

[Rex R]

I've seen a 'data' track for a stock sv, it was pulling 40-45amps w/ a spike over 50. holding it stationary in the 'test tank' it would likely be trying to pull 50-60amps... so yes batteries would be fairly high on my list of suspects. wish you had access to a set of known good cells. I've melted the shrink off a set of otherwise good cells(good enough for a brushed motor). the sv (and bl motors in general) demand a lot from a set of batteries...
edit
email sent w/ address of batt vendor

[Dale Koblitz]

I've seen a 'data' track for a stock sv, it was pulling 40-45amps w/ a spike over 50. holding it stationary in the 'test tank' it would likely be trying to pull 50-60amps... so yes batteries would be fairly high on my list of suspects. wish you had access to a set of known good cells. I've melted the shrink off a set of otherwise good cells(good enough for a brushed motor). the sv (and bl motors in general) demand a lot from a set of batteries...
edit
email sent w/ address of batt vendor
Yeah I know all about BL motor and amp draw. I run a mamba max 5700 in my rustler and before I got my lipo's I was running these batterys I mentioned. They would reach 200degrees in a couple minuites if I wasn't carefull. That's actually how I made them hiss and spray acid steam out of one. I ran my boat on one of my 3s's last night and bridged the other connector with a wire. The boat actually seemed like it had more power than with the 2-6cell packs and it never shut-off. So I think you'r right those venom batterys are in pretty bad shape and I think that is where my problem is.

[Fluid]

First off, never run a BL motor at full throttle out of the water!

If your packs got hot enough to visibly vent one or more cells - they are ruined. Under load they will not put out enough voltage to keep the ESC running, hence the shutdowns. The 3S pack does not have the voltage depression of even good nickel packs - and you nickels are 'way bad - so it makes sense that the boat ran better with the "low voltage" 3S LiPos.

Regardless of what experience you think you have with trucks, etc., boats are a whole different ballgame. The loads a boat encounters are far higher and longer lasting than in any truck. Cheezy cells will cause the problems you cited. The ESC may have a problem or not, but with the bad cells it is impossible to say.


.

[domwilson]

Agreed. Fluid, you hit the nail on the head with a big hammer! The amp draw in boats is much higher. If the batteries are bad, when under a heavy and sustained load, the voltage will drop significantly. This may cause your esc to shutdown as the voltage is below its operating threshold.

[Dale Koblitz]

First off, never run a BL motor at full throttle out of the water!

If your packs got hot enough to visibly vent one or more cells - they are ruined. Under load they will not put out enough voltage to keep the ESC running, hence the shutdowns. The 3S pack does not have the voltage depression of even good nickel packs - and you nickels are 'way bad - so it makes sense that the boat ran better with the "low voltage" 3S LiPos.

Regardless of what experience you think you have with trucks, etc., boats are a whole different ballgame. The loads a boat encounters are far higher and longer lasting than in any truck. Cheezy cells will cause the problems you cited. The ESC may have a problem or not, but with the bad cells it is impossible to say.


.
I never ran the boat unloaded, I'm not that stupid. All testing was done in a bathtub since all the water outside is froze. Even when I was holding the transom up the prop was at least half submerged mimiking a surface drive boat on plane.
It's definately the cells. It was clear after running just one 3s lipo giving it twice the power of the bad ni/mh's with no cutting off that my problem was the cells. I'm going to go ahead and order the lipo's I mentioned above. I know I have a truck that goes 60+mph so I do have a little experience with high power BL systems. The thing that threw me for a loop is when another guy said his SV was doing the exact thing and it was his esc. But thanks for the input, I appreciate any time invested in my thread even if it sounds a little like an insult. I'm not easily offended.
Thanks,
Scott

[domwilson]

Everyone is here to help each other out. Sometimes with typed messages the feeling or intent can be misunderstood from what the writer intended. But, I am glad you solved the issue. After all, that was your intent.

[Dale Koblitz]

Everyone is here to help each other out. Sometimes with typed messages the feeling or intent can be misunderstood from what the writer intended. But, I am glad you solved the issue. After all, that was your intent.

I realize this, no harm done. I didn't mean to sound like an @$$ either so sorry if I came off that way.
Peace,
Scott

[domwilson]

No need to apologize. We're all friends here. I didn't see any problem with your posts. It's all good in da hood.

[Dale Koblitz]

Right on brotha!